The Research On Low-rank Coal Microbial Multi-stage Flocculation

Currently,traditional non-bioflocculants,including organic polymer flocculants and inorganic flocculants,is the major flocculanting mathes to be used in the coal preparation plant.However,these two types of pharmaceuticals are mainly chemical agents,which have many bad effects on the environment.Compared with non-bioflocculants,microbial flocculant has more advantages in environmental protection and safety.Therefore,on the basis of the study of single and different metamorphism degree coal slurry flocculation.it has great importance to carry out biological multi-stage contact flocculation of low rank coal to study the flocculation characteristics and compound of bioflocculant and polyacrylamide to flocculate coal slurry.In this paper,Bacteria of Bacillus subtilis,Rhodopseudomonas spheroides and fungi of Phanerochaete chrysosporium,with good flocculation in slime water treatment,were selected.The single-factor experiment was designed to find out the optimum level range of a single species to flocculate low rank coal slime water with the light transmittance of slime supernatant as the index.The orthogonal design was used to determine the optimum factor combination of flocculation of low rank coal slime.Selecting incubation time,lurry pH,coagulant dosing quantity,biological flocculant dosing quantity as main fators in the the orthogonal design,carry out biological multi-stage flocculation of low rank coal and compound of bioflocculant and polyacrylamide to flocculate coal slurry to study the flocculation optimal process combination.Experimental results show that the effect of bioflocculant multi-stage flocculation is better.B.S.and R.S.two-stage flocculate low rank coal orthogonal results:1#(lignite coal)B.S dosing quantity:3ml,R.S dosing quantity:1ml,coagulant dosing quantity:1ml,PH value for 6 transmittance is 74.9%:2#(non-caking coal)B.S dosing quantity:2ml,R.S dosing quantity:1ml,coagulant dosing quantity:2ml,PH value for 6 transmittance is 75.5%;3#(weakly-caking coal)B.S dosing quantity:3ml,R.S dosing quantity:2ml,coagulant dosing quantity:3ml,PH value for 8 transmittance is 56.8%.B.S.and P.C.two-stage flocculate low rank coal orthogonal results:1#(lignite coal)B.S dosing quantity:3ml,P.C.dosing quantity:1ml,coagulant dosing quantity:3ml,PH value for 7 transmittance is 74.3%;2#(non-caking coal)B.S dosing quantity:3ml,P.C dosing quantity:1ml,coagulant dosing quantity:2ml,PH value for 8 transmittance is 76.8%;3#(weakly-caking coal)B.S dosing quantity:3ml,P.C dosing quantity:3ml,coagulant dosing quantity:2ml,PH value for 7 transmittance is 57.3%.B.S.,P.C and.R.S.multi-stage flocculate low rank coal orthogonal results:1#(lignite coal)B.S dosing quantity:2ml,P.C.dosing quantity:1.5ml,R.S dosing quantity:2ml,coagulant dosing quantity:4ml,PH value for 8 transmittance is 78.6%:2#((non-caking coal)B.S dosing quantity:2.0ml,P.C.dosing quantity:1.0ml,R.S dosing quantity:0.5ml,coagulant dosing quantity:3ml,PH value for 7 transmittance is 74.8%:3#(weakly-caking coal)B.S dosing quantity:2.0ml,P.C.dosing quantity:1.5ml,R.S dosing quantity:2.0ml,coagulant dosing quantity:3ml,PH value for 7 transmittance is 69.8%.Compound.of R.S,P.C and polyacrylamide flocculate low rank coal orthogonal results:1#(lignite coal)R.S dosing quantity:0.5ml,P.C.dosing quantity:0.5ml,polyacrylamide dosing quantity:0.2ml,coagulant dosing quantity:4ml,PH value for 8 transmittance is 81.8%;2#(non-caking coal)R.S dosing quantity:1.0ml,P.C.dosing quantity:0.5ml,polyacrylamide dosing quantity:0.15ml,coagulant dosing quantity:2ml,PH value for 9 transmittance is 95.3%;3#(weakly-caking coal)R.S dosing quantity:1.5ml,P.C.dosing quantity:1.5ml,polyacrylamide dosing quantity:0.2ml,coagulant dosing quantity:4ml,PH value for 9 transmittance is 94.6%.Through the analysis of the sugar biological flocculating agent,protein analysis;Dry coal slime XRD,FTIR,SEM analysis before and after the coal slurry flocs;The biological flocculation mechanism of the flocculating agent is that large flocs were formed to achieve flocculation in the role of gravity by electrical neutralization and swept volume,together with the trap process.Biological flocculant flocs settle slowly but stronger;Bioflocculant and polyacrylamide complex flocculation is fragile but settle quickly.