Hydrothermal treatment of perlite with caustic soda to produce metal silicate solutions

The effects of temperature, concentration of caustic soda and liquid to sol id ratio on hydrothermal treatment of perlite with caustic solution to prod uce metal silicate solutions were investigated. The reaction was carried ou t in laboratory autoclave of 1 L capacity over a range of experimental cond itions. The treatment time was kept constant at I hour. The chemical compos itions of liquid products were analyzed by standard wet chemical methods. T he results indicated that, under favorable conditions, aqueous metal silica te solutions with a high yield of about 80 percent, and having SiO2/Na2O mo lar ratios of 0.6 to 1 can be produced by this method. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.