Basic aluminium salt solns - flocculants for waste waters, from basic aluminium chloride solns.

摘要

A soln. of a basic Al salt is prepd. by (a) prepg. an Al chloride soln. contg. one or more polyvalent anions, and (b) adding a precipitant for the polyvalent anion(s) at higher temps. A sufficient quantity of the polyvalent anion in acid form is added to the aq. soln. of the basic Al chloride, such that the pptg. in (b) yields sufficient polyvalent anion to obtain a soln. which is stable at room temp. Solns. opt. in dilute form, are pref. used to flocculate suspended matl. contg. water, e.g. domestic or industrial waste waters, tanks for drinking water or industrial water; and for dehydrating organic or inorganic waste sludges. Stable salt solns. obtd. have good dilution props. and do not ppte. on standing.