为了获得能够对高硅铝土矿具有生物脱硅作用的硅酸盐细菌，通过亚历山大洛夫无氮培养基从野外采集的土壤样品中分离得到30株固氮解钾细菌。经与矿物的作用实验，选出脱硅能力较高的细菌。经过菌落形态学特征、显微镜染色观察、16S rRNA序列分析，确定该菌株为胶质类芽孢杆菌，并命名为BM-4。实验结果表明BM-4对硅酸盐矿物有一定的脱硅效果，更有利于层状结构硅酸盐矿物的脱硅。该菌株对高岭土和一水硬铝石有较强的吸附、絮凝和浮选作用。单矿物浮选试验结果表明BM-4在高岭土表面的吸附可将高岭土的浮选回收率从50%提高至75%，而对一水硬铝石的吸附可将其浮选回收率从49%降至27%。一水硬铝石：高岭石=5：1的混合矿物采用改进的哈里蒙德浮选管进行浮选试验，矿物的Al/Si由3.05升至8.6，氧化铝的回收率为83%。这说明，研究筛选出的胶质类芽孢杆菌BM-4对层状硅酸盐矿物有较好的溶蚀脱硅效果。通过对矿物表面的吸附，提高高岭土在浮选过程中的浮选回收率，降低一水硬铝石的浮选回收率，能够从两矿的混合体系中通过浮选的方法除去高岭石，提高铝土矿的铝硅比，从而实现应用生物浮选方法用于铝土矿预脱硅的的可能性。%30 strains of nitrogen-fixing and potassium-dissolving bacterium were screened to remove silicon from low grade bauxite. One strain with best desilication ability was characterized by morpholigical observation, biochemical, physiological identification and 16S rRNA sequence analysis. It was identificated as Paenibacillus mucilaginosus, named BM-4. Results of leaching show BM-4 can desiliconize from silicate minerals with different crystal structures. It exhibits better desilication-efficiency for silicate minerals with layered crystal structures. The adsorption of Paenibacillus mucilaginosus BM-4 on kaolinite and diaspore brings about flocculation and flotation effect. The flotation recovery of kaolinite rises from 50%to 75%, and that of diaspore decreases from 49%to 27%due to adsorption of BM-4. Flotation test of mixed minerals(diaspore:kaolinite=5:1) by modified Hallimond tube shows that Si is effectively removed. The Al/Si ratio rised from 3.05 to 8.6 with 83% Al2O3 recovery. This displays that Paenibacillus mucilaginosus BM-4 screened in this paper has more effective desilication rate for silicate minerals with layered crystal structures. The rise of kaolinite’s and the reduction of disapore’s flotation recovery makes it possible to separate kaolinite from bauxite after adsorption with BM-4.
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