A method for treating waste residue from the complete wet recovery of Pb and Zn in hydrometallurgical zinc smelting slag.

Abstract

This invention discloses a method for treating waste residue from hydrometallurgical zinc smelting slag, involving the complete wet recovery of Pb and Zn, belonging to the field of metallurgical waste residue treatment technology. The method involves washing the hydrometallurgical zinc slag with a sulfuric acid solution to remove residual Zn. 2+ Then, the first-stage solid-liquid separation is performed. The resulting filtrate is replenished with sulfuric acid solution and returned to the washing system for recirculation until Zn... 2+ Zn was extracted with P204 after the content was >20-25 g / L. 2+ The raffinate is replenished with sulfuric acid solution and returned to the washing system. The organic phase is back-extracted and then sent to the purification and electrowinning process to obtain zinc ingots. The filter residue is subjected to complexation with a complexing agent to remove Pb, undergoing a second-stage solid-liquid separation. A regenerant is added to the filtrate for regeneration and Pb removal, followed by a third-stage solid-liquid separation. The filtrate is returned to the complexation and Pb removal system for recirculation, and the filter residue is a PbS precipitate. The filter residue obtained from the second-stage solid-liquid separation is washed with water to obtain harmless slag. The residual valuable Pb and Zn in the smelting slag can be recovered to the maximum extent, with zinc ingot purity >99% and lead-rich slag Pb content >36%, while significantly reducing energy consumption, demonstrating energy-saving and environmental protection advantages.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical waste slag treatment technology, specifically relating to a waste slag treatment method for the complete wet recovery of Pb and Zn from wet zinc smelting slag. Background Technology

[0002] With the rapid development of the zinc smelting industry, resource and environmental conflicts have become increasingly prominent. The depletion of high-grade, easily processed zinc sulfide resources has made green metallurgy of low-grade oxygen-sulfur mixed / oxidized lead-zinc ores a crucial guarantee for the sustainable and healthy development of the domestic zinc smelting industry. It should be noted that some oxygen-sulfur mixed lead-zinc ores have complex ore properties, characterized by high oxidation rates, high mud content, and being lean, fine, and impure. Directly entering the smelting process is difficult and has a low recovery rate. Furthermore, apart from some valuable elements such as Pb, Zn, and Fe, the content of other valuable metal elements in these ores is extremely low, resulting in very low profits for enterprises processing them. If the smelting waste from these ores is further treated in a harmless manner, it can easily lead to losses for enterprises. Therefore, many resources have not been rationally and effectively developed and utilized.

[0003] With the nation placing increasing emphasis on ecological and environmental protection, low-cost, harmless treatment technology for smelting waste slag is crucial for the effective utilization of this type of ore. Due to the complex composition and significant grade fluctuations of this type of low-grade, difficult-to-process oxygen-sulfur mixed lead-zinc ore, the leaching residue after hydrometallurgical processes exhibits complex mineral phase composition. The presence and content of harmful heavy metals such as Pb and Zn vary considerably, resulting in the lack of an economical and technically stable low-cost harmless treatment process for the waste slag. Currently, many enterprises still rely on slag storage in slag heaps, leading to ever-growing slag piles and increasingly severe problems.

[0004] Long-term accumulation of smelting slag in slag yards exposes the area to acid rain and other acidic liquids. Prolonged immersion in these slags causes the heavy metals to dissolve, which are then washed into surface rivers, seep into surrounding soil, and eventually penetrate groundwater, posing a serious threat to the local ecosystem. Therefore, this invention aims to provide a method for recovering Pb and Zn from hydrometallurgical zinc slag. This method utilizes a fully hydrometallurgical process to recover most of the lead and zinc from the smelting slag. The recovered slag, after solidification treatment, meets the standards for general solid waste and can be used as raw material in cement plants, demonstrating high application value and economic benefits. Summary of the Invention

[0005] The purpose of this invention is to provide a method for treating waste residue from the complete wet recovery of Pb and Zn in hydrometallurgical zinc slag.

[0006] The objective of this invention is achieved as follows: the method for treating waste residue from the hydrometallurgical recovery of Pb and Zn in zinc smelting slag includes pickling, zinc recovery, lead recovery, and waste residue treatment processes, specifically including: A. Pickling: Add sulfuric acid solution to the wet zinc smelting slag and stir and wash to remove residual Zn from the zinc smelting slag. 2+ The liquid-to-solid ratio for washing is 3~6:1, the sulfuric acid concentration is 10~30g / L, the temperature is 20~80℃, the stirring speed is 300~600r / min, the washing time is 30~180min, and the first-stage solid-liquid separation is performed after washing.

[0007] B. Zinc Recovery: The filtrate from the first-stage solid-liquid separation is replenished with sulfuric acid solution and returned to the stirring and washing system for recirculation until Zn is removed from the washing liquid. 2+ After the content is >20-25g / L, the Zn is extracted with P204. 2+ The raffinate is returned to the stirring and washing system after being replenished with sulfuric acid solution. The organic phase is then sent to the purification and electrowinning system after back-extraction to obtain recovered zinc ingots.

[0008] C. Lead Recovery: After the filter residue obtained from the first-stage solid-liquid separation is slurryed, it is subjected to complexation to remove Pb by a complexing agent. The complexing agent is any one or a combination of several of the following: disodium ethylenediaminetetraacetate (EDTA-Na2), tetrasodium ethylenediaminetetraacetate (EDTA-Na4), dipotassium ethylenediaminetetraacetate (EDTA-K2), and tripotassium ethylenediaminetetraacetate (EDTA-K3). The concentration of the complexing agent is 50~70g / L. The liquid-solid ratio for complexation to remove Pb is 3~6:1, the pH is 5.2~6.7, the n(EDTA):n(Pb) ratio is 1~4:1, the temperature is 30~60℃, and the reaction time is 2~6h. Then, the second-stage solid-liquid separation is carried out.

[0009] The filtrate obtained from the second-stage solid-liquid separation is added with a regenerator to regenerate the complexing agent and remove Pb. The regenerator is any one or a combination of two of Na2S or K2S. The amount of regenerator added is 1 to 3 times the Pb content in the filtrate. The reaction temperature is 20 to 60°C and the reaction time is 1 to 4 hours. Then, the third-stage solid-liquid separation is carried out.

[0010] The filtrate obtained from the third-stage solid-liquid separation is the lead-removed liquid, which is returned to the complexation and Pb removal system for recirculation. The resulting filter residue is PbS precipitate, i.e., lead-rich slag.

[0011] D. Waste residue treatment: The filter residue obtained from the second-stage solid-liquid separation is washed with water and stirred. The filtered residue is harmless. The liquid-to-solid ratio for washing is 2~6:1, the temperature is 20~80℃, the stirring speed is 300~600r / min, and the washing time is 30~180min.

[0012] Compared with the prior art, the present invention has the following advantages: 1. The technical solution described in this invention can achieve the complete wet harmless treatment of zinc smelting slag, which significantly reduces energy consumption compared with the existing pyrometallurgical harmless treatment technology.

[0013] 2. Valuable Pb and Zn metals remaining in the smelting slag can be recovered to the maximum extent. The purity of zinc ingots is >99%, and the Pb content of lead-rich slag is >36%.

[0014] 3. The technical solution described in this invention has a short process flow, and the intermediate products of each process can be recycled and reused. The reagent consumption is low, which has outstanding environmental and economic benefits. Attached Figure Description

[0015] Figure 1 This is a flowchart of the technical solution described in this invention. Detailed Implementation

[0016] The present invention will be further described below, but this is not intended to limit the invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the scope of protection of the present invention.

[0017] The method for treating waste residue from the hydrometallurgical zinc slag recovery process includes pickling, zinc recovery, lead recovery, and waste residue treatment steps, specifically including: A. Pickling: Add sulfuric acid solution to the wet zinc smelting slag and stir and wash to remove residual Zn from the zinc smelting slag. 2+ The liquid-to-solid ratio for washing is 3~6:1, the sulfuric acid concentration is 10~30g / L, the temperature is 20~80℃, the stirring speed is 300~600r / min, the washing time is 30~180min, and the first-stage solid-liquid separation is performed after washing.

[0018] B. Zinc Recovery: The filtrate from the first-stage solid-liquid separation is replenished with sulfuric acid solution and returned to the stirring and washing system for recirculation until Zn is removed from the washing liquid. 2+ After the content is >20-25g / L, the Zn is extracted with P204. 2+ The raffinate is returned to the stirring and washing system after being replenished with sulfuric acid solution. The organic phase is then sent to the purification and electrowinning system after back-extraction to obtain recovered zinc ingots with a purity >99%.

[0019] C. Lead Recovery: After the filter residue obtained from the first-stage solid-liquid separation is slurryed, it is subjected to complexation to remove Pb by a complexing agent. The complexing agent is any one or a combination of several of the following: disodium ethylenediaminetetraacetate (EDTA-Na2), tetrasodium ethylenediaminetetraacetate (EDTA-Na4), dipotassium ethylenediaminetetraacetate (EDTA-K2), and tripotassium ethylenediaminetetraacetate (EDTA-K3). The concentration of the complexing agent is 50~70g / L. The liquid-solid ratio for complexation to remove Pb is 3~6:1, the pH is 5.2~6.7, the n(EDTA):n(Pb) ratio is 1~4:1, the temperature is 30~60℃, and the reaction time is 2~6h. Then, the second-stage solid-liquid separation is carried out.

[0020] The filtrate obtained from the second-stage solid-liquid separation is added with a regenerator to regenerate the complexing agent and remove Pb. The regenerator is any one or a combination of two of Na2S or K2S. The amount of regenerator added is 1 to 3 times the Pb content in the filtrate. The reaction temperature is 20-60℃ and the reaction time is 1 to 4 hours. Then, the third-stage solid-liquid separation is carried out.

[0021] The filtrate obtained from the third-stage solid-liquid separation is the lead-removed liquid, which is returned to the complexation and Pb removal system for recirculation. The resulting filter residue is PbS precipitate, i.e., lead-rich slag.

[0022] D. Waste residue treatment: The filter residue obtained from the second-stage solid-liquid separation is washed with water and stirred. The filtered residue is harmless. The liquid-to-solid ratio for washing is 2~6:1, the temperature is 20~80℃, the stirring speed is 300~600r / min, and the washing time is 30~180min.

[0023] In the pickling process, the optimal values ​​for each process parameter are as follows: liquid-to-solid ratio of 4~5:1, sulfuric acid concentration of 15~25g / L, temperature of 40~60℃, stirring speed of 400~500r / min, and washing time of 60~150min.

[0024] In the zinc recovery process, the filtrate obtained from the first-stage solid-liquid separation is returned to the stirring and washing system after being supplemented with sulfuric acid solution, and then circulated again 6 to 10 times.

[0025] In the lead recovery process, the optimal values ​​for each process parameter are as follows: complexing agent concentration is 55-65 g / L; liquid-to-solid ratio for Pb removal is 4-5:1; pH is 5.5-6.5; n(EDTA):n(Pb) ratio is 2-3:1; temperature is 40-50℃; and reaction time is 3-5 h. The amount of regenerator added is twice the Pb content in the filtrate, the reaction temperature is 30-50℃, and the reaction time is 2-3 h. The Pb content of the lead-rich slag is >36%.

[0026] In the waste residue treatment process, the optimal values ​​for each process parameter are as follows: liquid-to-solid ratio of 3~5:1, temperature of 40~60℃, stirring speed of 400~500 r / min, and washing time of 60~150 min. The washing water is returned to the waste residue washing system for recirculation.

[0027] Example 1 A. Pickling: Add 20g / L sulfuric acid solution to the wet zinc smelting slag and stir and wash to remove residual Zn from the zinc smelting slag. 2+ The washing liquid-to-solid ratio was 4:1, the temperature was 30℃, the stirring speed was 400r / min, the washing time was 60min, and the first stage of solid-liquid separation was performed after washing.

[0028] B. Zinc Recovery: The filtrate from the first-stage solid-liquid separation is replenished with sulfuric acid solution and returned to the stirring and washing system for recirculation until Zn is removed from the washing liquid. 2+After the content is >20g / L, the Zn is extracted with P204. 2+ The raffinate is returned to the stirring and washing system after being replenished with sulfuric acid solution. The organic phase is then sent to the purification and electrowinning system after back-extraction to obtain recovered zinc ingots.

[0029] C. Lead recovery: After the filter residue obtained from the first-stage solid-liquid separation is slurryed, it is complexed with 50 g / L disodium ethylenediaminetetraacetate (EDTA-Na2) to remove residual Pb from the filter residue. The liquid-solid ratio for complexing and removing Pb is 4:1, pH is 6.1, temperature is 40℃, and reaction time is 3 h. Then, the second-stage solid-liquid separation is carried out.

[0030] The filtrate obtained from the second-stage solid-liquid separation is added with regener Na2S to regenerate the complexing agent and remove Pb. The amount of regener added is twice the Pb content in the filtrate. The reaction temperature is 30℃ and the reaction time is 2 hours. Then, the third-stage solid-liquid separation is carried out.

[0031] The filtrate obtained from the third-stage solid-liquid separation is the lead-removed liquid, which is returned to the complexation and Pb removal system for recirculation. The resulting filter residue is PbS precipitate, i.e. lead-rich slag, with a Pb content of 38.13%.

[0032] D. Waste Residue Treatment: The filter residue obtained from the second-stage solid-liquid separation is washed with water and stirred. The filtered residue is harmless and sent for toxicity leaching identification, classifying it as Class I general solid waste. The washing liquid-to-solid ratio is 3:1, the temperature is 40℃, the stirring speed is 400 r / min, and the washing time is 60 min. The washing water is returned to the waste residue washing system for recirculation.

[0033] Example 2 A. Pickling: Add 15g / L sulfuric acid solution to the wet zinc smelting slag and stir and wash to remove residual Zn from the zinc smelting slag. 2+ The washing liquid-to-solid ratio was 5:1, the temperature was 25℃, the stirring speed was 500r / min, the washing time was 150min, and the first stage of solid-liquid separation was performed after washing.

[0034] B. Zinc Recovery: The filtrate from the first-stage solid-liquid separation is replenished with sulfuric acid solution and returned to the stirring and washing system for recirculation until Zn is removed from the washing liquid. 2+ After the content is >25g / L, the Zn is extracted with P204. 2+ The raffinate is returned to the stirring and washing system after being replenished with sulfuric acid solution. The organic phase is then sent to the purification and electrowinning system after back-extraction to obtain recovered zinc ingots.

[0035] C. Lead Recovery: After the filter residue obtained from the first-stage solid-liquid separation is slurryed, it is complexed with a 1:1 mixture of 70 g / L disodium ethylenediaminetetraacetate (EDTA-Na2) and 70 g / L tetrasodium ethylenediaminetetraacetate (EDTA-Na4) to remove residual Pb from the filter residue. The liquid-solid ratio for complexing and removing Pb is 3:1, the pH is 6.5, the temperature is 30℃, and the reaction time is 2.5 h. Then, the second-stage solid-liquid separation is carried out.

[0036] The filtrate obtained from the second-stage solid-liquid separation is added with regener K2S to regenerate the complexing agent and remove Pb. The amount of regener added is 1 times the Pb content in the filtrate. The reaction temperature is 40℃ and the reaction time is 1 hour. Then, the third-stage solid-liquid separation is carried out.

[0037] The filtrate obtained from the third-stage solid-liquid separation is the lead-removing solution, which is returned to the complexation and Pb removal system for recirculation. The resulting filter residue is PbS precipitate, i.e. lead-rich slag, with a Pb content of 36.26%.

[0038] D. Waste Residue Treatment: The filter residue obtained from the second-stage solid-liquid separation is washed with water and stirred. The filtered residue is harmless and sent for toxicity leaching identification, classifying it as Class I general solid waste. The washing liquid-to-solid ratio is 5:1, the temperature is 60℃, the stirring speed is 500 r / min, and the washing time is 150 min. The washing water is returned to the waste residue washing system for recirculation.

[0039] Example 3 A. Pickling: Add 10g / L sulfuric acid solution to the wet zinc smelting slag and stir and wash to remove residual Zn from the zinc smelting slag. 2+ The washing liquid-to-solid ratio was 3:1, the temperature was 60℃, the stirring speed was 300r / min, the washing time was 180min, and the first stage of solid-liquid separation was performed after washing.

[0040] B. Zinc Recovery: The filtrate from the first-stage solid-liquid separation is replenished with sulfuric acid solution and returned to the stirring and washing system for recirculation until Zn is removed from the washing liquid. 2+ After the content is >20g / L, the Zn is extracted with P204. 2+ The raffinate is returned to the stirring and washing system after being replenished with sulfuric acid solution. The organic phase is then sent to the purification and electrowinning system after back-extraction to obtain recovered zinc ingots.

[0041] C. Lead recovery: After the filter residue obtained from the first-stage solid-liquid separation is slurryed, it is complexed with 60 g / L dipotassium ethylenediaminetetraacetate (EDTA-K2) to remove residual Pb from the filter residue. The liquid-solid ratio for complexation and Pb removal is 6:1, pH is 5.2, temperature is 50℃, and reaction time is 6 h. Then, the second-stage solid-liquid separation is carried out.

[0042] The filtrate obtained from the second-stage solid-liquid separation is mixed with a 1:1 Na2S and K2S compound to regenerate the complexing agent and remove Pb. The amount of compound added is three times the Pb content in the filtrate. The reaction temperature is 20℃ and the reaction time is 4 hours. Then, the third-stage solid-liquid separation is carried out.

[0043] The filtrate obtained from the third-stage solid-liquid separation is the lead-removing liquid, which is returned to the complexation and Pb removal system for recirculation. The resulting filter residue is PbS precipitate, i.e. lead-rich slag, with a Pb content of 37.18%.

[0044] D. Waste Residue Treatment: The filter residue obtained from the second-stage solid-liquid separation is washed with water and stirred. The filtered residue is harmless and sent for toxicity leaching identification, classifying it as Class I general solid waste. The washing liquid-to-solid ratio is 2:1, the temperature is 80℃, the stirring speed is 600 r / min, and the washing time is 30 min. The washing water is returned to the waste residue washing system for recirculation.

[0045] Example 4 A. Pickling: Add the wet zinc smelting slag to a 30g / L sulfuric acid solution and stir to wash, removing residual Zn from the zinc smelting slag. 2+ The washing liquid-to-solid ratio was 6:1, the temperature was 80℃, the stirring speed was 600r / min, the washing time was 30min, and the first stage of solid-liquid separation was performed after washing.

[0046] B. Zinc Recovery: The filtrate from the first-stage solid-liquid separation is replenished with sulfuric acid solution and returned to the stirring and washing system for recirculation until Zn is removed from the washing liquid. 2+ After the content is >20g / L, the Zn is extracted with P204. 2+ The raffinate is returned to the stirring and washing system after being replenished with sulfuric acid solution. The organic phase is then sent to the purification and electrowinning system after back-extraction to obtain recovered zinc ingots.

[0047] C. Lead recovery: After the filter residue obtained from the first-stage solid-liquid separation is slurry-treated, it is subjected to complexation and Pb removal using 55 g / L tripotassium ethylenediaminetetraacetate (EDTA-K3) to remove residual Pb from the filter residue. The liquid-solid ratio for complexation and Pb removal is 5:1, pH is 6.7, temperature is 60℃, and reaction time is 4.5 h. Then, the second-stage solid-liquid separation is carried out.

[0048] The filtrate obtained from the second-stage solid-liquid separation is added with regener Na2S to regenerate the complexing agent and remove Pb. The amount of regener added is 1.5 times the Pb content in the filtrate. The reaction temperature is 60℃ and the reaction time is 3 hours. Then, the third-stage solid-liquid separation is carried out.

[0049] The filtrate obtained from the third-stage solid-liquid separation is the lead-removing solution, which is returned to the complexation and Pb removal system for recirculation. The resulting filter residue is PbS precipitate, i.e. lead-rich slag, with a Pb content of 36.49%.

[0050] D. Waste Residue Treatment: The filter residue obtained from the second-stage solid-liquid separation is washed with water and stirred. The filtered residue is harmless and sent for toxicity leaching identification, classifying it as Class I general solid waste. The washing liquid-to-solid ratio is 6:1, the temperature is 20℃, the stirring speed is 300 r / min, and the washing time is 180 min. The washing water is returned to the waste residue washing system for recirculation.

Claims

1. A method for treating waste residue from the complete wet recovery of Pb and Zn in hydrometallurgical zinc smelting slag, characterized in that... It includes pickling, zinc recovery, lead recovery, and waste residue treatment processes, specifically including: A. Pickling: Add sulfuric acid solution to the wet zinc smelting slag and stir and wash to remove residual Zn from the zinc smelting slag. 2+ The liquid-to-solid ratio for washing is 3~6:1, the sulfuric acid concentration is 10~30g / L, the temperature is 20~80℃, the stirring speed is 300~600r / min, the washing time is 30~180min, and the first-stage solid-liquid separation is performed after washing. B. Zinc Recovery: The filtrate from the first-stage solid-liquid separation is replenished with sulfuric acid solution and returned to the stirring and washing system for recirculation until Zn is removed from the washing liquid. 2+ After the concentration is >20 g / L, Zn is extracted with P204. 2+ The raffinate is returned to the stirring and washing system after being replenished with sulfuric acid solution. The organic phase is sent to the purification and electrowinning system after back-extraction to obtain recovered zinc ingots. The filtrate obtained from the first-stage solid-liquid separation is returned to the stirring and washing system after being replenished with sulfuric acid solution and recycled again 6 to 10 times. C. Lead Recovery: After slurry preparation, the filter residue obtained from the first-stage solid-liquid separation is subjected to complexation and Pb removal using a complexing agent. The complexing agent is any one or a combination of several of the following: disodium ethylenediaminetetraacetate (EDTA-Na2), tetrasodium ethylenediaminetetraacetate (EDTA-Na4), dipotassium ethylenediaminetetraacetate (EDTA-K2), and tripotassium ethylenediaminetetraacetate (EDTA-K3). The concentration of the complexing agent is 50-70 g / L. The liquid-to-solid ratio for Pb removal is 3-6:1, the pH is 5.2-6.7, the molar ratio of EDTA to Pb is 1-4:1, the temperature is 30-60℃, and the reaction time is 2-6 h. Then, the second-stage solid-liquid separation is carried out, and the Pb content of the lead-rich slag is >36%. The filtrate obtained from the second-stage solid-liquid separation is added with a regenerator to regenerate the complexing agent and remove Pb. The regenerator is any one or a combination of two of Na2S or K2S. The amount of regenerator added is 1 to 3 times the amount of Pb in the filtrate. The reaction temperature is 20 to 60°C and the reaction time is 1 to 4 hours. Then, the third-stage solid-liquid separation is carried out. The filtrate obtained from the third-stage solid-liquid separation is the lead-removing solution, which is returned to the complexation and Pb removal system for recirculation. The resulting filter residue is PbS precipitate, i.e. lead-rich slag. D. Waste residue treatment: The filter residue obtained from the second-stage solid-liquid separation is washed with water and stirred. The filtered residue is harmless. The liquid-to-solid ratio of the washing is 2~6:1, the temperature is 20~80℃, the stirring speed is 300~600r / min, and the washing time is 30~180min. The washing water is returned to the waste residue washing system for recirculation.

2. The waste residue treatment method according to claim 1, characterized in that... In the lead recycling process, the concentration of the complexing agent is 55~65g / L.

3. The waste residue treatment method according to claim 1, characterized in that... In the lead recovery process, the liquid-to-solid ratio of the complexation and Pb removal is 4-5:1, the pH is 5.5-6.5, the molar ratio of EDTA to Pb is 2-3:1, the temperature is 40-50℃, and the reaction time is 3-5h.

4. The waste residue treatment method according to claim 1, characterized in that... In the lead recovery process, the amount of regenerant added is twice the solid-liquid ratio of Pb in the filtrate, the reaction temperature is 30~50℃, and the reaction time is 2~3h.

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