Effects of different silicate minerals on silicon activation by Ochrobactium sp. T-07-B

As a kind of solid waste with a high silicon content, electrolytic manganese residue (EMR) can be utilized as silicon source by plants through bioleaching processes. EMR contains a variety of silicate minerals. In order to determine the source of available silicon in the bioleaching process of EMR, it is necessary to investigate the influence of silicate minerals in EMR on silicon-activating behavior of specific minerals. In this study, Ochrobactium sp. T-07-B was used to conduct bioleaching experiments on five kinds of silicate minerals with different structures (quartz, muscovite, biotite, olivine, and rhodonite); the growth of Ochrobactium sp. T-07-B, their acid- and polysaccharide-producing capacity, and evolution of surface morphology and structure of the silicate minerals in different systems were determined, so as to explore the silicon-activating capacity of Ochrobactium sp. T-07-B and the selectivity toward different minerals in the bioleaching process. Results showed that the effects of Ochrobactium sp. T-07-B for different silicate minerals were obviously different, and the sequence of silicon-activating efficiency from high to low was as follows: muscovite (65.84 mg.L-1) > biotite (63.84 mg.L-1) > olivine (55.76 mg.L-1) > rhodonite (50.98 mg.L-1) > quartz (23.63 mg.L-1). Results of this study may be of guiding significance for the future research on the silicon-activating behavior of solid waste.