Vulcan Chemicals

David August Hildebrand

Richard L Wilson

Kurtland Scott Campbell

A novel method and apparatus for photometrically analyzing a dilute solution containing chlorine dioxide is provided. The method includes introducing a sample flow into a conduit of a chlorine dioxide analyzer. At least one light emitting diode, in communication with the sample flow, is turned on and off to pass a light beam through the sample. Upon passing through the light beam through the sample the unabsorbed light is received onto a beam splitter which separates the light into a transmitted and a reflected light. The transmitted light is directed through a filter to a first detector which measures the low concentration chlorine dioxide and the reflected light is directed to a second detector which measures a high concentration of chlorine dioxide.

Method and apparatus for photometric analysis of chlorine dioxide solutions

An improvement is provided in a process for the preferential removal of chlorine from an aqueous solution of chlorine dioxide and chlorine which has been prepared by the process of reducing a chlorate with a reducing agent in a strong acid, and wherein the gases produced thereby are dissolved in water. The improvement comprises the step of adding hydrogen peroxide, oxalic acid or a salt of oxalic acid, to a cool (i.e. at a temperature of about 0.degree. C. to about 25.degree. C.) aqueous solution of the chlorine within a period of less than 2.5 hours dioxide and chlorine. Substantially all of the chlorine is destroyed with almost no destruction of the chlorine dioxide.

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Witchita, KS, United States of America

David August Hildebrand