Semi-industrial Experiment Study On The Improvement Flotation Of Oxidized Coal By Surface Grinding

A series of physical and chemical changes were caused by weathering on the surface of the coal slime at normal temperature,resulting in a decrease in hydrophobicity of the surface of the coal particles.The surface oxidation layer also prevented effective contact between the medicament and the hydrophobic parts in the flotation process,and reduced the effective recovery of the combustible body.Based on the previous research results of the research group,we used the surface polishing and grinding process to study the semi-industrial scale surface modification of taixi oxidized coal,and found the main impact factor and the optimal working conditions.The main conclusions are as follows:?1?The ash content of Taixi oxidized coal was 16.69%and the fixed carbon content was 70.54%.The main grain size was 0.5mm-0.25mm,accounting for34.10%;Without polishing the optimum dosage of flotation drugs was n-dodecane1.0kg/t and sec-octyl alcohols 0.1kg/t,the yield of flotation was 69.10%,and the recovery rate of the combustible body was 79.09%.?2?Through the influencing factor screening study of the concentration,grain size composition,grinding gap,mill speed,feed volume and the pressure of the output,the main influencing factors of surface polishing and grinding process on the surface property improvement were the concentration of feed pulp,grinding gap and speed of the mill.The corresponding prediction expressions of the fitting model were:Y=83.1644+10.03·X₁-1.0855·X₂+0.0015·X₃+?X₃-838.4615?×[?X₃-838.4615?×?-1.3412e?-5].?3?We found that with the concentration increased,grinding gap decreased,the increase in the mill speed,surface polishing and grinding machine for coal particles on the surface of the grinding strength increased,the efficiency of the coal flotation recovery was increasing,which was maintained near the highest point.?4?After the surface polishing and grinding of the oxidized coal,the yield of flotation and the recovery of the combustible body increased 17.06%and 14.92%under the condition that the floating fine ash was similar,and the technical and economic benefits were obvious.There is a shortage of energy in the world and abroad,with fewer resources and more environmental problems.Due to the limitations of the current technology,there is still a lot of irrational use of coal in the process of washing and processing.Paper based on previous laboratory research discovers,the industrial prototype is used for semi-industrial test,provided basic data for process industrial popularization and application.This is of practical significance for the exploitation and utilization of the oxidized coal resources.