Abstract: The present invention relates to a method for producing a polyaluminium hydroxide complex of a chloride and sulphate type in solid form, an aqueous solution of the polyaluminium hydroxide complex being admixed with at least one water-miscible organic solvent having 1-4 C, the weight ratio of the aqueous solution to the solvent being at least 1:0.70, preferably 1:1-2, to crystallize the complex.The method provides a highly stable, amorphous crystalline product.

Abstract: The present invention relates to storage-stable solutions of basic aluminium sulphate containing polynucleate aluminium hydroxide sulphate complexes of the formula[Al(OH).sub.x (SO.sub.4).sub.y (H.sub.2 O).sub.z ].sub.nin which x is 0.75-2.0; y is 0.5-1.12; 2x+y=3; and z is >>4, which solutions contain a stabilizing agent in the form of nitrilotriacetic acid, diethylene triaminopentaacetic acid and/or gallic acid.

Abstract: A pumpable water-purifying dispersion containing iron(II)sulphate, the iron(II)sulphate being dispersed in an aqueous phase with a dispersing agent containing an alkaline earth metal and a basic anion. The best dispersion properties are obtained when the dispersing agent is calcium carbonate or calcium hydroxide, whereby the resultant composition having a content of up to about 70% solid iron(II) sulphate, calculated as heptahydrate on the total weight of the composition, can be obtained and handled without difficulty. The aqueous phase can, to advantage, comprise metal ions active in water-purification, such as Fe.sup.2+, Fe.sup.3+ and Al.sup.3+.The invention also provides a method for producing the composition.