Treatment of raffinate and back-extracted liquid
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I would like to discuss with everyone the issues related to the treatment of raffinate and back-extraction solutions in the hydrometallurgical process. There are several issues: 1. The removal of the organic phase from the extract and back-extract, that is, oil removal. Some preliminary research has been done; different metals require different processes depending on the level of oil content allowed. Generally, 5-10 ppm is sufficient to meet the process requirements, but there are also processes that require a certain oil content
The oil content requirement is determined based on the product requirements and process requirements, and it’s hard to say exactly. The pH requirements for the raffinate and back-extracted liquid are also determined based on process requirements and product specifications. All of this needs to be determined based on your product requirements and manufacturing processes; it’s not possible to give you a specific answer
Also, I’ve seen the topics you posted – are you conducting market research? Just out of school? Are you just starting to work with this? Are you still developing new equipment?
It’s mainly market research, to prepare for the market demands of developing the next generation.
For the electroless plating of nickel, the electrolytic catholyte used requires a low oil content; 1 ppm or less is ideal. We generally use ultrasonic air flotation combined with activated carbon columns for treatment. In terms of nickel-cobalt extraction, the pH value of the raffinate is usually above 4, while in the back-extraction solution, the Ni concentration is around 4 and the Co concentration is around 2. These values depend on the extractant chosen, but the deviations are not significant
Thank you very much for your reply! One more question: I’ve seen many discussions about oil removal using resins. In what situations do you think resin-based oil removal methods have advantages? Thank you!
Resin has limited advantages in oil removal and its cost is relatively high.