Method for circularly removing chlorine in zinc sulphate solution by copper slag

Abstract

The invention relates to a method for circularly removing chlorine in a zinc sulphate solution by copper slag. The method comprises the following steps: copper ions, zinc powders and a zinc sulphate solution are added into a continuous reaction groove and react in a stirring state to obtain the zinc sulphate solution containing Cl<-> equal to or less than0.3g/l, and a CuCl precipitate generated in the reaction enters slag; a mixture of the zinc sulphate solution and the slag are treated by liquid-solid separation to obtain a dechlorinated zinc sulphate solution and copper slag; the separated copper slag is washed with alkali to remove chlorine ions; the copper slag after being washed with the alkali is returned to the continuous reaction groove for carrying out a circular reaction; and when the copper ions are deficient, a certain copper sulfate is added at proper time for replenishment. The invention utilizes the zinc powders as a reducer for reacting with the copper ions in the zinc sulphate solution to generate a CuCl copper slag precipitate, Cl<-> is eluted with the alkali, Cu2O is also obtained and is returned to react with the Cl<-> in the solution for circular dechlorination, copper sulfate does not need to be added or a little copper sulfate is only added in the dechlorination process, the consumption of raw materials is little, and the cost is low; compared with a method that the copper slag which can be changed is added continuously, the interference of external factors to a dechlorination technique is little, the process is easy to control, and the dechlorination effect is stable and reliable.

Description

technical field [0001] The invention relates to a method for circularly removing chlorine in zinc sulfate solution by copper slag. Background technique [0002] In the process of zinc hydrometallurgy, chlorine is a harmful impurity element, mainly derived from chlorides in zinc concentrate and zinc fume. The concentration of chlorine in the electrolytic circulating solution is high (Cl - >0.3g / l), the corrosion speed of electrolytic cathode and anode plates is greatly accelerated, which increases energy consumption and reduces the quality of electrolytic zinc. Therefore, before the zinc sulfate solution is sent to electrolysis, most of the chlorine in the solution must be removed. At present, some factories usually use the pre-fire method (such as multi-hearth furnace) roasting to remove the chlorine in the zinc fume, so that most of the chlorine does not enter the wet system, and when the chlorine in the zinc sulfate solution in the wet system reaches a certain concent...

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Problems solved by technology

[0008] The specific method of Chinese patent CN101113015 copper slag dechlorination is: add copper sulfate (copper ion) and copper slag (containing elemental copper) in zinc sulfate solution, the main source of copper sulfate is to purchase or copper slag acidification roasting, water immersion To obtain copper sulfate, the former (referring to the purchase of copper sulfate) needs to increase relatively more costs, and the latter (referring to copper slag acidified roasting and water immersion to obtain copper sulfate) has relatively more production costs, and the operation is relatively complicated. When the source of copper slag changes, the process is difficult to control, and the dechlorination effect is difficult to guarantee

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