Development of On-Line Analysis System for Concentration of Chromic Acid in Chromate Treatment Process

Abstract

An application of electric conductivity method was investigated in order to develop an on-line analysis system of the concentration of chromic acid in three kinds of chromate treatment baths of the galvernizing process. As the results, it was found that the additions such as colloidal silica, amine, and stynated polymer gave little influence to electric conductivity, which varied however by temperature in the chromate treatment bath. Reasonable correlation was recognized between the concentration of CrO₃ and electric conductivity for the process operation data by correcting the effect of temperature. An example of automatic control system suitable to apply to practical process was proposed. The proposed system consists of electric conductivity meter, liquid-level meter, electromagnetic vales and so on.