CN111333097A - Method for treating electrolytic aluminum cathode carbon block - Google Patents
Method for treating electrolytic aluminum cathode carbon block Download PDFInfo
- Publication number
- CN111333097A CN111333097A CN202010153242.XA CN202010153242A CN111333097A CN 111333097 A CN111333097 A CN 111333097A CN 202010153242 A CN202010153242 A CN 202010153242A CN 111333097 A CN111333097 A CN 111333097A
- Authority
- CN
- China
- Prior art keywords
- cathode carbon
- carbon powder
- filtrate
- filter residue
- electrolytic aluminum
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/20—Halides
- C01F11/22—Fluorides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/48—Halides, with or without other cations besides aluminium
- C01F7/50—Fluorides
- C01F7/54—Double compounds containing both aluminium and alkali metals or alkaline-earth metals
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention relates to the environmental protection technical field of electrolytic cell solid waste comprehensive treatment in the electrolytic aluminum industry, in particular to a method for treating electrolytic aluminum cathode carbon blocks, which comprises the following steps: s1, crushing, superfine grinding and grading the waste cathode carbon blocks to obtain cathode carbon powder; the particle size of the cathode carbon powder is 200-600 meshes; the weight of 200-600 mesh particles in the carbon powder particles accounts for more than 95% of the total weight of the carbon powder; s2, adding water into the cathode carbon powder obtained in the step S1, mixing to obtain slurry, and stirring and soaking in water; introducing ozone gas into the slurry, and stirring until the cyanide concentration is qualified to obtain the slurry; s3, carrying out solid-liquid separation on the slurry in the step S2 to obtain a first filtrate and a first filter residue. The method can dissolve sodium fluoride in the carbon powder into water, realize the separation of the sodium fluoride and cryolite, and thoroughly destroy cyanide to realize non-toxic treatment.
Description
Technical Field
The invention relates to the environmental protection technical field of electrolytic cell solid waste comprehensive treatment in the electrolytic aluminum industry, in particular to a method for treating electrolytic aluminum cathode carbon blocks.
Background
The lining of the aluminum electrolytic cell mainly comprises carbon materials and refractory materials. In the aluminum electrolysis production process, the inner lining structure of the aluminum electrolysis cell is deformed and cracked due to the permeation and corrosion of high-temperature electrolyte to the inner lining of the cell, and high-temperature aluminum liquid and electrolyte permeate into the inner lining of the cell from the deformed and cracked cracks, so that the electrolytic cell cannot be normally produced in severe cases. Therefore, the aluminum electrolysis cells which cannot be normally produced need to be shut down for overhaul, and the new aluminum electrolysis cells generally need to be shut down for overhaul after being used for 3-6 years. Therefore, the waste tank lining is solid waste which is inevitable in the aluminum electrolysis production process. According to the statistical analysis of many years, about 15-20 kg of waste cathode carbon blocks are generated per ton of produced electrolytic aluminum. The yield of electrolytic aluminum in the country in 2018 is 3000-3500 ten thousand tons, and about 50-70 ten thousand tons of waste cathode carbon blocks are produced.
The electrolytic aluminum cathode carbon block mainly comprises carbon and Na3AlF6(cryolite), NaF, small amounts of CaF2And a trace amount of cyanide, which is a solid waste with high fluorine content. The useful elements in the electrolytic aluminum cathode carbon block are recycled, so that the hazardous waste can be effectively reduced, and the waste is changed into valuable. The preparation of cryolite by using the electrolytic aluminum cathode carbon block is a comprehensive recycling means. The existing wet treatment methods mainly comprise acid leaching and alkali leaching.
Chinese patent CN106077036A, a method for treating aluminum electrolysis waste cathode carbon blocks by ultrasonic-assisted acid leaching, which comprises adding powder into acid liquor for ultrasonic leaching, adjusting pH value of the leaching solution, evaporating and crystallizing to obtain a mixture of cryolite and aluminum hydroxide. The product obtained by the method is a mixture of cryolite and aluminum hydroxide, the cryolite with higher purity can be obtained only by further treatment, and the equipment is seriously corroded by acid leaching.
Chinese patent CN106745137A, a method for preparing cryolite from alkaline leachate of cathode carbon block of aluminum electrolysis cell, which comprises mixing powder with alkali liquor to obtain alkaline leachate, further adjusting the ratio of aluminum, sodium and fluorine in the solution with sodium fluoride, and then introducing carbon dioxide gas to prepare cryolite. The leaching of the fluorine ions in the powder is insufficient, sodium fluoride is also added to adjust the proportion of each element, and the operation is complicated. And cyanide in the electrolytic aluminum cathode carbon block is not treated, so that potential safety hazards exist.
Disclosure of Invention
The invention aims to: aiming at the problems of high requirement on equipment and complex operation of fluorine element when the electrolytic aluminum cathode carbon block is used for preparing cryolite in the prior art, the method for treating the electrolytic aluminum cathode carbon block is provided. The method can realize the leaching of sodium fluoride by only using water, has low requirement on equipment, and the proportion of fluorine and aluminum in the obtained filter residue is suitable for the preparation of cryolite. The obtained product does not contain cyanide, so that the hazardous waste is changed into a precious resource.
In order to achieve the purpose, the invention adopts the technical scheme that:
a method for treating waste cathode carbon blocks of electrolytic aluminum comprises the following steps:
s1, crushing, superfine grinding and grading a cathode carbon block to obtain cathode carbon powder; the particle size of the cathode carbon powder is 200-600 meshes; the weight of 200-600 mesh particles in the carbon powder particles accounts for more than 95% of the total weight of the carbon powder;
s2, mixing the cathode carbon powder obtained in the step S1 with water to obtain slurry, and stirring and soaking in water; and (3) introducing ozone-containing gas into the slurry, and stirring until the cyanide concentration meets the required value to obtain the slurry.
Wherein the cyanide concentration meets the required value, which means that the cyanide concentration meets the national standard; in view of the subsequent treatment, it is preferable to control the cyanide concentration to 0.005mg/L or less.
S3, carrying out solid-liquid separation on the slurry in the step S2 to obtain a first filtrate and a first filter residue, wherein the first filter residue is a raw material for preparing cryolite.
According to the invention, the cathode carbon block is crushed, superfine-ground and classified to 200-600 meshes, wherein the weight of 200-600 meshes in carbon powder particles accounts for more than 95% of the total weight of the carbon powder, and the inventor finds that the carbon powder in the particle size range can leach sodium fluoride in the carbon powder through water leaching, so that the separation of sodium fluoride from cryolite in the carbon powder is realized. Fluorine neutralization of the first residue obtainedThe proportion of the aluminum element is close to the theoretical proportion of the cryolite, and the process is simpler and more convenient without adjusting the proportion of fluorine and aluminum when the cryolite is prepared by the subsequent treatment of the first filter residue. Acid is not used for direct leaching in the reaction process, hydrogen fluoride gas is not generated, and the requirement on equipment is low. Cyanide is dissolved in water by water immersion, and the cyanide is oxidized to nontoxic N by ozone gas passing through2And CO2And the like, the nontoxic treatment of the powder is realized.
As a preferable embodiment of the present invention, the crushing, ultrafine grinding and classification in step S1 is carried out by crushing the waste cathode carbon block into particles having a diameter of less than 5mm, and then ultrafine grinding and classification are carried out by using an ultrafine grinding classifier.
As a preferable scheme of the invention, the particle size of the cathode carbon powder in the step S1 is 400-600 meshes; the weight of 400-600 mesh particles in the carbon powder particles accounts for more than 95% of the total weight of the carbon powder.
When the mesh size is 400-600 meshes, the water immersion effect is better. Leaching of sodium fluoride and cyanide is more complete.
In a preferred embodiment of the present invention, in step S2, the liquid-solid ratio of water to the cathode carbon powder is 4 to 8:1 by mass.
Under the conditions of the solid-to-liquid ratio, the sodium fluoride in the cathode carbon powder can be fully leached.
In the preferred scheme of the invention, in the step S2, during the water immersion reaction, the stirring speed is 150-200 r/h, the reaction temperature is 20-90 ℃, and the reaction time is 1.5-3 h; when ozone-containing gas is introduced, the stirring speed is 150-200 r/h, and the reaction time is 5-30 min.
Under the conditions, the sodium fluoride in the cathode carbon powder can be fully leached. Both the increase in stirring speed and the increase in temperature favour the leaching reaction.
Preferably, the stirring speed is 180-200 r/h, the reaction temperature is 70-85 ℃, and the reaction time is 2-2.5 h; when ozone gas is introduced, the stirring speed is 180-200 r/h, and the reaction time is 15-20 min.
In a preferred embodiment of the present invention, the ozone is introduced and the water immersion reaction is performed simultaneously in step S2. The introduced ozone can consume cyanide in water, thereby reducing the concentration of cyanide and being beneficial to leaching of cyanide; ozone can be introduced before the water leaching reaction is finished, most cyanide is leached at the moment, and the whole reaction time can be shortened.
In a preferred embodiment of the present invention, in step S2, the ozone-containing gas contains 5 to 30% by volume of ozone, and the rest of the gas is air or nitrogen. Preferably, the volume fraction of the ozone is 10-20%.
The ozone-containing gas introduced in the above range can sufficiently oxidize cyanide. Too high concentration results in waste of ozone.
As a preferred embodiment of the present invention, the method further comprises the steps of:
s4, adding calcium chloride into the first filtrate obtained in the step S3, stirring, precipitating, carrying out solid-liquid separation to obtain a second filtrate and a second filter residue, and drying the second filter residue to obtain a calcium fluoride product; mixing the second filtrate with the cathode carbon powder in the step S2 to obtain slurry; and after the second filtrate is recycled for many times, when the salt concentration in the second filtrate reaches the crystallization concentration, evaporating the second filtrate to prepare sodium chloride, and recycling the distilled water obtained by evaporation.
As a preferred embodiment of the present invention, the method further comprises the steps of:
s5, mixing the first filter residue obtained in the step S3 with alkali liquor, carrying out ultrasonic agitation leaching, and carrying out solid-liquid separation to obtain a third filtrate and a third filter residue; wherein the liquid-solid ratio of the alkali liquor to the first filter residue is 4-8: 1 by mass; the mass fraction of the alkali liquor is 5-10%; the reaction temperature is 70-100 ℃; the ultrasonic frequency is 20-60 Hz; the stirring speed is 160-200 r/min; leaching for 2-4 h; drying the second filter residue to obtain a carbon powder product; the obtained carbon powder has high purity, and the product does not contain cyanide, so that the hazardous waste is changed into valuable resources.
Preferably, the reaction conditions of step S5 are:
the liquid-solid ratio of the alkali liquor to the first filter residue is 5-7: 1 by mass; the mass fraction of the alkali liquor is 6-8%; the reaction temperature is 85-90 ℃; the ultrasonic frequency is 30-40 Hz; the stirring speed is 180-200 r/min; leaching for 2-3 h; the alkali liquor is NaOH, KOH or Na2CO3One or more of aqueous solutions.
S6, adding acid into the third filtrate, adjusting the pH to be = 4.0-5.0, generating a precipitate, and performing solid-liquid separation to obtain a fourth filtrate and a fourth filter residue; and drying the fourth filter residue to obtain a cryolite product.
As a preferred embodiment of the present invention, the method further comprises the steps of:
s7, concentrating and crystallizing the fourth filtrate obtained in the step S6 to prepare a sodium salt product, and recycling distilled water obtained by evaporation.
The acid in step S6 is hydrochloric acid or sulfuric acid, and sodium chloride or sodium sulfate is obtained in step S7.
In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:
1. according to the method for treating the waste cathode carbon block of the electrolytic aluminum, the broken cathode carbon block is subjected to superfine grinding and classification to 200-600 meshes, so that sodium fluoride in the carbon powder can be fully dissolved in water, and the proportion of fluorine to aluminum in the obtained first filter residue is close to the theoretical proportion of cryolite.
2. According to the method for treating the electrolytic aluminum cathode carbon block, acid is not used in the water leaching process, hydrogen fluoride gas is not generated, the requirement on equipment is low, and the recovery rate of sodium fluoride reaches more than 97%.
3. According to the method for treating the electrolytic aluminum cathode carbon block, the cyanide is leached by water leaching, and then the cyanide is converted into nontoxic N by ozone2And CO2And the nontoxic treatment of the powder is realized.
4. The method for treating the electrolytic aluminum waste cathode carbon block realizes complete recycling of renewable resources by comprehensively utilizing products in the steps and discharging no waste water.
Drawings
FIG. 1 is a process flow diagram of a method of treating an electrolytic aluminum cathode carbon block in accordance with the present invention.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
The raw material adopted in the embodiment is a waste cathode carbon block when an electrolytic aluminum cell of a certain company is overhauled. The content of main elements (wt%) is 49.5% C; 26.7% Na3AlF6(cryolite); 21.8% NaF; 2% CaF2(ii) a A trace amount of Fe.
Crushing, superfine grinding and grading 100g of electrolytic aluminum cathode carbon block to obtain carbon powder, wherein 400-mesh in the carbon powder accounts for 95% of the total particle weight, then adding 600g of water, and leaching for 2.5h under the conditions of heating temperature of 80 ℃ and stirring speed of 180 r/min; the heating temperature and the stirring speed are unchanged, ozone with the volume fraction of 20 percent is introduced for 10min, and the detected cyanide concentration is 0.005 mg/L; after the reaction was completed, the mixture was filtered for the first time to obtain a first filtrate and a first residue (78.3 g).
Slowly adding CaCl into the first filtrate2Adding CaCl until no fluorine ion exists in the solution227.9g, stirring, precipitating, filtering for the second time to obtain a second filtrate and a second filter residue, and drying the second filter residue to obtain 19.6g of calcium fluoride. The second filtrate is used for leaching cathode carbon powder.
Putting 78.3g of the first filter residue into an ultrasonic stirring reaction kettle, adding 296g of sodium hydroxide solution with the mass fraction of 8%, leaching for 3 hours at the conditions of heating temperature of 85 ℃, ultrasonic frequency of 40Hz and stirring speed of 180r/min, filtering for the third time, washing the filter residue, combining washing liquid into filtrate to obtain third filtrate and third filter residue, wherein the third filter residue is a carbon powder product.
Adding hydrochloric acid into the third filtrate, adjusting the pH of the third filtrate to =5.0, generating cryolite precipitate, and filtering for the fourth time to obtain a fourth filtrate and a fourth filter residue; and drying the fourth filter residue to obtain a cryolite product. And after the fourth filtrate is concentrated and crystallized, the distilled water is used for diluting the sodium hydroxide added into the ultrasonic reaction kettle.
100g of cathode carbon block, and obtaining 52g of carbon powder with the purity of 95 percent through the treatment; 19.6g of calcium fluoride with the purity of 99 percent is prepared; 25.6g of cryolite is prepared, and the purity is 99 percent; no cyanide was detected in the above product.
Example 2
The raw material adopted in the embodiment is a waste cathode carbon block when an electrolytic aluminum cell of a certain company is overhauled. The content of main elements (wt%) is 49.5% C; 26.7% Na3AlF6(cryolite); 21.8% NaF; 2% CaF2(ii) a A trace amount of Fe.
Crushing, superfine grinding and grading 100g of electrolytic aluminum cathode carbon block to obtain carbon powder, wherein-200 to +300 meshes of the carbon powder account for 95 percent of the total particle weight, then adding 600g of water, and leaching for 2.5 hours under the conditions of heating temperature of 80 ℃ and stirring speed of 180 r/min; the heating temperature and the stirring speed are unchanged, ozone with the volume fraction of 20 percent is introduced for 10min, and the detected cyanide concentration is 0.005 mg/L; after the reaction, the mixture was filtered for the first time to obtain a first filtrate and 80.5g of a first residue.
Slowly adding CaCl into the first filtrate2To the newly added CaCl2Just no longer dissolved, CaCl is added225.9g, stirring, precipitating, filtering for the second time to obtain a second filtrate and a second filter residue, and drying the second filter residue to obtain 18.2g of calcium fluoride. The second filtrate is used for leaching cathode carbon powder.
Placing 80.5g of the first filter residue in an ultrasonic stirring reaction kettle, adding 300g of sodium hydroxide solution with the mass fraction of 8%, leaching for 3h under the conditions of heating temperature of 85 ℃, ultrasonic frequency of 40Hz and stirring speed of 180r/min, filtering for the third time, washing the filter residue, combining washing liquid to filtrate to obtain third filtrate and third filter residue, wherein the third filter residue is a carbon powder product.
Adding hydrochloric acid into the third filtrate, adjusting the pH of the third filtrate to =5.0, generating cryolite precipitate, and filtering for the fourth time to obtain a fourth filtrate and a fourth filter residue; and drying the fourth filter residue to obtain a cryolite product. And after the fourth filtrate is concentrated and crystallized, the distilled water is used for diluting sodium hydroxide which is added into the ultrasonic reaction kettle.
The cathode carbon block of 100g is processed to obtain carbon powder of 55.2g with the purity of 90 percent; 18.2g of calcium fluoride with the purity of 99 percent is prepared; 23g of cryolite is prepared, and the purity is 99%; no cyanide was detected in the above product.
Example 3
The raw material adopted in the embodiment is a waste cathode carbon block when an electrolytic aluminum cell of a certain company is overhauled. The content of main elements (wt%) is 49.5% C; 26.7% Na3AlF6(cryolite); 21.8% NaF; 2% CaF2(ii) a A trace amount of Fe.
Crushing, superfine grinding and grading 100g of electrolytic aluminum cathode carbon block to obtain carbon powder, wherein-300 to +400 meshes of the carbon powder account for 95 percent of the total particle weight, then adding 600g of water, and leaching for 2.5 hours under the conditions of heating temperature of 80 ℃ and stirring speed of 180 r/min; the heating temperature and the stirring speed are unchanged, ozone with the volume fraction of 20 percent is introduced for 10min, and the detected cyanide concentration is 0.005 mg/L; after the reaction was completed, the mixture was subjected to a first filtration to obtain 74.4g of a first filtrate and a first residue.
Slowly adding CaCl into the first filtrate2Adding CaCl until no fluorine ion exists in the solution227.4g, stirring, precipitating, filtering for the second time to obtain a second filtrate and a second filter residue, and drying the second filter residue to obtain 19.2g of calcium fluoride. The second filtrate is used for leaching cathode carbon powder.
Placing 74.4g of the first filter residue in an ultrasonic stirring reaction kettle, adding 300g of sodium hydroxide solution with the mass fraction of 8%, leaching for 3h under the conditions of heating temperature of 85 ℃, ultrasonic frequency of 40Hz and stirring speed of 180r/min, filtering for the third time, washing the filter residue, combining washing liquid to filtrate to obtain third filtrate and third filter residue, wherein the third filter residue is a carbon powder product.
Adding hydrochloric acid into the third filtrate, adjusting the pH of the third filtrate to =5.0, generating cryolite precipitate, and filtering for the fourth time to obtain a fourth filtrate and a fourth filter residue; and drying the fourth filter residue to obtain a cryolite product.
The cathode carbon block of 100g is treated to obtain carbon powder of 57.2g with the purity of 90 percent; 19.2g of calcium fluoride with the purity of 99 percent is prepared; 24.3g of cryolite is prepared, and the purity is 99 percent; no cyanide was detected in the above product.
Comparative example 1
Influence of powdered carbon of different particle size on water leaching
And (3) verifying the influence of the particle sizes of different carbon powder on water leaching under the condition of the same liquid-solid ratio.
1000g of electrolytic aluminum cathode carbon block is crushed, superfine ground and classified to obtain-120 to +200 meshes of particles, -200 to +300 meshes of particles, -300 to +400 meshes of particles, -400 to +600 meshes of particles and-600 meshes of particles. Respectively taking 50g of the carbon powder particles with different particle size ranges, and adding 300g of water; leaching for 2.5h under the conditions that the heating temperature is 80 ℃ and the stirring speed is 180 r/min; the heating temperature and the stirring speed are unchanged, ozone with the volume fraction of 20 percent is introduced for 10min, and the detected cyanide concentration is 0.005 mg/L; and after the reaction is finished, filtering to obtain a first filtrate and a first filter residue.
Adding CaCl into the first filtrate2Stirring, precipitating, filtering and drying to obtain the calcium fluoride.
The experimental protocol and experimental results are given in the following table:
TABLE 1 influence of carbon powders of different particle sizes on water leaching
49.5 percent of C according to the content of main elements in the carbon block (wt%); 26.7% Na3AlF6(cryolite); 21.8% NaF; 2% CaF2(ii) a The theoretical recovered weight of calcium fluoride in 50g of the carbon block was calculated to be 10.1 g.
Under the reaction conditions, water leaches sodium fluoride in the carbon powder, but does not leach cryolite in the carbon powder, calcium chloride is added to convert the sodium fluoride into calcium fluoride, calcium fluoride solid is obtained, and the weight of the leached sodium fluoride can be calculated according to the weight of the calcium fluoride solid. From the results in Table 1, it is understood that the weight of the obtained calcium fluoride gradually increased as the particle size of the carbon powder decreased. In the experiment of No. 3-5 having a particle size of 300 mesh or more, the weight of the recovered calcium fluoride was 95% or more of the theoretical value. The sodium fluoride is effectively leached. In the experiments numbered 1 and 2, the weight of calcium fluoride was only 83% and 90%, and sodium fluoride failed to leach effectively.
The carbon powder of-400 to +600 meshes is selected by comprehensively considering the process difficulty of crushing and grinding and the environmental protection requirement, and is more suitable for industrial production.
Comparative example 2
Influence of different liquid-solid ratios on water immersion
Taking 6 parts of waste cathode carbon powder (30 percent of NaF) with the granularity of-400 meshes, respectively adding 90g, 120g, 150g, 180g, 210g and 240g of water into 30g of waste cathode carbon powder, and leaching for 2.5 hours at the heating temperature of 80 ℃ and the stirring speed of 180 r/min; the heating temperature and the stirring speed are unchanged, ozone with the volume fraction of 20 percent is introduced for 10min, and the detected cyanide concentration is 0.005 mg/L; and after the reaction is finished, filtering to obtain a first filtrate and a first filter residue.
Adding CaCl into the first filtrate2Stirring, precipitating, filtering and drying to obtain the calcium fluoride.
TABLE 2 influence of different liquid-solid ratios on water immersion
| Numbering | 1 | 2 | 3 | 4 | 5 |
| Liquid-solid ratio (g/g) | 2:1 | 3:1 | 4:1 | 5:1 | 6:1 |
| Calcium fluoride (g) | 1.6 | 4.1 | 5.4 | 5.8 | 5.88 |
49.5 percent of C according to the content of main elements in the carbon block (wt%); 26.7% Na3AlF6(cryolite); 21.8% NaF; 2% CaF2(ii) a The theoretical recovered weight of calcium fluoride in 30g of the carbon block was calculated to be 6 g.
As can be seen from the data in table 2, when the liquid-solid ratio is 3:1, the leached sodium fluoride is only 68.3% of the theoretical value, and the sodium fluoride is not effectively leached, and when the liquid-solid ratio is 5-6: 1, the leached sodium fluoride is 96.7% and 98% or more of the theoretical value, and the effective leaching of the sodium fluoride is realized.
In conclusion, when the liquid-solid ratio is 4-7: 1, the leaching of sodium fluoride in the carbon powder by water can be realized, and the leaching rate is over 90%. Particularly, when the solid-to-liquid ratio is 5:1 or more, sufficient leaching can be achieved. Considering the leaching degree of sodium fluoride and the influence of the using amount of water on the environment, the sodium fluoride is fully utilized, and considering that the particle distribution in the carbon powder is basically normal, the liquid-solid ratio is 6-7: 1, so that the method is more suitable for industrial application.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A method for treating an electrolytic aluminum cathode carbon block is characterized by comprising the following steps:
s1, sequentially crushing, superfine grinding and grading the waste cathode carbon blocks to obtain cathode carbon powder; the particle size of the cathode carbon powder is 200-600 meshes; the weight of 200-600 mesh particles in the carbon powder particles accounts for more than 95% of the total weight of the carbon powder;
s2, adding water into the cathode carbon powder obtained in the step S1, mixing to obtain slurry, and stirring and soaking in water; introducing ozone-containing gas into the slurry, and stirring until the cyanide concentration meets the required value to obtain the slurry;
s3, carrying out solid-liquid separation on the slurry in the step S2 to obtain a first filtrate and a first filter residue.
2. The method of claim 1, wherein the crushing, micronizing and classifying in step S1 comprises crushing the cathode carbon block to particles with a diameter of less than 5mm, and micronizing and classifying with a micronizer.
3. The method for treating the electrolytic aluminum cathode carbon block as claimed in claim 1, wherein the particle size of the cathode carbon powder in step S1 is 400-600 mesh; the weight of 400-600 mesh particles in the carbon powder particles accounts for more than 95% of the total weight of the carbon powder.
4. The method for treating the electrolytic aluminum cathode carbon block as claimed in claim 1, wherein in step S2, the liquid-solid ratio of water to cathode carbon powder is 4-8: 1 by mass.
5. The method for treating the electrolytic aluminum cathode carbon block as claimed in claim 1, wherein in the step S2, the stirring speed is 150-200 r/h, the reaction temperature is 20-90 ℃, and the reaction time is 1.5-3 h during the water immersion reaction; when ozone gas is introduced, the stirring speed is 150-200 r/h, and the reaction time is 5-30 min.
6. The method for treating the electrolytic aluminum cathode carbon block as claimed in claim 1, wherein the step S2 is performed by introducing ozone-containing gas and water immersion reaction simultaneously.
7. The method for treating the electrolytic aluminum cathode carbon block as claimed in claim 1, wherein in step S2, the volume fraction of ozone in the ozone-containing gas is 5-30%; the rest gas is air or nitrogen.
8. The method of treating an electrolytic aluminum cathode carbon block as recited in claim 1, further comprising the steps of:
s4, adding calcium chloride into the first filtrate obtained in the step S3, stirring, precipitating, carrying out solid-liquid separation to obtain a second filtrate and a second filter residue, and drying the second filter residue to obtain a calcium fluoride product; mixing the second filtrate with the cathode carbon powder in the step S2 to obtain slurry; and after multiple cycles, if the salt concentration in the second filtrate reaches the crystallization concentration, evaporating the second filtrate to prepare sodium chloride, and recycling the distilled water obtained by evaporation.
9. The method of treating an electrolytic aluminum cathode carbon block as recited in claim 1, further comprising the steps of:
s5, mixing the first filter residue obtained in the step S3 with alkali liquor, carrying out ultrasonic agitation leaching, and carrying out solid-liquid separation to obtain a third filtrate and a third filter residue; wherein the liquid-solid ratio of the alkali liquor to the first filter residue is 4-8: 1 by mass; the mass fraction of the alkali liquor is 5-10%; the reaction temperature is 70-100 ℃; the ultrasonic frequency is 20-60 Hz; the stirring speed is 160-200 r/min; leaching for 2-4 h; drying the second filter residue to obtain a carbon powder product;
s6, adding acid into the third filtrate, adjusting the pH to be = 4.0-5.0, generating a precipitate, and carrying out solid-liquid separation to obtain a fourth filtrate and a fourth filter residue; and drying the fourth filter residue to obtain a cryolite product.
10. The method of treating an electrolytic aluminum cathode carbon block of claim 9, further comprising the steps of:
s7, concentrating and crystallizing the fourth filtrate in the step S6 to prepare sodium salt, and recycling distilled water obtained by evaporation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010153242.XA CN111333097A (en) | 2020-03-06 | 2020-03-06 | Method for treating electrolytic aluminum cathode carbon block |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010153242.XA CN111333097A (en) | 2020-03-06 | 2020-03-06 | Method for treating electrolytic aluminum cathode carbon block |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111333097A true CN111333097A (en) | 2020-06-26 |
Family
ID=71178015
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010153242.XA Pending CN111333097A (en) | 2020-03-06 | 2020-03-06 | Method for treating electrolytic aluminum cathode carbon block |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111333097A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112692029A (en) * | 2020-12-08 | 2021-04-23 | 广西博世科环保科技股份有限公司 | Efficient harmless method for fluoride and cyanide in waste refractory material |
| CN112707394A (en) * | 2020-12-10 | 2021-04-27 | 六盘水师范学院 | Method for removing cyanogen and recovering graphite by electrolysis under alkaline condition |
| CN112707395A (en) * | 2020-12-10 | 2021-04-27 | 六盘水师范学院 | Method for removing cyanogen and recovering graphite by electrolysis under acidic condition |
| CN112745606A (en) * | 2020-12-30 | 2021-05-04 | 郑州大学 | Rubber material based on waste cathode carbon blocks and preparation method thereof |
| CN113426807A (en) * | 2021-06-29 | 2021-09-24 | 云南云铝润鑫铝业有限公司 | Method for combined treatment and comprehensive utilization of resources of dangerous waste residues generated in aluminum electrolysis |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101804996A (en) * | 2010-04-02 | 2010-08-18 | 北京矿冶研究总院 | Method for recovering sodium fluoride from electrolytic aluminum waste cathode carbon block |
| CN105772486A (en) * | 2016-04-26 | 2016-07-20 | 中南大学 | Method for removing cyanide in waste cathode carbon in aluminum electrolysis cell |
| CN106064813A (en) * | 2016-05-27 | 2016-11-02 | 中南大学 | A kind of aluminum cell waste cathode carbon block comprehensive recovering process |
| CN106745137A (en) * | 2016-12-15 | 2017-05-31 | 中南大学 | A kind of method for producing ice crystal with cell cathode carbon block alkaline leaching liquid |
| CN108941167A (en) * | 2018-08-01 | 2018-12-07 | 湘潭大学 | Mechanochemistry conversion and recovery method in a kind of waste cathode of aluminum electrolytic cell carbon block containing sodium, fluorochemical |
| CN109734115A (en) * | 2019-01-18 | 2019-05-10 | 中南大学 | Fluorine leaches the method with recycling in a kind of aluminum cell waste cathode |
-
2020
- 2020-03-06 CN CN202010153242.XA patent/CN111333097A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101804996A (en) * | 2010-04-02 | 2010-08-18 | 北京矿冶研究总院 | Method for recovering sodium fluoride from electrolytic aluminum waste cathode carbon block |
| CN105772486A (en) * | 2016-04-26 | 2016-07-20 | 中南大学 | Method for removing cyanide in waste cathode carbon in aluminum electrolysis cell |
| CN106064813A (en) * | 2016-05-27 | 2016-11-02 | 中南大学 | A kind of aluminum cell waste cathode carbon block comprehensive recovering process |
| CN106745137A (en) * | 2016-12-15 | 2017-05-31 | 中南大学 | A kind of method for producing ice crystal with cell cathode carbon block alkaline leaching liquid |
| CN108941167A (en) * | 2018-08-01 | 2018-12-07 | 湘潭大学 | Mechanochemistry conversion and recovery method in a kind of waste cathode of aluminum electrolytic cell carbon block containing sodium, fluorochemical |
| CN109734115A (en) * | 2019-01-18 | 2019-05-10 | 中南大学 | Fluorine leaches the method with recycling in a kind of aluminum cell waste cathode |
Non-Patent Citations (6)
| Title |
|---|
| 李伟: "碱酸法处理铝电解废旧阴极的研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》 * |
| 李远兵: "《铝工业固体废弃物综合利用》", 31 March 2015, 冶金工业出版社 * |
| 申士富: "电解铝固体废弃物的环境危害及处理技术研究现状", 《环境污染防治技术研究与开发》 * |
| 赵俊学: "铝电解槽废旧阴极氟化物的浸出研究", 《有色金属（冶炼部分）》 * |
| 陈维杰: "《水致疾病风险与饮水安全技术》", 31 December 2009, 黄河水利出版社 * |
| 马建立: "电解铝工业危险废物处理技术的发展方向", 《化工环保》 * |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112692029A (en) * | 2020-12-08 | 2021-04-23 | 广西博世科环保科技股份有限公司 | Efficient harmless method for fluoride and cyanide in waste refractory material |
| CN112692029B (en) * | 2020-12-08 | 2021-12-07 | 广西博世科环保科技股份有限公司 | Efficient harmless method for fluoride and cyanide in waste refractory material |
| CN112707394A (en) * | 2020-12-10 | 2021-04-27 | 六盘水师范学院 | Method for removing cyanogen and recovering graphite by electrolysis under alkaline condition |
| CN112707395A (en) * | 2020-12-10 | 2021-04-27 | 六盘水师范学院 | Method for removing cyanogen and recovering graphite by electrolysis under acidic condition |
| CN112745606A (en) * | 2020-12-30 | 2021-05-04 | 郑州大学 | Rubber material based on waste cathode carbon blocks and preparation method thereof |
| CN112745606B (en) * | 2020-12-30 | 2022-05-06 | 郑州大学 | Rubber material based on waste cathode carbon blocks and preparation method thereof |
| CN113426807A (en) * | 2021-06-29 | 2021-09-24 | 云南云铝润鑫铝业有限公司 | Method for combined treatment and comprehensive utilization of resources of dangerous waste residues generated in aluminum electrolysis |
| CN113426807B (en) * | 2021-06-29 | 2022-05-17 | 云南云铝润鑫铝业有限公司 | Method for combined treatment and comprehensive utilization of resources of dangerous waste residues generated in aluminum electrolysis |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111333097A (en) | Method for treating electrolytic aluminum cathode carbon block | |
| CN112374511B (en) | Method for preparing lithium carbonate and ternary precursor by recycling waste ternary lithium battery | |
| CN110835682B (en) | Method for cooperatively treating positive and negative active materials of waste lithium ion battery | |
| CN110828926B (en) | Method for cooperatively recovering metal and graphite from anode and cathode materials of waste lithium ion battery | |
| US11760655B2 (en) | Method for recycling iron and aluminum in nickel-cobalt-manganese solution | |
| CA2808627C (en) | Processing of manganous sulphate/dithionate liquors | |
| WO2022213678A1 (en) | Method for recycling aluminum in waste positive electrode sheet by using selective leaching and application thereof | |
| CN110028111A (en) | The preparation method of ternary anode material precursor and lithium carbonate | |
| CN106399693A (en) | Overall treatment and utilization method for aluminum ash | |
| CN113501536A (en) | Method for preparing aluminum fluoride product by multi-waste combined treatment and aluminum fluoride product | |
| CN110407190A (en) | A kind of method of the useless cathode recycling charcoal of aluminium electroloysis | |
| CN112853120A (en) | LiHCO recovered and leached from waste lithium battery3Method for deeply removing fluorine from solution | |
| WO2022085222A1 (en) | Method for recovering lithium and method for producing lithium carbonate | |
| CN113072089B (en) | Method for recovering cryolite by combined treatment of aluminum electrolysis overhaul slag and aluminum ash | |
| JP2011129336A (en) | Recovery method of manganese from battery | |
| CN112645387A (en) | Method for preparing battery-grade manganese dioxide by using anode slag | |
| CN109182868B (en) | Low-impurity vanadium-aluminum alloy and preparation method thereof | |
| KR20210126606A (en) | How to recover minerals | |
| CN115976324A (en) | Method for extracting aluminum-gallium-lithium system from coal gangue | |
| CN111153395B (en) | Method for comprehensively recovering fluorine and carbon powder in electrolytic aluminum cathode carbon block | |
| CN212925126U (en) | Selection and smelting combined comprehensive recovery device for waste lithium ion batteries | |
| CN111172399A (en) | Method for extracting and treating copper-cobalt alloy by utilizing metal melt | |
| CN111100991A (en) | Treatment method of nickel wet refining tailings based on high-temperature oxygen pressure | |
| CN115959688B (en) | Method for preparing high-quality lithium salt by recycling rare earth molten salt slag | |
| CN110436452B (en) | Method for enriching vanadium pentoxide and graphite from graphite type vanadium ore |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200626 |