Determination of Calcium and Magnesium in Hydrochloric Acid
The purpose of monitoring calcium and magnesium levels in hydrochloric acid is to control brine acidification in chlorine electrolysis, which can be precisely monitored by means of AppliTek’s UPA® Universal Process Analyzer.
Acidification of brine before sending it to the electrolyzers is the standard but not universal practice. Purified brine is alkaline and contains carbonate added in excess during chemical treatment. Both hydroxide and carbonate reduce the effective anode current efficiency by consuming chlorine in the cells. The addition of HCl to the brine neutralizes the contained hydroxide and decomposes the carbonate to CO2 and water. More chlorine is produced with no increase in electrical load. Addition of excess acid can even neutralize some of the hydroxide that enters the acolyte by leakage back through diaphragms or membranes.
0 – 1000 µg/l or ppb as calcium and magnesium