Screening Of Microorganisms From Lignite And Surface Modification To Fine Coals By Rhodotorula Mucilaginosa

One of the important directions of the research on coal washing is developing the non-toxic flotation reagents with strong force and high selectivity. In this paper, some microorganisms with suface mldification to fine coals were screened by traditional microorganism separation methods from the lignite, and one of them designated KDY21was the best. Colony morphology, physiological and biochemical characteristics and some molecular sequence fragments showed that the strain KDY21was Rhodotorula mucilaginosa. Through the optimization culture conditition the harvest yield of strain KDY21was increased by32%. The KDY21cell production rate cultured with CSTR was1.5g/(L-h) after designing its growth dynamics. Then the surface modification to fine coals by KDY21was tested for the4kinds of different coalification range fine coals. Through the Zeta potential and contact angle measurement it was proved that using the KDY21could heighten the floatation rate greatly through changing the surface characteristics of coal. Cell adsorbing capacity on the coal surface was measured and the results showed that the order of influence factors was pH> coal particle size> contact time> concentration of bacilli. The pH determined the charging difference between cell and surface of coal. In addition, the mechanism of Rhodotorula mucilaginosa KDY21effects on the stability of fine coal disperse system had been discussed by using extended DLVO theory. All these results indicated that the modified flotation and flocculation rate of fine coal particles were improved using the strain KDY21adhered onto the fine coal surface through the electrostatic interactions and the hydrophobic interactions in different conditions.