Influence of soda-sulfate mixture on physicochemical properties of saponite suspension

Abstract

This article deals with the problem of clayey sludge utilization of diamondiferous ore enrichment. Thickening of saponite sludge by means of chemical treatment is currently considered as the most effective way to clarify the volume of water sufficient to maintain the recycling water supply of the enterprise and, as a consequence, to reduce the volume of additional water introduced into the process. The authors propose a new coagulant for settling saponite sludge - sodium sulfate mixture, which is a by-product of aluminum production. The use of sodosulfate mixture will reduce the amount of waste for both the diamond mining plant's concentrator and the alumina production. The question of the mechanism of interaction of saponite sludge particles with the proposed reagent is considered. The aim of the research is to find physical and chemical regularities of interaction of clayey slime particles with sodosulfate mixture. Chemical and mineral composition of used raw materials, surface charge of clay particles, granulometric composition of experimental samples and their electrokinetic potential were determined in the work. The results of the studies showed that the mineral composition of the clay slurry includes the following minerals: saponite, kaolin, serpentine, beidelite, dolomite. The surface charge of clay particles is negative. The chemical composition of the soda-sulfate mixture is represented in the form of oxides: Na2O, SO3, CO2, Al2O3. The dependence of the electrokinetic potential on the mass of the mineral additive introduced into the slurry was revealed. It was noted that the absolute value of ζ-potential remains above 30 mV despite increasing the concentration of the additive, but coagulation of clay particles occurs and the system in question loses sedimentation stability at a concentration of sodium sulfate mixture of 14.4 g/l.