CN113151674A

CN113151674A - Preparation process of pellet based on mineral dressing tailing replacing bentonite

Info

Publication number: CN113151674A
Application number: CN202110313665.8A
Authority: CN
Inventors: 焦林春; 梁宝东; 赵文旭; 闫得慧; 李伟
Original assignee: Inner Mongolia Jinhui Rare Ore Co ltd
Current assignee: DAZHONG MINING Co.,Ltd. INNER MONGOLIA
Priority date: 2021-03-24
Filing date: 2021-03-24
Publication date: 2021-07-23
Anticipated expiration: 2041-03-24
Also published as: CN113151674B

Abstract

The invention relates to a preparation process of pellets based on mineral dressing tailings replacing bentonite, which comprises the following steps: grinding iron ore powder to corresponding particle size; determining the mass ratio of the tailings to the iron powder according to the iron content in the tailings; mixing iron powder, tailings and auxiliary materials by using a mixing unit; starting a pelletizing unit to pelletize; measuring the average humidity and the size of the spherical particles in the pelletizing unit in real time until the humidity and the size of the spherical particles reach the standard; drying the pellets using a drying unit; and (4) firing the spherical particles by using a firing unit, and cooling the fired spherical particles to room temperature to complete the preparation of the pellet. According to the invention, by setting the preset mixing degree deviation value and the plurality of mixing rotating speed regulating amounts, when the tailing and the auxiliary material are judged to be unqualified after the primary mixing is finished, the mixing rotating speed can be regulated again according to the actual condition to further ensure that the tailing and the auxiliary material are uniformly mixed, so that the preparation efficiency of the process for the pellet ore is further improved.

Description

Preparation process of pellet based on mineral dressing tailing replacing bentonite

Technical Field

The invention relates to the technical field of pellet preparation, in particular to a pellet preparation process based on mineral separation tailings instead of bentonite.

Background

The existing pellet production process almost completely uses bentonite as a binder for pelletizing, improving a drying process and the like, and the bentonite has the effect of enabling magnetite pelletizing process performance such as good green pellet strength, high bursting temperature and the like.

In the prior art, the main process for producing the pellet is to mix iron powder and bentonite for pelletizing, dry, burn and cool, and the bentonite used in the process has production processes of mining, pit recovery and the like, SO that the ecological environment is greatly damaged, the resource waste is formed, and more harmful components (such as SO) are brought into the pellet production₂、Al₂O₃Etc.), Al in bentonite₂O₃The components not only increase the slag amount in the blast furnace ironmaking process, but also have the defect of deteriorating the performance of blast furnace primary slag, and meanwhile, the process has higher requirement on the raw material (iron powder) used for pelletizing, has larger reduction range of the iron grade and higher cost, and brings great trouble to the production of pellet ore.

Meanwhile, when a material containing CaO is added to improve the alkalinity of the pellets, the wet or semi-dry pellets have severe phenomena of cracking and pulverization in the roasting production process during the drying and oxidizing roasting processes of the wet pellets, and the pellets adopting the bentonite have the defects of large slag amount and large consumption of coke and limestone in the blast furnace iron-making process and also have the defect of consumption of bentonite resources.

At present, by utilizing the process which does not use bentonite and can be matched with hematite concentrate powder, the bentonite resource can be saved under the condition that the green pellet strength and the bursting temperature meet the actual requirements of the existing process equipment, the blast furnace slagging can be improved, and the consumption of ironmaking coke and limestone can be reduced.

However, in the existing pellet preparation process using tailings instead of bentonite, because the tailings and auxiliary materials cannot be mixed uniformly, when the pellets are prepared, the components in the pellets are not uniformly distributed, and the comprehensive properties of the produced pellets are unstable, thereby reducing the preparation efficiency of the process on the pellets.

Disclosure of Invention

Therefore, the invention provides a pellet preparation process based on mineral dressing tailings instead of bentonite, which is used for overcoming the problem of low pellet preparation efficiency caused by the fact that tailings and auxiliary materials cannot be uniformly mixed in the prior art.

In order to achieve the purpose, the invention provides a preparation process of pellet ore based on mineral dressing tailing replacing bentonite, which comprises the following steps:

step s1, the central control unit controls the grinding unit to grind the iron ore powder and controls the grinding unit to grind the iron ore powder to a corresponding particle size according to the size requirement of the pellet;

step s2, the central control unit controls the iron content detection unit to detect the iron content in the tailings, and determines the mass ratio of the tailings and the iron powder according to the iron content;

step s3, the central control unit determines the usage amount of the auxiliary material according to the actual usage amount of the tailings, conveys the tailings and the auxiliary material to the mixing unit, sets a preset stirring time and a preset mixing degree, starts the mixing unit and periodically samples and detects the mixing degree of the tailings and the auxiliary material in the mixing process when the setting is completed, controls the stirring unit to stop stirring and controls the grinding unit to convey the ground iron powder to the mixing unit for secondary stirring when the mixing degree of the tailings and the auxiliary material reaches a preset standard, and controls the stirring unit to convey the mixed material to the pelletizing unit when the secondary stirring is completed;

step s4, the central control unit controls the pelletizing unit to start and starts a water sprayer in the pelletizing unit to spray water into the material so that the pelletizing unit performs pelletizing, and the central control unit adjusts the rotating speed of a pelletizing disc in the pelletizing unit to a corresponding value according to the size requirement of the pellet ore;

step s5, when the pelletizing unit is running, the central control unit controls the humidity detector to detect the average humidity in the pelletizing unit in real time and controls the size detector to detect the average size of the pellets in real time, when the humidity in the pelletizing unit reaches a preset value, the central control unit controls the water sprayer to stop spraying water, and when the average size of the pellets reaches a preset standard, the central control unit controls the pelletizing unit to convey the pellets to the drying unit;

step s6, the central control unit adjusts the drying temperature of the drying unit to an initial value to dry the spherulites, determines the preset loss rate of the average water content in the spherulites in unit time in the drying process according to the average diameter of the spherulites, and adjusts the drying temperature of the drying unit to a corresponding value according to the actual loss rate of the average water content in the spherulites in unit time after the determination is completed;

step s7, after the drying is completed, the central control unit conveys the spherulites to the firing unit and controls the firing unit to fire the spherulites, in the firing process, the central control unit controls a visual detection device in the firing unit to detect the average apparent porosity of the spherulites in real time and adjusts the firing temperature of the firing unit when the actual average apparent porosity of the spherulites does not meet the preset standard, and when the average apparent porosity of the spherulites meets the preset standard, the central control unit controls the firing unit to stop firing and cools the fired spherulites to the room temperature to complete the preparation of the spherulites;

the central control unit is provided with a first preset mass M1, a second preset mass M2, a first preset stirring detection period t1, a second preset stirring detection period t2, a third preset stirring detection period t3, a first mixing degree E1, a second mixing degree E2 and a third mixing degree E3, wherein M1 is more than M2, t1 is more than t2, when the central control unit controls the mixing unit to mix the tailings and the auxiliary materials, the central control unit controls the mixing unit to detect the quality M of the tailings and sequentially compares M with M1 and M2, if M is less than or equal to M1, the central control unit sets the initial stirring detection period to t1 and the initial mixing degree of the tailings and the auxiliary materials to E1, if M1 is less than or equal to M2, the central control unit sets the initial stirring detection period to t2 and the initial mixing degree of the tailings and the auxiliary materials to E2, and if M is greater than M3, the central control unit sets the initial stirring detection period to t3 and the initial mixing degree of the tailings and the auxiliary materials to E3;

the central control unit is also provided with a preset mixing degree deviation value delta E0, a first preset mixing rotating speed regulating quantity delta W1, a second mixing rotating speed regulating quantity delta W2 and a third mixing rotating speed regulating quantity delta W3, when the central control unit stirs the tailings and the auxiliary materials, the central control unit samples and detects mixed materials with specified quality when the stirring detection period reaches a corresponding value and detects the mixing degree E of the tailings and the auxiliary materials in the mixed materials, if E is less than Ei, i is set to be 1, 2 and 3, the central control unit calculates the mixing degree difference value delta E, sets delta E to be Ei-E, and after calculation is finished, the central control unit compares the delta E with the delta E0,

when the delta E is less than or equal to delta E0, the central control unit does not adjust the initial mixing rotating speed W of the stirring paddle in the mixing unit;

when delta E is larger than delta E0 and i is equal to 1, the central control unit adjusts the initial mixing rotating speed W of the stirring paddle in the mixing unit by using delta W1, the adjusted mixing rotating speed of the stirring paddle is recorded as W ', and W' is set to be W +/delta W1;

when delta E is larger than delta E0 and i is equal to 2, the central control unit adjusts the initial mixing rotating speed W of the stirring paddle in the mixing unit by using delta W2, the adjusted mixing rotating speed of the stirring paddle is recorded as W ', and W' is set to be W +/delta W2;

when delta E is larger than delta E0 and i is equal to 3, the central control unit adjusts the initial mixing rotating speed W of the stirring paddle in the mixing unit by using delta W3, the adjusted mixing rotating speed of the stirring paddle is recorded as W ', and W' is set to be W +/delta W3;

when the mixing rotating speed W ' of the stirring paddle after adjustment is W plus delta Wi, the central control unit detects the mixing degree E ' of the mixed material again after the adjusted ti duration, if E ' is less than Ei, the central control unit recalculates the mixing degree difference delta E ', compares the delta E ' with the delta E0, and adjusts the mixing rotating speed of the stirring paddle to a corresponding value according to the comparison result so as to stir the mixed material again until the mixing degree of the mixed material after stirring is higher than the preset mixing degree Ei.

Furthermore, the central control unit is also provided with a preset size requirement interval D0, a first preset iron powder particle size r1, a second preset iron powder particle size r2 and a third preset iron powder particle size r3, D0(Da, Db) is set, r1 is more than r2 is more than r3, when the central control unit controls the grinding unit to grind the iron ore powder, the central control unit determines the size requirement D for preparing the secondary pellet in advance, if D is less than Da, the central control unit judges that the secondary process is used for preparing the micro pellet and controls the grinding unit to grind the particle size of the iron powder to r1, if Da is less than or equal to Db, the central control unit judges that the secondary process is used for preparing the conventional size pellet and controls the grinding unit to grind the particle size of the iron powder to r2, and if D is greater than Db, the central control unit judges that the secondary process is used for preparing the large size pellet and controls the grinding unit to grind the particle size of the iron powder to r 3;

the central control unit is also provided with a first average particle size deviation delta r1 and a second average particle size deviation delta r2, delta r1 is set to be less than delta r2, when the grinding unit finishes grinding the iron powder, the central control unit controls the grinding unit to detect the average particle size r of the ground iron powder and compares the r with the corresponding preset iron powder particle size,

when the central control unit takes the first preset iron powder particle size r1 as a particle size standard of the ground iron powder, the central control unit uses delta r1 as a detection standard for the particle size of the ground iron powder, compares the particle size r of the ground iron powder with r1, if r is larger than r1 and r-r1 is not more than delta r1 or r is smaller than r1 and r1-r is not more than delta r1, the central control unit judges that the particle size of the ground iron powder meets the standard and judges that the grinding is completed, and if r is larger than r1 and r-r1 is larger than delta r1 or r is smaller than r1 and r1-r is not completed and delta r1, the central control unit judges that the grinding is performed again until the particle size of the ground iron powder meets the standard;

when the central control unit takes the second preset iron powder particle size r2 or the third preset iron powder particle size r3 as the particle size standard of the ground iron powder, the central control unit uses delta r2 as a detection standard for the particle size of the ground iron powder, the central control unit compares the particle size r of the ground iron powder with ri, sets i to be 2, 3, and if r is greater than ri and r-ri is less than or equal to delta r2 or r is less than ri and ri-r is less than or equal to delta r2, the central control unit judges that the particle size of the ground iron powder meets the standard and judges that the grinding is completed, and if r is greater than ri and r-ri is greater than delta r2 or r is less than ri and ri is greater than delta r2, the central control unit judges that the grinding is completed and controls the grinding unit to grind the iron powder again until the particle size of the ground iron powder meets the standard.

Further, the central control unit is further provided with a first preset iron content F1, a second preset iron content F2, a first preset mass ratio B1 and a second preset mass ratio B2, F1 is set to be smaller than F2, when the central control unit determines the mass ratio of the tailings and the iron powder, the central control unit controls the iron content detection unit to detect the iron content F in the tailings, compares the F with F1 and F2 respectively, determines the mass ratio of the tailings and the iron powder according to the comparison result, if the F is larger than 0 and smaller than or equal to F1, the central control unit sets the mass ratio of the tailings and the iron powder to be B1, if the F is larger than or equal to F2, the central control unit sets the mass ratio of the tailings and the iron powder to be B2, if the F is larger than F2, the central control unit determines that the iron content in the tailings is too high, gives an alarm to give out tailings heavy screening, and re-detects the iron content F 'in the tailings again after the heavy screening is completed, and if the F' is larger than F8536, the iron content of the central control unit is equal to the second iron content F2 again, at the moment, the central control unit compares the iron content of the re-screened tailings with F1 and F2 in sequence and determines the mass ratio of the re-screened tailings to the iron powder according to the comparison result.

Furthermore, a first preset auxiliary material proportion b1, a second auxiliary material proportion b2 and a third auxiliary material proportion b3 are also arranged in the central control unit; before the tailing and the auxiliary material are mixed by the central control unit, the central control unit determines the mass M of the auxiliary material according to the mass M of the tailing, if the M is less than or equal to M1, the central control unit calculates the mass M of the auxiliary material by using the first preset auxiliary material proportion b1, if the M1 is less than or equal to M2, the central control unit calculates the mass M of the auxiliary material by using the second preset auxiliary material proportion b2, and if the M is more than M3, the central control unit calculates the mass M of the auxiliary material by using the third preset auxiliary material proportion b 3;

when the central control unit calculates the mass M of the auxiliary material by using the jth preset auxiliary material proportion bj, setting j to be 1, 2 and 3, and setting the mass M of the auxiliary material to be M multiplied by bj;

the central control unit is also provided with a preset maximum sampling detection time N0, when the central control unit performs N0 th sampling detection on the mixed material of the tailings and the auxiliary materials and the measured mixing degree En is less than Ei, the central control unit adds the auxiliary materials to the mixed material and sets the mass M' of the added auxiliary materials to be 0.25 xMxbj, after the addition is completed, the central control unit updates the preset maximum sampling detection time to be 0.5 xN 0, and after the update is completed, the central control unit controls the mixing unit to re-stir the mixed material and adds iron powder to the mixed material when the measured mixing degree of the mixed material is greater than or equal to Ei.

Furthermore, a first preset humidity S1, a second preset humidity S2, a third preset humidity S3, a first preset pelletizing rotation speed V1, a second preset pelletizing rotation speed V2 and a third preset pelletizing rotation speed V3 are further arranged in the central control unit, S1 is set to be more than S2 and less than S3, and V1 is set to be more than V2 and less than V3; when the central control unit controls the pelletizing unit to pelletize, the central control unit determines the initial humidity in the pelletizing disc and the initial rotating speed of the pelletizing disc according to the size requirement of the pellets, if D is less than Da, the central control unit sets the initial humidity in the pelletizing disc to be S1 and the initial rotating speed of the pelletizing disc to be V1, if Da is less than or equal to Db, the central control unit sets the initial humidity in the pelletizing disc to be S2 and the initial rotating speed of the pelletizing disc to be V2, and if D is more than Db, the central control unit sets the initial humidity in the pelletizing disc to be S3 and the initial rotating speed of the pelletizing disc to be V3;

when the central control unit completes the setting of the initial humidity in the balling disc and the initial rotating speed of the balling disc, the central control unit starts the balling unit and adjusts the humidity in the balling disc and the rotating speed of the balling disc in real time according to the diameter of the spherulites in the balling disc in the balling unit balling process.

Further, a first pelletizing rotation speed regulating quantity DeltaV 1, a second pelletizing rotation speed regulating quantity DeltaV 2 and a third pelletizing rotation speed regulating quantity DeltaV 3 are also arranged in the central control unit, DeltaV 1 < DeltaV 2 < DeltaV 3 is set, when the pelletizing unit performs pelletizing, the central control unit sets the pelletizing rotation speed of the pelletizing disk to V and detects the average size R of the pellets in real time by using the size detector, when the average size R of the pellets is maintained for a time period exceeding a preset time period t0, the central control unit regulates the rotation speed of the pelletizing disk to a corresponding value according to the relation between R and the size requirement D of the pellets to be prepared,

if R is more than 0 and less than or equal to 0.3D, the central control unit adjusts the pelletizing rotating speed V by using delta V1;

if R is more than 0.3D and less than or equal to 0.7D, the central control unit adjusts the pelletizing rotating speed V by using delta V2;

if R is more than 0.7D and less than or equal to D, the central control unit adjusts the pelletizing rotating speed V by using delta V3;

when the central control unit adjusts the pelletizing rotating speed V by using the jth pelletizing rotating speed adjusting quantity delta Vj, setting j to be 1, 2 and 3, recording the adjusted pelletizing rotating speed of the pelletizing disc as V', and setting V to be V plus delta Vj;

the central control unit is also provided with a first preset pelletizing rotating speed correction coefficient alpha 1, a second preset pelletizing rotating speed correction coefficient alpha 2 and a third preset pelletizing rotating speed correction coefficient alpha 3, when the central control unit adjusts the pelletizing rotating speed of the pelletizing disc, the central control unit selects a corresponding pelletizing rotating speed correction coefficient to correct the jth pelletizing rotating speed regulating quantity delta Vj according to the size requirement D for preparing the pellets in the preset time,

if D is less than Da, the central control unit corrects the jth pelletizing rotation speed adjustment quantity delta Vj by using a first preset pelletizing rotation speed correction coefficient alpha 1, and sets the pelletizing rotation speed V' ═ V + alpha 1 x delta Vj of the pelletizing disc after correction;

if Da is less than or equal to Db, the central control unit corrects the jth pelletizing rotation speed adjustment quantity Δ Vj by using a second preset pelletizing rotation speed correction coefficient α 2, and sets a pelletizing rotation speed V' ═ V + α 2 × Δ Vj of the pelletizing disc after correction;

if D > Db, the central control unit corrects the jth pelletizing rotation speed adjustment amount Δ Vj by using a third preset pelletizing rotation speed correction coefficient α 3, and sets a pelletizing rotation speed V' ═ V + α 3 × Δ Vj of the pelletizing disc after correction.

Furthermore, a preset pelletizing rotation speed critical value Vmax, a first preset size difference value delta R1, a second preset size difference value delta R2, a first preset water injection quantity Q1 and a second preset water injection quantity Q2 are further arranged in the central control unit, and delta R1 is smaller than delta R2, and Q1 is smaller than Q2;

when the central control unit adjusts the pelletizing rotating speed of the pelletizing disc to be V ', the central control unit compares the V ' with Vmax, if the V ' is less than or equal to the Vmax, the central control unit adjusts the rotating speed of the pelletizing disc to be V ', and if the V ' is greater than the Vmax, the central control unit adjusts the rotating speed of the pelletizing disc to be Vmax;

when the central control unit adjusts the pelletizing rotating speed of the pelletizing disc to Vmax and the maintaining time length of the average size R of the pellets exceeds the preset time length t0, the central control unit calculates the difference value delta R between R and the size requirement D of the pellets to be prepared, sets the delta R to be D-R, after the calculation is completed, the central control unit compares the delta R with delta R1 and the delta R2 in sequence and controls the water sprayer to start to spray water with corresponding amount according to the comparison result,

if the value of DeltaR is more than 0 and less than or equal to DeltaR 1, the central control unit does not start the water sprayer;

if delta R1 is less than delta R and less than delta R2, the central control unit starts the water sprayer and sets the single water spraying amount of the water sprayer to be Q1;

if DeltaR >. DeltaR 3, the central control unit starts the water sprayer and sets the single water spraying quantity of the water sprayer to be Q2.

Furthermore, a preset critical humidity Smax is also arranged in the central control unit; when the central control unit starts the water sprayer to adjust the size R of the spherulites to a preset value, the central control unit detects the average humidity S in the balling disk in real time in the water spraying process of the water sprayer, and if S is larger than Smax, the central control unit controls the water sprayer to be closed until the average humidity S in the balling disk is smaller than Smax.

Further, the auxiliary materials comprise sodium silicate, cellulose, sodium carbonate, magnesium oxide, a flocculating agent and humic acid.

Further, the iron ore powder includes 88% of magnetite concentrate powder and 12% of hematite concentrate powder.

Compared with the prior art, the invention has the advantages that by setting a plurality of preset qualities, a plurality of preset stirring detection periods and a plurality of preset mixing degrees, the central control unit can select the corresponding mixing degree of the tailings and the auxiliary materials according to the quality of the tailings used in a single preparation process, thereby effectively ensuring that the tailings and the auxiliary materials can be uniformly mixed when preparing the pellet, effectively improving the comprehensive performance of the prepared pellet, thereby effectively improving the preparation efficiency of the process for the pellet, and simultaneously, by setting a preset mixing degree deviation value and a plurality of mixing rotating speed regulating values, when the tailing and the auxiliary material are judged to be unqualified after the primary mixing is finished, the mixing rotating speed can be adjusted again according to the actual condition so as to further ensure that the tailing and the auxiliary material are uniformly mixed, and therefore the preparation efficiency of the process for the pellet is further improved.

Further, a preset size requirement interval D0, a first preset iron powder particle size r1, a second preset iron powder particle size r2 and a third preset iron powder particle size r3 are further arranged in the central control unit, when the central control unit controls the grinding unit to grind the iron ore powder, the central control unit determines the size requirement D for preparing the secondary pellet in advance and determines the grinding particle size of the iron powder according to the actual value of the size requirement, so that the iron powder is effectively bonded when the tailings and the auxiliary materials are uniformly mixed, a pellet with uniform iron powder distribution is formed, and the preparation efficiency of the process for the pellet is further improved.

Particularly, the central control unit is further provided with a first average particle size deviation delta r1 and a second average particle size deviation delta r2, the central control unit can select a corresponding average particle size deviation according to the predetermined iron powder particle size as a detection standard for the particle size of the ground iron powder to judge whether the grinding of the iron powder is finished, and the particle size of the ground iron powder can meet the requirement by further judging the particle size of the ground iron powder, so that the uniformity of the distribution of the iron powder in the prepared pellet is further ensured, and the preparation efficiency of the process for the pellet is further improved.

Further, a first preset iron content F1, a second preset iron content F2, a first preset mass ratio B1 and a second preset mass ratio B2 are further arranged in the central control unit, when the central control unit determines the mass ratio of the tailings to the iron powder, the central control unit controls the iron content detection unit to detect the iron content F in the tailings, compares the F with F1 and F2 respectively, determines the mass ratio of the tailings to the iron powder according to the comparison result, and determines the ratio between the tailings and the iron powder by determining the iron content in the tailings, so that the ratio between the tailings and the iron powder is ensured within a preset interval, and the preparation efficiency of the process for the pellets is further improved while the distribution uniformity degree of the iron powder in the prepared pellets is further ensured.

Further, a first preset auxiliary material proportion b1, a second auxiliary material proportion b2 and a third auxiliary material proportion b3 are further arranged in the central control unit, and before the central control unit mixes the tailings and the auxiliary materials, the central control unit selects a corresponding preset auxiliary material proportion according to the quality M of the tailings to determine the quality M of the auxiliary materials, so that the adhesive formed after the tailings and the auxiliary materials are mixed has the performance meeting the preparation requirement, the property of the spherulites prepared by the process meets the preset requirement, the uniformity degree of the distribution of iron powder in the prepared spherulites is further ensured, and the preparation efficiency of the process for the spherulites is further improved.

Particularly, the central control unit is further provided with a preset maximum sampling detection frequency N0, when the central control unit performs sampling detection on the mixed material of the tailings and the auxiliary materials for the N0 th time and the measured mixing degree En is less than Ei, the central control unit adds the auxiliary materials to the mixed material, sets the mass M' of the added auxiliary materials to be 0.25 xMxbj, updates the preset maximum sampling detection frequency to be 0.5 xN 0, and can judge that the tailings and the auxiliary materials in the preset proportion amount cannot reach the preset mixing degree when the preset detection frequency is reached by setting the maximum sampling detection frequency, so that the corresponding amount of the auxiliary materials are quickly added to ensure that the mixing degree of the tailings and the auxiliary materials is quickly adjusted to the preset requirement, further ensure the uniform distribution degree of iron powder in the prepared pellets, and further improve the preparation efficiency of the process for the pellets.

Furthermore, the central control unit is also provided with a first preset humidity S1, a second preset humidity S2, a third preset humidity S3, a first preset pelletizing rotation speed V1, a second preset pelletizing rotation speed V2 and a third preset pelletizing rotation speed V3, when the central control unit controls the pelletizing unit to pelletize, the central control unit determines the initial humidity in the pelletizing disc and the initial rotation speed of the pelletizing disc according to the size requirement of pellet, when the setting is completed, the central control unit starts the pelletizing unit and adjusts the humidity in the pelletizing disc and the rotation speed of the pelletizing disc in real time according to the diameter of the pellet in the pelletizing disc during the pelletizing process of the pelletizing unit, the rapid pelletizing of the tailings mixed with the iron powder and the auxiliary material can be completed by presetting the corresponding pelletizing rotation speed and the initial humidity, and simultaneously, the humidity in the pelletizing disc and the rotation speed of the pelletizing disc are adjusted in real time according to the diameter in the pelletizing disc, the uniformity of the distribution of the iron powder in the spherulites can be effectively ensured, the uniformity of the distribution of the iron powder in the prepared spherulites is further ensured, and the preparation efficiency of the process for the pellet is further improved.

Further, a first pelletizing rotation speed regulating quantity Δ V1, a second pelletizing rotation speed regulating quantity Δ V2 and a third pelletizing rotation speed regulating quantity Δ V3 are further arranged in the central control unit, when the pelletizing unit performs pelletizing, the central control unit sets the pelletizing rotation speed of the pelletizing disc to V and detects the average size R of the pellets in real time by using the size detector, when the average size R maintaining time of the pellets exceeds a preset time t0, the central control unit adjusts the rotation speed of the pelletizing disc to a corresponding value according to the relation between R and the size demand D of the pellets to be prepared, and the average size of the pellets can be quickly adjusted to the corresponding value by periodically detecting the average size of the pellets to adjust the pelletizing rotation speed of the pelletizing disc to the corresponding value, so that the preparation efficiency of the process for the pellets is further improved.

Particularly, the central control unit is further provided with a first preset pelletizing rotation speed correction coefficient alpha 1, a second preset pelletizing rotation speed correction coefficient alpha 2 and a third preset pelletizing rotation speed correction coefficient alpha 3, when the central control unit adjusts the pelletizing rotation speed of the pelletizing disc, the central control unit selects a corresponding pelletizing rotation speed correction coefficient to correct the jth pelletizing rotation speed regulating quantity Δ Vj according to a size requirement D which is predetermined for pellet preparation at the time, and performs targeted correction on the rotation speed regulating quantity by selecting a corresponding preset pelletizing rotation speed correction coefficient according to pellets with different size requirements, so that the change rate of the average size of the pellets can be maintained in a corresponding interval, the condition that the average size of the pellets does not accord with the preset size requirement due to too fast or too slow change of the average size of the pellets is effectively prevented, and the distribution uniformity degree of iron powder in the prepared pellets is further ensured, and the preparation efficiency of the process for the pellet ore is further improved.

Further, a preset pelletizing rotation speed critical value Vmax, a first preset size difference value delta R1, a second preset size difference value delta R2, a first preset water injection quantity Q1 and a second preset water injection quantity Q2 are further arranged in the central control unit, when the central control unit adjusts the pelletizing rotation speed of the pelletizing disc to be V ', the central control unit compares V ' with Vmax, if V ' is less than or equal to Vmax, the central control unit adjusts the rotation speed of the pelletizing disc to be V ', if V ' is greater than Vmax, the central control unit adjusts the rotation speed of the pelletizing disc to be Vmax, when the central control unit adjusts the pelletizing rotation speed of the pelletizing disc to be Vmax and the average size R maintaining time of the pellets exceeds a preset time t0, the central control unit calculates the difference value R between R and the size requirement D of the pellets to be prepared, compares the delta R with delta R1 and delta R2 in sequence and controls the corresponding water injection quantity according to the comparison result, by setting the maximum rotating speed value Vmax, the situation that the rotating speed is continuously adjusted due to insufficient water to damage the spherulites is avoided, the completeness of the prepared spherulites is ensured, and meanwhile, the preparation efficiency of the process for the pellet is further improved.

Furthermore, a preset critical humidity Smax is also arranged in the central control unit; when the central control unit starts the water sprayer to adjust the size R of the spherical particles to a preset value, the central control unit detects the average humidity S in the balling disc in real time in the water spraying process of the water sprayer, if S is larger than Smax, the central control unit controls the water sprayer to be closed until the average humidity S in the balling disc is smaller than Smax, and the situation that the spherical particles are bonded together due to the fact that the humidity in the balling disc is too high is prevented by setting a preset critical humidity, so that the preparation efficiency of the process for the spherical particles is further improved while the integrity of the prepared spherical particles is further guaranteed.

Furthermore, the auxiliary materials comprise sodium silicate, cellulose, sodium carbonate, magnesium oxide, a flocculating agent and humic acid, and the tailing sand has excellent adhesive property after the materials are mixed with the tailing sand, so that pellets meeting the requirement can be prepared when the iron powder is pelletized by the tailing sand, the integrity of the prepared pellets is further ensured, the uniform distribution degree of the iron powder in the prepared pellets is further ensured, and the preparation efficiency of the process for the pellets is further improved.

Drawings

FIG. 1 is a schematic view of a pellet preparation system using the process of the present invention;

FIG. 2 is a flow chart of the preparation process of pellets based on mineral dressing tailings instead of bentonite.

Detailed Description

In order that the objects and advantages of the invention will be more clearly understood, the invention is further described below with reference to examples; it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and do not limit the scope of the present invention.

It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Fig. 1 is a schematic structural diagram of a pellet production system using the process of the present invention. The pellet preparation system based on mineral separation tailings replacing bentonite comprises:

a grinding unit 1 for grinding iron powder;

the mixing unit 2 is connected with the grinding unit 1 and is used for mixing the tailings and the auxiliary materials and secondarily mixing the iron powder output by the grinding unit 1 and the mixed materials when the tailings and the auxiliary materials are mixed;

the iron content detection unit 3 is connected with the mixing unit 2 and used for storing the tailings and detecting the iron content in the tailings, and when the iron content detection unit 3 detects the iron content in the tailings, the iron content detection unit 3 conveys the tailings to the mixing unit 2;

the pelletizing unit 4 is connected with the mixing unit 2 and is used for pelletizing the materials subjected to secondary mixing; the pelletizing unit 4 comprises a pelletizing disc 41, a water sprayer 42 is arranged in the pelletizing unit 4 and used for spraying water into the pelletizing disc 41 to adjust the humidity in the pelletizing disc 41, a humidity detector 43 is arranged in the pelletizing disc 41 and used for detecting the humidity in the pelletizing disc, and a size detector 44 is further arranged in the pelletizing unit 4 and used for detecting the average size of pellets in the pelletizing disc;

a drying unit 5 connected with the pelletizing unit 4 for drying the pellets output from the pelletizing unit 4;

a burning unit 6 connected to the drying unit 5 for burning the dried pellets output from the drying unit 5, wherein the burning unit 6 is further provided with a visual detection device 61 for detecting the average apparent porosity of the pellets in real time when the burning unit 6 burns the pellets;

and the central control unit (not shown in the figure) is respectively connected with the grinding unit 1, the muddy shocking and the unit, the iron content detection unit 3, the pelletizing unit 4, the drying unit 5 and the burning unit 6, and is used for adjusting the operation parameters of the designated parts in the corresponding units to corresponding values according to the actual conditions of raw materials or pellets when the system is used for preparing the pellets.

Fig. 2 is a flow chart of a process for preparing pellets based on mineral dressing tailings instead of bentonite according to the present invention. The preparation process of the pellet based on the mineral dressing tailing replacing bentonite comprises the following steps:

step s1, the central control unit controls the grinding unit 1 to grind the iron ore powder and controls the grinding unit 1 to grind the iron ore powder to a corresponding particle size according to the size requirement of the pellet;

step s2, the central control unit controls the iron content detection unit 3 to detect the iron content in the tailings, and determines the mass ratio of the tailings and the iron powder according to the iron content;

step s3, the central control unit determines the usage amount of the auxiliary material according to the actual usage amount of the tailings, conveys the tailings and the auxiliary material to the mixing unit 2, sets a preset stirring time and a preset mixing degree, starts the mixing unit 2 when the setting is completed, periodically samples and detects the mixing degree of the tailings and the auxiliary material in the mixing process, controls the stirring unit to stop stirring and controls the grinding unit 1 to convey the ground iron powder to the mixing unit 2 for secondary stirring when the mixing degree of the tailings and the auxiliary material reaches a preset standard, and controls the stirring unit to convey the mixed material to the pelletizing unit 4 when the secondary stirring is completed;

step s4, the central control unit controls the pelletizing unit 4 to start and starts the water sprayer 42 in the pelletizing unit 4 to spray water into the material so that the pelletizing unit 4 performs pelletizing, and the central control unit adjusts the rotating speed of the pelletizing disc 41 in the pelletizing unit 4 to a corresponding value according to the size requirement of the pellets;

step s5, when the pelletizing unit 4 is in operation, the central control unit controls the moisture detector 43 to detect the average moisture in the pelletizing unit 4 in real time and controls the size detector 44 to detect the average size of the pellets in real time, when the moisture in the pelletizing unit 4 reaches a preset value, the central control unit controls the water sprayer 42 to stop spraying water, and when the average size of the pellets reaches a preset standard, the central control unit controls the pelletizing unit 4 to deliver the pellets to the drying unit 5;

step s6, the central control unit adjusts the drying temperature of the drying unit 5 to an initial value to dry the pellets, determines the preset loss rate of the average water content in the pellets in the unit time in the drying process according to the average diameter of the pellets, and adjusts the drying temperature of the drying unit 5 to a corresponding value according to the actual loss rate of the average water content in the pellets in the unit time after the determination is completed;

step s7, after the drying is completed, the central control unit conveys the pellets to the firing unit 6 and controls the firing unit 6 to fire the pellets, in the firing process, the central control unit controls the visual detection device 61 in the firing unit 6 to detect the average apparent porosity of the pellets in real time and adjusts the firing temperature of the firing unit 6 when the actual average apparent porosity of the pellets does not meet the preset standard, and when the average apparent porosity of the pellets meets the preset standard, the central control unit controls the firing unit 6 to stop firing and cools the fired pellets to room temperature to complete the preparation of the pellet ore;

the central control unit is provided with a first preset mass M1, a second preset mass M2, a first preset stirring detection period t1, a second preset stirring detection period t2, a third preset stirring detection period t3, a first mixing degree E1, a second mixing degree E2 and a third mixing degree E3, wherein M1 is more than M2, t1 is more than t2, when the central control unit controls the mixing unit 2 to mix the tailings and the auxiliary materials, the central control unit controls the mixing unit 2 to detect the quality M of the tailings and compare the quality M with M1 and M2 in sequence, if M is less than or equal to M1, the central control unit sets the initial stirring detection period to t1 and the initial mixing degree of the tailings and the auxiliary materials to E1, if M1 is less than or equal to M2, the central control unit sets the initial stirring detection period to t2 and the initial mixing degree of the tailings and the auxiliary materials to E2, and if M is greater than M3, the central control unit sets the initial stirring detection period to t3 and the initial mixing degree of the tailings and the auxiliary materials to E3;

when the delta E is less than or equal to delta E0, the central control unit does not adjust the initial mixing rotating speed W of the stirring paddle in the mixing unit 2;

when Δ E > [ Δ E0 and i is 1, the central control unit adjusts the initial mixing rotation speed W of the stirring paddle in the mixing unit 2 by using Δ W1, the adjusted mixing rotation speed of the stirring paddle is recorded as W ', and W' [ W + [ Δ ] W1 is set;

when Δ E > [ Δ E0 and i is 2, the central control unit adjusts the initial mixing rotation speed W of the stirring paddle in the mixing unit 2 by using Δ W2, the adjusted mixing rotation speed of the stirring paddle is recorded as W ', and W' [ W + [ Δ ] W2 is set;

when Δ E > [ Δ E0 and i is 3, the central control unit adjusts the initial mixing rotation speed W of the stirring paddle in the mixing unit 2 by using Δ W3, the adjusted mixing rotation speed of the stirring paddle is recorded as W ', and W' [ W + [ Δ ] W3 is set;

According to the invention, by setting a plurality of preset qualities, a plurality of preset stirring detection periods and a plurality of preset mixing degrees, the central control unit can select the corresponding mixing degree of the tailings and the auxiliary materials according to the quality of the tailings used in a single preparation process, so that when the pellets are prepared, the tailings and the auxiliary materials can be effectively uniformly mixed, the comprehensive performance of the prepared pellets is effectively improved, the preparation efficiency of the process for the pellets is effectively improved, and meanwhile, by setting a preset mixing degree deviation value and a plurality of mixing rotating speed regulating amounts, when the mixing of the tailings and the auxiliary materials is judged to be unqualified after the primary mixing is completed, the mixing rotating speed can be readjusted according to the actual condition to further ensure the uniform mixing of the tailings and the auxiliary materials, so that the preparation efficiency of the process for the pellets is further improved.

Specifically, the central control unit of the invention is further provided with a preset size requirement interval D0, a first preset iron powder particle size r1, a second preset iron powder particle size r2 and a third preset iron powder particle size r3, D0(Da, Db) is set, r1 < r2 < r3, when the central control unit controls the grinding unit 1 to grind the iron ore powder, the central control unit determines the size requirement D for preparing the secondary pellet in advance, if D is less than Da, the central control unit judges that the secondary process is used for preparing the micro pellet and controls the grinding unit 1 to grind the particle size of the iron powder to r1, if Da is less than or equal to Db, the central control unit judges that the secondary process is used for preparing the conventional size pellet and controls the grinding unit 1 to grind the particle size of the iron powder to r2, and if D is greater than Db, the central control unit judges that the secondary process is used for preparing the large size pellet and controls the grinding unit 1 to grind the particle size of the iron powder to r 3;

according to the invention, the size requirement D for preparing the pellet is determined in advance, and the grinding particle size of the iron powder is determined according to the actual value of the size requirement, so that the iron powder is effectively bonded when the tailings and the auxiliary materials are uniformly mixed, thereby forming the pellet with uniformly distributed iron powder, and further improving the preparation efficiency of the process for the pellet.

Specifically, the central control unit is further provided with a first average particle size deviation delta r1 and a second average particle size deviation delta r2, delta r1 is set to be less than delta r2, when the grinding unit 1 finishes grinding the iron powder, the central control unit controls the grinding unit 1 to detect the average particle size r of the ground iron powder and compare r with the corresponding preset iron powder particle size,

when the central control unit takes the first preset iron powder particle size r1 as a particle size standard of the ground iron powder, the central control unit uses delta r1 as a detection standard for the particle size of the ground iron powder, compares the particle size r of the ground iron powder with r1, if r > r1 and r-r1 are less than or equal to delta r1 or r < r1 and r1-r are less than or equal to delta r1, the central control unit judges that the particle size of the ground iron powder meets the standard and judges that the grinding is completed, and if r > r1 and r-r1 > -delta r1 or r < r1 and r1-r > -delta r1 are not completed, the central control unit judges that the grinding is completed and controls the grinding unit 1 to grind the iron powder again until the particle size of the ground iron powder meets the standard;

when the central control unit takes the second preset iron powder particle size r2 or the third preset iron powder particle size r3 as the particle size standard of the ground iron powder, the central control unit uses delta r2 as a detection standard for the particle size of the ground iron powder, the central control unit compares the particle size r of the ground iron powder with ri, sets i to be 2, 3, if r is greater than ri and r-ri is less than or equal to delta r2 or r is less than ri and ri-r is less than or equal to delta r2, the central control unit judges that the particle size of the ground iron powder meets the standard and judges that the grinding is completed, and if r is greater than ri and r-ri is greater than delta r2 or r is less than ri and ri is greater than delta r2, the central control unit judges that the grinding is completed and controls the grinding unit 1 to grind the iron powder again until the particle size of the ground iron powder meets the standard.

According to the invention, the particle size of the ground iron powder is further judged, so that the particle size of the ground iron powder meets the requirement, the uniform distribution degree of the iron powder in the prepared spherulites is further ensured, and the preparation efficiency of the process for the pellet is further improved.

Specifically, the central control unit is further provided with a first preset iron content F1, a second preset iron content F2, a first preset mass ratio B1 and a second preset mass ratio B2, F1 is set to be more than F2, when the central control unit determines the mass ratio of the tailings and the iron powder, the central control unit controls the iron content detection unit 3 to detect the iron content F in the tailings, compares the F with F1 and F2 respectively, determines the mass ratio of the tailings and the iron powder according to the comparison result, if F is more than 0 and less than F1, the central control unit sets the mass ratio of the tailings and the iron powder to be B1, if F1 is more than F and less than F2, the central control unit sets the mass ratio of the tailings and the iron powder to be B2, if F is more than F2, the central control unit judges that the iron content in the tailings is too high, sends out a heavy-sieving alarm and re-tests the iron content F 'after the tailing is re-sieved again, and if the iron content in the F' is more than the second repeated screening step, the central control unit judges that the iron content of the tailings and the iron content F2 is less than the second repeated step until the second iron content F3 is equal to be less than the second step And the iron content is F2, and the central control unit compares the iron content of the re-screened tailings with F1 and F2 in sequence and determines the mass ratio of the re-screened tailings to the iron powder according to the comparison result.

According to the invention, the ratio between the tailings and the iron powder is determined by determining the iron content in the tailings, so that the ratio between the tailings and the iron powder is ensured to be within a preset interval, the uniformity of the distribution of the iron powder in the prepared spherulites is further ensured, and the preparation efficiency of the process for the pellets is further improved.

Specifically, the central control unit is also provided with a first preset auxiliary material proportion b1, a second auxiliary material proportion b2 and a third auxiliary material proportion b 3; before the tailing and the auxiliary material are mixed by the central control unit, the central control unit determines the mass M of the auxiliary material according to the mass M of the tailing, if the M is less than or equal to M1, the central control unit calculates the mass M of the auxiliary material by using the first preset auxiliary material proportion b1, if the M1 is less than or equal to M2, the central control unit calculates the mass M of the auxiliary material by using the second preset auxiliary material proportion b2, and if the M is more than M3, the central control unit calculates the mass M of the auxiliary material by using the third preset auxiliary material proportion b 3;

the central control unit selects a corresponding preset auxiliary material ratio according to the mass M of the tailings to determine the mass M of the auxiliary material, so that the adhesive formed by mixing the tailings and the auxiliary material has the performance meeting the preparation requirement, the property of the spherulites prepared by the process meets the preset requirement, the uniformity of the distribution of iron powder in the prepared spherulites is further ensured, and the preparation efficiency of the process for the spherulites is further improved.

Specifically, the central control unit is further provided with a preset maximum sampling detection time N0, when the central control unit performs sampling detection on the mixed material of the tailings and the auxiliary materials for the nth 0 time and the measured mixing degree En is less than Ei, the central control unit adds the auxiliary materials to the mixed material and sets the mass M' of the added auxiliary materials to be 0.25 × M × bj, after the addition is completed, the central control unit updates the preset maximum sampling detection time to 0.5 × N0, and after the update is completed, the central control unit controls the mixing unit 2 to re-stir the mixed material and adds iron powder to the mixed material when the measured mixing degree of the mixed material is greater than or equal to Ei.

According to the invention, by setting the maximum sampling detection times, the situation that the tailing and the auxiliary material in the preset proportion amount cannot reach the preset mixing degree can be judged when the preset detection times are reached, so that the auxiliary material in the corresponding amount is quickly added to ensure that the mixing degree of the tailing and the auxiliary material is quickly adjusted to the preset requirement, and the preparation efficiency of the process for the pellet ore is further improved while the uniformity of the distribution of iron powder in the prepared pellet ore is further ensured.

Specifically, the central control unit is further provided with a first preset humidity S1, a second preset humidity S2, a third preset humidity S3, a first preset pelletizing rotation speed V1, a second preset pelletizing rotation speed V2 and a third preset pelletizing rotation speed V3, wherein S1 is greater than S2 and less than S3, and V1 is greater than V2 and less than V3; when the central control unit controls the pelletizing unit 4 to pelletize, the central control unit determines the initial humidity in the pelletizing disc 41 and the initial rotating speed of the pelletizing disc 41 according to the size requirement of the pellets, if D is less than Da, the central control unit sets the initial humidity in the pelletizing disc 41 to be S1 and the initial rotating speed of the pelletizing disc 41 to be V1, if Da is less than or equal to D and less than or equal to Db, the central control unit sets the initial humidity in the pelletizing disc 41 to be S2 and the initial rotating speed of the pelletizing disc 41 to be V2, and if D is greater than Db, the central control unit sets the initial humidity in the pelletizing disc 41 to be S3 and the initial rotating speed of the pelletizing disc 41 to be V3;

when the central control unit completes the setting of the initial humidity in the balling disc 41 and the initial rotating speed of the balling disc 41, the central control unit starts the balling unit 4 and adjusts the humidity in the balling disc 41 and the rotating speed of the balling disc 41 in real time according to the diameter of the spherulites in the balling disc 41 in the balling process of the balling unit 4.

According to the invention, the corresponding pelletizing rotating speed and the initial humidity are preset, so that the rapid pelletizing of the tailings mixed with the iron powder and the auxiliary materials can be completed, meanwhile, the uniformity of the distribution of the iron powder in the pellet can be effectively ensured by adjusting the humidity in the pelletizing disc 41 and the rotating speed of the pelletizing disc 41 in real time according to the diameter of the pellet in the pelletizing disc 41, and the preparation efficiency of the process for the pellet ore is further improved while the uniformity of the distribution of the iron powder in the prepared pellet is further ensured.

Specifically, the central control unit of the present invention is further provided with a first pelletizing rotation speed adjustment amount Δ V1, a second pelletizing rotation speed adjustment amount Δ V2 and a third pelletizing rotation speed adjustment amount Δ V3, sets Δ V1 < [ delta ] V2 < [ delta ] V3, sets the pelletizing rotation speed of the pelletizing disk 41 to V and detects the average size R of pellets in real time using the size detector 44 when the pelletizing unit 4 performs pelletizing, and adjusts the rotation speed of the pelletizing disk 41 to a corresponding value according to the relationship between R and the size demand D of the pellets to be produced when the average size R of pellets is maintained for more than a preset time period t0,

when the central control unit adjusts the pelletizing rotation speed V by using the jth pelletizing rotation speed adjustment quantity Δ Vj, setting j to be 1, 2, 3, and setting V 'to be V + Δ Vj, wherein the adjusted pelletizing rotation speed of the pelletizing disc 41 is set to be V';

the invention can adjust the pelletizing rotating speed of the pelletizing disc 41 to the corresponding value by periodically detecting the average size of the pellets, and can quickly adjust the average size of the pellets to the corresponding value, thereby further improving the preparation efficiency of the process for the pellets.

Specifically, the central control unit of the present invention is further provided with a first preset pelletizing rotation speed correction coefficient α 1, a second preset pelletizing rotation speed correction coefficient α 2, and a third preset pelletizing rotation speed correction coefficient α 3, and when the central control unit adjusts the pelletizing rotation speed of the pelletizing disc 41, the central control unit selects a corresponding pelletizing rotation speed correction coefficient to correct the jth pelletizing rotation speed adjustment quantity Δ Vj according to the size requirement D predetermined for the pellet preparation,

if D is less than Da, the central control unit corrects the jth pelletizing rotation speed adjustment amount Δ Vj by using a first preset pelletizing rotation speed correction coefficient α 1, and sets a pelletizing rotation speed V' ═ V + α 1 × Δ Vj of the pelletizing disc 41 after correction;

if Da is less than or equal to D and less than or equal to Db, the central control unit corrects the jth pelletizing rotation speed adjustment amount Δ Vj by using a second preset pelletizing rotation speed correction coefficient α 2, and sets a pelletizing rotation speed V' ═ V + α 2 × Δ Vj of the pelletizing disc 41 after correction;

if D > Db, the central control unit corrects the jth pelletizing rotation speed adjustment amount Δ Vj using a third preset pelletizing rotation speed correction coefficient α 3, and sets a corrected pelletizing rotation speed V' ═ V + α 3 × Δ Vj of the pelletizing disc 41.

According to the invention, the corresponding preset pelletizing rotating speed correction coefficients are selected according to the pellets with different size requirements to perform targeted correction on the rotating speed regulating quantity, and the change rate of the average size of the pellets can be maintained in the corresponding interval, so that the condition that the average size of the pellets does not meet the preset size requirement due to too fast or too slow change of the average size of the pellets is effectively prevented, the uniformity degree of the distribution of iron powder in the prepared pellets is further ensured, and the preparation efficiency of the process for the pellets is further improved.

Specifically, the central control unit is further provided with a preset pelletizing rotation speed critical value Vmax, a first preset size difference value delta R1, a second preset size difference value delta R2, a first preset water injection quantity Q1 and a second preset water injection quantity Q2, wherein delta R1 is smaller than delta R2, and Q1 is smaller than Q2;

when the central control unit adjusts the pelletizing rotating speed of the pelletizing disc 41 to be V ', the central control unit compares V ' with Vmax, if V ' is less than or equal to Vmax, the central control unit adjusts the rotating speed of the pelletizing disc 41 to be V ', and if V ' is greater than Vmax, the central control unit adjusts the rotating speed of the pelletizing disc 41 to be Vmax;

when the central control unit adjusts the pelletizing rotating speed of the pelletizing disc 41 to Vmax and the maintaining time length of the average size R of the pellets exceeds the preset time length t0, the central control unit calculates the difference value Delta R between R and the size requirement D of the pellets to be prepared, sets the Delta R to be D-R, after the calculation is completed, the central control unit compares the Delta R with the Delta R1 and the Delta R2 in sequence and controls the water sprayer 42 to start to spray water with corresponding amount according to the comparison result,

if the value of DeltaR is more than 0 and less than or equal to DeltaR 1, the central control unit does not start the water sprayer 42;

if delta R1 is less than delta R and less than delta R2, the central control unit starts the water sprayer 42 and sets the single water spraying quantity of the water sprayer 42 as Q1;

if Δ R > [ Δ R3, the central control unit activates the water jet 42 and sets the single water jet amount of the water jet 42 to Q2.

According to the invention, the maximum rotating speed value Vmax is set to avoid the situation that the rotating speed is continuously adjusted due to insufficient water to damage the spherulites, so that the completeness of the prepared spherulites is ensured, and the preparation efficiency of the process for the pellet ore is further improved.

Specifically, the central control unit is also provided with a preset critical humidity Smax; when the central control unit starts the water sprayer 42 to adjust the size R of the pellets to a preset value, the central control unit detects the average humidity S in the balling disk 41 in real time during the water spraying process of the water sprayer 42, and if S is more than Smax, the central control unit controls the water sprayer 42 to be closed until the average humidity S in the balling disk 41 is less than Smax.

According to the invention, the preset critical humidity is set to prevent the occurrence of the condition that the pellets are bonded together due to overhigh humidity in the pelletizing disc 41, so that the preparation efficiency of the process for the pellet ore is further improved while the integrity of the prepared pellets is further ensured.

Specifically, the auxiliary materials comprise sodium silicate, cellulose, sodium carbonate, magnesium oxide, a flocculating agent and humic acid. According to the invention, after the materials are mixed with the tailings, the tailings have excellent adhesive property, so that pellets meeting the requirements can be prepared when the tailings are used for pelletizing iron powder, the integrity of the prepared pellets is further ensured, the distribution uniformity of the iron powder in the prepared pellets is further ensured, and the preparation efficiency of the process for the pellets is further improved.

Specifically, the iron ore powder includes 88% of magnetite concentrate powder and 12% of hematite concentrate powder.

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention; various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pellet preparation process based on mineral separation tailings replacing bentonite is characterized by comprising the following steps:

2. The process for preparing pellets based on mineral processing tailings instead of bentonite according to claim 1, wherein the central control unit is further provided with a preset size requirement interval D0, a first preset iron powder particle size r1, a second preset iron powder particle size r2 and a third preset iron powder particle size r3, D0(Da, Db) is set, r1 < r2 < r3, when the central control unit controls the grinding unit to grind the iron ore powder, the central control unit determines the size requirement D for the preparation of the pellets in advance, if D < Da, the central control unit determines that the process is used for preparing micro pellets and controls the grinding unit to grind the iron powder particle size to r1, if Da < D < Db, the central control unit determines that the process is used for preparing regular-size pellets and controls the grinding unit to grind the iron powder particle size to r2, and if D > Db, the central control unit determines that the process is used for preparing large-size pellets and controls the grinding unit to grind the iron powder particle size to 3;

3. The process for preparing pellets based on mineral dressing tailings instead of bentonite according to claim 1, wherein the central control unit is further provided with a first preset iron content F1, a second preset iron content F2, a first preset mass ratio B1 and a second preset mass ratio B2, F1 is set to be more than F2, when the central control unit determines the mass ratio of the tailings and the iron powder, the central control unit controls the iron content detection unit to detect the iron content F in the tailings, F is respectively compared with F1 and F2, and the mass ratio of the tailings and the iron powder is determined according to the comparison result, if F is more than 0 and less than F1, the central control unit sets the mass ratio of the tailings and the iron powder to B1, if F1 is more than F and less than F2, the central control unit sets the mass ratio of the tailings and the iron powder to B2, if F is more than F2, the central control unit determines that the content of the tailings is too high, sends out an alarm and re-screens the tailings in-screening the tailings, if F' > F2, the central control unit repeats the steps until the iron content of the re-screened tailings is less than or equal to the second preset iron content F2, at the moment, the central control unit compares the iron content of the re-screened tailings with F1 and F2 in sequence and determines the mass ratio of the re-screened tailings to the iron powder according to the comparison result.

4. The process for preparing pellets based on mineral dressing tailings instead of bentonite according to claim 3, wherein the central control unit is further provided with a first preset auxiliary material proportion b1, a second auxiliary material proportion b2 and a third auxiliary material proportion b 3; before the tailing and the auxiliary material are mixed by the central control unit, the central control unit determines the mass M of the auxiliary material according to the mass M of the tailing, if the M is less than or equal to M1, the central control unit calculates the mass M of the auxiliary material by using the first preset auxiliary material proportion b1, if the M1 is less than or equal to M2, the central control unit calculates the mass M of the auxiliary material by using the second preset auxiliary material proportion b2, and if the M is more than M3, the central control unit calculates the mass M of the auxiliary material by using the third preset auxiliary material proportion b 3;

5. The process for preparing the pellet ore based on the mineral dressing tailings instead of the bentonite according to claim 2, wherein a first preset humidity S1, a second preset humidity S2, a third preset humidity S3, a first preset pelletizing rotation speed V1, a second preset pelletizing rotation speed V2 and a third preset pelletizing rotation speed V3 are further arranged in the central control unit, S1 < S2 < S3, and V1 < V2 < V3 are set; when the central control unit controls the pelletizing unit to pelletize, the central control unit determines the initial humidity in the pelletizing disc and the initial rotating speed of the pelletizing disc according to the size requirement of the pellets, if D is less than Da, the central control unit sets the initial humidity in the pelletizing disc to be S1 and the initial rotating speed of the pelletizing disc to be V1, if Da is less than or equal to Db, the central control unit sets the initial humidity in the pelletizing disc to be S2 and the initial rotating speed of the pelletizing disc to be V2, and if D is more than Db, the central control unit sets the initial humidity in the pelletizing disc to be S3 and the initial rotating speed of the pelletizing disc to be V3;

6. The process for preparing pellets based on mineral dressing tailings replacing bentonite according to claim 5, wherein the central control unit is further provided with a first pelletizing rotation speed regulating quantity Δ V1, a second pelletizing rotation speed regulating quantity Δ V2 and a third pelletizing rotation speed regulating quantity Δ V3, the setting is that Δ V1 < [ delta ] V2 < [ delta ] V3, when the pelletizing unit performs the pelletizing, the central control unit sets the pelletizing rotation speed of the pelletizing disc to V and detects the average size R of pellets in real time by using the size detector, when the average size R of pellets is maintained for a period exceeding a preset period t0, the central control unit adjusts the rotation speed of the pelletizing disc to a corresponding value according to the relationship between R and the size requirement D of the pellets to be prepared,

7. The process for preparing the pellet ore based on the mineral dressing tailings instead of the bentonite according to claim 6, wherein a preset pelletizing rotation speed critical value Vmax, a first preset size difference Delta R1, a second preset size difference Delta R2, a first preset water injection quantity Q1 and a second preset water injection quantity Q2 are further arranged in the central control unit, and the conditions that the Delta R1 is less than the Delta R2 and the Q1 is less than the Q2 are set;

8. The process for preparing the pellet based on the mineral processing tailings instead of the bentonite according to claim 7, wherein a preset critical humidity Smax is further arranged in the central control unit; when the central control unit starts the water sprayer to adjust the size R of the spherulites to a preset value, the central control unit detects the average humidity S in the balling disk in real time in the water spraying process of the water sprayer, and if S is larger than Smax, the central control unit controls the water sprayer to be closed until the average humidity S in the balling disk is smaller than Smax.

9. The process for preparing pellets based on mineral dressing tailings instead of bentonite according to claim 1, wherein the auxiliary materials comprise sodium silicate, cellulose, sodium carbonate, magnesium oxide, a flocculating agent and humic acid.

10. The process for preparing pellets based on mineral dressing tailings instead of bentonite according to claim 1, wherein the iron ore powder comprises 88% of magnetite concentrate powder and 12% of hematite concentrate powder.