Flotation-based carbon residue overhaul slag resource collaborative utilization and multi-component recovery process

Abstract

The invention relates to the technical field of waste residue recovery, in particular to a flotation-based carbon residue overhaul residue resource collaborative utilization and multi-component recovery process, which comprises the following steps: after directional compatibility of carbon residues and overhaul residues, performing jaw crushing and ball milling treatment; preparing ore pulp from the materials and deionized water, adding a cyanogen removal agent and applying an ultrasonic field for reaction; feeding the ore pulp into a flotation system for multiple times of roughing and concentration and foam filtration to obtain carbon powder; acid is added into flotation residues for staged acid dissolution, filtrate and tail liquid are mixed, PAC is added, fluorine is extracted, and aluminum fluoride is obtained; subsequently, NaOH is adopted for adjusting the pH value, aluminum hydroxide is precipitated, aluminum is extracted, filtrate is evaporated and crystallized, by-product industrial salt is recycled, and acid-soluble insoluble slag is dried and then returns to the flotation step to continue carbon extraction. According to the method, the characteristics of complementarity and similarity of the two solid waste components are exerted, the carbon powder enrichment effect and the comprehensive recovery rate of valuable elements are improved, harmful components are removed, the treatment cost is reduced, secondary solid waste is reduced, and resource recycling is achieved.

Description

Technical Field

[0001] This invention relates to the field of waste residue recycling technology, specifically to a flotation-based process for the synergistic utilization and multi-component recovery of carbon slag overhaul residue. Background Technology

[0002] Carbon slag and overhaul slag are typical industrial solid wastes generated in the chemical carbonization process and the electrolytic aluminum overhaul process, respectively. The annual production of both reaches millions of tons. They are complex in composition and contain toxic and harmful components. Carbon slag is rich in carbon elements, while overhaul slag contains fluorine, aluminum and residual cyanide. If traditional landfill methods are used for disposal, it will not only occupy a large amount of land resources, but also easily cause soil and groundwater pollution due to cyanide leakage and fluoride ion migration, which seriously violates the current solid waste disposal requirements of "reduction, resource utilization and harmlessness".

[0003] Existing technologies have explored single-resource recovery processes for carbon slag or overhaul slag, but these have significant limitations: First, there is a lack of synergistic utilization designs for the two types of solid waste. Single treatment cannot balance the complementarity of components, nor can it reduce the treatment cost of a single type of solid waste. Second, the flotation carbon extraction stage often adopts a simplified process of 3-5 stages of roughing and 2-3 stages of cleaning, resulting in poor carbon enrichment and carbon content that is difficult to meet the requirements for high-value applications. Third, the cyanide removal process relies on the static reaction of conventional chemical oxidizing reagents, which has a slow reaction rate and incomplete cyanide removal, leaving residual toxic components that can affect the safety properties of subsequent products. Fourth, acid leaching for the recovery of fluorine and aluminum often uses constant-temperature processes, resulting in low component leaching efficiency and insufficient synergy between solid fluorine and aluminum recovery, easily leading to resource waste. Fifth, the residue after acid leaching is often directly discarded, which not only loses the residual carbon resources but also increases the pressure of secondary solid waste disposal.

[0004] Meanwhile, existing processes suffer from incomplete resource recycling chains and weak targeting in multi-component recovery, making it difficult to simultaneously achieve carbon enrichment, high-value recovery of fluorine and aluminum, and complete removal of toxic components. This results in a trade-off between the environmental and economic benefits of solid waste treatment. Therefore, there is an urgent need for a resource recovery process that can co-process carbon slag and overhaul slag, efficiently recover multiple components, and construct a closed-loop cycle to address the problems of poor solid waste synergy, low resource utilization, and insufficient harmlessness in existing technologies. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a flotation-based process for the synergistic utilization and multi-component recovery of carbon slag overhaul residue resources.

[0006] (II) Technical Solution A flotation-based process for the synergistic utilization and multi-component recovery of carbon slag overhaul residue includes the following steps: S1: The carbon slag and overhaul slag are directionally blended, and the blended raw materials are processed by a combination of jaw crushing and ball milling to control the particle size distribution of the crushed material to be D90≤200 mesh and D50≤150 mesh. S2: Prepare a slurry with a mass concentration of 26%-30% by mixing the material obtained in step S1 with deionized water, add H2O2 as a cyanide removal agent to the slurry, and apply an ultrasonic field while stirring and reacting for 20-30 minutes. S3: The slurry obtained in step S2 is introduced into the flotation system and subjected to 8 roughing and 4 cleaning stages in sequence. During the roughing stage, the diameter of the flotation bubbles is controlled to be 0.8-1.2 mm, and during the cleaning stage, the diameter of the flotation bubbles is gradually reduced to 0.3-0.5 mm. The collected froth product is filtered by disc filter at a pressure of 0.2 MPa to obtain carbon powder. The flotation tailings enter the wet recovery process. S4: Add HCl to the flotation residue obtained in step S3, control the liquid-solid ratio to 8-10:1, stir and acid dissolve at 50-55℃ for 20 minutes, then raise the temperature to 70-75℃ and continue acid dissolving for 20 minutes; after acid dissolving is completed, filter, mix the filtrate with the flotation tailings, add PAC as a fluorine-fixing agent, the amount of PAC added is 1.9%-2.5% of the tailings mass, and simultaneously complex to generate AlF3; S5: Add NaOH to the filtrate obtained in step S4 to adjust the pH to 8.6-9.0, and precipitate Al(OH)3; introduce the remaining filtrate into the MVR evaporation system, concentrate it to 1 / 5 of the original volume under a negative pressure of -0.08MPa, and crystallize to recover NaCl; add Na2CO3 to the concentrate to obtain LiCO3; S6: The insoluble residue after acid dissolution in step S4 is dried at 100-110℃ until the moisture content is ≤5%, and then returned to the raw material matching process in step S1 for reuse.

[0007] Preferably, in step S1, the proportions of carbon (C) in the blended raw materials of carbon slag and overhaul slag are 53%-57%, F (F) is 18%-22%, and Al (Al) is 8%-12%; in step S2, the amount of H2O2 added is 1.6%-2.0% of the raw material mass, the ultrasonic field frequency is 25-30kHz, and the ultrasonic power density is 0.5W / cm³. 2 .

[0008] Preferably, in step S3, the flotation reagent is a compound system of diesel oil and turpentine oil, and the amount of diesel oil added is 0.8%-1.0% of the raw material mass, and the amount of turpentine oil added is 0.3%-0.5% of the raw material mass; the pH of the flotation process is controlled at 6.5-7.5 and the flotation temperature is 26-30℃.

[0009] Preferably, the slurry flow rate of the flotation system in step S3 is controlled at 0.6-1.0 m / s. 3 / h, the aeration rate of the flotation cell is 0.25-0.35m³ / h.3 / (m 2 ·min).

[0010] Preferably, in step S4, the HCl concentration is 3-5 mol / L, and the addition method is dropwise, with the dropwise addition rate controlled at 15-25 mL / min.

[0011] Preferably, in step S4, the PAC is of type PAC-30, with an Al2O3 content ≥30%, and the stirring speed after adding PAC is controlled at 180-220 r / min, and the reaction time is 25-35 min.

[0012] Preferably, the AlF3 generated in step S4 is centrifuged at a speed of 2500-3500 r / min and then dried at 75-85℃ to obtain an AlF3 product with a purity of ≥95%.

[0013] Preferably, in step S5, the Al(OH)3 precipitate is washed three times with deionized water, with a liquid-to-solid ratio of 5:1 for each wash, and the purity of Al(OH)3 after washing is ≥96%.

[0014] Preferably, the heating temperature of the MVR evaporation system in step S5 is controlled at 85-95℃, and the steam condensate generated during the evaporation process is recycled to the slurry preparation process in step S2.

[0015] Preferably, the carbon content of the insoluble residue after drying in step S6 is ≥85%, and its addition ratio when returned to the blending process does not exceed 15% of the total mass of the raw materials in step S1.

[0016] (iii) Beneficial technical effects Compared with existing technologies, the beneficial effects of this invention are: 1. By precisely matching raw materials, the complementary nature of the two types of solid waste is fully utilized, avoiding the problem of component imbalance in the treatment of a single solid waste. At the same time, the treatment cost of a single type of solid waste is reduced, and the overall efficiency of solid waste disposal is improved.

[0017] 2. The optimized 8-stage roughing and 4-stage cleaning flotation combined with graded bubble control significantly improves the enrichment effect of carbon powder. Compared with the traditional simplified flotation process, carbon separation is more thorough and the quality of the obtained carbon powder is better, which can be directly adapted to high-value application scenarios. Combined with the ultrasonic enhanced cyanide removal process, it not only accelerates the degradation rate of cyanide but also improves the thoroughness of removal, effectively avoiding the impact of toxic components on subsequent products and the environment, and ensuring the harmlessness level of the process.

[0018] 3. The segmented temperature-controlled acid leaching process improves the leaching efficiency of fluorine and aluminum components. Combined with the PAC synchronous fluorine fixation design, it enhances the synergistic recovery effect of fluorine and aluminum, avoiding the waste of resources from single recovery. The combination of directional aluminum precipitation and negative pressure evaporation enables the orderly recovery of aluminum compounds and industrial salts, further expanding the dimensions of resource recovery. Attached Figure Description

[0019] Figure 1 This invention discloses a process flow diagram for the synergistic utilization and multi-component recovery of carbon slag overhaul residue based on flotation. Figure 2 This is a line graph comparing the carbon content of toner and the toner recovery rate of the examples and comparative examples; Figure 3 It is a bar chart comparing the purity of AlF3 and Al(OH)3 in the implementation and comparative examples; Figure 4 This is a line graph comparing the fluoride ion removal rate and LiCO3 recovery rate of the examples and comparative examples. Detailed Implementation

[0020] according to Figures 1 to 4 The specific embodiments of the present invention are as follows: The technical solution of the present invention will be described in detail below with reference to embodiments and comparative examples. All experiments were conducted in experimental apparatus that conforms to industrial production standards, and the equipment used was conventional industrial-grade equipment. Unless otherwise specified, all reagents were of analytical grade, and all operations strictly followed the process parameter requirements.

[0021] I. General Test Preparation Raw material pretreatment: The carbon slag is taken from the chemical carbonization process, with a carbon content of 78% and a moisture content of 8%; the overhaul slag is taken from the electrolytic aluminum overhaul process, with a fluorine content of 32%, an aluminum content of 15%, and a cyanide content of 0.8%. Both raw materials are naturally air-dried to ensure that the moisture content is reduced to below 5% before use.

[0022] Reagents and equipment: 30% H2O2 (mass fraction), 37% HCl, 96% NaOH (purity), PAC-30 (Al2O3 content ≥30%), diesel oil, turpentine, 98% Na2CO3 (purity); jaw crusher, ball mill, ultrasonic generator, flotation machine, disc filter, constant temperature stirred reactor, centrifuge, MVR evaporation system, and forced-air drying oven.

[0023] Detection methods: Particle size distribution was determined using a laser particle size analyzer; cyanide content was determined using isonicotinic acid-pyrazolone spectrophotometry; fluoride ion content was determined using an ion-selective electrode method; the purity of Al(OH)3 and AlF3 was determined using an X-ray fluorescence spectrometer; the carbon content of the toner was determined using a high-frequency infrared carbon-sulfur analyzer; the moisture content was determined using a gravimetric method; and the purity and recovery rate of NaCl and LiCO3 were determined by chemical titration.

[0024] Example 1 Step S1: Mix the carbon slag and overhaul slag evenly to obtain a blended raw material. Testing revealed that the blended raw material contained 55.2% carbon, 20.1% phosphorus, and 10.3% aluminum. The blended raw material was fed into a jaw crusher with a feed rate of 5 kg / min and a discharge port gap of 10 mm, crushing it to particles ≤10 mm in diameter. The crushed particles were then transferred to a ball mill with a rotation speed of 280 r / min and a milling time of 30 min. After discharge, the material was measured by a laser particle size analyzer, and the particle size distribution was D90=182 mesh and D50=135 mesh, meeting the process requirements of D90≤200 mesh and D50≤150 mesh.

[0025] Step S2: Transfer all the material processed in Step S1 into the slurry preparation tank. Calculate the amount of deionized water to be added according to the required mass concentration of 28.0%. Turn on the agitator and set the speed to 150 r / min, stirring continuously for 30 min to prepare the slurry of the target concentration. Slowly add a 30% mass fraction H2O2 solution to the slurry, equivalent to pure H2O2 accounting for 1.8% of the raw material mass. Simultaneously start the ultrasonic generator, setting the ultrasonic frequency to 28 kHz and the ultrasonic power density to 0.5 W / cm³. 2 The stirring speed was maintained at 150 r / min, and the reaction was carried out at room temperature for 25 min. After the reaction was completed, samples were taken for testing, and the cyanide content in the slurry was 0.003 mg / L, with a removal rate of 99.6%.

[0026] Step S3: The slurry processed in step S2 is pumped to the flotation system, and the slurry flow rate is set to 0.8 m / s. 3 / h, flotation cell aeration rate 0.3m³ 3 / (m 2Adjust the pulp pH to 7.0 and control the flotation temperature at 28℃. Add 0.9% diesel oil and 0.4% turpentine oil (by weight of raw material) to the pulp and stir for 10 minutes to ensure thorough dispersion of the reagents. A flotation process of 8 roughing stages and 4 cleaning stages is adopted: In the roughing stage, the bubble diameter is controlled to 1.0 mm using a bubble generator. After each roughing stage, the froth product is collected and sent to the next roughing stage, while the tailings are sent to subsequent processes. In the cleaning stage, starting from the first stage, the bubble diameter decreases by 0.2 mm in each stage, successively to 0.8 mm, 0.6 mm, and 0.4 mm, with the final bubble diameter in the fourth cleaning stage being 0.4 mm. All flotation froth products are combined and sent to a disc filter. Filtration at 0.2 MPa pressure yields wet carbon powder, which, after drying, is tested and found to have a carbon content of 92.5% and a recovery rate of 89.2%. The flotation tailings are collected in a dedicated storage tank for later use.

[0027] Step S4: Transfer the flotation residue obtained in Step S3 to a constant-temperature stirred reactor, and add a 37% HCl solution at a liquid-to-solid ratio of 9:1. Add the solution using a peristaltic pump, controlling the dropping rate at 20 mL / min, and calculate the dropping time based on the total amount of HCl solution. After dropping, raise the reactor temperature to 52°C, maintain the stirring speed at 200 r / min, and perform an acid dissolution reaction for 20 min; then raise the temperature to 72°C and continue stirring for another 20 min. After acid dissolution, filter while hot to separate the acid-dissolved filtrate and insoluble residue. Mix the acid-dissolved filtrate with the flotation tailings collected in Step S3, add 2.2% PAC-30 (based on the total mass of the tailings) to the mixture, adjust the stirring speed to 200 r / min, and react for 30 min to allow F⁻ to react with Al⁻. 3 ⁺ The reaction mixture was fully complexed to form AlF3 precipitate. The reaction solution was sent to a centrifuge, and the centrifugation speed was set to 3000 r / min for 15 min. The precipitate was collected and placed in a forced-air drying oven and dried at 80℃ for 2 h to obtain AlF3 product. The purity was tested to be 96.3%.

[0028] Step S5: Slowly add flake NaOH to the filtrate after centrifugation in Step S4, stirring continuously at a speed of 150 r / min. Adjust the pH of the filtrate to 8.8, and allow it to stand for 30 min to precipitate Al(OH)3. Filter the precipitate and wash it three times with deionized water at a liquid-to-solid ratio of 5:1, filtering after each wash. Dry the washed Al(OH)3 in a drying oven, and check its purity to 97.1%. Pump the remaining filtrate into the MVR evaporation system, setting the evaporation pressure to -0.08 MPa and the heating temperature to 90℃. Concentrate the filtrate to 1 / 5 of its original volume, cool and crystallize, then filter to recover the NaCl crystals, with a NaCl purity of 98.5%. Add solid Na2CO3 to the concentrated mother liquor, stir and react for 1 h to generate LiCO3 precipitate. After filtration and drying, obtain the LiCO3 product with a recovery rate of 78.5%. The steam condensate generated by the MVR evaporation system is collected and reused in the slurry preparation process of Step S2, with a reuse rate of 85%.

[0029] Step S6: The insoluble residue after acid dissolution in step S4 is sent to a forced-air drying oven and dried at 105℃ for 3 hours. Its moisture content is 4.2% and carbon content is 88.3%. According to the proportion of 12% of the total mass of raw materials in step S1, the dried insoluble residue is returned to the raw material blending process in step S1, mixed with new carbon slag and overhaul slag, and then reintroduced into the process flow.

[0030] Example 2 Step S1: Mix the carbon slag and overhaul slag to obtain a blended raw material. Testing showed that the raw material contained 53.1% carbon, 18.2% phosphorus, and 8.1% aluminum. The blended raw material was fed into a jaw crusher with a feed rate of 4 kg / min and a discharge opening gap of 8 mm, and crushed to a particle size ≤ 8 mm. It was then transferred to a ball mill with a speed of 260 r / min and a milling time of 25 min. After discharge, the particle size distribution was measured to be D90 = 191 mesh and D50 = 142 mesh, meeting the particle size control standards.

[0031] Step S2: Add deionized water to the slurry mixing tank and mix it with the material obtained in Step S1. Adjust the liquid-to-material ratio to meet the required mass concentration of 26.0%. Stir at 140 r / min for 30 min to prepare the slurry of the target concentration. Add 30% (w / w) H2O2 solution, equivalent to 1.6% pure H2O2 by mass of the raw material. Start the ultrasonic generator and set the frequency to 25 kHz and the power density to 0.5 W / cm³. 2 The stirring speed was maintained at 140 r / min, and the reaction was carried out at room temperature for 20 min. After the reaction was completed, the cyanide content in the slurry was measured to be 0.004 mg / L, with a removal rate of 99.5%.

[0032] Step S3: Pump the slurry into the flotation system and set the slurry flow rate to 0.6 m / s. 3 / h, flotation cell aeration rate 0.25m³ / h 3 / (m 2 Adjust the pulp pH to 6.5 and control the flotation temperature at 26℃. Add 0.8% diesel oil and 0.3% turpentine oil by weight of the raw material, and stir for 8 minutes to ensure uniform dispersion of the reagents. A process of 8 roughing stages followed by 4 cleaning stages is adopted: the bubble diameter is controlled at 0.8 mm in the roughing stage, and 0.6 mm, 0.5 mm, 0.4 mm, and 0.3 mm respectively in the cleaning stage. The flotation froth product is filtered through a disc filter at 0.2 MPa pressure. After drying, the carbon content of the carbon powder is found to be 90.3%, with a recovery rate of 87.5%. The flotation tailings are collected for later use.

[0033] Step S4: Transfer the flotation residue obtained in Step S3 to a constant-temperature stirred reactor. Add 3 mol / L HCl solution at a liquid-to-solid ratio of 8:1 using a peristaltic pump, controlling the dropping rate at 15 mL / min. Calculate the dropping time based on the total amount of HCl solution. After dropping, heat the reactor to 50°C, stir at 180 r / min, and allow the acid dissolution reaction to proceed for 20 min. Then heat to 70°C and continue stirring for another 20 min. After acid dissolution, filter while hot. Mix the filtrate with the flotation tailings, add 1.9% PAC-30 (by mass of the tailings), stir at 180 r / min, and react for 25 min. Centrifuge the reaction solution at 2500 r / min for 20 min, collect the precipitate, and dry at 75°C for 2.5 h to obtain AlF3 product with a purity of 95.1%.

[0034] Step S5: Add NaOH to the centrifuged filtrate to adjust the pH to 8.6, and let it stand for 30 minutes to precipitate Al(OH)3. Wash the precipitate three times with deionized water at a liquid-to-solid ratio of 5:1, filter, dry, and test the purity to be 96.0%. Send the remaining filtrate to the MVR evaporation system, set the pressure to -0.08 MPa and the heating temperature to 85℃, concentrate to 1 / 5 of the original volume, cool and crystallize to recover NaCl, with a purity of 98.2%. Add Na2CO3 solid to the concentrated mother liquor, stir and react for 1 hour, filter and dry to obtain LiCO3 product, with a recovery rate of 76.3%. The steam condensate generated by MVR evaporation is recycled to the slurry preparation process in step S2, with a recycling rate of 82%.

[0035] Step S6: The insoluble residue after acid dissolution is sent to a forced-air drying oven and dried at 100℃ for 4 hours. The moisture content is 4.8% and the carbon content is 85.2%. According to the proportion of 10% of the total mass of raw materials in Step S1, the dried insoluble residue is returned to the blending process, mixed with new raw materials, and then added to the process again.

[0036] Example 3 Step S1: Mix the carbon slag and overhaul slag to prepare the raw material. The raw material was found to contain 56.8% carbon, 21.8% phosphorus, and 11.9% aluminum, meeting the design requirements. The raw material was fed into a jaw crusher with a feed rate of 6 kg / min and a discharge opening gap of 12 mm, crushing it to particles ≤12 mm in diameter. It was then transferred to a ball mill with a speed of 300 r / min and a milling time of 35 min. After discharge, the particle size distribution was found to be D90 = 173 mesh and D50 = 121 mesh, meeting the particle size control requirements.

[0037] Step S2: Add deionized water to the slurry mixing tank to remove cyanide, mix with the material obtained in Step S1, adjust the liquid-to-material ratio to meet the required concentration of 30.0% (by mass), stir at 160 r / min for 30 min to prepare the slurry of the target concentration. Add 30% (by mass) H2O2 solution, equivalent to 2.0% pure H2O2 by the raw material mass. Start the ultrasonic generator, setting the frequency to 30 kHz and the power density to 0.5 W / cm³. 2 The stirring speed was maintained at 160 r / min, and the reaction was carried out at room temperature for 30 min. After the reaction was completed, the cyanide content in the slurry was measured to be 0.002 mg / L, with a removal rate of 99.7%.

[0038] Step S3: Pump the slurry into the flotation system and set the slurry flow rate to 1.0 m / s. 3 / h, flotation cell aeration rate 0.35m³ 3 / (m 2 Adjust the pulp pH to 7.5 and control the flotation temperature at 30℃. Add 1.0% diesel oil and 0.5% turpentine oil by weight of the raw material, and stir for 12 minutes to ensure thorough dispersion of the reagents. A process of 8 roughing stages followed by 4 cleaning stages is employed: the bubble diameter in the roughing stage is 1.2 mm, and the bubble diameters in the cleaning stages are 1.0 mm, 0.8 mm, 0.6 mm, and 0.5 mm respectively. The flotation froth product is filtered through a disc filter at 0.2 MPa pressure. After drying, the carbon content of the carbon powder is 94.2%, and the recovery rate is 91.3%. The flotation tailings are collected for later use.

[0039] Step S4: Transfer the flotation residue obtained in Step S3 to a constant-temperature stirred reactor. Add 5 mol / L HCl solution at a liquid-to-solid ratio of 10:1 using a peristaltic pump, controlling the dropping rate at 25 mL / min. Calculate the dropping time based on the total amount of HCl solution. After dropping, raise the reactor temperature to 55°C, stir at 220 r / min, and perform acid dissolution for 20 min. Then raise the temperature to 75°C and continue stirring for another 20 min. After acid dissolution, filter while hot. Mix the filtrate with the flotation tailings, add 2.5% PAC-30 (by mass of the tailings), stir at 220 r / min, and react for 35 min. Centrifuge the reaction solution at 3500 r / min for 10 min, collect the precipitate, and dry at 85°C for 1.5 h to obtain AlF3 product with a purity of 97.5%.

[0040] Step S5: Add NaOH to the centrifuged filtrate to adjust the pH to 9.0, and let it stand for 30 minutes to precipitate Al(OH)3. Wash the precipitate three times with deionized water at a liquid-to-solid ratio of 5:1, filter, dry, and test the purity to 98.2%. Send the remaining filtrate to the MVR evaporation system, set the pressure to -0.08 MPa and the heating temperature to 95℃, concentrate to 1 / 5 of the original volume, cool and crystallize to recover NaCl, with a purity of 98.8%. Add solid Na2CO3 to the concentrated mother liquor, stir and react for 1 hour, filter and dry to obtain LiCO3 product, with a recovery rate of 80.7%. The steam condensate generated by MVR evaporation is recycled to the slurry preparation process in step S2, with a recycling rate of 88%.

[0041] Step S6: The insoluble residue after acid dissolution is sent to a forced-air drying oven and dried at 110℃ for 2.5 hours. The moisture content is 3.5% and the carbon content is 90.1%. According to the proportion of 15% of the total mass of raw materials in Step S1, the dried insoluble residue is returned to the blending process, mixed with new raw materials, and then added to the process again.

[0042] Comparative Example Step S1: Mix the carbon slag and overhaul slag to obtain the blended raw materials. Testing showed that the raw materials contained 61.3% carbon, 15.7% phosphorus, and 6.8% aluminum. After crushing in a jaw crusher, the raw materials were transferred to a ball mill and ball-milled for 20 minutes. The particle size distribution of the discharged material was D90=225 mesh and D50=168 mesh.

[0043] Step S2: Deionized water was added to the slurry mixing tank and mixed with the crushed material. The mixture was stirred to produce a slurry with a mass concentration of 26.7%, deviating from the standard range of 26%-30%. A 30% mass fraction H2O2 solution was added, equivalent to 1.0% pure H2O2 by mass of the raw material. No ultrasonic field was applied; the reaction was simply stirred for 15 minutes. After the reaction, the cyanide content in the slurry was measured to be 0.08 mg / L, with a removal rate of only 90.0%.

[0044] Step S3: Flotation recovery adopts a simplified flotation process of 3 roughing stages plus 2 cleaning stages, with the pulp flow rate set at 0.5m. 3 / h; Aeration rate of 0.2m³ / h for the flotation cell 3 / (m 2 Diesel oil was added to the slurry at a rate of 1.0% of the raw material mass. The slurry pH was adjusted to 6.0 and the temperature to 25°C. The bubble diameter was uniformly controlled to 0.8 mm during the flotation process. The flotation froth product was dried after disc filtration. The carbon content of the carbon powder was found to be 78.5%, and the recovery rate was 65.3%.

[0045] Step S4: Add 2 mol / L HCl solution to the flotation residue, with a liquid-to-solid ratio of 7:1, lower than the standard of 8-10:1. Use a one-time addition method and acid dissolve at a constant temperature of 60℃ for 40 min. After acid dissolution, filter the solution, mix the filtrate with the flotation tailings, and add 1.5% PAC-30 (by mass of the tailings). Stir at 150 r / min and react for 20 min. After centrifugation, dry the reaction solution to obtain an AlF3 product with a purity of 82.3%.

[0046] Step S5: Add NaOH to adjust the pH of the filtrate to 8.0, which is below the standard range of 8.6-9.0. Wash the generated AlF3 precipitate once, dry it, and test its purity at 89.5%. Send the remaining filtrate to the MVR evaporation system, set the heating temperature to 80℃, and concentrate it to 1 / 4 of its original volume. Cool and crystallize to recover NaCl with a purity of 95.2%; add Na2CO3 to the concentrated mother liquor to react, and the LiCO3 recovery rate is 52.8%. The steam condensate generated by MVR evaporation was not reused.

[0047] The performance test results of the examples and comparative examples are compared in the table below: The data in the table clearly shows that the embodiments of the present invention outperform the comparative examples in all core indicators: the carbon content of the toner in the embodiments exceeds 90% and the recovery rate exceeds 87%, while the comparative examples are only 78.5% and 65.3%; the purity of AlF3 and Al(OH)3 is stable at over 95% and 96% respectively, far higher than the 82.3% and 89.5% of the comparative examples; the cyanide removal rate reaches over 99.5% and the fluoride ion removal rate exceeds 98%, with more thorough removal of toxic components, while the comparative examples are only 90.0% and 85.7%; the LiCO3 recovery rate is increased to over 76%, significantly higher than the 52.8% of the comparative examples.

[0048] Meanwhile, the unit raw material processing cost of the embodiment is controlled at RMB 1.79-1.85 / kg, and the amount of secondary solid waste generated is only 11.2-13.8 kg / t of raw material, both lower than the comparative examples of RMB 2.36 / kg and 48.6 kg / t of raw material. Furthermore, it achieves water resource reuse and insoluble residue recycling, fully demonstrating the comprehensive advantages of the process of the present invention in terms of resource recovery efficiency, product purity, harmlessness level and economy.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flotation-based process for the synergistic utilization and multi-component recovery of carbon slag overhaul residue, characterized in that, Includes the following steps: S1: The carbon slag and overhaul slag are directionally blended, and the blended raw materials are processed by a combination of jaw crushing and ball milling to control the particle size distribution of the crushed material to be D90≤200 mesh and D50≤150 mesh. S2: Prepare a slurry with a mass concentration of 26%-30% by mixing the material obtained in step S1 with deionized water, add H2O2 as a cyanide removal agent to the slurry, and apply an ultrasonic field while stirring and reacting for 20-30 minutes. S3: The slurry obtained in step S2 is introduced into the flotation system and subjected to 8 roughing and 4 cleaning stages in sequence. During the roughing stage, the diameter of the flotation bubbles is controlled to be 0.8-1.2 mm, and during the cleaning stage, the diameter of the flotation bubbles is gradually reduced to 0.3-0.5 mm. The collected froth product is filtered by disc filter at a pressure of 0.2 MPa to obtain carbon powder. The flotation tailings enter the wet recovery process. S4: Add HCl to the flotation residue obtained in step S3, control the liquid-solid ratio to 8-10:1, stir and acid dissolve at 50-55℃ for 20 minutes, then raise the temperature to 70-75℃ and continue acid dissolving for 20 minutes; after acid dissolving is completed, filter, mix the filtrate with the flotation tailings, add PAC as a fluorine-fixing agent, the amount of PAC added is 1.9%-2.5% of the tailings mass, and simultaneously complex to generate AlF3; S5: Add NaOH to the filtrate obtained in step S4 to adjust the pH to 8.6-9.0, and precipitate Al(OH)3; introduce the remaining filtrate into the MVR evaporation system, concentrate it to 1 / 5 of the original volume under a negative pressure of -0.08MPa, and crystallize to recover NaCl; add Na2CO3 to the concentrate to obtain LiCO3; S6: The insoluble residue after acid dissolution in step S4 is dried at 100-110℃ until the moisture content is ≤5%, and then returned to the raw material matching process in step S1 for reuse.

2. The flotation-based co-utilization and multi-component recovery process for carbon slag overhaul slag as described in claim 1, characterized in that, In step S1, the proportions of carbon (C) in the blended raw materials of carbon slag and overhaul slag are 53%-57%, F (F) is 18%-22%, and Al (Al) is 8%-12%. In step S2, the amount of H2O2 added is 1.6%-2.0% of the raw material mass, the ultrasonic field frequency is 25-30kHz, and the ultrasonic power density is 0.5W / cm³. 2 .

3. The flotation-based co-utilization and multi-component recovery process for carbon slag overhaul slag as described in claim 1, characterized in that, In step S3, the flotation reagent uses a compound system of diesel oil and turpentine oil, with the amount of diesel oil added being 0.8%-1.0% of the raw material mass and the amount of turpentine oil added being 0.3%-0.5% of the raw material mass; the pH of the flotation process is controlled at 6.5-7.5 and the flotation temperature at 26-30℃.

4. The flotation-based co-utilization and multi-component recovery process for carbon slag overhaul slag as described in claim 1, characterized in that, In step S3, the slurry flow rate of the flotation system is controlled to be 0.6-1.0 m / s. 3 / h, the aeration rate of the flotation cell is 0.25-0.35m³ / h. 3 / (m 2 ·min).

5. The flotation-based co-utilization and multi-component recovery process for carbon slag overhaul slag as described in claim 1, characterized in that, In step S4, the HCl concentration is 3-5 mol / L, and it is added dropwise at a rate of 15-25 mL / min.

6. The flotation-based co-utilization and multi-component recovery process for carbon slag overhaul slag as described in claim 1, characterized in that, In step S4, the PAC is of type PAC-30, with an Al2O3 content ≥30%. After adding PAC, the stirring speed is controlled at 180-220 r / min, and the reaction time is 25-35 min.

7. The flotation-based co-utilization and multi-component recovery process for carbon slag overhaul slag according to claim 1, characterized in that, The AlF3 generated in step S4 is centrifuged at a speed of 2500-3500 r / min and then dried at 75-85℃ to obtain an AlF3 product with a purity of ≥95%.

8. The flotation-based co-utilization and multi-component recovery process for carbon slag overhaul slag according to claim 1, characterized in that, In step S5, the Al(OH)3 precipitate is washed three times with deionized water, with a liquid-to-solid ratio of 5:1 each time. After washing, the purity of Al(OH)3 is ≥96%.

9. The flotation-based co-utilization and multi-component recovery process for carbon slag overhaul slag according to claim 1, characterized in that, In step S5, the heating temperature of the MVR evaporation system is controlled at 85-95℃, and the steam condensate generated during the evaporation process is recycled to the slurry preparation process in step S2.

10. The flotation-based co-utilization and multi-component recovery process for the resource recovery of carbon slag overhaul slag according to claim 1, characterized in that, The carbon content of the insoluble residue after drying in step S6 is ≥85%, and its addition ratio when returned to the blending process shall not exceed 15% of the total mass of the raw materials in step S1.

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