Techniques and Technology of Waste Disposal of Lignite Briquettes

Abstract

Development of a waste-free technology for lignite slurry upgrading at briquetting factories, which provides for getting cleared water for closed-loop water supply and transportable product for burning or briquetting with sustainable equipment application. Detection and study of peculiarities of lignite coal and slurry of briquetting factories, as well as research on slurry surface properties for substantiating a separation ratio. Determination of the separation ratio of lignite coal slurry taking into account its surface properties to estimate technological efficiency of reagentless flotation separation. Research on kinetics of settling and influence of different flocculants on efficiency of the slurry thickening process for sludge collection and getting circulating water. Development of waste-free technology for lignite slurry upgrading with the purpose of slurry recycling based on the substantiation of rational technological parameters and appropriate equipment. Regularities of the process of reagentless flotation separation of lignite coal slurry, kinetics of settling are defined, which is the basis of technological solutions on separate briquetting waste treatment. A waste-free technology for upgrading lignite slurry and cinders with closed-cycle of water supply and transportable final product for burning and briquetting with moisture content of 26% ... 28 % is developed. Floating and sinking fractions of lignite slurry are studied and necessity of separate treatment of these fractions is substantiated. Kinetic regularities of deposition of heat-treated lignite particles are determined; rational modes which provide for efficient deposition of particles of the sinking fraction with minimum flow of a flocculant are defined. A phenomenon of hydrophobic behaviour of mineral particle surface after heat treating and briquetting of lignite coal is revealed, which is taken as a separation ratio; this allowed substantiating the waste-free technology for lignite slurry upgrading through reagentless flotation separation. The practical value of the results obtained involves development of a waste treatment technology at a briquetting factory (slurries and cinders) and its conversion into closed-loop water supply, which will allow obtaining 23 t/year of transportable final product additionally as well as decreasing consumption of pure water considerably and eliminating environment pollution.