Abstract: An improved process for precipitating alumina from Bayer process liquors is disclosed. The process involves dividing an incoming pregnant liquor stream into a minor portion of about 10 to about 25% of the total incoming pregnant liquor stream, and directing that stream into a series of small tanks where the minor stream is permitted to agglomerate. Fine aluminum hydroxide seed having a median particle size of between about 30 and about 60 microns is added to this stream. The slurry resulting from the agglomeration stage is then directed to a set of larger vessels in which the growth stage will take place. At this point, the remaining portion of the pregnant liquor is combined with the slurry resulting from the agglomeration stage. A coarse seed charge of about 150 to about 600 grams/liter of seed having a median particle size of between about 80 and about 100 microns is charged into the second set of vessels. This improved process helps to increase the yield of a strong coarse aluminum trihydroxide product.

Abstract: Phosphates, e.g., the polyphosphates and halophosphates, are prepared in high purity by melt thermocondensing corresponding precursors thereof, e.g., salts of orthophosphoric, pyrophosphoric or metaphosphoric acid, via electromagnetic induction heating, for example in an auto-crucible furnace.

Abstract: The present invention provides a coating for electrodes for use in electrochemical cells having an electrochemically active species and an electrolyte. The coating contains active species material and is selectively permeable allowing for the diffusion of the active species through the coating during operation of the cell while providing a substantially impervious barrier to the electrolyte. The coating optionally further includes a polymer layer over the active species containing coating or layer for maintaining the mechanical integrity of the active species layer.Electrodes utilizing the coatings described herein may be used in primary and secondary cells over a wide range of operating temperatures to deliver better electrochemical performance even at room temperature.Methods of making the coating and an apparatus for performing these methods on a continuous basis are disclosed.A novel composition of matter is disclosed comprising lithium, silicon, and fluorine prepared by exposing lithium metal to SiF.sub.

Abstract: A method of producing fluorapatite wherein predetermined amounts of calcium monohydrogen phosphate, calcium carbonate, and calcium fluoride are weighed, subjected to a mechanochemical action, and caused to react with one another in water. With this method, a fluorapatite having a uniform composition can be obtained without the accompaniment of by-products. A moisture sensitive resistor of the present invention can be obtained by sintering the fluorapatite produced in accordance with this method. This moisture sensitive resistor has a sufficiently low resistance corresponding to a humidity, and has substantially no hysteresis.

Abstract: The method for preparing a gaseous metallic floride is here disclosed which comprises reacting a metal or its oxide with a fluorine gas or nitrogen trifluoride gas, the aforesaid method being characterized by comprising the steps of mixing the metal or its oxide with a molding auxiliary comprising a solid metallic fluoride which does not react with fluorine and nitrogen trifluoride; molding the resulting mixture under pressure; and contacting the molded pieces with the fluorine gas or nitrogen trifluoride gas, while the molded pieces are heated.

Abstract: The present invention provides a coating for electrodes for use in electrochemical cells having an electrochemically active species and an electrolyte. The coating contains active species material and is selectively permeable allowing for the diffusion of the active species through the coating during operation of the cell while providing a substantially impervious barrier to the electrolyte. The coating optionally further includes a polymer layer over the active species containing coating or layer for maintaining the mechanical integrity of the active species layer.Electrodes utilizing the coatings described herein may be used in primary and secondary cells over a wide range of operating temperatures to deliver better electrochemical performance even at room temperature.Methods of making the coating and an apparatus for performing these methods on a continuous basis are disclosed.A novel composition of matter is disclosed comprising lithium, silicon, and fluorine prepared by exposing lithium metal to SiF.sub.

Abstract: A method of producing fluorapatite wherein predetermined amounts of calcium monohydrogen phosphate, calcium carbonate, and calcium fluoride are weighed, subjected to a mechanochemical action, and caused to react with one another in water. With this method, a fluorapatite having a uniform composition can be obtained without the accompaniment of by-products. A moisture sensitive resistor of the present invention can be obtained by sintering the fluorapatite produced in accordance with this method. This moisture sensitive resistor has a sufficiently low resistance corresponding to a humidity, and has substantially no hysteresis.

Abstract: Fluorine in phosphate ores is present as the mineral fluorapatite. When the ores are digested with sulfuric acid a slurry is formed which can be filtered to make wet-process phosphoric acid. But fluorine compounds are discharged into the surrounding air during digestion and filtration. The fluorine-containing air is scrubbed with water to prevent air pollution. Scrubber water is cooled in ponds and is recycled to the scrubber. However, fluorine compounds are emitted from the cooling ponds and cause air pollution. In the present invention, processes are disclosed for treating fluorine-containing gases without use of cooling ponds thereby eliminating the air pollution problem. A facility is provided for treating fluorine-containing gases wherein fluosilicic acid or fluosilicate salts are converted to a fluoride salt by the addition of an alkaline substance. A slightly acidic scrubber water is concentrated in an absorption tower.

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: New compositions of matter which are halogenated derivatives of borates are disclosed which are catalytically active in the polymerization of halogenated phosphazene trimers and other oligomers are disclosed.

Abstract: Simple nitronium salts are formed by adding nitrogen dioxide, a simple nitronium salt former, and fluorine gas to a vessel held at a low temperature, and allowing the vessel to warm until a reaction occurs.

Abstract: The present invention provides a process for the production of solid ion ductor materials (electrolytes) based on lithium or sodium compounds which stand in thermodynamic equilibrium with their alkali metal and have a high decomposition voltage, wherein two or more binary lithium or sodium compounds with an anion which is formed from one or more elements of the group consisting of nitrogen, phosphorus, arsenic, oxygen, sulphur, selenium, tellurium, hydrogen, fluorine, chlorine, bromine and iodine and which stand in thermodynamic equilibrium with their alkali metal are reacted together in such amounts and for such a period of time that a radiographically phase-pure product is formed.The present invention also provides ion conductor materials based on lithium or sodium compounds, which have the general formula:A.sub.3u+2v+w X.sub.u Y.sub.v Z.sub.

Abstract: An alkali monofluorophosphate expressed by the formula M.sub.2 PO.sub.3 F, where M represents Na or K, can readily be synthesized under a relatively mild reaction condition by making HF gas contact with powdery or fine granular M.sub.4 P.sub.2 O.sub.7 or M.sub.2 HPO.sub.4 placed in a reaction vessel and maintained at a temperature in the range from about 200.degree. C. to about 450.degree. C., and more preferably in the range of 280.degree.-360.degree. C. It is suitable to make HF gas continuously flow into and pass through the reaction vessel until the total quantity of HF flowed into the vessel amounts to 100 to 150% of the theoretical value for conversion of M.sub.4 P.sub.2 O.sub.7 or M.sub.2 HPO.sub.4 to M.sub.2 PO.sub.3 F.

Abstract: An improved method for producing hydrogen fluoride from fluoride bearing ores, such as fluorospar and fluorapatite, by reaction of the ore as a slurry in fluorosulfonic acid. The slurry is heated by the exothermic heat of the reaction to vaporize volatile phosphorous compounds and substantial quantities of hydrogen fluoride. The calcium fluoride is substantially reacted to form hydrogen fluoride. High silica fluorospar ores can be used since silicon tetrafluoride is not formed with fluorosulfonic acid. Another feature provides for addition of calcium fluoride to the slurry to react with the by-product sulfuric acid in the residual solids to eliminate the sulfuric acid recovery step in the process. Hydrogen fluoride produced is recovered, together with the hydrogen fluoride produced from the hydrolysis or pyrolysis of the intermediate fluorophosphorous compounds. Additionally, at least a portion of the hydrogen fluoride can be reacted with sulfur trioxide to form fluorosulfonic acid for makeup in the process.

Abstract: An ionized gas plasma is established in an electrical field in contact with a non-vapor volume monomer (liquid and/or solid). The plasma causes polymerization of the monomers which are of the phosphazene or carborane type.

Abstract: Bone china is produced by including a boron-containing substance in the composition in water-insoluble form. Use of the boron-containing compound results in a lowering of the firing temperature and widening of the firing temperature range.

Abstract: An improved method for treating calcium phosphate sources such as bone phosphate and phosphate rock with fluorosulfonic acid in the presence of a limited amount of moisture whereby over 98.00% of the phosphorous is converted to volatile compounds that can be subsequently hydrolyzed. A substantial excess of fluorosulfonic acid is utilized to contact the phosphate ore as a slurry. The phosphorous products are primarily phosphorous pentafluoride and phosphorous oxyfluoride, and to a limited extent difluorophosphoric acid. A trace of water apparently catalyzes the reaction. The production of phosphorous pentafluoride is favored by up to one part of water to eight parts of ore by weight in the presence of excesses of fluorosulfonic acid. The method includes the hydrolysis of the volatile compounds to phosphoric acid and hydrogen fluoride. Hydrogen fluoride is then recycled to react with the required sulfur trioxide to make the requirement of fluorosulfonic acid for the process.

Abstract: Disclosed is a method of electrolyzing an alkali metal chloride brine in an electrolytic cell by feeding an aqueous alkali metal chloride brine containing less than 20 parts per billion dissolved alkaline earth metal ions, e.g., calcium, to the anolyte compartment of an electrolytic cell. Also disclosed is an alkali metal chloride brine containing less than 20 parts per billion of alkaline earth metal ions, e.g., calcium ion. There is also disclosed a method of purifying alkaline earth metal-containing brines, e.g., calcium-containing brines, by maintaining the brine alkaline, adding a phosphate to the alkaline brine whereby to form a calcium compound substantially insoluble in brine and thereafter separating the compound from the brine.

Abstract: A method of producing NF.sub.4 PF.sub.6 by a displacement reaction between NF.sub.4 BF.sub.4 and PF.sub.5.

Abstract: The process of preparing analytically pure fluorapatite comprising reacting dicalcium phosphate dihydrate with hydrogen fluoride in aqueous solution, at a pH of from about 5 to about 8, at from about room temperature for about 7 days to about 100.degree. C. for about 2 days, the amount of fluoride ion being from about stoichiometric to about 1.1 times the stoichiometric amount of dicalcium phosphate dihydrate whereby solid analytically pure fluorapatite is formed.

Abstract: High molecular weight poly(dihalophosphazenes) which exhibit solubility in benzene and in substituted benzenes are prepared in solution or in bulk from dihalophosphazenes such as (Cl.sub.2 PN).sub.3-7 at moderate temperatures by the use of novel polymerization catalysts.

Abstract: A method of producing NF.sub.4 PF.sub.6 by ultraviolet photolysis at -196.degree. C of a mixture of NF.sub.3, F.sub.2 and PF.sub.5.

Abstract: HIgh molecular weight poly(dihalophosphazenes) which exhibit solubility in benzene and in substituted benzenes are prepared in solution or in bulk from dihalophosphazenes such as (Cl.sub.2 PN).sub.3.sub.-7 at moderate temperatures by the use of novel polymerization catalysts.

Abstract: A process for preparing oxygenated products comprising aldehydes, which have high normal to branched-chain isomer ratios. The process involves using particularly characterized rhodium-containing complex catalysts under a specific combination of carefully controlled reaction conditions. The product aldehydes as made above may be condensed and hydrogenated to form saturated aldehyde dimers thereof.