Method for recovering metal from high-nickel copper fire refining slag and application of method

Abstract

The invention discloses a method for recovering metal from high-nickel copper fire refining slag and application of the method, and relates to the technical field of metal metallurgy. Comprising the following steps: carrying out weak acid arsenic leaching on the copper fire refining slag to obtain arsenic-removed leaching slag and arsenic-containing copper liquid; copper removal is carried out on the arsenic-containing copper liquid to obtain a copper-containing material and copper-removed liquid, and arsenic precipitation is carried out on the copper-removed liquid; the arsenic-removed leaching residues are subjected to oxidation copper leaching to obtain copper leaching residues and a copper sulfate solution, and the copper leaching residues are subjected to reduction vulcanization smelting to obtain nickel matte, tin-antimony smoke dust and smelting residues. According to the method, the cost of separation of copper and arsenic in the raw materials can be reduced, the problem of furnace caking caused in the reduction smelting process is avoided, the obtained copper sulfate solution serves as electrolyte replenishing liquid to be applied to the copper electrolysis process, and the influence on the self-purification process of electrolyte is small. According to the method, nickel and copper are enriched in matte nickel through reduction vulcanization smelting, then copper-nickel separation is conducted through the post-treatment process, the post-treatment process is shorter, nickel recovery is achieved while copper recovery is guaranteed, and better economic benefits are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of metal metallurgy, and in particular to a method for recovering metal from high-nickel copper pyrometallurgical refining slag and application thereof. Background Art

[0002] The process of copper pyro-refining includes the process of preparing copper anode plates by refining and removing impurities from crude copper in an anode furnace. In the above refining process, refining slags with different copper contents are produced. According to the copper grade and physical phase difference of the slags, the refining slags can be divided into primary refining slags and secondary refining slags. Among them, the primary refining slag contains about 10% copper, and the secondary refining slag contains about 40-60% copper. In addition to copper, the refining slag also contains metal elements such as nickel or iron. Since the content of metal elements in the refining slag is relatively high, the recovery of copper and other metal elements (such as nickel) in the refining slag is conducive to the resource treatment of metals in the copper pyro-refining process.

[0003] At present, the treatment method for refined secondary slag includes directly reducing and smelting the refined secondary slag with high-nickel raw materials to obtain electrolytic copper products, but the process is prone to furnace agglomeration, which affects production. In addition, since the copper content in the refined secondary slag is high, and the refined secondary slag is mainly cuprous oxide, and there are also a small amount of metallic copper, copper oxide and cuprous sulfide, some processes separate and recover the copper in the refined secondary slag, and the obtained copper sulfate solution is used as an electrolyte supplement to participate in the preparation of electrolytic copper, but it usually affects the self-purification process of the electrolyte and reduces the added value of metal recovery.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a method for recovering metal from high-nickel copper pyrometallurgical refining slag and its application.

[0006] The present invention is achieved in that:

[0007] In a first aspect, the present invention provides a method for recovering metals from high-nickel copper pyrometallurgical refining slag, comprising subjecting the copper pyrometallurgical refining slag to weak acid arsenic leaching to obtain arsenic-removed leaching slag and arsenic-containing copper liquid; then decopperizing the arsenic-containing copper liquid to obtain copper-containing material and decopperized liquid, and then precipitating arsenic on the decopperized liquid; subjecting the decopperized leaching slag to oxidative copper leaching to obtain copper-leached slag and copper sulfate solution, and subjecting the copper-leached slag to reduction sulfide smelting to obtain nickel matte, tin-antimony smoke and smelting slag.

[0008] In a second aspect, the present invention provides an application of a method as described in any of the aforementioned embodiments in improving the grade of recovered metals or reducing the cost of producing electrolytic copper from copper pyrometallurgical refining slag.

[0009] The present invention has the following beneficial effects:

[0010] The present invention provides a method for recovering metals from high-nickel copper pyrometallurgical refining slag and its application. By adopting a weak acid arsenic leaching method, copper and arsenic in the raw material are separated, and the arsenic content in the de-arsenic leaching slag is significantly reduced. Then, the de-arsenic leaching slag is subjected to oxidation copper leaching to reduce the copper grade in the de-arsenic leaching slag, thereby reducing the copper-nickel ratio in the de-arsenic leaching slag, so that the copper leaching slag obtained by oxidation copper leaching meets the standard for preparing matte nickel by reduction sulfidation smelting. By adopting reduction sulfidation smelting to enrich nickel and copper in matte nickel, and then separating copper and nickel through a post-treatment process, copper concentrate and nickel concentrate can be obtained respectively. Compared with the existing process of preparing copper anode plates by reduction smelting, the post-treatment process is shorter, and the added value of nickel recovery is increased while maintaining the added value of copper recovery, which has better economic benefits. At the same time, since the method provided by the present invention changes the traditional copper leaching slag recovery process, and the arsenic content in the copper leaching slag is extremely low, the furnace stagnation problem caused by the reduction smelting process is avoided. In addition, the copper sulfate solution obtained by oxidative copper leaching can also be used as an electrolytic supplementary solution in the process of electrolytic copper. Since the arsenic content in the copper sulfate solution is low, it has little effect on the self-purification process of the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0012] Figure 1 A flow chart of a method for recovering metals from high-nickel copper pyrometallurgical refining slag provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0014] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0015] The existing method of recovering metals from copper pyrometallurgical refining slag generally involves subjecting copper pyrometallurgical refining slag (primary refining slag and / or secondary refining slag) to at least one of reduction smelting or direct pyrometallurgical smelting to prepare black copper anode plates, and then subjecting the black copper anode plates to electrolytic refining to obtain electrolytic copper products. Although this process effectively realizes the recovery of copper elements in the refining slag, the recovery rate of other metal elements is low; and in the process of obtaining electrolytic copper by electrolytic refining of black copper anode plates, the self-purification process of the electrolytic system is easily affected, and the electrolyte needs to be additionally purified to ensure the smooth progress of the electrolytic process, which is not conducive to improving the added value of metal recovery. Therefore, the inventor proposes the following solution.

[0016] In the first aspect, the present invention provides a method for recovering metal from high-nickel copper pyrometallurgical refining slag, the process flow of which is as follows: Figure 1 As shown, it includes subjecting the copper pyrometallurgical refining slag to weak acid arsenic leaching to obtain arsenic-free leaching slag and arsenic-containing copper liquid; then decopperizing the arsenic-containing copper liquid to obtain copper-containing material and decopperized liquid, and then precipitating arsenic on the decopperized liquid; oxidizing and copper-leaching the arsenic-free leaching slag to obtain copper-leaching slag and copper sulfate solution, and reducing and sulfiding the copper-leaching slag to obtain nickel matte, tin-antimony smoke and smelting slag.

[0017] In the traditional metal recovery process of copper pyrometallurgical refining slag, the slag is generally reduced and smelted to prepare black copper anode plates, and then the black copper anode plates are used to prepare electrolytic copper. The inventors have found that due to the high impurity content in the copper pyrometallurgical refining slag, such as the high arsenic content, the arsenic content in the black copper anode plates prepared therefrom is also high. When it is used to prepare electrolytic copper, it is easy to cause the rapid accumulation of arsenic in the electrolytic system, resulting in an imbalance in the ratio of arsenic, antimony, bismuth and other elements required for the self-purification process of the electrolytic system, and the accumulation of arsenic in the electrolyte and anode mud increases, affecting the smooth progress of the electrolytic process. Therefore, it is necessary to increase the frequency of external treatment of the electrolyte, such as electrolytic decoppering, electrolytic dearsenicing, and evaporation and crystallization separation of the electrolyte to prepare crude nickel sulfate, so as to ensure the purity of the electrolyte and the smooth progress of the electrolytic process.

[0018] However, the cost of electrolytic demetallization is high, which leads to a decrease in the added value of metal recovery in the process and affects the recycling of copper pyrometallurgical refining slag. For example, electrolytic dearsenication usually uses the induction method to produce copper-arsenic powder, and the copper-arsenic ratio in the copper-arsenic powder is about 3:1, which reduces the direct recovery rate of copper in the electrolysis process. In addition, the obtained copper-arsenic powder is usually returned to the pyrometallurgical system, and most of the arsenic in it will be returned to the electrolysis system, which cannot completely open the circuit for arsenic, and the electrolytic dearsenication process is prone to produce highly toxic gas AsH 3 For example, nickel will enter the electrolyte during the electrolysis of black copper anode plates. Nickel can only be used to produce crude nickel sulfate through evaporation and crystallization during the purification of the electrolyte. The evaporation cost is high, the product contains high impurities, and the added value is low.

[0019] Therefore, the inventor creatively proposed to pre-de-arsenicize the pyrometallurgical refining slag with high copper and nickel content, completely remove most of the arsenic from the system, and then oxidize and leach copper on the de-arsenicized leaching slag to reduce the copper grade in the de-arsenicized leaching slag, thereby reducing the copper-nickel ratio in the de-arsenicized leaching slag to obtain copper-leached slag. The copper-nickel ratio of the copper-leached slag is relatively low, which meets the standard for preparing nickel matte by reduction sulfidation. After grinding and flotation separation, the nickel matte can obtain Cu with high purity. 2 S and Ni 3 S 2 , which are used to recover nickel and copper metal elements respectively. The added value of metal recovery is increased, while the post-processing process is shortened and the process cost is reduced.

[0020] Specifically, the inventors proposed to first separate copper and arsenic from the raw material (copper pyrometallurgical refining slag) to obtain arsenic-removed leaching slag and arsenic-containing copper liquid, wherein the metal element in the arsenic-removed leaching slag is mainly copper, and the arsenic content is extremely low, and the main element in the arsenic-containing copper liquid is arsenic. However, in order to ensure that the arsenic content in the arsenic-removed leaching slag is low, the arsenic-containing copper liquid will also contain some copper, and this part of copper can be separated from the large amount of arsenic in the arsenic-containing copper liquid through a subsequent copper removal process.

[0021] The copper-containing material obtained by copper removal can be used to enrich the copper in the arsenic-containing copper liquid, and this part of the copper can be recycled; and the main metal element in the copper-removed liquid obtained by copper removal is arsenic, and the copper content is extremely low, so the copper-removed liquid can be directly precipitated with arsenic, realizing the separation and treatment of arsenic in copper pyrometallurgical refining slag.

[0022] By adopting the weak acid arsenic leaching process, arsenic in copper pyrometallurgical refining slag can be separated from other metal elements, thereby reducing the arsenic content in the de-arsenicized leached slag as much as possible, thereby avoiding the rapid accumulation of arsenic in the system during the electrolysis process, creating conditions for efficiently solving the self-purification open circuit problem of the arsenic electrolysis system and realizing the stable operation of the electrolysis system. However, the arsenic-containing copper liquid obtained in the weak acid arsenic leaching process contains some leached copper elements, so the arsenic-containing copper liquid is de-coppered to ensure the recovery rate of the copper element.

[0023] Since the present invention realizes the separation of copper and arsenic in the copper pyrometallurgical refining slag in advance by weak acid arsenic leaching, the arsenic-free leaching slag with extremely low arsenic content is directly reduced and smelted to prepare black copper anode plates. Therefore, the arsenic content in the black copper anode plates prepared by the present invention is extremely low, and using them to prepare electrolytic copper can solve the problem of self-purification open circuit of arsenic electrolysis system.

[0024] The leaching solution obtained after oxidative copper leaching, that is, the copper sulfate solution, can be directly used as an electrolyte replenisher in the electrolytic copper production process. Since the arsenic element in the raw material (copper pyrometallurgical refining slag) is removed in advance, the copper sulfate solution obtained after oxidative copper leaching will not cause rapid accumulation of arsenic when used as an electrolyte replenisher, thereby solving the open circuit problem of arsenic and ensuring the stability of the electrolytic system operation process.

[0025] In addition, the nickel matte obtained by reducing and sulfiding the copper-leached slag is enriched with copper and nickel, which is convenient for recovering the two metal elements. Impurity metals such as tin and antimony are separated from the nickel matte in the form of smoke, ensuring the purity of the nickel matte product and thus the purity of the recovered copper and nickel.

[0026] In an optional embodiment, the copper pyrometallurgical refining slag is a secondary refining slag, in which, by mass percentage, Cu≥40wt.%, As≥2wt.%, Ni>1.1wt.%, and the mass percentage of copper and nickel is 13.6-33.3. Since the copper content in the secondary refining slag is relatively high, its recycling value is relatively high.

[0027] When the nickel content in the refined secondary slag is high, the copper-nickel ratio is relatively low, so that the refined secondary slag after arsenic removal (i.e., arsenic-free leaching slag) is oxidized and copper-leached, and the copper-leached slag obtained meets the requirements of reduction sulfidation smelting to prepare nickel matte.

[0028] It is understandable that, in addition to the copper, nickel and arsenic elements mentioned above, the secondary slag contains other metal impurities, such as antimony and tin. In addition, the refined slag contains slag-forming materials, such as FeO and SiO, in addition to metal elements. 2 wait.

[0029] In an optional embodiment, during the weak acid leaching of arsenic, the leaching rate of arsenic is ≥60%, the leaching rate of copper is <5%, the leaching rate of nickel is ≤5%, and the leaching rates of tin and antimony are both ≤1%.

[0030] Preferably, during the weak acid leaching of arsenic, the leaching rate of arsenic is 60-70%.

[0031] Preferably, during the weak acid leaching of arsenic, the pH of the acid solution is 2-3, and the pH at the reaction endpoint is 2.5-3.

[0032] Preferably, the acid solution includes any one of sulfuric acid or copper electrolysis waste acid, as long as it can leach out the arsenic element. However, in order to ensure the substances in the reaction process, for example, the copper sulfate solution for oxidative copper leaching can be directly used as the electrolyte replenisher, the acid solution is more preferably sulfuric acid.

[0033] Preferably, during the weak acid leaching of arsenic, the mass percentage of free sulfuric acid is 0.5-2wt.%, for example, it can be any value among 0.5wt.%, 0.6wt.%, 0.7wt.%, 0.8wt.%, 0.9wt.%, 1.0wt.%, 1.1wt.%, 1.2wt.%, 1.3wt.%, 1.4wt.%, 1.5wt.%, 1.6wt.%, 1.7wt.%, 1.8wt.%, 1.9wt.% or 2.0wt.%, or a range value between any two values.

[0034] Preferably, in order to ensure the leaching rate of arsenic, the mass concentration of the slurry during weak acid leaching of arsenic is 10 to 20 wt.%, for example, it can be any value among 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, 14 wt.%, 15 wt.%, 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.% or 20 wt.%, or a range value between any two values.

[0035] Preferably, in order to ensure the leaching rate of arsenic, during the weak acid leaching of arsenic, the reaction temperature is 25 to 80° C. and the reaction time is 0.5 to 2.0 h.

[0036] In an optional embodiment, the oxidative copper leaching includes adding an oxidant to treat the dearsenicized leaching residue under acidic and normal pressure conditions. The purpose is to reduce the copper grade in the copper leaching residue, so that the obtained copper leaching residue meets the copper-nickel ratio requirement for preparing nickel matte, and the obtained copper sulfate solution can be directly used as an electrolyte supplement to recover copper, and the metal recovery effect is better.

[0037] Preferably, the molar ratio of copper to nickel in the copper leaching slag is 1.5 to 4.0, for example, it can be any value among 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 or 4.0, or a range value between any two values.

[0038] Preferably, during the copper oxidation leaching process, the copper leaching rate is ≥80%.

[0039] Preferably, in the copper leaching slag, As is less than 0.7 wt.%; in the copper sulfate solution, As is less than 1.0 g / L. This means that the weak acid arsenic leaching process has a significant effect on removing arsenic.

[0040] Preferably, the acidic condition is a sulfuric acid solution, and the concentration of sulfuric acid is 2.0 to 3.0 mol / L.

[0041] Preferably, the oxidant includes any one of hydrogen peroxide, air or oxygen.

[0042] Preferably, the hydrogen peroxide is industrial hydrogen peroxide, the concentration of the industrial hydrogen peroxide is 27.5%, and the dosage of the industrial hydrogen peroxide is 0.3-0.8 L / kg of arsenic removal leaching residue, that is, 0.3-0.8 L of hydrogen peroxide needs to be added per kilogram of arsenic removal leaching residue.

[0043] Preferably, the reaction temperature of the copper leaching is 60-70°C, and the solid-liquid ratio is 1.0t:7.5-8.5m 3 , the reaction time is 40 to 80 minutes.

[0044] In an optional embodiment, the smelting temperature of the reduction sulfidation smelting is 1200-1300° C., and the amount of coke used is 16-25 wt.%.

[0045] In an optional embodiment, the decoppering process includes decoppering the arsenic-containing copper solution by an extraction method or a precipitation method.

[0046] Preferably, the copper removal treatment is performed when the arsenic concentration in the arsenic-containing copper solution is ≥16 g / L to ensure smooth separation of copper and arsenic in the arsenic-containing copper solution while controlling the cost of copper removal.

[0047] In an optional embodiment, the arsenic removal leaching residue is washed before the oxidation copper leaching to wash away the arsenic element remaining on the surface of the arsenic removal leaching residue. The washing liquid obtained by washing is mixed with the arsenic-containing copper liquid and partially returned to the weak acid arsenic leaching process for cyclic leaching.

[0048] Preferably, the cleaning may be performed multiple times to ensure that the leached arsenic element is completely separated from the de-arsenicized leaching residue.

[0049] In an optional embodiment, the arsenic precipitation process includes using iron salt or calcium salt to precipitate arsenic, and obtaining arsenic precipitation residue and arsenic precipitation liquid. The arsenic precipitation residue can be harmlessly treated by conventional operations. Preferably, the arsenic precipitation liquid is returned to the weak acid arsenic leaching process for cyclic leaching.

[0050] In an optional embodiment, in order to ensure the treatment effect of the subsequent process, the copper pyro-refining slag is further subjected to pre-treatment before weak acid arsenic leaching, and the pre-treatment includes crushing and grinding. By crushing and grinding the copper pyro-refining slag, the recovery rate of the metal in the copper pyro-refining slag can be improved.

[0051] Preferably, after the ore crushing process, the particle size of the copper pyrometallurgical refining slag is 0 to 10 mm.

[0052] Preferably, the ore is crushed in two stages of closed circuit, with a jaw crusher for coarse crushing, a cone crusher for fine crushing, and a vibrating screen for screening.

[0053] Preferably, the grinding adopts two-stage closed-circuit grinding, the first-stage grinding fineness -0.074mm accounts for 60-78%, and the final grinding fineness -0.10mm accounts for 82-92%.

[0054] Preferably, a ball mill is used for grinding, and a cyclone group is used for both the first stage classification and the second stage classification.

[0055] In a second aspect, the present invention provides an application of a method as described in any of the aforementioned embodiments in improving the grade of recovered metals or reducing the cost of producing electrolytic copper from copper pyrometallurgical refining slag.

[0056] Example 1

[0057] This embodiment provides a method for recovering metal from high-nickel copper pyrometallurgical refining slag, and its process flow is as follows: Figure 1 As shown, the specific steps are as follows:

[0058] The element composition of the copper pyrometallurgical refining slag, by mass percentage, includes Cu: 61.45%, As: 2.04%, Ni: 2.34%, Sb: 0.55% and Sn: 2.29%.

[0059] S01. Pre-treatment

[0060] The copper pyrometallurgical refining slag is subjected to two-stage closed-circuit crushing and two-stage closed-circuit grinding to obtain finely ground slurry.

[0061] Among them, jaw crusher is used for coarse crushing, cone crusher is used for fine crushing, and vibrating screen is used for screening. After crushing, the particle size of copper pyrometallurgical refining slag is 50 mesh.

[0062] Ball mill is used for grinding, and cyclone group is used for both the first and second stage classification. The first stage grinding fineness is -0.074mm, accounting for 66%, and the final grinding fineness is -0.10mm, accounting for 88%.

[0063] S02, weak acid arsenic leaching

[0064] The finely ground slurry obtained in step S01 is transported to a leaching reactor or a reaction tank by a mortar pump for weak acid arsenic leaching. The reaction equipment is made of corrosion-resistant materials or corrosion-resistant design to obtain arsenic-free leaching slag and arsenic-containing copper liquid.

[0065] The liquid-solid ratio of the reaction system in the weak acid leaching process is 10L:1kg, a solution containing dilute sulfuric acid is used as the leaching agent, the system pH is adjusted to 2.5-3.0, the reaction time of the weak acid leaching is 1h, the reaction temperature is 30°C, and the system pH at the end of the reaction is 2.87. After the reaction is completed, the leaching rate of arsenic is 62.9%, the leaching rate of copper is 1.5%, the leaching rate of nickel is 0.31%, and the leaching rates of tin and antimony are 0.0% and 0.25% respectively.

[0066] S03, copper removal

[0067] The arsenic-removed leaching residue obtained in step S02 is washed and filtered multiple times, and the washing liquid obtained by separation is mixed with the arsenic-containing copper liquid obtained in step S02. Part of the mixed arsenic-containing copper liquid is recycled to step S01 for use as a leaching liquid, and the remaining part is subjected to precipitation decoppering after the arsenic concentration is ≥16 g / L to obtain a copper-containing material and a decoppered liquid, and the copper in the copper-containing material can be recycled again.

[0068] S04, arsenic precipitation

[0069] The decoppered liquid obtained in step S03 is subjected to arsenic precipitation. The arsenic precipitation is carried out by mixing iron salt with the decoppered liquid to obtain arsenic precipitation slag (i.e. arsenic iron slag) and arsenic precipitation liquid (arsenic <100ppm). The arsenic precipitation slag is harmlessly treated, and the arsenic precipitation liquid is returned to step S01 for recycling as a leaching liquid.

[0070] S05, Oxidation Copper

[0071] The arsenic removal leaching residue obtained after washing and filtering in step S03 is subjected to oxidative copper leaching. The oxidant for oxidative copper leaching is a mixed solvent of hydrogen peroxide and sulfuric acid. The concentration of sulfuric acid is 2.5 mol / L, the amount of hydrogen peroxide is 0.5 L / kg of arsenic removal leaching residue, the liquid-solid ratio is 8 L:1 kg, the reaction temperature is 65 ° C, and the reaction time is 1 h.

[0072] After the reaction is completed, copper leaching slag and copper sulfate solution are obtained. The copper sulfate solution is used as an electrolyte supplement, and the copper sulfate solution contains 67.1g / L copper and 0.64g / L arsenic. The copper leaching slag contains 20.15% copper, 0.79% arsenic, 8.15% nickel, 0.91% antimony and 8.51% tin by mass percentage.

[0073] S06, reduction sulfidation smelting

[0074] The copper-impregnated slag obtained in step S05 is subjected to reduction sulfidation smelting at a smelting temperature of 1250°C and a coke dosage of 19wt.%, to obtain nickel matte, tin-antimony smoke and smelting slag. The nickel matte obtained after reduction sulfidation smelting in this embodiment is low-grade nickel matte, which contains 37.5wt.% copper and 15.05wt.% nickel. The smoke contains tin and antimony.

[0075] Example 2

[0076] This embodiment provides a method for recovering metal from high-nickel copper pyrometallurgical refining slag. The copper pyrometallurgical refining slag to be treated is the same as that in Example 1, and the method for recovering metal is similar to that in Example 1, except that steps S05 and S06 are different, as follows:

[0077] S05, Oxidation Copper

[0078] The arsenic removal leaching residue obtained after washing and filtering in step S03 is subjected to oxidative copper leaching. The oxidative copper leaching adopts sulfuric acid leaching with air blowing. The sulfuric acid concentration is 3 mol / L, the liquid-solid ratio is 8L:1kg, the reaction temperature is 65°C, and the reaction time is 1h.

[0079] After the reaction is completed, copper leaching slag and copper sulfate solution are obtained. The copper sulfate solution is used as an electrolyte supplement, and the copper sulfate solution contains 64.9 g / L copper and 0.56 g / L arsenic. The copper leaching slag contains 24.58% copper, 0.94% arsenic, 8.17% nickel, 0.93% antimony and 8.52% tin by mass percentage.

[0080] S06, reduction sulfidation smelting

[0081] The copper-impregnated slag obtained in step S05 is subjected to reduction sulfidation smelting at a smelting temperature of 1250°C and a coke dosage of 20wt.%, to obtain nickel matte, tin-antimony smoke and smelting slag. The nickel matte obtained after reduction sulfidation smelting in this embodiment is low-grade nickel matte, which contains 45.72wt.% copper and 15.17wt.% nickel. The smoke contains tin and antimony.

[0082] Example 3

[0083] This embodiment provides a method for recovering metal from high-nickel copper pyrometallurgical refining slag, and its process flow is as follows: Figure 1 As shown, the specific steps are as follows:

[0084] The element composition of the copper pyrometallurgical refining slag, by mass percentage, includes Cu: 45.64%, As: 3.63%, Ni: 3.38%, Sb: 1.47 and Sn: 1.27%.

[0085] S01. Pre-treatment

[0086] The copper pyrometallurgical refining slag is subjected to two-stage closed-circuit crushing and two-stage closed-circuit grinding to obtain finely ground slurry.

[0087] Among them, jaw crusher is used for coarse crushing, cone crusher is used for fine crushing, and vibrating screen is used for screening. After crushing, the particle size of copper pyrometallurgical refining slag is 50 mesh.

[0088] Ball mill is used for grinding, and cyclone group is used for both the first and second stage classification. The first stage grinding fineness is -0.074mm, accounting for 66%, and the final grinding fineness is -0.10mm, accounting for 88%.

[0089] S02, weak acid arsenic leaching

[0090] The finely ground slurry obtained in step S01 is transported to a leaching reactor or a reaction tank by a mortar pump for weak acid arsenic leaching. The reaction equipment is made of corrosion-resistant materials or corrosion-resistant design to obtain arsenic-free leaching slag and arsenic-containing copper liquid.

[0091] The liquid-solid ratio of the reaction system in the weak acid leaching process is 10L:1kg, a solution containing dilute sulfuric acid is used as the leaching agent, the system pH is adjusted to 2.5-3.0, the reaction time of the weak acid leaching is 1h, the reaction temperature is 35°C, and the system pH at the end of the reaction is 2.75. After the reaction is completed, the leaching rate of arsenic is 68.5%, the leaching rate of copper is 1.25%, the leaching rate of nickel is 0.25%, and the leaching rates of tin and antimony are 0.35% and 0.00% respectively.

[0092] S03, copper removal

[0093] The arsenic-removed leaching residue obtained in step S02 is washed and filtered multiple times, and the washing liquid obtained by separation is mixed with the arsenic-containing copper liquid obtained in step S02. Part of the mixed arsenic-containing copper liquid is recycled to step S01 for use as a leaching liquid, and the remaining part is subjected to precipitation decoppering after the arsenic concentration is ≥16 g / L to obtain a copper-containing material and a decoppered liquid, and the copper in the copper-containing material can be recycled again.

[0094] S04, arsenic precipitation

[0095] The decoppered liquid obtained in step S03 is subjected to arsenic precipitation. The arsenic precipitation is carried out by mixing calcium salt with the decoppered liquid to obtain arsenic precipitation slag (containing a large amount of arsenic) and arsenic precipitation liquid (the arsenic content is greatly reduced). The arsenic precipitation slag is harmlessly treated, and the arsenic precipitation liquid is returned to step S01 for recycling as a leaching liquid.

[0096] S05, Oxidation Copper

[0097] The arsenic removal leaching residue obtained after washing and filtering in step S03 is subjected to oxidative copper leaching. The oxidant for oxidative copper leaching is a mixed solvent of hydrogen peroxide and sulfuric acid. The concentration of sulfuric acid is 2.5 mol / L, the amount of hydrogen peroxide is 0.5 L / kg of arsenic removal leaching residue, the liquid-solid ratio is 8 L:1 kg, the reaction temperature is 65 ° C, and the reaction time is 1 h.

[0098] After the reaction is completed, copper leaching slag and copper sulfate solution are obtained. The copper sulfate solution is used as an electrolyte supplement, and the copper sulfate solution contains 49.5g / L copper and 0.88g / L arsenic. The copper leaching slag contains 15.65% copper, 1.24% arsenic, 8.87% nickel, 2.31% antimony and 3.59% tin by mass.

[0099] S06, reduction sulfidation smelting

[0100] The copper-impregnated slag obtained in step S05 is subjected to reduction sulfidation smelting at a smelting temperature of 1250°C and a coke dosage of 17wt.%, to obtain nickel matte, tin-antimony smoke and smelting slag. The nickel matte obtained after reduction sulfidation smelting in this embodiment is low-grade nickel matte, which contains 28.89wt.% copper and 16.37wt.% nickel. The smoke contains tin and antimony.

[0101] Comparative Example 1

[0102] This comparative example provides a method for recovering metal from high-nickel copper pyrometallurgical slag. The copper pyrometallurgical slag to be treated is the same as that in Example 1, and the method for recovering metal is similar to that in Example 1, except that the step of weak acid arsenic leaching in S02 is different, as follows:

[0103] S02, weak acid arsenic leaching

[0104] The finely ground slurry obtained in step S01 is transported to a leaching reactor or a reaction tank by a mortar pump for weak acid arsenic leaching. The reaction equipment is made of corrosion-resistant materials or corrosion-resistant design to obtain arsenic-free leaching slag and arsenic-containing copper liquid.

[0105] The liquid-solid ratio of the reaction system in the weak acid leaching process is 10L:1kg, a solution containing dilute sulfuric acid is used as the leaching agent, the system pH is adjusted to 1.5-2.0, the reaction time of the weak acid leaching is 1h, the reaction temperature is 30°C, and the system pH at the end of the reaction is 1.6. After the reaction is completed, the leaching rate of arsenic is 75.8%, the leaching rate of copper is 30.68%, the leaching rate of nickel is 0.62%, and the leaching rates of tin and antimony are 0.42% and 0.00% respectively.

[0106] Since the copper leaching rate in the arsenic-containing copper solution obtained in step S02 is high and the copper loss rate is large, the copper in the arsenic-containing copper solution needs to be further recovered subsequently, which increases the process cost.

[0107] S05, Oxidation Copper

[0108] After the reaction is completed, copper leaching slag and copper sulfate solution are obtained. The copper sulfate solution is used as an electrolyte supplement, and the copper sulfate solution contains 45g / L copper and 0.30g / L arsenic. Due to the low copper content in the copper sulfate solution, the consumption of copper sulfate increases during the production of electrolytic copper, which increases the cost. The copper leaching slag contains 20.23% copper, 0.79% arsenic, 8.15% nickel, 0.91% antimony and 8.51% tin by mass.

[0109] S06, reduction sulfidation smelting

[0110] The copper-leached slag obtained in step S05 is subjected to reduction sulfidation smelting at a smelting temperature of 1250°C and a coke dosage of 17wt.%, to obtain nickel matte, tin-antimony smoke and smelting slag. The nickel matte obtained after reduction sulfidation smelting in this comparative example is low-grade nickel matte, which contains 37.55wt.% copper and 15.06wt.% nickel. The smoke contains tin and antimony.

[0111] Comparative Example 2

[0112] This comparative example provides a method for recovering metal from high-nickel copper pyrometallurgical slag. The copper pyrometallurgical slag to be treated is the same as that in Example 1, and the method for recovering metal is similar to that in Example 1, except that step S02 is different, as follows:

[0113] S02, weak acid arsenic leaching

[0114] The finely ground slurry obtained in step S01 is transported to a leaching reactor or a reaction tank by a mortar pump for weak acid arsenic leaching. The reaction equipment is made of corrosion-resistant materials or corrosion-resistant design to obtain arsenic-free leaching slag and arsenic-containing copper liquid.

[0115] The liquid-solid ratio of the reaction system in the weak acid leaching process is 10L:1kg, a solution containing dilute sulfuric acid is used as the leaching agent, the system pH is adjusted to 4.0-4.5, the reaction time of the weak acid leaching is 1h, the reaction temperature is 30°C, and the system pH at the end of the reaction is 4.38. After the reaction is completed, the leaching rate of arsenic is 25.6%, the leaching rate of copper is 0.18%, the leaching rate of nickel is 0.12%, and the leaching rates of tin and antimony are 0.21% and 0.00%, respectively.

[0116] Since the arsenic leaching rate in the arsenic-containing copper solution obtained in step S02 is low, most of the arsenic is still present in the de-arsenicizing leaching residue. After the de-arsenicizing leaching residue is subjected to oxidation copper leaching in the same manner as step S05 of Example 1, the obtained copper sulfate solution contains 67.46 g / L of copper and 1.59 g / L of arsenic. The arsenic content in the copper sulfate solution is relatively high, which is likely to affect the preparation process of electrolytic copper. The obtained copper leaching slag contains 22.69% copper, 0.75% arsenic, 7.90% nickel, 0.90% antimony and 8.50% tin by mass.

[0117] The reduction sulfidation smelting was carried out in the same manner as step S06 of Example 1, with the smelting temperature being 1250°C and the amount of coke being 17 wt.%. The nickel matte obtained after the reduction sulfidation smelting was low nickel matte, which contained 42.89 wt.% of copper and 14.19 wt.% of nickel. The smoke contained tin and antimony.

[0118] Comparative Example 3

[0119] This comparative example provides a method for recovering metal from high-nickel copper pyrometallurgical refining slag. The copper pyrometallurgical refining slag to be treated is the same as that in Example 1, and the method for recovering metal is similar to that in Example 1, except that step S05 is not included, and the arsenic-free leaching slag obtained after washing and filtering in step S03 is directly subjected to reduction sulfidation smelting in the same manner as step S06 in Example 1, the smelting temperature is 1200°C, and the amount of coke used is 15wt.%.

[0120] Since the copper and nickel content of the arsenic removal leaching residue obtained after washing and filtering in step S03 is relatively high, nickel matte cannot be obtained after reduction sulfidation smelting, and only black copper anode plates, tin-antimony smoke and smelting slag can be obtained. The black copper plate contains 89.01wt.%, 3.86wt.% nickel, and 1.058wt.% arsenic. The smoke contains tin and antimony.

[0121] Comparative Example 4

[0122] This comparative example provides a method for recovering metals from high-nickel copper pyrometallurgical refining slag. The specific steps are the same as those in Example 1, except that the elemental composition of the copper pyrometallurgical refining slag is different. The elemental composition of the copper pyrometallurgical refining slag, measured by mass percentage, includes Cu: 50.25%, As: 3.52%, Ni: 1.05%, Sb: 1.67 and Sn: 2.34%.

[0123] The copper pyrometallurgical refining slag provided in this comparative example was recovered in the same manner as in Example 1. In the weak acid leaching of arsenic in step S02, the system pH at the end of the reaction was 2.72. After the reaction was completed, the leaching rate of arsenic was 64.4%, the leaching rate of copper was 1.12%, the leaching rate of nickel was 0.2%, and the leaching rates of tin and antimony were 0.31% and 0.00%, respectively.

[0124] The copper leaching slag and copper sulfate solution obtained by oxidation leaching of copper in step S05. The copper sulfate solution is used as an electrolyte supplement, and the copper sulfate solution contains 54.57 g / L of copper and 0.98 g / L of arsenic. The copper leaching slag contains 17.23% copper, 1.20% arsenic, 2.86% nickel, 2.62% antimony and 6.61% tin by mass.

[0125] The smelting temperature of the reduction sulfidation smelting in step S06 is 1250°C, the amount of coke used is 17wt.%, and matte, tin-antimony smoke and smelting slag are obtained. The matte obtained after the reduction sulfidation smelting in this comparative example is matte, which contains 31.98wt.% copper and 5.13wt.% nickel. The smoke contains tin and antimony.

[0126] Test Example 1

[0127] The recovery rates of copper and nickel metals and the removal rate of arsenic in the copper pyrometallurgical refining slag by the methods of Examples 1 to 3 and Comparative Examples 1 to 5 were calculated, and the results shown in Table 1 were obtained.

[0128] Table 1 Metal recovery and arsenic removal rate in copper pyrometallurgical refining slag

[0129] Copper / wt.% Nickel / wt.% Arsenic / wt.% Example 1 97.64 91.17 62.9 Example 2 97.58 91.15 62.9 Example 3 97.89 91.20 68.5 Comparative Example 1 70.92 90.88 75.8 Comparative Example 2 98.87 91.61 25.6 Comparative Example 3 96.56 91.74 62.9 Comparative Example 4 98.00 90.3 64.4

[0130] Note: The metal recovery rate is calculated as the percentage of the sum of the mass of metal in the copper sulfate solution in the oxidation copper leaching step and the mass of metal recovered in the nickel matte / black copper anode plate / matte obtained by reduction sulfidation smelting to the total mass of metal in the copper pyro-refining slag. For example, copper recovery rate = the sum of the mass of copper in the copper sulfate solution in the oxidation copper leaching step and the mass of copper in the nickel matte obtained by reduction sulfidation smelting to the total mass of copper in the copper pyro-refining slag; the arsenic removal rate is calculated as the mass of arsenic leached by weak acid to the total mass of arsenic in the copper pyro-refining slag.

[0131] It can be seen from Table 1 that the method provided in the embodiment of the present invention can effectively realize the recovery of metals and the separation of copper and arsenic at the same time. The metal recovery rate is high and the separation effect between copper nickel and tin antimony is good. The metals finally recovered are sold as nickel matte products. The nickel has a high pricing coefficient and is more valuable. In Comparative Example 1, since the copper leaching rate in the arsenic-containing copper liquid is relatively high, the copper recovery rate is low, and the metal recovery value is relatively low compared with the example, and the copper in the weak acid arsenic leaching liquid needs to be further recovered, which increases the cost; on the other hand, the copper sulfate solution obtained by oxidative leaching of copper in Comparative Example 1 has a concentration 32.9% lower than that in Example 1. When used as an electrolyte replenisher, the electrolyte purification is accelerated and the cost increases; in Comparative Example 2, since the arsenic leaching rate in the S02 step is low, the arsenic content in the obtained nickel matte is high and the value is low; Comparative Example 3 cannot obtain nickel matte products, and is sold as black copper plates. The copper pricing coefficient is low and the value is relatively low; the copper pyrometallurgical refining slag in Comparative Example 4 has a relatively high copper-nickel ratio, and cannot obtain nickel matte products. It can only be sold as copper matte products, and the copper pricing coefficient is low, and the value is relatively low.

[0132] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for recovering metal from high-nickel copper pyrometallurgical refining slag, characterized in that: The method comprises subjecting the copper pyrometallurgical refining slag to weak acid arsenic leaching to obtain arsenic-removed leaching slag and arsenic-containing copper liquid; then decopperizing the arsenic-containing copper liquid to obtain copper-containing material and decopperized liquid, and then precipitating arsenic on the decopperized liquid; subjecting the dearsenic-refining leaching slag to oxidative copper leaching to obtain copper-leaching slag and copper sulfate solution, and subjecting the copper-leaching slag to reduction sulfide smelting to obtain nickel matte, tin-antimony smoke and smelting slag.

2. The method according to claim 1, characterized in that The copper pyrometallurgical refining slag is a secondary refined slag. In the secondary refined slag, Cu≥40wt.%, As≥2wt.%, Ni>1.1wt.%, and the mass percentage of copper and nickel is 13.6-33.

3.

3. The method according to claim 1, characterized in that During the weak acid leaching of arsenic, the leaching rate of arsenic is ≥60%, the leaching rate of copper is <5%, the leaching rate of nickel is ≤5%, and the leaching rates of tin and antimony are both ≤1%; Preferably, during the weak acid leaching of arsenic, the leaching rate of arsenic is 60-70%; Preferably, during the weak acid leaching of arsenic, the pH of the acid solution is 2 to 3; Preferably, the acid solution comprises any one of sulfuric acid and copper electrolysis waste acid, more preferably sulfuric acid; Preferably, the concentration of free sulfuric acid in the acid solution is 0.5 to 2 wt.%; Preferably, during the weak acid leaching of arsenic, the concentration of the slurry is 10-20wt.%; Preferably, during the weak acid leaching of arsenic, the reaction temperature is 25-80° C., the reaction time is 0.5-2.0 h, and the pH at the reaction endpoint is 2.5-3.

4. The method according to claim 1, characterized in that: The oxidative copper leaching comprises adding an oxidant to treat the dearsenicized leaching residue under acidic conditions; Preferably, the molar ratio of copper to nickel in the copper leaching slag is 1.5 to 4.0; During the oxidation copper leaching process, the copper leaching rate is ≥80%; in the copper leaching slag, As is <0.7wt.%; in the copper sulfate solution, As is <1.0g / L; Preferably, the acidic condition is a sulfuric acid solution, and the concentration of the sulfuric acid is 2.0 to 3.0 mol / L; Preferably, the oxidant comprises any one of hydrogen peroxide, air or oxygen; Preferably, the dosage of the hydrogen peroxide is 0.3-0.8 L / kg of the arsenic removal leaching residue; Preferably, the reaction temperature of the copper leaching is 60-70°C, and the solid-liquid ratio is 1.0t:7.5-8.5m 3 , the reaction time is 40 to 80 minutes.

5. The method according to claim 1 or 4, characterized in that: The smelting temperature of the reduction sulfidation smelting is 1200-1300° C., and the amount of coke used is 16-25wt.%.

6. The method according to claim 1, characterized in that The decoppering process includes decoppering the arsenic-containing copper solution by an extraction method or a precipitation method; Preferably, decoppering is performed when the arsenic concentration in the arsenic-containing copper solution is ≥16 g / L.

7. The method according to claim 6, characterized in that The process also includes washing the de-arsenicized leaching residue before oxidative copper leaching, mixing the washing liquid obtained by washing with the arsenic-containing copper liquid and returning the washing liquid to the weak acid arsenic leaching process for cyclic leaching.

8. The method according to claim 1, characterized in that The copper pyrometallurgical slag further comprises pre-treatment of the copper pyrometallurgical slag before weak acid arsenic leaching, wherein the pre-treatment comprises ore crushing and ore grinding; Preferably, after the ore crushing process, the particle size of the copper pyrometallurgical refining slag is 0 to 10 mm; Preferably, the ore crushing adopts two-stage closed-circuit ore crushing, the coarse crushing adopts a jaw crusher, the fine crushing adopts a cone crusher, and the screening adopts a vibrating screen; Preferably, the grinding adopts two-stage closed-circuit grinding, the first-stage grinding fineness -0.074mm accounts for 60-68%, and the final grinding fineness -0.10mm accounts for 82-92%; Preferably, the grinding is performed by a ball mill, and both the first-stage classification and the second-stage classification are performed by a cyclone group.

9. The method according to claim 1, characterized in that: The arsenic precipitation process comprises using iron salt or calcium salt to precipitate arsenic, and obtaining arsenic precipitation residue and arsenic precipitation liquid; Preferably, the liquid after arsenic precipitation is returned to the weak acid arsenic leaching process for cyclic leaching.

10. Use of the method according to any one of claims 1 to 9 in improving the grade of recovered metals or reducing the cost of producing electrolytic copper from copper pyrometallurgical refining slag.

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