Abstract: A process is provided for recovering fluorine from dilute hydrofluoric acid solutions, such as waste scrubber solution obtained in the treatment of phosphates. The dilute solution is used to react with oxidic titanium material to solubilize the contained titanium and subsequently form, in the presence of potassium ions, crystals of K.sub.2 TiF.sub.6 which are commercially useful as a grain-refining agent in the manufacture of aluminum alloys.

Abstract: A process is provided for leaching nickeliferous sulfide material, such as NiS precipitate and thermally activated nickel sulfide material, e.g., nickel matte, the process comprising subjecting nickeliferous sulfide material in the finely divided state to leaching in hydrochloric acid of concentration ranging from about 3 N to 8 N at a temperature of over 50.degree. C., the temperature and acid concentration being selected to dissolve at least about 50% by weight of the total contained nickel.

Abstract: A method is provided for extracting at least one of the trivalent ions Fe and Al from an acid solution. The method comprises uniformly mixing the acid solution with a liquid organic extractant comprising an organophosphorus compound and an alkylaromatic sulfonic acid dissolved in a water-immiscible organic solvent, the extractant being selective to the solvent extraction of said trivalent ions under acidic conditions. The molar ratio of the sulfonic acid to the organophosphorus compound is controlled over a range of about 1:4 to 10:1 and the mixing carried out for a time sufficient to effect solvent extraction of said trivalent ions and provide a raffinate substantially impoverished in said trivalent ions and a loaded extractant containing said trivalent ions, following which the loaded extractant is separated from the raffinate.

Abstract: Aqueous nickel chloride solutions containing such impurities as copper, iron, and zinc, and optionally, cobalt, and having an acid concentration ranging from about 0.2 N to 4 N HCl together with a total chloride concentration of about 4 N to 11 N are purified of said impurities by solvent extraction with an organic extractant of essentially tributyl phosphate (TBP) dissolved in a water-immiscible organic solvent, the solvent extraction being carried out at a selected concentration of TBP and a selected volume ratio of organic to the aqueous solution effective to produce a nickel raffinate substantially impoverished in said impurities.

Abstract: Nickel and cobalt are separated from aqueous process solutions having pH values below about 4 and containing other metal ions by contacting the process solutions with liquid organic extractants containing a mixture of .alpha.-hydroxyoximes and sulfonic acids dissolved in water-immiscible organic solvents.

Abstract: A method for efficiently precipitating nickel sulfide from an acidic nickel sulfate solution having a pH between 1.5 and 4, containing about 1 to 40 gpl nickel, optionally containing cobalt, and containing sufficient inert soluble sulfate salt to buffer the solution during the precipitation of nickel sulfide at relatively low temperature and pressure.