COAL FROTH CONCENTRATE DEWATERING PROCESSES
This review is aimed at identifying advantages and disadvantages of applied filtering equipment and seeking ways to intensify coal concentrate dewatering, when increasing a share of fine particles to produce clean filtrate suitable for a recycling water supply line of plants. The paper describes processes and equipment of leading Russian and foreign manufacturers currently applied at beneficiation plants for coal concentrate dewatering. Vacuum and hyperbaric disc filters are noted to be mostly used, while the latter are characterized by high specific performance; therefore, it is feasible to use them for dewatering rather difficult-to-filter suspended matters. Chamber and belt filter presses are comparatively rare yet. Decanter centrifuges are operated at some coal preparation plants for dewatering mixtures of coal froth and fine gravity concentrates. The paper contains the values of cake moisture and solids content in the filtrate for the processes under consideration, and solid-phase specific output for dewatering by filtration. The authors describe advantages and disadvantages of the equipment and methods for intensifying dewatering. It is shown that the use of flocculants on vacuum disc filters provides for an increase in the rate of separation of suspended matters and a decrease in the solids content in the filtrate. To exclude thermal drying from the process cycle, hyperbaric filters may be used with a superheated steam supply system. An important condition for increasing efficiency of froth concentrate dewatering is a preliminary froth destruction. One of the promising methods is the jet supply of flocculants to the froth. It is noted that the problem of dewatering the froth concentrate to produce a clean filtrate suitable for supplying to the recycling water supply line of coal preparation plants has not been solved yet. This leads to increased complexity of the process flow chart and a decreased yield of marketable products.