Aqueous basic polyaluminum-iron halide solutions

Abstract

Aqueous basic polyaluminum-iron halide solutions, useful as coagulants in waste water treatment are disclosed. The polyaluminum-iron halide solution is prepared by reacting an aqueous polyaluminum halide solution with one or more members of the group consisting of ferrous halide and ferric halide resulting in a solution containing a concentration of metal ions ranging from about 1.35 to 4.5 mol/liter as a dissolved salt of the formula Al.sub.1-x Fe.sub.x.sup.III Fe.sub.y.sup.II (OH).sub.3+2y-z Hal.sub.z wherein Hal is chlorine, bromine, iodine or mixtures thereof; (x+y)/(1-x) is about 0.2 to 1.5; 3+2y-z/3+2y is about 0.24 to 0.67; and z is less than 3+2y. Alternatively, the coagulant solution is prepared by reacting an aqueous aluminum halide solution or low basic polyaluminum halide solution with iron. Preferably the halide employed is chloride.

Dependencies are inferred from the claim text.