Difference in the ratios of acid, water, and no water added to the electrolytic cell
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This post was last edited by paul2100 on 2015-6-18 22:31. What is the difference in the ratios of acid, water, and no water when adding them to the electrolyte tank?
Water is added, I suppose, to avoid the common-ion effect. If no water is used with salts and acids, their concentration becomes high; this leads to an increase in chloride ions at the point where the acid is added, which reduces the solubility of sodium chloride and results in its precipitation. To prevent sodium chloride from clogging the pipes, the high-concentration salt acid is diluted.
Isn’t it because of the high local salt and acid concentrations that cause an acidic film to form? In our company, there were instances where no water was added; due to the high designed production capacity and the operation of only one unit, the acid and water were not mixed properly – either there was only acid or only water. So acid was added alone for some time, and it was found that it was difficult to adjust the pH of the brine at the outlet. Increasing the amount of acid used caused the voltage to rise, by up to 0.1V per unit cell, with the pH of the brine at the outlet dropping to around 3.5. Only after switching to using diluted acid did things gradually return to normal. Therefore, it was temporarily concluded that high acid concentration was the cause. I still haven’t figured out exactly why
We also add dilute salt and acid to prevent the film from becoming overly acidic and to avoid blockages in the pipes.