A method for multi-metal matte pretreatment and valuable metal synergistic recovery

Abstract

The application provides a multi-metallic matte pretreatment and valuable metal cooperative recovery method, and belongs to the technical field of comprehensive recovery of hydrometallurgy. The application realizes efficient leaching of copper and indium in multi-metallic matte through ball milling pre-decontamination, low-acid oxidation leaching, high-acid oxidation leaching, copper reduction and precipitation, indium recovery and arsenic oxidation and precipitation processes, synchronously enriches lead, silver, tin and antimony in leaching residue, and then realizes resource utilization through fire metallurgy, solves the technical bottleneck of low comprehensive efficient recovery of valuable metals in the multi-metallic matte treatment process, and simultaneously realizes concentrated solidification and removal of arsenic. Copper, arsenic and indium are respectively recovered in the form of sponge copper, solid arsenic residue and sponge indium; lead, silver, tin and antimony are enriched in the leaching residue, and the valuable metals in the leaching residue are comprehensively recovered after being treated by the fire metallurgy process, thereby realizing resource utilization of the multi-metallic matte.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology. Specifically, it relates to a method for comprehensively recovering valuable metals such as lead, silver, tin, antimony, copper, arsenic, and indium using polymetallic matte as raw material. Background Technology

[0002] Polymetallic matte is an intermediate byproduct of lead smelting systems. It is rich in valuable metals such as copper, indium, lead, silver, and antimony, but also contains large amounts of harmful elements such as fluorine, chlorine, and arsenic, as well as iron impurities. Conventional processing methods are divided into pyrometallurgical and hydrometallurgical methods, both of which have the following significant technical defects.

[0003] When polymetallic materials enter the pyrometallurgical copper smelting system, lead, arsenic, and other elements are extremely detrimental to the stability of the production process and the quality control of cathode copper products. Most of the lead, indium, and antimony end up in the smelting slag and cannot be recovered. Furthermore, fluorine, chlorine, and arsenic are easily volatilized at high temperatures and enter the flue gas, corroding dust collection and smelting equipment, and generating hazardous waste flue gas with high arsenic and high fluorine content. The investment and maintenance costs for tail gas treatment are extremely high. Therefore, the current pyrometallurgical process has significant problems such as a large impact on the stable operation of the main copper smelting system, low comprehensive recovery rate of valuable metals, and severe equipment corrosion.

[0004] In existing wet processing techniques, fluorine and chlorine directly enter the leaching system, causing long-term and continuous corrosion of leaching, extraction, and purification equipment, significantly increasing the cost of equipment corrosion protection upgrades, maintenance, and replacement. Furthermore, current wet processing techniques generally suffer from low levels of valuable metal recovery, significant indium co-precipitation losses, and poor stability of indium solvent extraction processes.

[0005] Overall, existing processing technologies have low comprehensive yields of valuable metals, and high costs for environmental governance and equipment operation and maintenance, failing to meet the industry's development needs for cleaner production and efficient comprehensive utilization of secondary resources in non-ferrous smelting. Summary of the Invention

[0006] To address the problems identified in the background technology, this invention provides a method for the pretreatment and co-recovery of valuable metals in polymetallic matte. Through core processes including ball milling for pre-impurity removal, low-acid oxidation leaching, high-acid oxidation leaching, reduction copper precipitation, indium recovery, and oxidative arsenic precipitation, this method achieves efficient leaching of copper and indium from polymetallic matte. Simultaneously, lead, silver, tin, and antimony are enriched in the leaching residue and then recycled via pyrometallurgical processes. This method overcomes the technical bottlenecks of low overall recovery rate of valuable metals and difficulty in centralized removal of arsenic during polymetallic matte treatment. Copper, arsenic, and indium are recovered as sponge copper, solidified arsenic slag, and sponge indium, respectively. Lead, silver, tin, and antimony are enriched together in the leaching residue, which is then treated using pyrometallurgical processes to achieve comprehensive recovery of valuable metals, thus realizing the efficient resource utilization of polymetallic matte.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] The method for pretreatment of polymetallic matte and co-recovery of valuable metals includes the following steps:

[0009] (1) Ball milling pre-removal: Mix polymetallic matte with water at a liquid-solid ratio of 1:2 to 5, and then feed it into a ball mill to complete grinding and water washing to remove impurities simultaneously; after grinding to a particle size of <74μm, discharge the slurry, and after liquid-solid separation, obtain the removed fine material with chlorine residue <0.5% and fluorine residue <0.1%, as well as fluorine-containing chlorine wastewater.

[0010] (2) Low acid oxidation leaching: The impurity-removed fine material obtained in step (1) is mixed with high acid leaching solution and sent to a stirred reactor; oxygen is continuously introduced or hydrogen peroxide is added for oxidation leaching. After the reaction is completed, liquid and solid are separated to obtain low acid leaching solution and low acid leaching residue with sulfuric acid concentration of 10-40 g / L.

[0011] (3) High acid enhanced leaching: Take the low acid leaching residue produced in step (2), add sulfuric acid solution to adjust the slurry and send it to the stirred reactor; continuously introduce oxygen or add hydrogen peroxide for deep leaching. After the reaction is completed, the liquid and solid are separated to obtain a high acid leaching solution with a sulfuric acid concentration of 80-120 g / L and lead-based leaching residue.

[0012] (4) Reduction of copper plating: The low-acid leaching solution obtained in step (2) is transferred to a stirred reactor, and iron filings are continuously added. The reaction temperature is 40-70℃ and the reaction time is 0.5-1.5h. The Fe content in the solution after copper plating is controlled. 3+ ≤500mg / L, residual Cu 2+ The concentration of In in the solution 3+ The concentration is 1.5 to 2 times that of copper. After the reaction is completed, the liquid and solid are separated, producing sponge copper and copper precipitate liquid.

[0013] Furthermore, if the ball milling fines produced in step (1) contain more than 0.5% chlorine or more than 0.1% fluorine, an alkaline washing and defluorination / chlorine removal process is added; the alkaline solution is prepared using the fluorine-containing chlorine wastewater obtained in step (1) to perform a second washing of the ball milling fines until the fluorine and chlorine residues meet the requirements.

[0014] Furthermore, the method for pretreatment of polymetallic matte and synergistic recovery of valuable metals also includes indium recovery and arsenic removal by oxidation:

[0015] (5) Indium recovery: Take the copper precipitation liquid from step (4), add an organic extractant and mix thoroughly for extraction, and indium selectively enters the organic phase; after acid washing to remove co-extraction impurities, the indium-loaded organic phase is back-extracted using a back-extraction reagent to obtain a high-concentration indium-containing back-extraction solution; add a displacement agent to the indium-containing back-extraction solution to reduce and precipitate crude indium, and after solid-liquid separation, water washing and drying, sponge indium is obtained, and the remaining liquid phase is the indium-extracted liquid and the indium-precipitated liquid.

[0016] (6) Oxidation to solidify arsenic and remove impurities: The indium extraction liquid produced in step (5) is sent to a stirred reactor, the pH of the system is adjusted and an oxidant is introduced to oxidize the precipitation; after the reaction is completed, the liquid and solid are separated to produce solidified arsenic residue and arsenic precipitation liquid.

[0017] Furthermore, the mass fractions of each component in the polymetallic matte are as follows: lead 10%–20%, copper 20%–35%, indium 0.06%–0.15%, antimony 1.0%–2.5%, silver 0.1%–0.3%, iron 5%–15%, arsenic 5%–15%, fluorine 0.5%–1.2%, and chlorine 0.5%–2.0%.

[0018] Furthermore, the control indicators for step (5) of the indium recovery section are: residual In in the indium extraction solution. 3+ The concentration of In in the back-extraction solution is 5–15 mg / L. 3+ Concentration 3-20 g / L, Cu 2 ⁺≤0.01g / L, Fe 2+ The concentration was kept stable at 0.05–0.20 g / L.

[0019] Furthermore, in step (6) the oxidative precipitation of arsenic, if the iron-arsenic molar ratio of the system is lower than 1.0, ferrous sulfate is added to adjust the iron-arsenic molar ratio to the range of 1.0 to 1.3.

[0020] The beneficial effects of this invention are:

[0021] This invention addresses the industry challenges of traditional wet recovery processes for multimetallic matte with high levels of fluorine, chlorine, and arsenic, including severe fluorine and chlorine corrosion, incomplete recovery of valuable metals, difficulties in separating copper and indium with significant indium loss, high costs of arsenic-containing wastewater disposal, and poor material utilization. It employs an integrated wet co-recovery process involving ball milling for pre-purification, two-stage countercurrent oxidation acid leaching, reduction copper precipitation, indium recovery, and ferric salt synergistic arsenic fixation. This process offers multiple advantages, including raw material pretreatment, multimetal cascade separation, and harmless disposal of hazardous materials. Specific beneficial effects are as follows:

[0022] Ball milling pre-removal simultaneously achieves fine grinding and defluorination / chlorination of materials, eliminating fluoride / chlorine corrosion problems at the source. The ball milling pre-removal process grinds multi-metal matte to below 74μm while simultaneously dissolving fluoride and chlorine impurities, directly controlling the residual fluoride and chlorine in the material to below 0.1% and 0.5%, respectively. This avoids fluoride and chlorine entering subsequent processes and causing equipment corrosion and operational safety issues, while also reducing the impact of fluoride and chlorine on the recovery of valuable metals. High- and low-acid two-stage countercurrent acid leaching achieves efficient separation and enrichment of copper, indium, and valuable metals such as lead, silver, and antimony. Low-acid oxidation leaching first prepares a qualified leaching solution for subsequent indium and copper recovery, followed by high-acid enhanced leaching to ensure efficient leaching of copper and indium, while enriching lead, antimony, and silver in the lead-based leaching residue. Precise reduction copper precipitation control technology balances copper product purity with suppression of indium co-precipitation loss. The copper precipitation process strictly controls residual Cu. 2⁺ for In 3+ Concentration 1.5 to 2 times, Fe 3+ With a concentration ≤500mg / L, it can efficiently precipitate high-purity sponge copper products without losing indium due to excessive reduction and simultaneous co-precipitation. It maximizes the retention of liquid indium while fully recovering copper, minimizing indium loss. The selective extraction-displacement coupled process ultimately displaces high-quality sponge indium with high efficiency. Precise control of the iron-arsenic ratio leads to stable arsenic solidification through oxidation. The entire process incorporates internal wastewater recycling; fluoride- and chlorine-containing wastewater from ball milling can be reused to prepare alkaline washing solutions, and acid solutions in the high and low acid leaching sections are internally circulated and adjusted, reducing wastewater treatment costs. Attached Figure Description

[0023] Figure 1 This is a simplified process flow diagram of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are all within the scope of protection of this invention.

[0025] The method for pretreatment of polymetallic matte and co-recovery of valuable metals of the present invention includes the following steps:

[0026] (1) Pre-purification by ball milling: After pre-crushing the polymetallic matte, it is mixed with water at a liquid-to-solid ratio of 1:(2-5) and fed into a ball mill. The ball-to-material mass ratio is 4:1 to 6:1. The ball milling speed is 350-500 r / min. The proportion of particles with a particle size <74µm is more than 80% after ball milling. After ball milling, the slurry is discharged and separated into liquid and solid, yielding purified fine material and fluoride-containing chlorine wastewater. The residual chlorine content in the purified fine material is controlled to be less than 0.5% and the residual fluorine content is less than 0.1%. When the chlorine content in the ball milled fine material obtained by liquid-solid separation is greater than 0.5% or the fluorine content is greater than 0.1%, an alkaline washing defluorination and dechlorination process is added.

[0027] Fluorine- and chlorine-containing wastewater from ball milling is used as the solution preparation water. Sodium carbonate, sodium hydroxide, or a mixture of the two are added to prepare an alkaline solution with a concentration of 20–50 g / L. The alkaline washing solution-solid ratio is 3:1–5:1 mL / g, and the alkaline washing temperature is 60–80 ℃. The ball milled fines are then washed a second time until the residual fluorine and chlorine levels meet the requirements.

[0028] (2) Low-acid oxidative leaching: The purified fine material obtained in step (1) is mixed with the system's recycled high-acid solution at a solid-liquid ratio of 1:5-10 kg:L and then fed into a stirred reactor. The initial acidity is controlled at 40-60 g / L. Oxygen is continuously introduced during the leaching process, or hydrogen peroxide is continuously added as an oxidant. The reaction is carried out at 50-90℃ for 1-3 hours, and the sulfuric acid concentration at the final reaction point is controlled at 10-40 g / L. After the reaction is completed, liquid-solid separation is performed to obtain low-acid leaching solution and low-acid leaching residue. The obtained low-acid leaching solution enters the reduction copper precipitation process, while lead, silver, tin, antimony, etc. are retained in the low-acid leaching residue and enter the next step of high-acid enhanced leaching.

[0029] (3) High-acid enhanced leaching: The low-acid leaching residue obtained in step (2) is added to the arsenic precipitation solution and sulfuric acid solution, and the mixture is prepared by adjusting the solid-liquid ratio to 1:5-10 kg:L and then fed into a stirred reactor. The initial acidity of the leaching process is 180-230 g / L, and oxygen is continuously introduced or hydrogen peroxide is continuously added. The reaction is carried out at 50-90 °C for 1-3 h, and the sulfuric acid concentration at the end of the reaction is controlled to be 80-120 g / L. After the reaction, the liquid and solid are separated to obtain high-acid leaching solution and lead-based leaching residue. The high-acid leaching solution is returned to step (2) as the slurry preparation solution for low-acid oxidative leaching; valuable metals such as lead, silver, tin, and antimony are directionally enriched in the lead-based leaching residue, which can be sent to a side-blown furnace or other pyrometallurgical smelting system for further recovery of valuable metals.

[0030] (4) Reduction of copper leaching: The low-acid leaching solution obtained in step (2) is fed into a stirred reactor, and pure iron filings are continuously added at 40–70 °C for a reaction time of 0.5–1.5 h. The reaction pH is 2–3. The Fe content in the solution after copper leaching is controlled. 3+ Concentration below 500 mg / L, and residual Cu 2+ The concentration of In in the solution 3+ The concentration was 1.5 to 2 times higher. Liquid-solid separation was then performed to obtain sponge copper and the copper-precipitated liquid.

[0031] (5) Indium recovery: Add an organic extractant to the copper precipitate solution obtained in step (4) and mix thoroughly to allow In to be recovered. 3+ Selective entry into the organic phase. A P204-sulfonated kerosene system was used, with an extraction ratio of O / A of 1:3 to 1:1, 2 to 5 extraction stages, a mixing time of 3 to 15 min, a clarification time of 5 to 30 min, and an extraction temperature of 15 to 50 °C. The resulting indium-loaded organic phase was subjected to 1 to 3 stages of acid washing with 0.1 to 0.8 mol / L sulfuric acid solution to remove co-extracted impurities such as copper and iron. The acid-washed indium-loaded organic phase was then subjected to 2 to 4 stages of back-extraction with 3 to 8 mol / L hydrochloric acid or 1 to 4 mol / L sulfuric acid to obtain a high-concentration indium-containing back-extraction solution. The In content in the back-extraction solution was controlled. 3+ Concentration of 3–20 g / L, Cu 2+Concentration not exceeding 0.01 g / L, Fe 2+ The concentration is 0.05–0.20 g / L. Zinc powder, aluminum powder, and other displacement agents are added to the indium-containing back-extraction solution to allow the In... 3+ Reduction precipitation, while simultaneously removing residual In from the liquid phase 3+ The concentration was controlled between 5 and 15 mg / L. Finally, after liquid-solid separation, washing with water, and drying, sponge indium and the indium extraction solution were obtained.

[0032] (6) Oxidation and Arsenic Removal: The indium-extracted liquid produced in step (5) is sent to a stirred reactor, and samples are taken to determine the total arsenic and total iron content in the solution. When the iron-arsenic molar ratio of the system is lower than 1.0, ferrous sulfate is added to the system to control the iron-arsenic molar ratio of the reaction system at 1.0-1.3. Then, the pH of the system is adjusted and oxygen or hydrogen peroxide or other oxidants are introduced for oxidation and precipitation. The reaction is carried out at 60-85 °C and pH 2-3 for 1-4 h, and the pH of the system is monitored at any time and the reaction pH is maintained by slowly adding dilute sodium hydroxide solution. After the reaction is completed, liquid-solid separation is carried out to obtain arsenic-fixed slag and arsenic-precipitated liquid. The arsenic-precipitated liquid is returned to step (3) for high acid enhanced leaching.

[0033] To illustrate the present invention more clearly, the following specific embodiments will be described in detail.

[0034] Example 1

[0035] A method for pretreatment of polymetallic matte and co-recovery of valuable metals, comprising the following specific steps:

[0036] (1) Pre-purification by ball milling: Multi-metal matte (lead 20%, copper 20%, indium 0.06%, antimony 1.6%, silver 0.3%, iron 5%, arsenic 15%, chlorine 1.7%, fluorine 1.2%) was pre-crushed and mixed with water at a liquid-solid ratio of 1:5 and fed into a ball mill. The ball-to-material mass ratio was 6:1, and the ball milling speed was 350 r / min. The ball milling was carried out until the particle size <74μm and the particle size percentage was 86%. The slurry was separated into liquid and solid to obtain the purified fine material. The residual chlorine was 0.8% and the residual fluorine was 0.4%. The fluorine-containing chlorine wastewater was used to prepare an alkaline solution with sodium hydroxide for alkaline washing to remove fluorine and chlorine. The alkaline solution concentration was 50 g / L, the alkaline washing liquid-solid ratio was 4:1 mL / g, and the temperature was 80 ℃ for a second washing. The purified fine material after treatment contained 0.35% chlorine and 0.07% fluorine. The chlorine removal rate was 85% and the fluorine removal rate was 96%.

[0037] (2) Low acid oxidation leaching: The depurified fine material obtained in step (1) is mixed with the system recycled high acid liquid at a solid-liquid ratio of 1:7 kg:L, and oxygen is introduced for oxidation leaching. The oxygen introduction rate is 10 L / h per kilogram of depurified fine material, the initial acidity is controlled at 50 g / L, the reaction temperature is 90℃, and the reaction time is 1 h. The liquid and solid are separated to obtain a low acid leaching solution with a sulfuric acid concentration of 37 g / L and a low acid leaching residue.

[0038] (3) High acid enhanced leaching: After adding arsenic precipitation liquid and sulfuric acid solution to the low acid leaching residue, the solid-liquid ratio is 1:8 kg:L, the initial acidity is 200 g / L, oxygen is continuously introduced, the oxygen introduction rate is 6 L / h per kilogram of low acid leaching residue, the temperature is 90 ℃, and the reaction time is 1 h; liquid-solid separation yields high acid leaching solution with sulfuric acid concentration of 95 g / L and lead-based leaching residue; the high acid leaching solution is returned to step (2) for slurry preparation; the lead-based leaching residue is sent to a side-blown furnace for pyrometallurgical recovery of lead, silver, tin and antimony.

[0039] (4) Reduction copper precipitation: The low-acid leaching solution is transferred to the reaction tank, iron filings are added, the temperature is 70 ℃, and the reaction is carried out for 0.5 h; the Fe in the liquid after copper precipitation is controlled. 3+ 170 mg / L, residual Cu 2+ For In 3+ The concentration was twice that of copper; liquid-solid separation yielded sponge copper with a copper grade of 71% and a copper-precipitated liquid.

[0040] (5) Indium recovery: Indium was extracted from the copper-precipitated solution using a P204-sulfonated kerosene extraction system with an extraction ratio of O / A of 1:1, 4-stage countercurrent extraction, a mixing time of 15 min, a clarification time of 15 min, and an extraction temperature of 35℃. The supported organic phase was 0.1 mol / L and acid-washed twice with sulfuric acid. The acid-washed supported organic phase was back-extracted with 3 mol / L hydrochloric acid to obtain an indium-containing back-extraction solution. 3+ Concentration of 3 g / L, Cu 2+ Concentration 0.009 g / L, Fe 2+ The concentration was 0.15 g / L; zinc plate was added for displacement, and liquid-solid separation was performed to obtain sponge indium and residual In. 3+ The replacement solution with a concentration of 12 mg / L.

[0041] (6) Oxidation to solidify arsenic and remove impurities: The iron-arsenic molar ratio of the indium extraction liquid is 0.5. Ferrous sulfate is added to the system to control the iron-arsenic molar ratio of the reaction system at 1.3. Sodium hydroxide solution is continuously added to adjust the pH to 3, oxygen is introduced, the reaction temperature is 75℃, and the reaction is carried out for 3 hours. The solid arsenic residue and the liquid after arsenic precipitation are separated into liquid and solid. The liquid after arsenic precipitation is returned to the high acid enhanced leaching process.

[0042] The overall performance indicators of this embodiment are as follows: total copper recovery rate of 98%, total indium recovery rate of 92%; lead, silver and antimony are enriched in lead-based leaching residue and sent to the pyrometallurgical system for further recovery.

[0043] Example 2

[0044] A method for pretreatment of polymetallic matte and co-recovery of valuable metals, comprising the following specific steps:

[0045] (1) Ball milling pre-purification: Multi-metal matte (lead 10%, copper 26%, indium 0.15%, antimony 1.0%, silver 0.2%, iron 15%, arsenic 10%, chlorine 0.5%, fluorine 0.5%) was pre-crushed and mixed with water at a liquid-to-solid ratio of 1:4 and fed into a ball mill. The ball-to-material mass ratio was 4:1, and the ball milling speed was 500 r / min. The mixture was ball-milled until the particle size <74μm accounted for 85%. The slurry was separated into liquid and solid components to obtain purified fine material. The residual chlorine was 0.25% and the residual fluorine was 0.08%, which met the requirements. Fluorine-containing chlorine wastewater was produced. The chlorine removal rate was 55% and the fluorine removal rate was 85%.

[0046] (2) Low acid oxidation leaching: The impurity-removed fine material obtained in step (1) is mixed with the system recycled high acid liquid at a solid-liquid ratio of 1:5 kg:L, and hydrogen peroxide is added for oxidation leaching. The amount of hydrogen peroxide added is 12% of the mass of the impurity-removed fine material. The initial acidity is controlled at 40 g / L, the reaction temperature is 75℃, and the reaction time is 2 h. The liquid and solid are separated to obtain a low acid leaching solution with a sulfuric acid concentration of 10 g / L and a low acid leaching residue.

[0047] (3) High acid enhanced leaching: After adding arsenic precipitation liquid and sulfuric acid solution to the low acid leaching residue, the solid-liquid ratio is 1:5 kg:L, the initial acidity is 180 g / L, hydrogen peroxide is continuously added, the amount of hydrogen peroxide added is 3% of the mass of the low acid leaching residue, the temperature is 70 ℃, and the reaction time is 2 h; liquid-solid separation yields high acid leaching solution with sulfuric acid concentration of 80 g / L and lead-based leaching residue; the high acid leaching solution is returned to step (2) for slurry preparation; the lead-based leaching residue is sent to a side-blown furnace for pyrometallurgical recovery of lead, silver, tin and antimony.

[0048] (4) Reduction copper precipitation: The low-acid leaching solution is transferred to the reaction tank, iron filings are added, the temperature is 55 ℃, and the reaction is carried out for 1.0 h; the Fe in the liquid after copper precipitation is controlled. 3+ 450 mg / L, residual Cu 2+ For In 3+ The concentration was 1.5 times that of copper; liquid-solid separation yielded sponge copper with a copper grade of 69% and a copper precipitate solution.

[0049] (5) Indium recovery: Indium was extracted from the copper-precipitated solution using a P204-sulfonated kerosene extraction system with an extraction ratio of O / A of 1:3, a 5-stage countercurrent extraction, a mixing time of 5 min, a clarification time of 30 min, and an extraction temperature of 50 ℃. The supported organic phase was washed once with 0.8 mol / L sulfuric acid. The acid-washed supported organic phase was back-extracted with 8 mol / L hydrochloric acid to obtain an indium-containing back-extract. 3+ Concentration of 20 g / L, Cu 2+ Concentration 0.008 g / L, Fe 2+ The concentration was 0.20 g / L; aluminum plate was added for displacement, and liquid-solid separation was performed to obtain sponge indium and residual In. 3+The replacement solution has a concentration of 15 mg / L.

[0050] (6) Oxidation to solidify arsenic and remove impurities: The iron-arsenic molar ratio of the indium extraction liquid is 0.9. Ferrous sulfate is added to the system to control the iron-arsenic molar ratio of the reaction system at 1.0. Sodium hydroxide solution is continuously added to adjust the pH to 2.5, oxygen is introduced, the reaction temperature is 85℃, and the reaction is carried out for 1 h. The solid arsenic residue and the liquid after arsenic precipitation are produced by liquid-solid separation. The liquid after arsenic precipitation is returned to the high acid enhanced leaching process.

[0051] The overall performance indicators of this embodiment are as follows: total copper recovery rate of 97% and total indium recovery rate of 93%; lead, silver and antimony are enriched in lead-based leaching residue and sent to the pyrometallurgical system for further recovery.

[0052] Example 3

[0053] A method for pretreatment of polymetallic matte and co-recovery of valuable metals, comprising the following specific steps:

[0054] (1) Pre-purification by ball milling: Multi-metal matte (17% lead, 35% copper, 0.11% indium, 2.5% antimony, 0.1% silver, 8% iron, 5% arsenic, 2.0% chlorine, and 0.7% fluorine) was pre-crushed and mixed with water at a liquid-to-solid ratio of 1:2 and fed into a ball mill. The ball-to-material mass ratio was 5:1, and the ball milling speed was 400 r / min. The ball milling was carried out until the particle size <74μm accounted for 90%. The slurry was separated into liquid and solid to obtain the purified fine material. The residual chlorine was 0.75% and the residual fluorine was 0.2%. The fluorine-containing chlorine wastewater was mixed with sodium hydroxide and sodium carbonate to prepare a mixed alkaline solution for alkaline washing to remove fluorine and chlorine. The alkaline solution concentration was 35 g / L, and the alkaline washing liquid-to-solid ratio was 3:1 mL / g. The washing was carried out twice at 70 ℃. After treatment, the purified fine material contained 0.35% chlorine and 0.09% fluorine. The chlorine removal rate was 89% and the fluorine removal rate was 90%.

[0055] (2) Low-acid oxidative leaching: The depurified fine material obtained in step (1) is mixed with the system recycled high-acid liquid at a solid-liquid ratio of 1:10 kg:L, and oxygen is introduced for oxidative leaching. The oxygen introduction rate is 10 L / h per kilogram of depurified fine material, the initial acidity is controlled at 60 g / L, the reaction temperature is 50℃, and the reaction time is 1.5h. The liquid and solid are separated to obtain a low-acid leaching solution with a sulfuric acid concentration of 40 g / L and a low-acid leaching residue.

[0056] (3) High acid enhanced leaching: After adding arsenic precipitation liquid and sulfuric acid solution to the low acid leaching residue, the solid-liquid ratio is 1:10 kg:L, the initial acidity is 230 g / L, oxygen is continuously introduced, the oxygen introduction rate is 8 L / h per kilogram of low acid leaching residue, the temperature is 50 ℃, and the reaction time is 3 h; liquid-solid separation yields high acid leaching solution with sulfuric acid concentration of 120 g / L and lead-based leaching residue; the high acid leaching solution is returned to step (2) for slurry preparation; the lead-based leaching residue is sent to a side-blown furnace for pyrometallurgical recovery of lead, silver, tin and antimony.

[0057] (4) Reduction copper precipitation: The low-acid leaching solution is transferred to the reaction tank, iron filings are added, the temperature is 40 ℃, and the reaction is carried out for 1.5 h; the Fe in the liquid after copper precipitation is controlled. 3+ 200 mg / L, residual Cu 2+ For In 3+ The concentration was 1.8 times that of copper; liquid-solid separation yielded sponge copper with a copper grade of 75% and a copper-precipitated liquid.

[0058] (5) Indium recovery: Indium was extracted from the copper-precipitated solution using a P204-sulfonated kerosene extraction system with an extraction ratio of O / A of 1:2, two-stage countercurrent extraction, a mixing time of 3 min, a clarification time of 10 min, and an extraction temperature of 15 ℃. The supported organic phase was 0.5 mol / L and acid-washed three times with sulfuric acid. The acid-washed supported organic phase was back-extracted with 6 mol / L hydrochloric acid to obtain an indium-containing back-extraction solution. 3+ Concentration of 18 g / L, Cu 2+ Concentration 0.007 g / L, Fe 2+ The concentration was 0.05 g / L; zinc plate was added for displacement, and liquid-solid separation was performed to obtain sponge indium and residual In. 3+ The replacement solution has a concentration of 5 mg / L.

[0059] (6) Oxidation to solidify arsenic and remove impurities: The iron-arsenic molar ratio in the indium extraction liquid is 1.2, and no ferrous sulfate needs to be added; sodium hydroxide solution is continuously added to adjust the pH to 2, oxygen is introduced, the reaction temperature is 60 ℃, and the reaction is carried out for 4 h; liquid-solid separation produces solidified arsenic residue and arsenic-precipitated liquid, and the arsenic-precipitated liquid is returned to the high acid enhanced leaching process.

[0060] The overall performance indicators of this embodiment are as follows: total copper recovery rate of 99% and total indium recovery rate of 92%; lead, silver, and antimony are enriched in lead-based leaching residue and sent to a pyrometallurgical system for further recovery.

[0061] Example 4

[0062] A method for pretreatment of polymetallic matte and co-recovery of valuable metals, comprising the following specific steps:

[0063] (1) Pre-purification by ball milling: Multi-metal matte (15% lead, 30% copper, 0.09% indium, 1.2% antimony, 0.15% silver, 6% iron, 12% arsenic, 1.3% chlorine, and 1.0% fluorine) was pre-crushed and mixed with water at a liquid-to-solid ratio of 1:3 and fed into a ball mill. The ball-to-material mass ratio was 5:1, and the ball milling speed was 450 r / min. The mixture was ball-milled until the particle size <74μm accounted for 87%. The slurry was separated into liquid and solid components to obtain the purified fine material. The residual chlorine was 0.7% and the residual fluorine was less than 0.16%. The fluorine-containing chlorine wastewater was mixed with sodium carbonate to prepare an alkaline solution for alkaline washing to remove fluorine and chlorine. The alkaline solution concentration was 20 g / L, the alkaline washing liquid-to-solid ratio was 5:1 mL / g, and the temperature was 60 ℃ for a second washing. After treatment, the purified fine material contained 0.4% chlorine and 0.08% fluorine. The chlorine removal rate was 92% and the fluorine removal rate was 91%.

[0064] (2) Low-acid oxidation leaching: The impurity-removed fine material obtained in step (1) and the system recycled high-acid liquid are mixed at a solid-liquid ratio of 1:6 kg:L, and hydrogen peroxide is added for oxidation leaching. The amount of hydrogen peroxide added is 8% of the mass of the impurity-removed fine material. The initial acidity is controlled at 45 g / L, the reaction temperature is 65 ℃, and the reaction time is 1.5 h. The liquid and solid are separated to obtain a low-acid leaching solution with a sulfuric acid concentration of 32 g / L and a low-acid leaching residue.

[0065] (3) High acid enhanced leaching: After adding arsenic precipitation liquid and sulfuric acid solution to the low acid leaching residue, the solid-liquid ratio is 1:7 kg:L, the initial acidity is 210 g / L, hydrogen peroxide is continuously added, the amount of hydrogen peroxide added is 6% of the mass of the low acid leaching residue, the temperature is 65 ℃, and the reaction time is 2 h; liquid-solid separation yields high acid leaching solution with sulfuric acid concentration of 100 g / L and lead-based leaching residue; the high acid leaching solution is returned to step (2) for slurry preparation; the lead-based leaching residue is sent to a side-blown furnace for pyrometallurgical recovery of lead, silver, tin and antimony.

[0066] (4) Reduction copper precipitation: The low-acid leaching solution is transferred to the reaction tank, iron filings are added, the temperature is 60 ℃, and the reaction is carried out for 0.5 h; the Fe in the solution after copper precipitation is controlled. 3+ 250 mg / L, residual Cu 2+ For In 3+ The concentration was 1.6 times that of copper; liquid-solid separation yielded sponge copper with a copper grade of 73% and a copper-precipitated liquid.

[0067] (5) Indium recovery: Indium was extracted from the copper-precipitated solution using a P204-sulfonated kerosene extraction system with an extraction ratio of O / A of 1:3, a three-stage countercurrent extraction, a mixing time of 6 min, a clarification time of 8 min, and an extraction temperature of 25 ℃. The supported organic phase was 0.5 mol / L and acid-washed twice with sulfuric acid. The acid-washed supported organic phase was back-extracted with 5 mol / L hydrochloric acid to obtain an indium-containing back-extraction solution. 3+ Concentration of 16 g / L, Cu 2+Concentration 0.007 g / L, Fe 2+ The concentration was 0.1 g / L; aluminum plate was added for displacement, and liquid-solid separation was performed to obtain sponge indium and residual In. 3+ The replacement solution has a concentration of 7 mg / L.

[0068] (6) Oxidation to solidify arsenic and remove impurities: The iron-arsenic molar ratio of the indium extraction liquid is 0.7. Ferrous sulfate is added to the system to control the iron-arsenic molar ratio of the reaction system to 1.2. Sodium hydroxide solution is continuously added to adjust the pH to 2.5, oxygen is introduced, the reaction temperature is 80 ℃, and the reaction is carried out for 3 h. The solid arsenic residue and the liquid after arsenic precipitation are separated into liquid and solid. The liquid after arsenic precipitation is returned to the high acid enhanced leaching process.

[0069] The overall performance indicators of this embodiment are as follows: total copper recovery rate of 98.5% and total indium recovery rate of 93%; lead, silver, and antimony are enriched in lead-based leaching residue and sent to the pyrometallurgical system for further recovery.

[0070] Comparative Example 1 (material treated by existing wet process as in Example 1)

[0071] Compared with Example 1, this comparative example omits the ball milling pre-removal process in step (1) and directly introduces the original polymetallic matte into low-acid oxidation leaching. The remaining process parameters are consistent with those in Example 1.

[0072] A method for pretreatment of polymetallic matte and co-recovery of valuable metals, comprising the following specific steps:

[0073] (1) Low acid oxidation leaching: After crushing and grinding the polymetallic matte, low acid oxidation leaching was carried out to obtain a high fluorine-chlorine low acid leaching solution and low acid leaching residue with sulfuric acid concentration of 42 g / L, chloride ion concentration of 2.4 g / L and fluorine ion concentration of 1.7 g / L.

[0074] (2) High acid enhanced leaching: high acid leachate and lead-based leaching residue are obtained.

[0075] (3) Reduction copper precipitation: A mixture of cuprous chloride and sponge copper with a copper grade of 40% and a chlorine content of 17% is obtained, as well as the copper precipitation solution.

[0076] (4) Indium recovery: sponge indium and the replacement solution are obtained.

[0077] (5) Oxidation to solidify arsenic and remove impurities: produces solidified arsenic residue and liquid after arsenic precipitation.

[0078] The raw materials were directly fed into the leaching system, resulting in a solution concentration of 2.4 g / L chloride ions and 1.7 g / L fluoride ions. This significantly exacerbated equipment corrosion and posed serious safety hazards. Furthermore, during the reduction copper precipitation stage, chloride ions and cuprous ions in the solution formed cuprous chloride precipitate, yielding a mixture of cuprous chloride (17% chloride content) and sponge copper, which negatively impacted the quality of the sponge copper. The lack of pre-purification also affected the leaching efficiency of copper and indium, with a total copper recovery rate of 83% and an indium recovery rate of 74%. Significant corrosion and wear were observed in the leaching, extraction, and purification equipment.

[0079] In summary, eliminating ball milling for pre-removal of impurities allows fluorine and chlorine to directly enter the leaching system, leading to increased equipment corrosion, a significant decrease in copper and indium recovery rates, and a decline in the quality of sponge copper. Therefore, the ball milling pre-removal process is extremely critical.

[0080] Comparative Example 2 (only one acid leaching step after ball milling pre-purification)

[0081] Compared with Example 1, this comparative example omits the high acid enhanced leaching process in step (3), and directly performs reduction copper deposition after ball milling-low acid oxidation leaching. The remaining process parameters are the same as in Example 1.

[0082] A method for pretreatment of polymetallic matte and co-recovery of valuable metals, comprising the following specific steps:

[0083] (1) Ball milling pre-removal: The removed fine material is obtained, which contains 0.35% chlorine and 0.07% fluorine.

[0084] (2) Low acid oxidation leaching: Low acid leaching solution with sulfuric acid concentration of 49 g / L and low acid leaching residue were obtained.

[0085] (3) Reduction of copper plating: sponge copper with a copper grade of 61% and copper plating solution were obtained.

[0086] (4) Indium recovery: In back-extraction solution 3+ Concentration of 2 g / L, Cu 2+ Concentration 0.008 g / L, Fe 2+ The concentration was 0.17 g / L; zinc plate was added for displacement, and liquid-solid separation was performed to obtain sponge indium and residual In. 3+ The replacement solution with a concentration of 12 mg / L.

[0087] (5) Oxidation to solidify arsenic and remove impurities: produces solidified arsenic residue and liquid after arsenic precipitation.

[0088] After eliminating high-acid enhanced leaching, a large amount of copper and indium remained in the low-acid leaching residue; the total copper recovery rate was 76.4%, and the total indium recovery rate was 68.8%; the copper and indium grades in the lead-silver-antimony enriched residue increased significantly, the processing load of the pyrometallurgical system increased, and the loss of valuable metals increased. Two-stage coupled high-acid and low-acid leaching is the key to ensuring efficient copper and indium leaching; single-stage low-acid leaching alone will result in a large amount of copper and indium remaining in the residue, and the recovery rate will be greatly reduced.

[0089] Note: Unless otherwise specified, all percentage contents mentioned in this invention are mass percentage contents.

[0090] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for pretreatment of polymetallic matte and co-recovery of valuable metals, characterized in that, Includes the following steps: (1) Ball milling pre-removal: Mix polymetallic matte with water at a liquid-solid ratio of 1:2 to 5 and feed it into a ball mill to complete grinding and water washing to remove impurities simultaneously; after grinding to a particle size of <74μm, discharge the slurry and separate it into liquid and solid to obtain fine material with chlorine residue <0.5% and fluorine residue <0.1%, as well as fluorine-containing chlorine wastewater; (2) Low acid oxidation leaching: The impurity-removed fine material obtained in step (1) is mixed with high acid leaching solution and slurry is fed into a stirred reactor; oxygen is continuously introduced or hydrogen peroxide is added for oxidation leaching. After the reaction is completed, liquid and solid are separated to obtain low acid leaching solution and low acid leaching residue with sulfuric acid concentration of 10-40 g / L. (3) High acid enhanced leaching: Take the low acid leaching residue produced in step (2), add sulfuric acid solution to adjust the slurry and send it into a stirred reactor; continuously introduce oxygen or add hydrogen peroxide for deep leaching. After the reaction is completed, the liquid and solid are separated to obtain a high acid leaching solution with a sulfuric acid concentration of 80-120 g / L and lead-based leaching residue. (4) Reduction of copper plating: The low-acid leaching solution obtained in step (2) is transferred to a stirred reactor, and iron filings are continuously added. The reaction temperature is 40-70℃ and the reaction time is 0.5-1.5h. The Fe content in the solution after copper plating is controlled. 3+ ≤500mg / L, residual Cu 2+ The concentration of In in the solution 3+ The concentration is 1.5 to 2 times that of copper. After the reaction is completed, the liquid and solid are separated, producing sponge copper and copper precipitate liquid.

2. The method for pretreatment of polymetallic matte and co-recovery of valuable metals according to claim 1, characterized in that: If the ball milling fines produced in step (1) contain more than 0.5% chlorine or more than 0.1% fluorine, an alkaline washing and defluorination / chlorine removal process is added. The alkaline solution is prepared using the fluorine-containing chlorine wastewater obtained in step (1) to perform a second washing of the ball milling fines until the fluorine and chlorine residues meet the requirements.

3. The method for pretreatment of polymetallic matte and co-recovery of valuable metals according to claim 1 or 2, characterized in that, It also includes indium recovery and arsenic removal through oxidation: (5) Indium recovery: Take the copper precipitation liquid from step (4), add an organic extractant and mix thoroughly for extraction, indium selectively enters the organic phase; after acid washing to remove co-extraction impurities, the indium-loaded organic phase is back-extracted using a back-extraction reagent to obtain a high-concentration indium-containing back-extraction solution; add a displacement agent to the indium-containing back-extraction solution to reduce and precipitate crude indium, and after solid-liquid separation, water washing and drying, sponge indium is obtained, and the remaining liquid phase is the indium-extracted liquid and the indium-precipitated liquid; (6) Oxidation to solidify arsenic and remove impurities: The indium extraction liquid produced in step (5) is sent to a stirred reactor, the pH of the system is adjusted and an oxidant is introduced to oxidize the precipitation; after the reaction is completed, the liquid and solid are separated to produce solidified arsenic residue and arsenic precipitation liquid.

4. The method for pretreatment of polymetallic matte and co-recovery of valuable metals according to claim 3, characterized in that: Step (5) Control indicators for indium recovery section: residual In in the indium extraction solution 3+ The concentration of In in the back-extraction solution is 5–15 mg / L. 3+ Concentration 3-20 g / L, Cu 2 ⁺≤0.01g / L, Fe 2+ The concentration was kept stable at 0.05–0.20 g / L.

5. The method for pretreatment of polymetallic matte and co-recovery of valuable metals according to claim 3 or 4, characterized in that: In step (6) of the arsenic oxidation precipitation process, if the iron-arsenic molar ratio of the system is lower than 1.0, ferrous sulfate is added to adjust the iron-arsenic molar ratio to the range of 1.0 to 1.

3.

6. The method for pretreatment of polymetallic matte and co-recovery of valuable metals according to claim 1, characterized in that: The mass fractions of the components in the polymetallic matte are as follows: lead 10%–20%, copper 20%–35%, indium 0.06%–0.15%, antimony 1.0%–2.5%, silver 0.1%–0.3%, iron 5%–15%, arsenic 5%–15%, fluorine 0.5%–1.2%, and chlorine 0.5%–2.0%.

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