Prepn. of zeolite f from power plant waste - with alkali under defined conditions of molar ratios, temp. and duration

摘要

In prepn. of zeolite F by hydrothermal reaction of glassy waste materials from power plants using solid, fossil fuels, with aq. alkalies, opt. in admixture with alkaline earths and/or (in)organic NH4 cpds., with establishment of a required molar ratio of M2/nO/Al2O3 and H2O/Al2O3, for up to 1 day, opt. with stirring and heating at a definite temp., followed by sepg. the prod. formed, with other solid components, from the aq. phase, phase, washing and opt. drying, (a) the molar ratio of K2O/SiO2 in the reation mixt. is 2-3, (b) the molar ratio H2O/K2O is 10-15, (c) the molar ratio SiO2/Al2O3 is 1-3 (1-2), the molar ratio K2O/Al2O3 is 2-10 (2-4), (e) the molar ratio H2O/Al2O3 is 20-150 (20-50), (f) up to 50% of the K2O may be replaced by Na2O, (g) the reaction temp. is 90-130 deg. C, and (h) the reaction time is 10-24 h. ADVANTAGE - The zeolite has little contamination by other amorphous and crystalline impurities, and is obtd. in high yield from cheap materials. Dusty wastes from pumice and perlite-processing can also be used as raw materials. The zeolite has high selective absorption capacity for NH4 ions, even in presence of Ca and Mg ions. The zeolite can be used for selective absportion of NH4 ions from waste water, even in presence of relatively high concns. of Ca and Mg ions.