Abstract: Aqueous effluent solutions containing metal cations may be treated with an extractant comprising an organophosphinic acid, a di-2-ethylhexyl phosphoric acid and/or an aliphatic amine to selectively separate chromium, nickel, cobalt, copper and lead cations from the aqueous solution. Typical extraction techniques include liquid-liquid extraction employing either mixer settlers or columns, liquid membrane extraction and selective supported membrane extraction.

Abstract: Relatively pure monopotassium phosphate is produced from wet process phosphoric acid in a process wherein the phosphoric acid is mixed with potassium chloride and recycled components from downstream product and by-product recovery steps and heated to permit hydrogen and chloride to evolve from the melt as gases and wherein the melt is subsequently treated so as to remove impurities so that the monopotassium phosphate may be recovered as a relatively pure crystalline product with low chloride content.

Abstract: Potassium chloride and sulfuric acid are reacted in a recycled aqueous solution in the stoichiometric ratio required for potassium sulfate production. Hydrogen chloride produced by the reaction of the potassium chloride and sulfuric acid is evaporated in admixture with water or in anhdrous form. The resulting solution is cooled to crystallize a potassium sulfate salt, preferably potassium bisulfate. The potassium sulfate salt is separated from the mother liquor and the mother liquor is recycled to the reaction step. The potassium sulfate salt is dissolved in an aqueous solution and sequentially decomposed to produce potassium sulfate and a mother liquor rich in sulfuric acid. The mother liquor rich in sulfuric acid is concentrated and recycled to the reaction step.

Abstract: A process for producing K.sub.2 SO.sub.4 from potassium chloride salts, calcium sulfate salts and another sulfate source wherein syngenite is formed and then decomposed with mineral acid to produce crystalline K.sub.3 H(SO.sub.4).sub.2. The K.sub.3 H(SO.sub.4).sub.2 crystals are recrystallized to produce K.sub.2 SO.sub.4 crystals.

Abstract: An improved method and apparatus for producing a dispersion of substantially immiscible liquids which employs a conduit having an upstream section divided into first and second channels of variable length and a downstream section for mixing the liquids. The apparatus also includes means for varying the length of the first and second channels and means for flowing the liquids separately through the channels whereby the liquids mix in the downstream section of the conduit to form the dispersion. In accordance with one embodiment, a conventional mixer-settler is modified to include the conduit mounted at an upstream end of the settling chamber so that its inlet is adjacent the mixing chamber and its outlet is approximately at the same height as the organic-aqueous interface in the settling chamber.

Abstract: An improved method and apparatus for producing a dispersion of substantially immiscible liquids which employs a conduit having an upstream section divided into first and second channels of variable length and a downstream section for mixing the liquids. The apparatus also includes means for varying the length of the first and second channels and means for flowing the liquids separately through the channels whereby the liquids mix in the downstream section of the conduit to form the dispersion. In accordance with one embodiment, a conventional mixer-settler is modified to include the conduit mounted at an upstream end of the settling chamber so that its inlet is adjacent the mixing chamber and its outlet is approximately at the same height as the organic-aqueous interface in the settling chamber.