Prepn. of agent for redn. of calcium sulphate content of soln. - by heating ash contg. aluminosilicate with alkali hydroxide soln. and sepg. solid

摘要

An agent for redn. of the CaSO4 content of solns. is prepd. by treating ash contg. aluminosilicate with an alkali hydroxide soln., heating and sepg. the soln. by solid/liq. sepn. after 5-30 mins. Pref. the ash has more than 8% Al2O3 content and the alkali soln. is a 5-30% soln. of NaOH or KOH. The ash treated with alkali hydroxide soln. is heated to above 50 deg.C. Before the solid/liq. sepn., the ash, treated with alkali hydroxide soln. is treated with water in ratio 1:1. The solid prod. from the sepn. is dried. Pref. the solid prod. is added to the soln. contg. Ca and/or sulphate ions in a ratio of 5-30 g. of dry substance to 1 l. of satd. CaSO4 soln., followed by a solid/liq. sepn. after 1-2 hrs. ADVANTAGE - Flue ash consisting of at least 8% Al2O3 and obtd. in burning lignite in heat-generating plant can be used as raw material