Method for preparing copper sulfate in mode that stanniferous copper slag is leached in selective mode and free of evaporation

Abstract

The invention provides a method for preparing copper sulfate in the mode that stanniferous copper slag is leached in selective mode and free of evaporation. The method includes utilizing sulfuric acid with the density as 70-250g / L as a leaching agent, conducting leaching on burning copper slag produced in the tin smelting process for 0.5 hour to 2 hours under the temperature of 80-98 DEG C according to the solid-to-liquid ratio of 1:3-6 to obtain slurry, conducting filtering on the leached slurry under the temperature of 80-98 DEG C to obtain leachate and leaching slag respectively, conducting conventional cooling on the leachate for crystallization and then conducting centrifuging separation to obtain copper sulfate and crystallization mother liquid. The method does not require adding a purifying agent or setting independent purifying and purity-removing work procedures and has no evaporation condensation process, thereby being high in production speed and remarkable in energy-saving effect, remarkably reducing energy consumption due to the fact that the energy consumption is only about 10% of the traditional evaporation condensation process, avoiding vicious circle of copper in the tin smelting process and being free of waste liquid and waste slag discharge and high in resource comprehensive utilization rate.

Description

technical field [0001] The invention relates to a method for selectively leaching copper from roasted copper slag produced by tin refining to avoid evaporation and concentration to prepare copper sulfate crystals, belonging to the technical fields of hydrometallurgy and chemical industry. Background technique [0002] In the tin pyro-refining process, high-copper slag containing high tin, copper and a certain amount of lead, arsenic and iron is produced. After a part of tin is extracted by electrolysis, it is roasted and desulfurized, and finally roasted copper slag is obtained. If the slag is returned The tin smelting system will cause a vicious circle of impurities and reduce product quality. Usually the slag is used to produce copper sulfate. The oxidized copper is leached with sulfuric acid to obtain a copper sulfate solution. Finally, the copper sulfate solution is heated to boiling, evaporated and concentrated, so that the copper sulfate reaches a high-temperature satu...

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Problems solved by technology

From the perspective of solution evaporation, due to the high phase change heat of water, this process needs to absorb a large amount of energy; from the perspective of steam utilization, in order to ensure the evaporation speed of the solution, it is necessary to keep the solution in a boiling state, which is It will inevitably lead to the need to maintain a certain residual pressure of high-temperature and high-pressure steam, resulting in a large amount of lack of air, which eventually leads to a large consumption of steam. No matter whether it is the traditional methods and equipment to reduce steam consumption such as decompression evaporation or multi-effect evaporation, this core cannot be avoided. This is also the root cause of high energy consumption in the evaporation and concentration process

At the same time, in the process of evaporation and concentration, some impurities will reach supersaturation and precipitate out in the concentrated mother liquor, which will affect the quality of copper sulfate products. In order to ensure the quality of copper sulfate products, it is often necessary to use copper raw materials with less impurities, resulting in an increase in raw material costs and a decline in economic benefits. ; Although the method of using solution purification to remove impurities such as arsenic and iron has a certain effect, it also makes the operation complicated, increases the production cost, and introduces new impurities, and the purification slag produced will also reduce the copper recovery rate

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