Cost Estimates for Production of Flyash Based Zeolite -A

Abstract

National Environmental Engineering Research Institute (NEERI) has developed a process to manufacture zeolite-A using flyash as a substitute for conventional raw materials viz. sodium silicate and aluminate. This process has been patented nationally and internationally. The process developed consists of three majors steps viz. fusion of caustic soda and flyash for optimal extraction of silicates and aluminate, aging step which provides time for formation of nuclei and hydrothermal crystallization resulting in activation of nuclei into well defined crystals. Low temperature, operation simplicity of process and optimal recycling of unused reactants and process water are special features of NEERI Technology. Based on the laboratory-scale process, estimates have been worked out for cost benefit analyses. The process appears to be cost-effective wherein the cost of production is about 25-30 per cent less than the commercial zeolite-A. Further reduction in cost is envisaged due to reuse of mother liquor in the process itself.