On temperature control of the copper-removing electrolyte in electrowinning
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The liquid purification system in our electrolysis workshop is about to be put into operation. The idea of the relevant process engineers is to conduct electrowinning after the waste electrolyte has been naturally cooled and crystallized. Given the complex contamination situation in our electrolyte at present, passivation often occurs during the copper removal tests I conduct in the laboratory; therefore, I am concerned that passivation might also occur if the circulation rate and temperature are not properly controlled during the electrowinning process. The topic for discussion in this post is: 1. Can the process objectives of copper and impurity removal be achieved without adding an electrolyte heating system? 2. Are there any specific requirements regarding the temperature of the copper-free solution during the impurity removal process? 3. Technicians say that an electrothermal effect occurs during the electrowinning process; I don’t know since it hasn’t been tried yet. To summarize the issue, it boils down to one question: Is a heating system necessary during the electrowinning process to maintain a certain temperature of the copper-free solution?
The situation is actually as follows: at present, our company does not have highly skilled technical personnel, so it is not possible to determine the potential problems that may arise in the processes we have established. I have just started working with production lines and am not familiar with many aspects of them; I have no prior experience in tasks such as electrolysis and electrowinning, as well as no practical work experience. Based on the electrowinning experiments conducted in my laboratory: when using platinum electrodes for electrowinning, substances such as copper sulfate form at the cathode, leading to passivation. I believe this is caused by temperature, solubility, and concentration polarization; of course, I did not control the current density during the copper removal process in the laboratory… Our current approach is to allow the electrolyte to cool naturally before carrying out electrowinning (since the liquid extraction process is intermittent). After cooling, copper will crystallize, and perhaps concentration polarization during electrowinning will prevent crystalline passivation from occurring The key is also to consider the impurity removal efficiency.