How to remove chlorine in industry grade zinc sulfate?

Recently, there have some customers want to know the reason why zinc sulfate heptahydrate is caking. Rech Chemical Technical explains the reason of this phenomenon. The main reason for caking is that chlorine ion in zinc sulfate solution stays high. How to remove chlorine in industry grade zinc sulfate solution without influence the purity? Please check the explanations as follows. 

First, oxidized copper slag to make sure the copper in copper slag transformed into Cu2+. Then, Cu2+ will reacted with chlorine ion in the solution, which would form hard dissolve precipitate—Cucl. By doing this, we can make full use of the copper in zinc hydrometallurgy without increasing any waste. Moreover, it would get more benefits in economy. 

Second, as for the electrolytic zinc customers, the fastest way to get high purity zinc sulfate heptahydrate is to evaporate saturated solution. First evaporate the solution. Next, they need to grind zinc sulfate heptahydrate and to add excessive barium chloride and concentrated sulfuric acid in zinc sulfate heptahydrate. By filtration, they could get high purity zinc sulfate solution. 

More information in http://www.rqsulfates.com