Investigation of the Physical and Chemical Properties of Spent Zinc Catalysts and the Process of Processing with Nitric Acid

Abstract

This article examines the physical and chemical properties of spent zinc catalysts and the process of processing 30% nitric acid. Used zinc catalysts contain at least 95% zinc oxide. The treatment process was carried out in 30% nitric acid in a cycle closed at a temperature of 85-950C, pH within 3-4, by mixing the solution for 5 hours. The mass fraction of Zn(NO3)2 in the solution obtained according to the above parameters is higher than 400 g/dm 3 , and the density of the liquid phase after decomposition varies from 1.312 gr/cm3 to 1.273 gr/cm3 , depending on the pH value of the medium and temperature. The viscosity under these conditions varies from 0.02 sPa to 0.008 sPa.