APPLICATION OF DOUBLE TRACER TECHNIQUE IN THE PROCESS ANALYSIS OF CARBON BLACK PLANT

The double tracer technique in which P/sup 32/ and nonradioactive Au were introduced into the system was used for the process analysis of carbon black. After sampling from each step of the process, P/sup 32/ was measured, and the nonradioactive Au was determined by irradiating the sample in a reactor and measuring Au/sup 198/ obtained from the reaction of Au/sup 197/(n, sigma )Au/sup 198/ by means of gamma spectrometry. The experiment showed that both tracers had the same residence time, which was shorter than expected. Useful data were also obtained from the dispersion pattem of the material flow for controlling future operations includng the time required to change from one grade of product to another. As to the environmental contamination, the conditions of such contamination were checked by collecting dust by an electric cottrell. (P.C.H.)