mica and feldspar

In order to comprehensively utilize coal gangue as the main raw material in cementitious materials, improving its cementitious activity is a question of fundamental importance. In this paper, we present a new compound mechanical-hydro-thermal activation (CMHTA) technology to investigate the activation effect of coal gangue, and the traditional mechanical-thermal activation (TMTA) technology was used as reference. The purpose of this study is to give a detailed comparison between these two methods with regard to the mineral composition, crystal structure and microstructure, by XRD, IR, MAS NMR, XPS and mechanical property analysis. The prepared coal gangue based blended cement, containing 52% of activated coal gangue C (by CMHTA technology), has a better mechanical property than activated coal gangue T (by TMTA technology) and raw coal gangue. The results show that both of the TMTA and CMHTA technologies can improve the cementitious activity of raw gangue greatly. Moreover, compared with TMTA, the mineral phases such as feldspar and muscovite in raw coal gangue were partially decomposed, and the crystallinity of quartz decreased, due to the effect of adding CaO and hydro-thermal process of CMHTA technology.

Topics: Aluminum Silicates; Coal; Crystallization; Industrial Waste; Magnetic Resonance Spectroscopy; Oxides; Potassium Compounds; Spectrometry, X-Ray Emission; Spectrophotometry, Infrared; X-Ray Diffraction

A silicate mineral-solubilizing bacterial strain Q12 was isolated from the surfaces of weathered feldspar and identified as Bacillus globisporus Q12 based on the 16S rDNA gene sequence analysis. Three silicate minerals (feldspar, muscovite, and biotite) were used to investigate potassium and silicon mobilization by strain Q12. In liquid cultures, the strain showed better growth on the biotite than on feldspar and muscovite. The biotite was the best potassium source for growth of the strain. Solubilization of potassium and silicon from the silicate minerals by the strain resulted mostly from the action of organic acids. Gluconic acid seemed to be the most active agent for the solubilization of the 3 silicate minerals. Gluconic and acetic acids were likely involved in the solubilization of feldspar. The strain could be acid or alkali and salt tolerant and temperature resistant.

Topics: Acetic Acid; Aluminum Silicates; Bacillus; DNA, Bacterial; Ferrous Compounds; Gluconates; Molecular Sequence Data; Potassium; Potassium Compounds; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Silicon