Overview of coal sludge gravity concentration technologies

The purpose of the study is to collect data and analyze modern development trends of gravity concentration technologies and equipment for coal sludge enrichment. Conducted generalization and analysis of scientific and technical information allowed to state that some attempts have been made recently to enrich coal slimes using mainly gravity concentration methods. Each of these methods involves a number of processes based on general physical and physicochemical properties serving the criteria for material separation as well as on the differently applied additional separating forces and machinery and apparatus designs. The latter include heavy-media cyclones, spiral separators, hydrosizers, concentration tables and wash boxes. The author considers the operation principle of the listed gravity equipment, demonstrates the advantages and disadvantages of each of the apparatuses. The data given indicate that, modern gravity equipment used for coal sludge enrichment features satisfactory indicators of the average probable deviation. To identify the rational topology of concentration diagrams for a particular object, the most optimal type of gravity concentration equipment or its combination is selected depending on the characteristics of the material composition. The analysis of data has shown that the most promising, highly efficient, effective, environmentally friendly and resource-saving gravity concentration method is spiral separation.