A Study on the Separation of Cadmium from Zinc in Synthesized Waste Cyanide Water by Precipitation-Flotation Method

Abstract

The femoval of heavy metal compounds from sypthesized waste cyanide water is achievable by a precipitation-flotation method. However, the differential separation of constituting metals by this method was thought to be very difficult.
The authors found that the addition of some decomposing reagents to the synthesized waste cyanide water of cadmium and zinc can modify the separation characteristics of tnese metals. In this paper, the separation of cadmium from zinc in the synthesized waste cyanide water by the preclpltatlon-flotatlon method is discussed. The proposed method was to use sodium sulphide as a decomposing reagent in the first stage of flotation and hydrogen peroxldte in the second stage in order to decompose Cd-CN and Zn-CN complexes, respectively. rurmermore, the use of such Cation flocculant as FC-80 was considerably ettective for the removal of Cd-CN complex.
Based on a series of fundamental flotation tests, actual differential flotation tests were made. The senaration of endmium from Zinc in the synthesized waste cyanide water was found to be satisfactory.
Tnis memod can be effective for the removal of ditfficult-to-separate colloidal precipitates from liquids by the sedimentation method, provided the applicability of this method to the separation of the other metals is promising. this consists of the intensive studies which have been conducted at authors' laboratory.