Abstract: A method for recovering useful animal feed supplements and a purefied brine from saline waters, such as oil and gas field brine wastes, involving the steps of adding an oxidizing agent to the brine to convert the divalent ferrous ions in the brine to ferric ions, then adding phosphoric acid in an amount approaching the stoicheometric equivalent of the divalent calcium ion the brine, then raising the pH of the brine to between 9 and 10 utilizing a material selected from the group consisting of sodium hydroxide or a mixture of sodium hydroxide and sodium carbonate followed by filtration to extract the feed supplement and thereafter adding a sufficient amount of hydrochloric acid to bring the pH to 7 and then crystallizing the sodium chloride from the resultant purefied brine solution.

Abstract: A process is provided for the recovery of one or more useful products including fertilizer, animal feed supplements, iron oxide, magnesia, salt, purified brine, and purified water from brines. The source of the brines can be oil and gas field wastes, seawater or effluent from a seawater desalination plant, or other inland brine sources. Iron and magnesium are initially precipitated from the brine. Then phosphoric acid is added to the brine followed by an alkaline agent to produce precipitates useful as fertilizer and animal feed supplements. The remaining salt in the brine may then be removed and recovered along with purified water.

Abstract: A process for removing impurities from phosphoric acid, especially concentrated wet process phosphoric acid, comprises filtering phosphoric acid through a filter cake (e.g., diatomite) on a porous member at a temperature in the range of about 57.degree. C. to about 77.degree. C. The filter cake retains some phosphate values. A major portion of the phosphate values retained by the filter cake can be introduced into the phosphoric acid manufacturing process, as by slurrying the filter cake in water, separating the aqueous phase from the solid phase, and introducing the aqueous phase to a wet process phosphoric acid process (e.g., as a "gypsum" filter wash).