Issue with the content in the back-extraction solution
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Are there any disadvantages in the back-extraction solution due to its high concentration? I’ve raised it to 87% in our factory. I’m not sure if there are any difficulties with the replacement.1
You are involved in indium extraction, right? The concentration of the liquid after back-extraction in indium extraction should not be too high, as zinc sheets will be used for displacement at the end; a high concentration makes it difficult to achieve complete displacement, which means that zinc chloride may end up being saturated
-- Zinc chloride is highly soluble in water and has the highest solubility among solid salts. I don’t know what the saturation method is Could the site reach saturation? --
Reply to 3# FILTRATION-MAN: Since the solution contains not only zinc chloride but also a large amount of chloride ions, the saturation level in this case is not the one specified in textbooks. There is a salting-out effect at play; in simple terms, zinc needs to enter the solution in order to displace indium. The higher the zinc concentration, the harder it is for zinc to enter the solution. Do you understand this concept? After back-extraction for indium extraction, the concentration of the solution should not exceed 60 g/kg; otherwise, more than 1 g will remain. It’s a shame to discard such a solution – since indium cannot be displaced, one can only add it gradually in small amounts to the solution used for the next displacement process. This is quite troublesome. It’s better to reduce the concentration of the solution after back-extraction right from the start, so that the displacement time over 24 hours can be kept below 10 mg/kg
-- I’m not quite sure, but thanks for the advice. I don’t know much about indium couples. --