CHEMICAL AND MICROBIOLOGICAL SOLUBILIZATION OF SILICATES

The solubilization of silicates was investigated using kaolin and quar tz sand as model substances. The mineral solubilization was studied in the concentration of solubilized Si and Al. The chemical leaching of the silicates was carried out using inorganic and organic acids as wel l as sodium hydroxide. The process was more effective in the alkine th an in the acid pH range. In the acid medium, oxalic acid showed maximu m acidity and a tendency to form complex structures, especially with a luminium, and was most effective in leaching. The microbiological infl uence on solubilization reactions was tested using a number of microor ganisms among them acid, alkali and slime-forming species. The highest leaching activity was observed in the case of Thiobacillus thiooxidan s, whereas the heterotrophic microorganisms (among them Bacillus mucil aginosus) did not exercise a solubilizing effect on the, silicates. X- ray phase analysis of leached kaolin samples did not show any differen ces from the non-leached mineral.