Method for treating tin-copper slag through whole wet method

Abstract

The invention discloses a method for treating tin-copper slag through a whole wet method. The method comprises the following steps of: performing oxygen-pressure alkaline leaching on tin-copper slag through sodium hydroxide or potassium hydroxide, wherein a liquid-solid mass ratio is (3-12) to 1, initial alkaline concentration of alkaline liquor is 60-200g / l, reaction temperature ranges from 110 DEG C to 150 DEG C, reaction is performed for 2-6 hours, and reaction pressure is 1-2 MPa; getting leach liquor which is a sodium stannate solution or a potassium stannate solution, adding tin to replace stibium and copper, adding sodium sulfide to remove lead, purifying the solution, evaporating, concentrating, cooling and crystallizing the purified solution to obtain a stannate product; washing leach residues, performing sulfuric acid normal-pressure leaching, and separately generating a secondary leach liquor copper sulfate solution and secondary leach residue tin concentrate, wherein acidity of H2SO4 is 50-150g / l, a liquid-solid mass ratio is (2-10) to 1, and a leaching temperature is 40-95 DEG C; evaporating, concentrating, cooling and crystallizing the copper sulfate solution to obtain a copper sulfate product, drying and returning the tin concentrate to a tin smelting system. The method can generate a stannate product, and also can effectively separate copper in the tin-copper slag.

Description

technical field [0001] The invention belongs to the technical field of hydrometallurgy and chemical industry, and in particular relates to a method for removing copper slag from tin refining. Background technique [0002] In the tin smelting process, after the tin concentrate is reduced and smelted into crude tin, due to the existence of copper in the tin smelting raw materials, the copper content in the crude tin is relatively high. Tin-copper slag (also known as sulfur slag) with a tin content of 10-30% and a tin content of 30-80%. Most of the tin in this slag exists in the form of metal, oxide or alloy, and most of the copper exists in the form of copper sulfide. There are mainly the following methods for the treatment of such tin-copper slag at home and abroad: [0003] (1) Pyromelting: A certain proportion of flux is added to smelt in a short kiln to produce a semi-product of tin-copper alloy. Because a large amount of impurities in the slag enter the alloy, it is dif...

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Problems solved by technology

[0003] (1) Pyromelting: A certain proportion of flux is mixed in a short kiln for smelting to produce semi-products of tin-copper alloy. Due to the large amount of impurities in the slag entering the alloy, it is difficult to further process the alloy product

[0004] (2) Roasting-leaching method: After the tin-copper slag is roasted, sulfuric acid is used to leaching the calcine, so that copper is opened from the tin smelting system in the form of copper sulfate products. This method has a low softening point of the tin-copper slag due to the existence of a large amount of metallic tin. , it is necessary to carry out multi-stage roasting to achieve the purpose of roasting without kiln formation and desulfurization, so that the roasting time is very long and the processing cost is high

Due to the existence of powdery copper sulfide in this method, the direct recovery rate of tin during electrolysis is low, and the current efficiency is low, resulting in poor economic benefits.

[0006] (4) Full wet process: Some researchers have conducted research on the full wet process of tin-copper slag, which is to decompose the tin-copper slag with hydrochloric acid, so that all the components in the slag enter the solution, and then carry out the treatment of each element in the solution. The separation of the method makes the process lengthy and the process is complicated.

[0007] (5) fire-wet process: publication number is the processing method of a kind of tin-copper slag that the Chinese patent of CN1786226 proposes, adopts sulfuric acid one-stage leaching, can obtain the stannous sulfate product of high grade after the stannous sulfate solution purification that obtains, one-stage After oxidizing and roasting the leaching slag, sulfuric acid is leached in the second stage to obtain a copper sulfate solution, which can be concentrated and crystallized to produce copper sulfate products or enter the copper electrolysis system to produce copper. The second-stage leaching slag is tin concentrate and returned to the tin smelting system. Disadvantages of high amount of tin returning to tin smelting

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