Abstract: Methods for making an aqueous polyaluminum chloride (PAC) are disclosed that include adding an amount of a chloride-containing aluminum compound simultaneously with an amount of a base to a reaction vessel, mixing the two solutions in the reaction vessel, to produce a mixture, until a pH between 4.5 and 10 of the mixture is attained, maintaining the pH of the mixture between 4.5 and 10 during the mixing to produce an aluminum hydroxide precipitate dispersed in a liquid, allowing the aluminum hydroxide precipitate in the mixture to settle and creating a supernatant liquid, removing an amount of the supernatant liquid from the mixture to form a slurry, and adding a low- to mid-basicity polyaluminum chloride solution, an aluminum chloride solution, and/or a hydrochloric acid solution to the slurry to dissolve the aluminum hydroxide precipitate to form the aqueous polyaluminum chloride.

Abstract: Methods for making a sulfated polyaluminum chloride (PACS) flocculating agent solution, which may be aqueous, include neutralizing an aqueous sulfate-containing aluminum compound with an aqueous base to produce an aluminum hydroxide precipitate dispersed in a liquid, settling the aluminum hydroxide precipitate to create a supernatant liquid, removing an amount of the supernatant liquid to leave a remainder that contributes a selected concentration of sulfate to the PACS, and bringing the precipitate back into solution thereby forming the PACS flocculating agent.

Abstract: Methods are described for manufacturing ultra-low chloride, polyaluminum sulfate (PAS) coagulants useful for removing suspended colloidal matter and organic carbon in potable water, industrial process water and wastewater. A method of preparing a PAS solution includes forming a basic solution of sodium carbonate and sodium aluminate, adding an aqueous solution of aluminum sulfate and the basic solution to water to form a mixture having a pH between about 5 to 7, allowing precipitates of aluminum hydroxide to form in the mixture, and adding an additional aqueous solution of aluminum sulfate in an amount sufficient to dissolve the precipitates of the aluminum hydroxide and to form the PAS solution. The PAS solution has reduced corrosivity compared to other aluminum-based coagulants, and is particularly suitable for drinking water applications. The simplified methods used to produce the PAS coagulant provide a high quality product that is less expensive to produce than current methods.

Abstract: Methods for making a sulfated polyaluminum chloride (PACS) flocculating agent solution, which may be aqueous, include neutralizing an aqueous sulfate-containing aluminum compound with an aqueous base to produce an aluminum hydroxide precipitate dispersed in a liquid, settling the aluminum hydroxide precipitate to create a supernatant liquid, removing an amount of the supernatant liquid to leave a remainder that contributes a selected concentration of sulfate to the PACS, and bringing the precipitate back into solution thereby forming the PACS flocculating agent.