Patent ID: 7651865

Claim:
A method of measuring the concentration of at least one dissolved component selected from the group consisting of sodium chlorate and sulfuric acid present in the liquid phase of a slurry of crystalline sodium sulfate in a spent reaction medium from a chlorine dioxide generating process in which chlorine dioxide is generated by reducing sodium chlorate with a reducing agent in an aqueous reaction medium containing sulfuric acid at the boiling point of the reaction medium under a sub-atmospheric pressure, which comprises: providing an analytical unit having a vertical orientation defining a straight line flow path from a lower inlet to an upper outlet and comprising a lower inlet chamber for said slurry in communication with said lower inlet, a filtration medium for removing the crystalline sodium sulfate from the slurry located downstream of the lower inlet chamber and transverse to said flow path, and an upper chamber downstream of the filtration medium in communication with said upper outlet; applying vacuum to said upper outlet to draw said slurry into said lower inlet and thence into said lower inlet chamber, then through said filtration medium to separate said crystalline sodium sulfate from the liquid phase with the filtration liquid phase passing through the filtration medium into said upper chamber until a predetermined amount of said liquid phase has entered said upper chamber; and measuring the concentration of the at least one dissolved component in the liquid phase in said upper chamber.