CN108070713B - Iron ore sintering method using light-burned magnesium balls - Google Patents
Iron ore sintering method using light-burned magnesium balls Download PDFInfo
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Abstract
The invention discloses an iron ore sintering method using light-burned magnesium balls, which is mainly characterized in that in an iron ore sintering process, the light-burned magnesium balls are proportionally prepared with iron ore powder, return ores, coke powder and a fusing agent, and then water is added for uniformly mixing, granulating, distributing, igniting, sintering, cooling and crushing to obtain a sintered ore finished product. The sintering mineralization rate is improved by replacing dolomite powder with the lightly calcined magnesium balls, and reasonable mineral composition and mineral phase structure are obtained.
Description
Technical Field
The invention relates to the field of iron ore sintering, in particular to an iron ore sintering method using light-burned magnesium balls.
Background
Sintering (air draft sintering) is the most widely adopted iron-containing raw material agglomeration method for iron and steel enterprises at home and abroad. The sintering process can be summarized as follows: the sintering mixture (iron-containing raw material, fuel, flux and return ore, etc.) is mixed with proper amount of water, and after uniformly mixing and granulating, the mixture is spread on the trolley of sintering machine, after the surface of sintering material is ignited, under the action of forced air draft of lower air box, the fuel in material layer is combusted from top to bottom and releases heat, and under the action of high temp., the mixture can produce a series of physical and chemical changes, and finally can be consolidated into sintering ore.
As a main blast furnace ironmaking raw material, the sintered ore needs to meet the requirements of chemical components besides meeting the requirements of strength and granularity, and mainly comprises iron grade and binary alkalinity R2(CaO/SiO2)、MgO、Al2O3P, S, Zn, Pb, etc., wherein Al2O3The lower the 5 types P, S, Zn and Pb, the better, and the iron grade, the binary basicity R2(CaO/SiO2) MgO, 3 kinds of them are required to be kept in an appropriate range. The flux commonly used for sintering comprises powdery (granularity is 0-3 mm) limestone, dolomite, serpentine and silica sand. Wherein, the limestone is mainly provided with CaO after high-temperature calcination, the dolomite is mainly provided with CaO and MgO after high-temperature calcination, and the serpentine is mainly provided with MgO and SiO2Silica sand mainly provides SiO2. Along with the popularization of iron-making concentrate guidelines, the production of high-iron low-silicon sintered ores is gradually known, and in recent years, iron ore resource deterioration gangue is increased, so that serpentine and silica sand type silicon-containing fluxes are rarely added in the sintering process, and thus dolomite is often the most main magnesium-containing flux for iron ore sintering. However, dolomite has many adverse effects including a reduction in sintering yield, an increase in fuel consumption, etc. while improving the low-temperature reduction pulverization performance of the sintered ore.
The magnesium-containing flux is added into the sintered ore to meet the requirement of blast furnace slagging, and the blast furnace slag generally has binary basicity R2(CaO/SiO2)1.10 to 1.25 of Al2O3Under the condition that the content is 14-18%, the MgO content needs to be maintained between 4-8% so as to ensure the fluidity of the slag and the smooth operation of the smelting process.
At present, the relevant patents and the known technical documents which introduce magnesium-containing fluxes are as follows:
patent CN 100465306C introduces "sinter for improving viscosity of blast furnace slag and preparation method thereof", which mainly solves the problem of high Al content after iron ore deterioration2O3The enrichment causes the problem that the fluidity of the blast furnace slag is poor. The core of the patent claims is that on the basis of traditional sintering, dolomite and light-burned magnesia powder are used in a matching way, the MgO content of the sintering ore is increased, and can be adjusted within the range of 1.5-4.0%, and the measure can effectively reduce the viscosity of the blast furnace slag and improve the fluidity of the blast furnace slag. Wherein the content of the light-burned magnesium powder added in the sintering process is more than 90 percent with the granularity of 0-3mm, the content of magnesium is as high as 80-95 percent, and the burning loss rate is 1.5-4.5 percent. The light-burned magnesium balls used in the invention are different in particle size, components, properties and purposes.
Patent CN 104531923A introduces a blast furnace smelting raw material and a blast furnace smelting method, and provides a high-aluminum low-magnesium blast furnace smelting raw material which comprises high-aluminum low-magnesium sinter ore, pellet ore and raw ore, wherein magnesium-containing ore is not added in the furnace materials, and a method for smelting high-aluminum low-magnesium high-aluminum by using the furnace materials. The claims of this patent focus on blast furnace operating methods, describing ambiguities in smelting raw materials. For example, in the original patent, magnesium-containing ore is not added to blast furnace smelting material for many times, but in table 1, the high-grade iron concentrate contains only 0.06-0.55% of MgO, but the magnesium content of pellets produced by roasting the iron concentrate is 1.22-2.75%, and if magnesium-containing ore is not added, where the MgO comes from the pellets?
Patent CN101906533 introduces "a low-silicon magnesium-containing pellet and its production method", the invention is primarily aimed at solving the defect that the conventional sintering ore has too high magnesium oxide content and is very unfavorable for the quality of sintering ore, therefore, the magnesium-containing flux is added into the pellet to ensure the magnesium oxide content in the slag in the blast furnace smelting. 1-4% of magnesium-containing flux, iron ore concentrate and binder are mixed and proportioned, and then the magnesium-containing pellets with excellent strength and metallurgical performance are obtained through pelletizing, drying, preheating and roasting, and the measure can well solve the adverse effect of the dolomite conventional flux on the quality of sintered ore. However, the difficulty is left to the production of pellets, and generally, after a magnesium-containing flux is added, if the same roasting system is maintained, the strength of the pellets is reduced due to the addition of the high-melting-point magnesium-containing mineral, and if the same strength is maintained, the roasting temperature of the pellets needs to be appropriately increased.
Patent CN103131851 introduces a 'magnesium-rich bentonite binder for pellets', which mainly comprises mixing 20-30% magnesite powder into bentonite, and the thinking is similar to that of the previous patent CN101906533, and the similar problem also exists, and in addition, the other problem also exists, namely the addition amount of MgO is limited by the proportion of the bentonite, and cannot be too high, otherwise, the MgO is brought into aluminosilicate which is not needed in the smelting process, and the iron grade of the pellets is further influenced.
Patent CN103898316 introduces "a magnesium composite bentonite for pellet", which mainly comprises mixing 20-30% of light-burned magnesium powder into bentonite, and compared with the former patent, the content of MgO in bentonite is slightly increased, but the same problem of increased impurities caused by the increased consumption of bentonite exists, and the same problem exists as the former two patents, i.e. the roasting temperature needs to be increased to ensure that the compressive strength of the finished pellet is not reduced.
Patent CN94110210.6 introduces 'magnesium blending and slagging agent for light-burned magnesium pellets for steelmaking', a light-burned magnesium pellet for steelmaking slagging, which is mainly used in the enhanced magnesium blending and slagging process of converter steelmaking. The method is characterized in that light-burned magnesium pellets are prepared by mixing, molding and drying light-burned magnesium powder with the MgO content of more than 90 percent as a raw material and water as a binding agent according to the weight ratio of 100: 5-10. The magnesium-added slag-making method for steel making can greatly reduce the cost, improve the furnace life, increase the steel yield and has obvious economic benefit. The patent mainly uses cheap light-burned magnesium balls to replace original blocky high-quality light-burned magnesium blocks, and liquid slag is formed after melting to protect the converter lining. The scheme utilizes the characteristics of high melting point and high magnesium content of the light-burned magnesium balls, so that the light-burned magnesium balls play a role in improving thermal state air permeability in the iron ore sintering process. Meanwhile, the content of carbonate in the light-burned magnesium balls is low, and CO in the sintering process can be reduced after the carbonate replaces magnesium carbonate in dolomite2And (4) discharging. And MgO in the light-burned magnesium balls can participate in blast furnace slagging in the same way as conventional sintering ores in the blast furnace, and the performance of blast furnace slag is not influenced. The granularity, the application, the use procedure and the action principle of the light-burned magnesium balls in the scheme are all different from those of CN 94110210.6.
The Yuan Xianheyuan, Shenezmin and the like introduce 'test research and application of economic steel sintering with composite light-burned magnesium powder' (Jiangxi metallurgy, 2013, Vol.33, No.6, P1-5), the test researches the influence of the composite light-burned magnesium powder to the sintering production index instead of light-burned dolomite powder, the MgO content of the used powdery (the granularity of 0-325 meshes accounts for more than 90 percent) light-burned magnesium powder is 90.74 percent, and the test result of a sintering cup shows that after the composite light-burned magnesium powder is adopted, the sintering utilization coefficient, the vertical sintering speed, the rotary drum index and the low-temperature reduction pulverization index are all improved, but the solid fuel consumption of the simultaneous sintering is also increased by 1.7kg/t, in addition, the alkalinity is also increased by 0.04, and the finished product rate is increased while the partial quality index of the sintered ore is improved by adopting the composite light-burned magnesium powderMaterial consumption and discharge. The reasons for limiting the popularization of the technology include two points: firstly, the high-purity light-burned magnesium powder (containing more than 90 percent of MgO) has high price; and secondly, the transportation process of the superfine light-burned magnesium powder causes pollution such as dust emission and the like. In the technology, the superfine light-burned magnesium powder has high activity and is easy to CaO and SiO in the sintering process2Form diopside (CaO. MgO. 2 SiO)2Melting point 1391 ℃), forsterite (melting point 1357-. The scheme uses the blocky light-burned magnesium ball blocks, mainly utilizes the high melting point of the blocky light-burned magnesium ball blocks, forms a supporting effect in the sintering process, improves the thermal state air permeability, improves the sintering speed and increases the yield.
Therefore, if the novel magnesium-containing flux is used and the adding mode is changed, the requirement of blast furnace smelting on sintering and mineralizing MgO can be ensured, the sintering process is not deteriorated, and the method has important practical significance undoubtedly.
Disclosure of Invention
The invention aims to provide an iron ore sintering method using light-burned magnesium balls, which replaces dolomite powder with the light-burned magnesium balls, thereby improving the sintering and mineralization rate, obtaining reasonable mineral composition and mineral phase structure and mainly solving the cost problem in the prior art.
The technical scheme adopted by the patent application is as follows:
in the iron ore sintering process, the light-burned magnesium balls are proportionally prepared with iron ore powder, return fines, coke powder and a flux, and then water is added for uniformly mixing, granulating, distributing, igniting, sintering, cooling and crushing to obtain a sintered ore finished product, wherein the specific operation steps are as follows:
1) the following components are prepared into dry materials according to weight percentage: 0.5-3.5% of light-burned magnesium balls, 60-65% of iron ore powder, 20-25% of return ores, 3.5-4.5% of coke powder and 5-11% of flux; adding water accounting for 7.0-8.5% of the total weight of the dry materials, and uniformly mixing;
2) putting the mixed materials into a mixer, mixing and granulating for 5-8 min;
3) uniformly distributing the mixture after granulation into a sintering cup;
4) igniting the mixture in the sintering cup, wherein the ignition temperature is 1050 +/-50 ℃, the ignition time is 1.5-2.5 min, and the ignition negative pressure is 7-8 kPa;
5) after ignition is finished, igniting coke powder in the mixed material layer, adjusting the negative pressure to 14-16 kPa, starting sintering the mixed material, and after sintering is finished, continuing cooling in a sintering cup;
6) and crushing the cooled sinter to obtain a finished sinter product.
Preferably, the first and second liquid crystal materials are,
in the step 1), the step (A) is carried out,
the iron ore powder is one or more of iron ore blending ores of magnetite, hematite and limonite;
the fusing agent is one or more of limestone and quicklime; preferably, the flux is a mixture of quicklime and limestone; preferably, the fusing agent is a mixture of quicklime and limestone in a weight ratio of 2-5: 3-6;
the granularity of the iron ore powder is below 8mm, the granularity of the return fines is below 5mm, the granularity of the coke powder is 0-3mm, and the granularity of the flux is 0-3 mm;
the light-burned magnesium ball comprises the following components in percentage by weight: 60-85% of MgO content and 60-85% of CaO content<2.5％，SiO2Content (wt.)<3.0％，Al2O3Content (wt.)<0.3 percent; more preferably, the light-burned magnesium balls comprise the following components in percentage by weight: 60-70% of MgO, 1.5-2.3% of CaO and SiO22.4-3.0% of Al2O3The content is 0-0.015%;
the particle size of the light-burned magnesium balls is 5-20 mm, the compressive strength is more than 1000N/ball, and the light-burned magnesium balls are blocky or spherical.
In the step 6), the crushing is carried out by adopting a single-toothed-roller crusher.
In the embodiment of the invention, the equivalent amount of MgO in the raw material dolomite powder (with the granularity of 0-3 mm) in the common sintering production is converted into the proportion of light-burned magnesium balls, CaO in the dolomite is provided by limestone powder or quicklime, the calculation is carried out according to the sintering and proportioning procedure, and the proportion of iron ore, limestone, quicklime, light-burned magnesium balls, coke powder and return ores is obtained on the premise of not changing the chemical components.
In one embodiment of the present invention, the light-burned magnesium balls can be directly obtained by calcining magnesite, or can be obtained by calcining magnesite powder and performing agglomeration processes such as pelletizing or briquetting.
In the finished sintered ore product, the content of MgO is 1.0-3.1%, and the binary alkalinity R of the sintered ore2(CaO/SiO2) 1.75 to 2.0.
In addition, the melting point of MgO is as high as 2800 ℃, and the highest temperature of the iron ore sintering process is about 1400 ℃, so that the inside of the light-burned magnesium ball is solid except for the ultra-thin sintering liquid phase permeating through the surface in the sintering process. One benefit that the solid light-burned magnesium balls can bring to the sintering process is that the temperature of the combustion zone is highest in the sintering process, and a partial liquid phase is formed, the liquid phase flows under the action of the airflow, so that the gas resistance in the sintering process is increased, and the solid light-burned magnesium balls can play a role in supporting a material layer structure and improving the air permeability, as shown in fig. 2. Due to the existence of the light-burned magnesium balls, airflow can always have enough gaps to flow to the bottom, so that oxygen can smoothly react with fuel, and the improvement of air permeability is favorable for improving the combustion speed of the fuel and the vertical sintering speed in the sintering process.
Advantageous effects
The beneficial effects of the invention include: optimizing the technical indexes of sintering production, particularly improving the sintering utilization coefficient and improving the yield means reducing the production cost. In addition, the magnesia content of the light-burned magnesium balls is about 3 times of that of dolomite, the burning loss is about 2/3 times of that of the dolomite, and the contents of other gangue are lower.
Uses the light-burned magnesium balls with low carbonate content to replace dolomite to reduce CO in the ironmaking process2The discharge of the process can reduce dust in the material conveying process, 1700 ten thousand tons of sinter ore are produced annually, the unit ore consumption ratio is 1.13, the dry ratio of dolomite is 3 percent, 57.63 ten thousand tons of dolomite are consumed annually, wherein the MgCO is used for reducing the dust3Decomposition of discharged CO2The total amount of the magnesium pellets is 13.03 ten thousand tons, and if the light-burned magnesium pellets are used, 18.62 ten thousand tons of the agglomerates are consumed, CO is decomposed and discharged21.91 ten thousand tons in total and reduce CO2The discharge was 11.12 million tons, which corresponds to a reduction of 4.And 12 ten thousand tons of standard coal are discharged.
After the light-burned magnesium balls with high magnesium content are used for replacing dolomite, CaO in the original dolomite can be supplemented by limestone powder, and the light-burned magnesium balls have large particles, so that the light-burned magnesium balls are beneficial to granulating a sintering mixture, the using amount of quicklime can be reduced, and the lime is used for replacing and providing the CaO. The price of the quicklime is about 400 yuan/t, the limestone powder is about 100 yuan/t, and if the quicklime is converted into a ton of CaO source, the price of the quicklime is 490 yuan/t-CaO and 182 yuan/t-CaO. The sintering cost can be reduced to a certain extent.
In addition, the use of the light-burned magnesium balls can solve the problem of utilization of fine powdery materials after the magnesite is calcined, and a reasonable comprehensive utilization approach is found for leftovers after the Liaoning magnesite produces light-burned magnesium oxide.
Drawings
FIG. 1 is a damascene structure formed by soft-burned magnesium balls in a material layer;
FIG. 2 is a schematic view of an air stream flowing through solid light-burned magnesium spheres;
FIG. 3 shows the appearance (5 to 20mm) of the light-burned magnesium ball 1;
FIG. 4 is a cut surface after mixing and granulating in example 1;
FIG. 5 shows an appearance (upper part in FIG. 5) and a cut surface (lower part in FIG. 5) of a reference sintered ore;
FIG. 6 shows the appearance (upper part of FIG. 6) and cut surface (lower part of FIG. 6) of a sintered ore obtained by using the soft-burned magnesium balls in example 1.
Detailed Description
The invention will now be further illustrated, but is not limited, by the following specific examples.
The lightly calcined magnesium balls 1 and 2 used in the present invention are provided by Shanghai Baoye refractory Co., Ltd, and the lightly calcined magnesium balls 1 and 2 have original length and width of 55X 55mm, thickness of 25mm, and pillow shape. Before the test, the light-burned magnesium balls 1 and 2 are crushed by a crusher until the granularity is 5-20 mm for later use, and the appearance of the light-burned magnesium balls 1 is shown in figure 3.
The sintering raw material and the traditional dolomite component for sintering of the invention are detected according to the GB/T6730.68-2009 method, and the detection results are shown in Table 1.
TABLE 1 chemical composition of raw materials for sintering and burn-out (%)
| Item | MgO | CaO | SiO2 | Al2O3 | TFe | P2O5 | S | K2O | Na2O | Burn out of the furnace |
| Iron ore blending ore | 0.23 | 0.93 | 4.47 | 1.76 | 59.72 | 0.13 | 0.011 | — | — | 6.15 |
| Return ore | 1.65 | 7.61 | 4.78 | 1.72 | 58.96 | 0.12 | 0.012 | — | — | — |
| Coke powder | 0.13 | 0.51 | 6.44 | 4.51 | 0.62 | 0.13 | 0.74 | 0.079 | 0.077 | 87.8 |
| Quick lime | 0.69 | 81.61 | 2.43 | 1.19 | 0.10 | — | — | — | — | 13.66 |
| Limestone powder | 0.41 | 54.97 | 0.63 | 0.17 | 0.13 | — | — | — | — | 42.92 |
| Dolomite | 20.56 | 30.92 | 1.66 | 0.32 | 0.16 | 0.01 | 0.014 | — | — | 45.67 |
| Light-burned magnesium ball 1 | 63.62 | 1.90 | 2.49 | 0.13 | 0.22 | 0.08 | <0.005 | 0.016 | 0.012 | 30.25 |
| Light-burned magnesium ball 2 | 69.04 | 2.25 | 2.95 | 0.04 | 0.26 | 0.10 | — | — | — | 19.94 |
Note: the burning loss is detected according to the GB/T6730.68-2009 method, namely the weight loss of 1h burned at 1000 +/-25 ℃ in the air.
Reference examples and examples in the test, the mixing time was 2min, the granulation time was 5min, the bed height was 780mm, the ignition temperature was 1050 ℃, the ignition time was 1.5min, and the sintering negative pressure was 14.7kPa, a sintering test was carried out using a sintering cup with a diameter of 300mm, and the finished sintered ore was tested according to the method of GB/T245731-. After the test, the indexes of finished product rate, utilization coefficient, solid fuel consumption and the like are calculated by adopting a general experimental method in the university of China and south, Press, 1996, P205-208.
In the sintering test of the reference example, dolomite is used for providing MgO, the mixture ratio of other ingredients is calculated according to the weight percentage shown in table 2, water accounting for 7.5 percent of the weight of dry materials is added for mixing and granulating after the ingredients are mixed, then sintering is carried out according to the experimental flow, and the indexes of sintering technical parameters are shown in table 4.
In examples 1 to 6, the dolomite powder is replaced by the light-burned magnesium balls, the mixture ratio of other ingredients is calculated according to the weight percentage shown in table 2, water accounting for 7.5 percent of the weight of the dry material is added for mixing and granulating after the ingredients are mixed, then the sintering is carried out according to the experimental flow, and the sintering technical parameter indexes are shown in table 4.
Example 1
As shown in table 2, the raw materials of this example are prepared by mixing light-burned magnesium balls 1 with iron ore powder, return fines, coke powder, quicklime and limestone powder in proportion, adding water, mixing, granulating, distributing, igniting, sintering, cooling and crushing to obtain a sintered ore finished product, and the specific operation steps are as follows:
mixing light-burned magnesium balls with the particle size of 5-20 mm with iron ore powder with the particle size of 0-8 mm, return ores with the particle size of 0-5 mm, coke powder with the particle size of 0-3mm, quick lime with the particle size of 0-3mm and limestone powder with the particle size of 0-3mm according to the proportion, and adding 7.5% of water to mix uniformly for 2 minutes; granulating the mixed materials for 5 minutes, and after the prepared granules are distributed into a sintering cup with the diameter of 300mm, forming an embedded structure as shown in figure 1, wherein the height of a material layer is 780 mm; and (3) carrying out a sintering test at the ignition temperature of 1050 ℃, the ignition time of 1.5min and the sintering negative pressure of 14.7kPa, cooling in a sintering cup continuously after sintering is finished, and crushing the cooled sinter by using a single-toothed-roller crusher to obtain a sinter finished product.
The chemical components of the finished sintered ore are subjected to fluorescence analysis by using an ARL 9900xp type X-ray fluorescence spectrometer of ThermoFisher company in America according to GB/T6730.62-2005 analysis standard, and the chemical components and alkalinity of the finished sintered ore obtained by testing are shown in Table 3.
Table 2 sintering test ingredients table (weight of dry material,%)
TABLE 3 chemical composition and basicity (%)
| Numbering | TFe | MgO | CaO | SiO2 | Al2O3 | R2(binary basicity) |
| Reference example | 57.51 | 1.44 | 8.64 | 4.84 | 1.94 | 1.78 |
| Example 1 | 57.51 | 1.45 | 8.61 | 4.82 | 1.93 | 1.79 |
| Example 2 | 57.47 | 1.70 | 8.64 | 4.81 | 1.92 | 1.79 |
| Example 3 | 57.14 | 2.20 | 8.53 | 4.80 | 1.91 | 1.78 |
| Example 4 | 56.46 | 3.10 | 8.39 | 4.79 | 1.89 | 1.78 |
| Example 5 | 57.91 | 1.02 | 8.58 | 4.81 | 1.93 | 1.76 |
| Example 6 | 56.96 | 2.46 | 8.42 | 4.79 | 1.90 | 1.76 |
TABLE 4 technical indices of sintering process
Note: yield, utilization factor, and solid burnup are technical indicators for return ore equilibrium (B1 ± 0.05).
The test of example 1 was most significant compared with that of the reference exampleThe difference lies in that 1.2% of light-burned magnesium balls 1 are used for replacing dolomite to provide MgO, CaO in the dolomite is replaced by the limestone, and the iron grade, the binary alkalinity and the MgO content of the obtained sintering ore are basically unchanged. The utilization coefficient of sintering is 1.67t/m2H increased to 1.74t/m2H, the increase in yield reaches 4.2%. The tumbling index is slightly reduced, the finished product ratio is slightly improved, the solid fuel consumption is reduced, the highest sintering exhaust gas temperature is greatly increased from 509.6 ℃ to 609.4 ℃, which is mainly caused by the reduction of heat consumption for the decomposition of carbonate in a material layer after the light-burned magnesium balls replace dolomite.
The appearance of the sintered ore and the structure of the lightly-calcined magnesium balls after slicing in the reference example and the example 1 are shown in fig. 5 and 6. As is clear from the figure, the sintered ore of the reference example was relatively uniform in appearance and microscopic scale. The lightly-fired magnesium balls in example 1 remained granular after being subjected to high sintering temperatures (-1400 ℃), and the surfaces were infiltrated or coated with iron ore.
Example 2
The experimental procedure was as in example 1, using the formulation as shown in table 2. The most remarkable difference of the example 2 compared with the benchmark test is that 1.5 percent of light-burned magnesium balls 1 are used for replacing dolomite to provide MgO, the iron grade and the binary alkalinity of the obtained sintered ore are basically unchanged, and the MgO content is improved from 1.44 percent to 1.70 percent. The utilization coefficient of sintering is 1.67t/m2H increased to 1.76t/m2H, the increase in yield reaches 5.4%. It can be seen that the block-shaped high-temperature-resistant light-burned magnesium balls in the sinter bed do improve the air permeability of the bed, so that the vertical sintering speed and the utilization coefficient are improved. The drum index is slightly reduced, the finished product rate is improved, the solid fuel consumption is reduced, and the highest sintering exhaust gas temperature is increased from 509.6 ℃ to 598.3 ℃.
Example 3
The experimental procedure was as in example 1, using the formulation as shown in table 2. In the embodiment 3, the proportion of the light-burned magnesium balls 1 is increased to 2.2 percent, the binary alkalinity of the sinter is kept unchanged, the iron grade is slightly reduced, and the MgO content is increased from 1.44 percent to 2.20 percent. The utilization coefficient of sintering is 1.67t/m2H increased to 1.75t/m2H, the increase in yield reaches 4.8%. The drum index is slightly reduced, and the yield is slightly improvedHigh, solid burnup is reduced, and the highest sintering exhaust gas temperature is increased from 509.6 ℃ to 552.3 ℃.
Example 4
The experimental procedure was as in example 1, using the formulation as shown in table 2. In example 4, the proportion of the lightly calcined magnesium balls 1 is increased to 3.5%, the binary basicity of the sintered ore is slightly increased, the iron grade is reduced to 56.46% from 57.51%, and the MgO content is increased to 3.10% from 1.44%. The utilization coefficient of sintering is 1.67t/m2H increased to 1.81t/m2H, the increase in yield reaches 8.4%. The drum index is slightly reduced, the yield is slightly reduced, the solid fuel consumption is reduced, and the highest sintering exhaust gas temperature is increased from 509.6 ℃ to 593.5 ℃.
Example 5
The experimental procedure was as in example 1, using the formulation as shown in table 2. In example 4, the light-burned magnesium balls 2 are used to replace dolomite, the proportion is 0.5%, the binary basicity of the sintered ore is slightly reduced, the iron grade is improved from 57.51% to 57.91%, and the MgO content is reduced from 1.44% to 1.02%. The utilization coefficient of sintering is 1.67t/m2H increased to 1.71t/m2H, yield increase by 2.4%. The drum index is slightly reduced, the yield is basically equivalent, the solid burnup is reduced, and the highest sintering exhaust gas temperature is increased from 509.6 ℃ to 557.7 ℃.
Example 6
The experimental procedure was as in example 1, using the formulation as shown in table 2. The proportion of the light-burned magnesium balls 2 used for replacing dolomite is 2.4%, the binary alkalinity of the sinter is slightly reduced, the iron grade is reduced from 57.51% to 56.96%, and the MgO content is increased from 1.44% to 2.46%. The utilization coefficient of sintering is 1.67t/m2H increased to 1.73t/m2H, yield increase by 3.6%. The tumbler index is slightly reduced, the yield is slightly improved, the solid fuel consumption is reduced, and the highest sintering exhaust gas temperature is increased from 509.6 ℃ to 602.4 ℃.
The inventor of the invention has shown through theoretical analysis and experimental research that in the sintering production process, under the premise of not changing the whole chemical composition of the sintering ore, the light-burned magnesium balls with the granularity of 5-20 mm are used for replacing dolomite to form a heterogeneous structure, so that the sintering can be improvedThe air permeability of the material layer is improved, the sintering utilization coefficient is improved, and the sintered ore with excellent metallurgical performance is obtained. Meanwhile, the yield of the sinter can be improved, and CO in the sintering process can be reduced2And (4) discharging and reducing solid fuel consumption.
Claims (6)
1. A method for sintering iron ore by using light-burned magnesium balls is characterized by comprising the following steps:
1) the following components are prepared into dry materials according to weight percentage: 0.5-3.5% of light-burned magnesium balls, 60-65% of iron ore powder, 20-25% of return ores, 3.5-4.5% of coke powder and 5-11% of flux; adding water accounting for 7.0-8.5% of the total weight of the dry materials, and uniformly mixing;
2) putting the mixed materials into a mixer, mixing and granulating for 5-8 min;
3) uniformly distributing the mixture after granulation into a sintering cup;
4) igniting the mixture in the sintering cup, wherein the ignition temperature is 1050 +/-50 ℃, the ignition time is 1.5-2.5 min, and the ignition negative pressure is 7-8 kPa;
5) after ignition is finished, igniting coke powder in the mixed material layer, adjusting the negative pressure to 14-16 kPa, starting sintering the mixed material, and after sintering is finished, continuing cooling in a sintering cup;
6) crushing the cooled sinter to obtain a finished sinter product;
in the step 1), the light-burned magnesium ball comprises the following components in percentage by weight: 60-70% of MgO, 1.5-2.3% of CaO and SiO22.4-3.0% of Al2O3The content is 0-0.015%.
2. The iron ore sintering method according to claim 1, characterized in that the lightly calcined magnesium pellets have a particle size of 5 to 20mm, a compressive strength of more than 1000N/pellet, and a shape of a block or a sphere.
3. The method for sintering iron ore according to claim 1, characterized in that in step 1),
the iron ore powder is one or more of iron ore blending ores of magnetite, hematite and limonite;
the flux is one or two of limestone and quicklime.
4. The iron ore sintering process according to claim 3, characterized in that the flux is a mixture of quicklime and limestone.
5. The method for sintering iron ore according to claim 1, characterized in that in step 1),
the granularity of the iron ore powder is below 8mm, and the granularity of the return fines is below 5 mm;
the particle size of the coke powder is 0-3mm, and the particle size of the flux is 0-3 mm;
the flux is a mixture of quicklime and limestone in a weight ratio of 2-5: 3-6.
6. The method for sintering iron ores according to claim 1, characterized in that in step 6), the crushing is carried out by a single-tooth roller crusher.
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| CN108950189B (en) * | 2018-07-13 | 2020-01-31 | 武汉科技大学 | method for producing MgO-containing sintered ore by using waste magnesia carbon bricks |
| CN110672458B (en) * | 2019-09-04 | 2022-05-24 | 攀钢集团攀枝花钢铁研究院有限公司 | Method for rapidly evaluating vanadium-titanium magnetite concentrate agglomeration economy |
| CN111057842A (en) * | 2019-12-28 | 2020-04-24 | 海城市鹏程镁矿有限公司 | Method for preparing magnesite powder ore green ball by carbon dioxide carbonization method |
| CN111057841A (en) * | 2019-12-28 | 2020-04-24 | 海城市鹏程镁矿有限公司 | Magnesite powder ore pelletizing method using inorganic binder |
| CN114763582B (en) * | 2021-01-15 | 2023-09-12 | 宝山钢铁股份有限公司 | Method for producing magnesium pellets by using oriented silicon steel magnesia waste |
| CN115786694B (en) * | 2023-01-29 | 2023-05-26 | 中南大学 | Pretreatment method of zinc-lead-copper mineral aggregate and application thereof |
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