Abstract: A process for manufacturing high purity anhydrous hydrogen fluoride (HF) having low levels of arsenic impurity by contacting anhydrous hydrogen fluoride product, or an intermediate product obtained during the manufacture of HF, with hydrogen peroxide to oxidize the arsenic impurity in the presence of a catalyst which comprises a catalytic amount of a component selected from the group consisting of molybdenum, a molybdenum compound, vanadium, and a vanadium compound, and a phosphate compound. The volatile trivalent arsenic impurity in the anhydrous hydrogen fluoride is oxidized to a non-volatile pentavalent arsenic compound and the resultant mixture is distilled to recover high purity anhydrous hydrogen fluoride with reduced levels of arsenic impurity. In one embodiment, an oxidizing agent such as nitric acid or a nitrate salt is added to the reaction mixture to oxidize organic compounds.

Abstract: Aqueous basic polyaluminum-iron halide solutions, useful as coagulants in waste water treatment are disclosed. The polyaluminum-iron halide solution is prepared by reacting an aqueous polyaluminum halide solution with one or more members of the group consisting of ferrous halide and ferric halide resulting in a solution containing a concentration of metal ions ranging from about 1.35 to 4.5 mol/liter as a dissolved salt of the formulaAl.sub.1-x Fe.sub.x.sup.III Fe.sub.y.sup.II (OH).sub.3+2y-z Hal.sub.zwherein Hal is chlorine, bromine, iodine or mixtures thereof; (x+y)(1-x) is about 0.2 to 1.5; (3+2y-z)(3+2y) is about 0.24 to 0.67; and z is less than 3+2y wherein x/y is about 0 to 1. Alternatively, the coagulant solution is prepared by reacting an aqueous aluminum halide solution or low basic polyaluminum halide solution with iron. Preferably the halide employed is chloride.

Abstract: Aqueous basic polyaluminum-iron halide solutions, useful as coagulants in waste water treatment are disclosed. The polyaluminum-iron halide solution is prepared by reacting an aqueous polyaluminum halide solution with one or more members of the group consisting of ferrous halide and ferric halide resulting in a solution containing a concentration of metal ions ranging from about 1.35 to 4.5 mol/liter as a dissolved salt of the formulaAl.sub.1-x Fe.sub.x.sup.III Fe.sub.y.sup.II (OH).sub.3+2y-z Hal.sub.zwherein Hal is chlorine, bromine, iodine or mixtures thereof; (x+y)/(1-x) is about 0.2 to 1.5; 3+2y-z/3+2y is about 0.24 to 0.67; and z is less than 3+2y. Alternatively, the coagulant solution is prepared by reacting an aqueous aluminum halide solution or low basic polyaluminum halide solution with iron. Preferably the halide employed is chloride.

Abstract: A physically and functionally stable solution for water treatment comprises an about 1.2-2.7 molar aqueous phosphate-stabilized polyaluminum sulfate solution of a composition having the formulaAl(OH).sub.x (SO.sub.4).sub.y (H.sub.2 PO.sub.4).sub.zwhereinx is about 1.2 to 1.62;y is about 0.595 to 0.87; andz is about 0.06 to 0.19with the proviso that the sum of x+2y+z is 3. The aqueous phosphate-stabilized polyaluminum sulfate solution can be prepared by reacting alumina hydrate with phosphoric acid and contacting the reacted alumina hydrate with an aqueous polyaluminum sulfate solution. Alternatively, the aqueous phosphate-stabilized polyaluminum sulfate solution can be prepared by reacting an aqueous overbasified polyaluminum sulfate phosphate solution with an aqueous aluminum sulfate solution.

Abstract: A process is disclosed for preparation of an amorphous polyaluminum sulfate composition of the formulaAl(OH).sub.x (SO.sub.4).sub.y (H.sub.2 PO.sub.4).sub.z (H.sub.2 O).sub.wwhereinx is about 0.75 to 1.5y is about 0.7 to 1.07z is about 0 to 0.2w is about 2.0 to 4.2with the proviso that the sum x+2y+z is 3. Water is withdrawn from a fairly fresh polyaluminum sulfate solution having the formulaAl(OH).sub.x' (SO.sub.4).sub.y' (H.sub.2 PO.sub.4).sub.z' (H.sub.2 O).sub.w'whereinx' is about 0.75 to 1.5y' is about 0.7 to 1.07z' is about 0 to 0.2w' is about 18 to 65with the proviso that the sum x'+2y'+z' is 3. The amorphous composition is useful for reconstitution with water to prepare a coagulant solution.

Abstract: A method of treating solid waste material containing minor amounts of water soluble chromium compounds with a reductant, particularly sulfide ions, to convert the soluble chromium to an insoluble state, and produce a solid waste from which substantially no chromium can be leached by water, as by exposure to rain.

Abstract: A method for recovering substantially all of the fluorine and uranium values and at least 90 percent of the rare earth metal values from brine raffinate obtained as by-product in the production of phosphoric acid by the hydrochloric acid decomposition of tricalcium phosphate minerals. A basically reacting compound is added to the brine raffinate to effect a pH of at least about 9, whereby fluorine, uranium and rare earth metal values are simultaneously precipitated therefrom. These values may then be separately recovered from the precipitate by known processes.