Abstract: A method of removing aluminum, magnesium, iron and other impurities from wet process phosphoric acid is provided. The method comprises partially ammoniating the acid and reacting the acid with a fluoride ion donating compound to precipitate aluminum- and magnesium-containing ralstonite and ammonium fluorosilicate which can be easily separated from the acid thereby producing a partially ammoniated wet process phosphoric acid of reduced impurities content.

Abstract: The color level of poly(tetramethylene ether) glycol made by polymerizing tetrahydrofuran using fluosulfonic acid as the catalyst is significantly lower if the fluosulfonic acid contains no more than about 1200 ppm of iron sulfites.

Abstract: A process for defluorinating a solution of a sulphate of Zn, Ni, Cd, Mn and/or Mg, in which Al.sup.3+ and PO.sub.4.sup.3- ions are added to the solution, then the solution is neutralized up to a pH higher than 4 and lower than that one that causes a substantial precipitation of Zn, Ni, Cd, Mn and/or Mg, thereby producing a fluorinated precipitate, and the precipitate is separated from the solution.

Abstract: Magnesium and aluminum impurities are removed from aqueous phosphoric acid by treatment with a fluorine material and an alkali metal containing material in such a manner that the atomic ratio of fluorine to aluminum is adjusted so that it is greater than about 2 and the alkali metal plus magnesium to aluminum atomic ratio to a value no greater than about 2. In one embodiment the fluorine to aluminum ratio is below about 11, preferably between about 4 and about 8. By controlling such atomic ratios in the limits prescribed, a more purified aqueous phosphoric acid can be produced having a substantial reduction in the magnesium and aluminum content thereof. The process is useful for wet-process phosphoric acids. The process is also particularly useful for acids having low P.sub.2 O.sub.5 content and/or high aluminum concentration. The purification process does not require evaporation for the removal of impurities, as for example fluorine as silicon tetrafluoride.

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: Formation of hydrous alumina in the reticules of a weak-base anion exchange resin, wherein AlCl.sub.3 has been precipitated as hydrous alumina by reaction with ammonia, is improved by employing a subsequent treatment with HCl or with NH.sub.4 Cl and HCl to convert the exchange resin to the chloride form, thereby increasing the reticular volume of the resin, thus permitting subsequent precipitation of additional hydrous alumina therein.

Abstract: Potassium tetrafluoro aluminate of a melting point not exceeding 575.degree. C. is produced by reacting an aqueous solution of fluoro aluminum acid with an aqueous solution of a potassium compound, especially of potassium hydroxide, the amount of potassium in said solution being less than the stoichiometrically required amount.

Abstract: Fibrous hydrotalcites having a hexagonal needle-like crystal structure. The fibrous hydrotalcites are produced by contacting a basic magnesium compound having a needle-like crystal structure and expressed by the following formula (2)Mg(OH).sub.2-n'x.sbsb.2 A.sub.x.sbsb.2.sup.n'.spsp.-.m.sub.2 H.sub.2 O (2)wherein A.sup.n'.spsp.- represents a monovalent or divalent anion, n' is 1 or 2, and x.sub.2 and m.sub.2 are numbers satisfying the following conditions,0.2.ltoreq.x.sub.2 .ltoreq.0.5,O.ltoreq.m.sub.2 .ltoreq.2,with a compound capable of providing a trivalent metal cation and being soluble in a liquid reaction medium which is chemically inert and is a non-solvent for the basic magnesium compound, the contacting being carried out in said liquid reaction medium under conditions which do not cause a loss of the needle-like crystal form of the basic magnesium compound, while maintaining the ratio of M.sup.3+ to the sum of Mg and M.sup.3+ at O<M.sup.3+ /(Mg+M.sup.3+).ltoreq.0.

Abstract: Hydrofluoric acid and/or other fluorine compounds are recovered by reacting fluosilicic acid with a sodium-containing compound to form an alkaline aqueous slurry comprising precipitated amorphous silica and dissolved sodium fluoride. The precipitated amorphous silica is separated from the alkaline aqueous slurry leaving an aqueous solution of sodium fluoride. The sodium fluoride solution can be used as such or reacted with other substances (such as alumina, to form synthetic cryolite). Sodium fluoride is recovered from the aqueous solution (as by evaporation or extraction) and used per se or reacted with sulfuric acid to produce hydrogen fluoride.

Abstract: A process of precipitating cryolite from a reaction solution given by mixing a sodium aluminate solution with a fluoride solution containing silica dissolved therein as impurity at reaction temperatures above 60.degree. C. To reduce silica content in the precipitated cryolite, the reaction solution is made to contain carbonate ions, 1-20 g/l as CO.sub.2, by introducing either carbon dioxide gas or a soluble carbonate into the fluoride solution Moreover, ignition loss of the cryolite can be decreased by preheating the sodium aluminate solution to 90.degree. C. or above.

Abstract: An improved process for the preparation of crystalline cryolite having a molar ratio Na:Al of 2.9:1 to 3.0:1, by reacting aqueous solutions of aluminum fluoride with at least a stoichiometric amount of sodium fluoride in aqueous solution, while heating, in the presence of cryolite seed crystals, wherein the sodium fluoride is used in an amount of 3.2 to 3.5 moles of sodium per mole of aluminum, the aluminum fluoride concentration being from 15 to 250 g./l., the sodium fluoride concentration being from 30 to 42 g./l., the reaction temperature being from 85.degree. to 100.degree. C., the reaction time from 0.5 to 3 hours and the pH value in the reaction mixture from 5 to 8, to provide an end product having an adsorbed water content of 8% or less.

Abstract: Industrial waste gases containing sulfur dioxide, hydrogen fluoride, hydrochloric acid and sulfur trioxide are treated within a reaction tank in a first stage with a solution containing ammonium ions to increase the dew point of the gases. The gases are then cooled below the elevated dew point in a second stage below which a deflector system directs the gases along the wall of the reaction tank into a third stage where the gases are cooled by a spray mist of an ammonia mixture to form ammonium salts. The gases are then treated in a fourth stage at the bottom of the reaction tank with the solution containing ammonium ions to precipitate ammonium salts into a reservoir below the reaction tank. Purified waste gases are discharged into a cooler where a stripper removes entrained droplets of liquid before discharge into the atmosphere. The droplet size of the solution sprayed into the second stage is larger than the droplet size of the solution sprayed into the first stage.

Abstract: In the purification of an ammonium fluoride solution containing silicic acid by adding iron (III) ions and precipitating the iron (III) ions at a pH above 8.5 and a concentration of free ammonia in the solution of more than about 1% by weight, the silicic acid being carried with the iron (III) ion precipitate, the improvement which comprises adding the iron (III) ions to the ammonium fluoride solution at a temperature below about 30.degree. C. and, before removal of the precipitate, to the solution a salt of at least one of the alkali metals, alkaline earth metals, zinc, aluminum and lead in such quantity that the solution becomes saturated with such salt.

Abstract: Tris-tetrafluorammonium hexafluoraluminate, (NF.sub.4).sub.3 AlF.sub.6, a new compound, is synthesized by forming a mixture of solid aluminum trichloride in a solution of a molar excess tetrafluorammonium bifluoride in anhydrous hydrogen fluoride, at a temperature of about -78.degree. C. or less. The mix is then rapidly heated to a temperature of about 40.degree. C. to the decomposition temperature of the product until all the solids dissolve. The solution containing the dissolved aluminum trichloride is evaporated under vacuum conditions to cause crystallization of (NF.sub.4).sub.3 AlF.sub.6.

Abstract: Bimetallic salts, having the generic formula MM'X.sub.n wherein M is a Group IB metal, M' is a Group IIIA metal, X is a halide and n is equal to the sum of the valences of M and M', are prepared by reacting the halogen salts of the individual metals, M and M', in a suitable solvent. The bimetallic salt formed thereby is a discrete monomeric species and can be utilized in the separation and recovery of various ligands, by preferential complexation. Complexation can be conducted with the bimetallic salt in the solid state, in solution, or as a slurry, and with the complexible ligand in the gaseous or liquid state. The ligand is recovered by decomplexation of the bimetallic salt-ligand complex or by displacement of the complexed ligand with another ligand.

Abstract: Alumina-cryolite waste from aluminum pot lines is subjected to oxidation in a fluidized bed reactor to remove carbon and organic contamination. Agglomeration of the alumina-cryolite product occurs in the fluidized bed and a pellet product suitable for return to the aluminum pot lines is produced.

Abstract: An inorganic acid typified by H.sub.2 SO.sub.4 is added to an aqueous slurry of (NH.sub.4).sub.3 AlF.sub.6 and either Al(OH).sub.3 or Al.sub.2 O.sub.3, and the resulting mixture is kept for a while under the atmospheric pressure at or somewhat above room temperature. The acid is added preferably in such an amount that the pH of the slurry after completion of the reaction is 4 to 7.

Abstract: This invention concerns a process for preparing metal and metal fluoride products. A molten mixture containing a metal oxide, a molten metal fluorinating agent and carbon is reacted to produce a gaseous oxide of carbon, a metal fluorinated product derived from the cation of the metal oxide, and a metal derived from the cation of the metal fluorinating agent.