Effects of thermal modification on the separation of clay-containing waste slurries

Abstract

This paper summarizes the results of studies on the use of thermal modification in the separation of slurries of clay-containing ores. It is currently vital to minimize the environmental footprint of tailings storage facilities of mining and processing enterprises and municipal waste landfills handling liquid wastes and to ensure their respective sanitary and epidemiological safety. The main liquid waste management problems are due to high process water consumption, high energy costs for dewatering and drying of concentrates, caking and congelation of concentrates, complexity and environmental hazards of storing wet waste (tailings), unsuitable for use as mine backfill material, as well as the use of inefficient TSF liner systems with potential soil and effluent contamination risks. This article considers the properties of clay-containing slurries, coal tailings, and halitic potash flotation tailings. It is shown that heat treatment improves waste slurry separation. For dry kaolin separation tailings, heat treatment at 200–400 °C significantly reduces tailings plasticity and fluidity, weakening soil interparticle cohesion and facilitating larger internal friction angles of the particles. The resulting data is used to analyze the potential applications of clay-containing ore processing wastes as a replacement for cement and lime in soil stabilization, land improvement, and mine reclamation, or as components in liner systems of municipal solid waste landfills.This study was carried out under the grant issued by the Russian Science Foundation (project No. 19-79-10114).