Treatment method of pyrometallurgy zinc slag

Abstract

The invention discloses a treatment method of pyrogenic process zinc slag, which comprises the following steps: (1) sorting the pyrogenic process zinc slag, picking out bulk metallic materials with the particle size of more than 50mm for independent treatment, crushing the residual pyrogenic process zinc slag, and controlling the particle size of the residual pyrogenic process zinc slag to be less than 15mm; (2) grinding the crushed pyrometallurgy zinc slag, wherein the proportion of materials less than 80 meshes exceeds 75%; and (3) the ground material is subjected to oxidation leaching with hydrochloric acid and hydrogen peroxide, most of metal elements of iron, tin, zinc, copper, nickel, indium, gallium and germanium are dissolved in a leaching solution, and Pb, Sb and Ag are mainly enriched in leaching residues. According to the method, valuable elements in the pyrometallurgy zinc slag which is difficult to treat and high in added value are recycled through the crushing-grinding-oxidation leaching technology, the technological method is simple, efficient and reliable, the metal recycling rate is high, energy consumption is low, the hydrometallurgy treatment process is adopted, the equipment investment cost is low, environmental pollution is small, the requirements for energy conservation and emission reduction and clean metallurgy are met, and the method is suitable for industrial production. Wide popularization and application values are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for treating pyrometallurgical zinc slag. Background Art

[0002] There are two current industrial zinc smelting methods: pyrometallurgical zinc smelting and hydrometallurgical zinc smelting. Pyrometallurgical zinc smelting is divided into blast furnace, vertical tank smelting, electric furnace zinc and other methods. Zinc-containing materials are mixed with coke and flux as raw materials, and reduction smelting is carried out under high temperature conditions in a closed furnace. Generally, there are problems such as high energy consumption and environmental pollution, but it has high production efficiency and low investment. Hydrometallurgical zinc smelting is currently the most widely used zinc smelting process, with high smelting recovery rate and low environmental pollution, but hydrometallurgical zinc smelting also has problems such as long process flow, complex procedures and large investment.

[0003] Electric furnace zinc smelting has the characteristics of high smelting recovery efficiency, simple industrial equipment, high thermal efficiency and low environmental pollution. It is one of the important technologies of pyrometallurgical zinc smelting. Most of the valuable elements in zinc concentrate are enriched in the slag during pyrometallurgical zinc smelting, forming bottom slag containing iron, lead, copper and rare precious metals. Since the slag of pyrometallurgical zinc smelting is difficult to handle, the bottom slag of most pyrometallurgical zinc smelting enterprises is discharged from the furnace after further heating and melting, and is directly stored or sold at a low price, causing serious environmental pollution and waste of valuable metal resources. Therefore, the development of new technologies for the effective treatment of bottom slag of pyrometallurgical zinc smelting is of great significance to reducing environmental pollution and effectively utilizing resources.

[0004] Pyrometallurgical zinc slag is a by-product produced during the pyrometallurgical smelting of zinc concentrate. Due to its complex composition and stable structure, it is difficult to handle and requires the use of new technologies and methods for continuous attempts and research. Common treatment methods include physical separation and chemical treatment. Due to the high density of zinc slag, the metals and impurities in it can be separated by gravity separation or flotation, so that recyclable metals such as zinc, lead, and iron can be extracted. Chemical treatment is to react zinc slag with acidic or alkaline solutions to dissolve or precipitate the metal ions therein, thereby realizing the recovery or solidification of metals. Another treatment method is pyrometallurgical treatment, such as smelting, roasting, etc. The zinc slag is heated to cause a series of physical and chemical changes in the metals therein, thereby realizing their separation and recovery.

[0005] In the process of zinc slag treatment, it is necessary to pay attention to the principles of environmental protection and resource utilization, strictly control waste discharge, and prevent the generation of harmful substances. At the same time, the metal recovery rate should be improved and resources should be used efficiently.

[0006] In summary, the treatment of zinc slag requires comprehensive consideration of physical separation, chemical treatment and thermal treatment methods, and selection and optimization based on the composition of zinc slag and the characteristics of the metal to be recovered. At the same time, attention should be paid to environmental protection and resource utilization to achieve efficient, energy-saving and environmentally friendly zinc slag treatment.

[0007] For example, the Chinese invention patent disclosed in CN107739838B discloses a method for recovering iron and enriching copper and tin from bottom slag of electric furnace zinc smelting, wherein the mass percentage of the chemical composition of the bottom slag of electric furnace zinc smelting is: Fe55%~85%, Cu6%~25%, Sn1%~2.5%, As0.2%~1%, In800~1500g / t, and the specific operation is as follows: first, the bottom iron is cut and crushed, and after the alloy is completely melted at high temperature, the molten alloy liquid is selectively oxidized in an oxidizing atmosphere to obtain tin-containing crude copper and ferrous oxide slag, and at the same time, indium and part of arsenic are volatilized and separated, and then the ferrous oxide slag is leached with hydrochloric acid, and a filtrate and a filter residue are obtained after filtration. After the filtrate is decoppered and the copper removal liquid is deeply decontaminated, a pure FeCl2 solution is obtained, and finally spray thermal decomposition is performed to obtain iron red and hydrochloric acid, and the hydrochloric acid regeneration rate is 95%~99%. This process includes pyrolysis and wet treatment processes, with a long process flow, high technical requirements and high production costs, making it difficult to promote and apply on a large scale in industrial production processes.

[0008] CN1113520 discloses a hydrometallurgical method for recovering copper and zinc from copper-zinc materials, wherein ammonia is used to leach the copper-zinc materials, and then the copper and zinc in the leachate are separated by extraction, the copper-rich solution is sent to electrowinning to produce electro-copper, and the raffinate is subjected to ammonia evaporation to obtain basic zinc carbonate, which is then sent to calcination to obtain active zinc oxide. The method of the present invention belongs to normal pressure ammonia leaching, which mainly achieves the dissolution of copper and zinc into the solution, and impurities such as calcium, magnesium, manganese, and iron remain in the slag, and then the copper and zinc are separated by extraction, which mainly achieves the efficient recovery of copper and zinc, and is difficult to be applied to pyrometallurgical zinc slag containing many types of valuable elements.

[0009] Therefore, after fully detecting and analyzing the types, contents and phases of valuable elements in pyrometallurgical zinc slag and evaluating the existing technical processing level and the urgent needs of enterprises, the present invention has developed and completed this technology after conducting a lot of theoretical discussions, experimental research and production practices. Summary of the invention

[0010] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for treating pyrometallurgical zinc slag. To solve the above technical problem, the basic concept of the technical solution adopted by the present invention is: A method for treating pyrometallurgical zinc slag comprises the following steps: (1) Sorting the pyrometallurgical zinc slag, selecting the large metallic materials larger than 50 mm for separate treatment, and crushing the remaining pyrometallurgical zinc slag to control its particle size to less than 15 mm; (2) Grinding the crushed pyrometallurgical zinc slag, with the proportion of materials smaller than 80 mesh exceeding 75%; (3) The ground material is oxidized and leached with hydrochloric acid and hydrogen peroxide. Most of the metal elements such as iron, tin, zinc, copper, nickel, indium, gallium and germanium are dissolved in the leaching solution, while Pb, Sb and Ag are mainly enriched in the leaching residue.

[0011] Furthermore, in step (3), the reaction temperature of the oxidation leaching is 40°C to 60°C, the reaction time is 4h to 6h, the liquid-to-solid ratio is 5 to 8:1, the concentration of hydrochloric acid used is 120 to 180 g / L, and the concentration of hydrogen peroxide is 80 to 120 g / L.

[0012] Furthermore, the metal elements of iron, tin, zinc, copper, nickel, indium, gallium and germanium in the leaching solution of step (3) are extracted by displacement, sedimentation or extraction.

[0013] Furthermore, a smelting method is used to recover the Pb, Sb and Ag metal elements in the leached slag in step (3).

[0014] After adopting the above technical scheme, the present invention has the following beneficial effects compared with the prior art.

[0015] The invention realizes the recovery of valuable elements in the difficult-to-treat high-value-added pyrometallurgical zinc slag through a crushing-grinding-oxidation leaching process, and the leaching rates of Zn, In, Cu, Ni, Sn and Fe can all reach more than 95%, the leaching rate of Ge can reach 85%, the leaching rate of Ga can reach 94.03%, and Pb, Sb and Ag are mainly enriched in the leached slag. The process method of the invention is simple, efficient and reliable, with high metal recovery rate and low energy consumption. The hydrometallurgical treatment process is adopted, the equipment investment cost is low, the environmental pollution is small, the requirements of energy conservation, emission reduction and clean metallurgy are met, and the invention has wide promotion and application value.

[0016] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are part of this application and are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the drawings described below are only some embodiments. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings: Figure 1 It is a schematic diagram of the process flow of the present invention.

[0018] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention. Example

[0020] The pyrometallurgical zinc slag is sorted, and the large metallic materials larger than 50mm are selected for separate treatment. The remaining pyrometallurgical zinc slag is crushed to control its particle size to be less than 15mm. The crushed pyrometallurgical zinc slag is then ground, and the proportion of materials smaller than 80 mesh is more than 75%. 100g of the ground material is oxidized and leached with hydrochloric acid and hydrogen peroxide, with a reaction temperature of 40°C, a reaction time of 6h, a liquid-to-solid ratio of 6:1, a hydrochloric acid concentration of 120g / L, and a hydrogen peroxide concentration of 80g / L.

[0021] After the reaction is completed, the elements in the leaching solution and the leaching residue are determined. The leaching rates of zinc Zn, indium In, copper Cu, nickel Ni, tin Sn, and iron Fe can all reach more than 90%, the leaching rate of germanium Ge can reach 81%, and the leaching rate of gallium Ga can reach 90%; the leaching residue contains Pb 58.21%, Sb 9.35%, and Ag 5384g / t; the treatment results of the invention have achieved the expected goals and the effect is relatively ideal. Example

[0022] The pyrometallurgical slag is sorted, and the large metallic materials larger than 50mm are selected and processed separately. The remaining pyrometallurgical slag is crushed to control its particle size to be less than 15mm; then the crushed pyrometallurgical slag is ground, and the proportion of materials smaller than 80 mesh is more than 75%; 100g of the ground material is oxidized and leached with hydrochloric acid and hydrogen peroxide, with a reaction temperature of 50℃, a reaction time of 6h, a liquid-to-solid ratio of 8:1, a hydrochloric acid concentration of 150g / L, and a hydrogen peroxide concentration of 100g / L.

[0023] After the reaction is completed, the elements in the leachate and the leaching residue are determined. The leaching rates of zinc Zn, indium In, copper Cu, nickel Ni, tin Sn, and iron Fe can all reach more than 95%, the leaching rate of germanium Ge can reach 85%, and the leaching rate of gallium Ga can reach 94.03; the leaching residue contains Pb 55.18%, Sb 8.42%, and Ag 5297g / t; the treatment results of the invention have achieved the expected goals and the effect is relatively ideal. Example

[0024] The pyrometallurgical zinc slag is sorted, and the large metallic materials larger than 50mm are selected and processed separately. The remaining pyrometallurgical zinc slag is crushed to control its particle size to be less than 15mm. The crushed pyrometallurgical zinc slag is then ground, and the proportion of materials smaller than 80 mesh is more than 75%. 100g of the ground material is oxidized and leached with hydrochloric acid and hydrogen peroxide, with a reaction temperature of 60℃, a reaction time of 6h, a liquid-to-solid ratio of 8:1, a hydrochloric acid concentration of 180g / L, and a hydrogen peroxide concentration of 120g / L.

[0025] After the reaction is completed, the elements in the leachate and the leaching residue are determined. The leaching rates of zinc Zn, indium In, copper Cu, nickel Ni, tin Sn, and iron Fe can all reach more than 95%, the leaching rate of germanium Ge can reach 84%, and the leaching rate of gallium Ga can reach 93%; the leaching residue contains Pb 56.33%, Sb 9.35%, and Ag 5278g / t; the treatment results of the invention have achieved the expected goals and the effect is relatively ideal.

[0026] In summary, the present invention provides a method for treating pyrometallurgical zinc slag, which is an effective method for extracting valuable metal elements such as Zn, In, Cu, Ni, Sn, Fe, Ge, Ga, Pb, Sb, Ag, etc. from pyrometallurgical zinc slag, has high recovery rate, low energy consumption, mainly based on hydrometallurgical process, simple and reliable process, economical and controllable production cost, and has wide promotion and application value.

[0027] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A method for treating pyrometallurgical zinc slag, characterized in that: The following steps are involved: Step (1), sorting the pyrometallurgical zinc slag, selecting the large metal-like materials larger than 50 mm and treating them separately, and crushing the remaining pyrometallurgical zinc slag to control the particle size of the crushed particles to be less than 15 mm; Step (2), grinding the crushed pyrometallurgical zinc slag, wherein the proportion of materials smaller than 80 meshes exceeds 75%; Step (3), the ground material is oxidized and leached with hydrochloric acid and hydrogen peroxide, and the metal elements of iron, tin, zinc, copper, nickel, indium, gallium and germanium are dissolved in the leaching solution, and Pb, Sb and Ag are enriched in the leaching residue.

2. The method for treating zinc slag by pyrometallurgy according to claim 1, characterized in that: The reaction temperature of the oxidation leaching in step (3) is 40°C to 60°C, the reaction time is 4h to 6h, the liquid-to-solid ratio is 5 to 8:1, the concentration of hydrochloric acid used is 120 to 180 g / L, and the concentration of hydrogen peroxide is 80 to 120 g / L.

3. The method for treating zinc slag by pyrometallurgy according to claim 1, characterized in that: The metal elements of iron, tin, zinc, copper, nickel, indium, gallium and germanium in the leaching solution of step (3) are extracted by replacement, sedimentation or extraction.

4. The method for treating zinc slag by pyrometallurgy according to claim 1, characterized in that: The Pb, Sb and Ag metal elements in the leached slag of step (3) are recovered by a smelting method.

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