Experimental Study To Flotation Process Of Coal Slurry Strengthened By Electrolytic Method

There is a dramatic increase in mineral impurities mixed in the raw coal in the process of mining and transportation. The mudding phenomenon of gangue is also more and more serious. A change is made in the feeding nature of flotation of the coal slurry. The outstanding performance is changing worse of the floatability of coal, reducing the selectivity of agents, and the effect of flotation is significantly worse, the quality of fine coal of flotation is difficult to guarantee, even the production of coal preparation is difficult to carry out. This thesis uses flotation process of coal slurry strengthend by electrolytic method to improve the separation effect of slime.This thesis researched raw coal of Malan 8#, examined different electrolyte affecting the effect of flotation in the process of electrolysis, and used relative means of character to characterization for the coal sample which is before or after dealing, and made further exploration to the mechanism, than obtained the following conclusions:1. Through optimized research to the flotation reagent system of Malan 8#, getting the best flotation reagent system as follows:collecting agent is kerosene, foaming agents is Octanol, dosage of collector is 800g/t dry slime, dosage of foaming agent is 200g/t dry slime, getting the productivity and ash content of the clean coal.2. After adding six kinds of electrolyte of NaCl, KCl, MgCl2, CaCl2, AlC13 and FeCl3 for electrolyzing coal samples, come to flotation, getting the absolute yield rate of clean coal is 1.67,1.82,3.43,4.15,4.3,4.6, the electrolysis order of absolute yield rate of clean coal is NaCl<KCl<MgCl2<CaCl2<AlCl3<FeCl3, the law presented by the results is consistent with law of radius variation of the cation ionic, when the anions is Cl", with the ionic radius of cation increases, the absolute yield rate of clean coal is gradually increasing, namely the flotation selectivity enhanced, and flotation effect improved.3. By researching flotation effect after adding KCl, CaCl2 and FeCl3, Na2SO4, MgSO4 and A12(SO4)3 for electrolyzing coal samples, getting the absolute yield rate of clean coal is 1.82,4.15,4.6,2.07,4.9,5.52, the electrolysis order of absolute yield rate of clean coal is KCl<CaCl2<FeCl3, Na2SO4<MgSO4<Al2(SO4)3, when the anions is Cl-and SO42-, with the valence of caption increases, the absolute yield rate of clean coal is gradually increasing, namely the flotation selectivity enhanced, and flotation effect improved. The best experimental condition is:electrolyte A12(SO4)3, the concentration is 4000g/t dry slime, coal slurry concentration is 100g/L, the electrolytic current is 0.5A, the electrolytic time is 5min, at this time absolute yield rate of clean coal was the highest,5.52.4. By the of result infrared analysis, contact angle analysis, laser particle size analysis, and the Zeta potential analysis can be drawn:after coal samples through electrolytic pretreatment, the—OH,>C=O and —COOH oxygen functional groups of coal surface reduced, the contact angle of coal sample becomes larger, hydrophobic enhances, is good for the interaction of coal and air bubbles in the flotation process, optimizing the flotation effect; electrolytic flotation makes Zeta potential of coal surface decreases, so that the coal and collector can better interact, enhance the activity of flotation; and coal samples through electrolytic pretreatment can make a dissociation of the clay material of coal surface, and ultimately reduce the ash content of the flotation concentrate. It can be seen through the results of test and characterization of analysis: electrolytic pretreatment have a promote role on the flotation process.