Abstract: Crude sodium hexafluorosilicate containing gypsum and various metal phosphates is refined into highly pure and sufficiently large crystals. First, the crude fluorosilicate is treated with a sodium chloride solution to dissolve gypsum. Then the solid phase is reconstituted into an aqueous slurry in which the concentration of Na is limited. This slurry is acidified and maintained at temperatures not lower than 80.degree. C. with continued stirring to cause recrystallization of sodium hexafluorosilicate.

Abstract: A process for recovering aluminum from fly ash containing iron, silicon and titanium which comprises: (a) chlorinating the fly ash in an oxidizing atmosphere to selectively chlorinate and vaporize iron chloride from the remaining chlorides, (b) chlorinating the residue from step (a) in a reducing atmosphere of carbon monoxide, in the presence of added silicon chloride to suppress the chlorination of silicon, and vaporizing the chlorides of aluminum, silicon, titanium, and the residual iron, (c) separating and recovering the vaporized chlorides by selective condensation, and treating the residue of step (b) with sulfuric acid to convert calcium chloride to gypsum, and to regenerate a chloridizing and binder solution for pelletizing fly ash feed.

Abstract: A process for safely and conveniently disposing of active metal residue, such as a mixture of alkali metal and alkaline earth metal, by introducing the residue into a furnace in which it is completely transformed into harmless metal salts or oxides, which can be disposed of safely and inexpensively.

Abstract: A process of melting down and purifying silicon, which comprises melting silicon in at least half of the amount up to double of the amount of a silicate melt heated by resistance heating up to a temperature of at least 1,420.degree. C., said melt consisting of 2-30% by weight of calcium oxide, 5-35% by weight of magnesium oxide, wherein the sum of calcium oxide and magnesium oxide will be 15-38% by weight, 0.5-28% by weight of aluminum oxide and 45-70% by weight of silicon dioxide, and wherein, to the melt are added at least 0.29% by weight of elementary and/or chemically bound copper, preferably 0.50-3% by weight, calculated on the silicon amount.

Abstract: An organic waste containing at least one element selected from the group consisting of strontium, cesium, iodine and ruthenium is treated to achieve a substantial reduction in the volume of the waste and provide for fixation of the selected element in an inert salt. The method of treatment comprises introducing the organic waste and a source of oxygen into a molten salt bath maintained at an elevated temperature to produce solid and gaseous reaction products. The gaseous reaction products comprise carbon dioxide and water vapor, and the solid reaction products comprise the inorganic ash constituents of the organic waste and the selected element which is retained in the molten salt. The molten salt bath comprises one or more alkali metal carbonates, and may optionally include from 1 to about 25 wt.% of an alkali metal sulfate.

Abstract: A process for purifying organically polluted salts comprising forming a melt of said salts at a temperature of from about 600.degree.to 1000.degree. C., and contacting salt melt with an oxygen-containing gas. Acidic or basic fluxes may be present. The heat to maintain the mass molten may be supplied by electrodes which dip into the melt and which may be hollow so oxygen can be introduced therethrough. A suitable apparatus is also described.

Abstract: Magnesia is recovered from scrap lining material rich in magnesia by leach treatment of the material with water in the presence of carbon dioxide under pressure, separating the leaching solution from solid leaching residues, precipitating out magnesium hydrocarbonates from the leaching solution and calcining the precipitate to form magnesia. To make the scrap lining material more readily leachable and enable the production of a rich leaching solution said lining material, prior to the leaching treatment, is treated with steam at a temperature within the range of 100 - 300.degree. C. and corresponding saturation pressures for a period of 1 - 50 hours.

Abstract: Leaching of water-soluble constituents from particles containing treated oil shale and including oxides of alkaline earth metals, such as particles in an in situ oil shale retort, is inhibited by contacting the particles with carbon dioxide in the presence of water for a sufficient time to produce a substantially water-insoluble and/or impermeable barrier of carbonates of alkaline earth metals at the surface of the particles.

Abstract: A process for recovering iron, nickel and magnesium metal from low grade nickeliferrous ores is described. This process which requires little energy input comprises the steps of(a) grinding the ore to reduce the particle size of the ore,(b) preparing a slurry of the ground ore in sulfuric acid containing less than ten percent of water,(c) adding water to the acid:ore slurry in an amount which is effective to initiate a sulfation reaction,(d) allowing the sulfation reaction to continue utilizing the heat of the sulfation reaction, whereby water-soluble metal sulfates are formed,(e) leaching the sulfation product with water to extract the water-soluble salts of iron, nickel and magnesium from the insoluble residue, and(f) recovering the nickel, magnesium and iron from the leach solution.The desired metals which are recovered in this manner contain significantly reduced levels of undesirable silica.

Abstract: Ores or mineral mixtures containing zinc sulphides and magnesium and/or calcium in the form of carbonates, oxides and/or hydroxides are leached with an aqueous sulphur dioxide bearing solution to selectively dissolve magnesium and/or calcium leaving the zinc sulphides in the undissolved residue in concentrated form. During the dissolution reaction, the pH is maintained within the range of about 1 to about 4 by the addition of sulphur dioxide to the leach solution at a rate at least sufficient to replace sulphur dioxide taken up in the dissolution of magnesium and/or calcium thereby promoting selective dissolution of the magnesium and calcium compounds and non-dissolution of the zinc sulphides.

Abstract: A process for extracting non-ferrous metal values from an oxide ore. The process comprises leaching the ore with a solution containing at least one alkali metal chloride or alkaline earth chloride salt in the presence of an oxygen-containing gas at a temperature and pressure sufficient to solubilize the non-ferrous metal values into the solution of the metal chloride salt.

Abstract: A process for the production of magnesium oxide of moderate activity and high availability from a waste material containing dead-burned magnesium oxide of essentially no activity and lower availability (e.g., spent basic oxygen furnace firebrick) is disclosed. Spent basic oxygen furnace firebrick particles are calcined at a temperature of about 1000.degree. to about 2000.degree. F. for a time of from about 15 to about 60 minutes. The magnesium oxide in the spent, calcined firebrick is thus converted from dead-burned magnesium oxide to a magnesium oxide having a solubility of above about 90% in dilute hydrochloric acid and moderate activity in the nature of light-burned magnesium oxide. The color of the calcined magnesium oxide is also improved and the carbon content of the spent firebrick is essentially removed. The resulting product is generally useful in the same manner as conventional light-burned magnesium oxide.

Abstract: Ceramic mold and core materials of magnesia doped alumina are removed from castings by a solution of either KOH or NaOH at elevated temperatures and pressures in an autoclave.

Abstract: Finely-divided metal oxides are prepared by the steps of (a) contacting a compound of a metal with a carbohydrate material to obtain an intimate mixture thereof, (b) igniting this mixture to oxidize the same and to insure conversion of substantially all of said metal compound to a fragile agglomerate of its metal oxide, and (c) pulverizing the product of step (b) to form a finely-divided metal oxide powder having a mean particle size below about 1.0 micron. Certain of the finely-divided metal oxide powders produced by this process have the useful property of sinterability at temperatures significantly lower than metal oxide powders heretofore readily available. The powders are useful in the preparation of high strength compacted shapes for use in high temperature and/or corrosive environment, in the preparation of refractory cements, catalysts, catalysts supports and the like.

Abstract: There is disclosed a process for converting an alkaline earth metal sulfite or bisulfite selected from the group consisting of the sulfites or bisulfites of calcium and magnesium into an oxide form by reaction with hydrogen and water vapor at elevated temperatures particularly in connection with processes for the treatment of flue gases to reduce the amount of sulfur dioxide therein.

Abstract: This invention relates to the disposal of aluminum hydrocarbyl, aluminum hydrocarbyloxy, aluminum halide or aluminum hydride waste materials. Such materials are used as catalysts and may be present alone as well as in combination with similar compounds of other elements typically of Group IV-B, V-B, VI-B, VII-B or VIII. The present disposal process seeks to minimize environmental pollution and provide a product that is suitably used as land-fill. In the process of the invention, a system containing an aluminum hydrocarbon, hydrocarbonoxy, halide or hydride waste stream either with or without a co-present compound of another element as set forth is reacted with a hydroxide or carbonate of a Group I-A, II-A, IV-A, or V-A element under substantially anhydrous conditions. The reaction is comparatively mild and is suitably conducted in ordinary steel equipment without excessive corrosion problems. Diluents co-present with the waste materials are recovered for recycle in anhydrous form without requiring drying.

Abstract: Spent oil shale from retorting operations, containing water-soluble alkaline oxides such as calcium oxide is subjected to a recarbonation process in order to reduce its alkalinity and thereby prevent ecological damage to plant and aquatic animal life which could result from alkaline leachings derived rom rain or snowfall on open dumps of such spent shale. For economic reasons, a rapid recarbonation is necessary, and such is achieved herein by wetting the spent shale with water containing dissolved carbonate and/or bicarbonate salts, and contacting the so wetted spent shale with an atmosphere comprising a substantial partial pressure of carbon dioxide for a period of time ranging between about 10 minutes and two hours.

Abstract: Pellet-shaped calcium hydroxide forming part of the mixture of flux and ores in electrothermal calcium carbide furnaces is calcined. The pellets are made by granulating or briquetting moist calcium hydroxide, delivered to a sintering grate and conveyed thereon through a heating zone, wherein high temperatures are produced by the combustion of gas, above the grate, and wherein the combustion gas is exhausted, below the grate. The calcium hydroxide pellets are more especially placed on to the grate, covered with a layer of broken limestone and the undried pellets are directly conveyed through the heating zone, in an apparatus for carrying out the process.

Abstract: Magnesium chloride-containing material for use in the electrolytic cell for the production of elemental magnesium is melted and contacted with vaporized magnesium metal, preferably by direct injection of the vaporized magnesium metal into a body or pool of the molten magnesium chloride-containing material under conditions of vigorous agitation. The resulting treated molten magnesium chloride-containing material, after settling and separation of sludge and impurities therefrom, is introduced into an electrolytic cell for the production of elemental magnesium.

Abstract: Calcium silicate insulation consisting mainly of long, mutually entangled, fibrous synthetic xonotlite crystals and having a bulk specific gravity of 0.10 to 0.20 g/cm.sup.3 is produced at a very low cost without using any asbestos fibers by stirring very fine scattered ashes consisting mostly of amorphous silica, generated from furnaces where metallic silicon, silicon carbide, ferrosilicon, etc. are produced, with lime raw materials and water with heating, thereby obtaining a gel; kneading the gel under pressure, thereby obtaining a viscoelastic material just before transition to xonotlite crystals; pouring the viscoelastic material in a mold; and treating the viscoelastic material placed in the mold under saturated steam, thereby forming crystals, and successively treating the viscoelastic material under superheated steam, thereby effecting growth and drying of the crystals.

Abstract: A method for disposing of tracer bullets having in a steel bullet a pyrotnic material containing strontium nitrate, magnesium, strontium peroxide, polyvinyl chloride, calcium resinate, barium peroxide, oxamide, zinc stearate, polyethylene, strontium oxalate and lead dioxide, with strontium nitrate and magnesium accounting for about sixty percent of the total material. The pyrotechnic material is removed from the steel bullet by drilling and the steel is used as scrap. Strontium nitrate is first removed from the material by dissolving in cold water, and the water solution of strontium nitrate is evaporated to reclaim the strontium nitrate. The remaining materials are given successive washes in hot water, isopropyl alcohol and methylene chloride to remove all the other materials except magnesium. The magnesium is dried and reclaimed.

Abstract: A gelling agent is added to a brine containing magnesium chloride to convert the brine into a gel which is spray dried to produce dried magnesium chloride comprising substantially solid discrete particles of magnesium chloride having bulk densities in the range from about 12 to 45 pounds per cubic foot.

Abstract: A SO.sub.2 containing gas, for example a stack gas, is purified according to a multi-step process, which comprises washing said gas with an aqueous ammonia solution, treating the resulting solution with hydrochloric acid, whereby SO.sub.2 and an aqueous ammonium chloride solution are obtained and separated. The ammonium chloride solution is then reacted with magnesium oxide to recovery ammonia and the resulting magnesium chloride is cracked to produce hydrochloric acid and magnesium oxide, the ammonia, hydrochloric acid and magnesium oxide being recycled to the process.

Abstract: Caustic magnesia and magnesium hydroxide slurry are mixed together with sufficient energy in a counter-current high energy mixer to form pellets of various sizes during hydration of the caustic magnesia. The pellets may be used as formed or may be calcined to caustic magnesia or deadburned in a kiln to refractory periclase.

Abstract: A process for removing tremolite impurity from talc by subjecting finely ground talc to a combination of steps including froth flotation and pressure leaching with a strong acid at an elevated temperature. The recovered talc is characterized by a tremolite content of less than 1.0 percent by weight.

Abstract: A vapor phase process for preparing allylic alcohols which comprises reacting an allylic ester of a lower alkyl carboxylic acid with a lower alkanol in the presence of a transesterification catalyst comprising magnesia.

Abstract: This invention relates to a process for the treatment of the reaction mass produced during the joint elimination of barium-containing nitrite-/nitrate-bearing carburizing salt wastes and cyanide-/cyanate-bearing wastes by ignition of the dry mixture at elevated temperatures, comprising suspending the reaction mass in water and either (a) adding a water-soluble barium salt to the aqueous suspension in equimolar quantities, based upon carbonate ions, and separating precipitated barium carbonate, or (b) freeing the alkaline suspension from barium carbonate by filtration, reacting the filtrate with a water-soluble calcium salt, and separating precipitated calcium carbonate, concentrating the clear solutions obtained according to (a) or (b) to a water content of 10 - 20% by weight, separating precipitated sodium chloride, and evaporating the residual solution to dryness.

Abstract: This invention relates to a process for the treatment of the reaction mass produced during the joint elimination of barium-containing nitrite-/nitrate-bearing carburizing salt wastes and cyanide-/cyanate-bearing wastes by ignition of the dry mixture at elevated temperatures, comprising suspending the reaction mass in water and eitherA. neutralizing the alkaline suspension obtained with concentrated nitric acid to a pH value of 6, the feed velocity of the acid and conditions of agitation being so selected that the pH value of the suspension will at no time fall below pH 6, and separating the barium carbonate,OrB. freeing the alkaline suspension obtained from barium carbonate, and neutralizing the filtrate with concentrated nitric acid to a pH value of 7.2, the feed velocity of the acid and conditions of agitation being so selected that the pH value of the suspension will at no time fall below pH 7.

Abstract: This invention relates to a process for the treatment of the reaction mass produced during the joint elimination of barium-containing nitrite-/nitrate-bearing carburizing salt wastes and cyanide-/cyanate-bearing wastes by ignition of the dry mixture at elevated temperatures, comprising suspending the reaction mass in water and either (a) adding a water-soluble barium salt to the aqueous suspension in equimolar quantities, based upon carbonate ions, and separating precipitated barium carbonate, or (b) freeing the alkaline suspension from barium carbonate by filtration, reacting the filtrate with a water-soluble calcium salt, and separating precipitated calcium carbonate, concentrating the clear solutions obtained according to (a) or (b) to a water content of 10-20% by weight, separating precipitated sodium chloride, and evaporating the residual solution to dryness.

Abstract: This invention relates to a process for the treatment of the reaction mass produced during the joint elimination of barium-containing nitrite-/nitrate-bearing carburizing salt wastes and cyanide-/cyanate-bearing wastes by ignition of the dry mixture at elevated temperatures, comprising suspending the reaction mass in water and eitherA. neutralizing the alkaline suspension obtained with concentrated nitric acid to a pH value of 6, the feed velocity of the acid and conditions of agitation being so selected that the pH value of the suspension will at no time fall below pH 6, and separating the barium carbonate, orB. freeing the alkaline suspension obtained from barium carbonate, and neutralizing the filtrate with concentrated nitric acid to a pH value of 7.2, the feed velocity of the acid and conditions of agitation being so selected that the pH value of the suspension will at no time fall below pH 7.

Abstract: Alumina is reacted with magnesium chloride in accordance with the chemical reactionAl.sub.2 O.sub.3 + 3MgCl.sub.2 .fwdarw.3MgO + 2AlCl.sub.3In the presence of a mixed mass of inert solid contact material, such as a fluidized mass of magnesium oxide particles. The aluminum trichloride is recovered and is advantageously employed in the treatment of hydrocarbonaceous material, such as retorted shale oil, to improve the physical and/or chemical properties thereof. The substantially carbon and/or hydrocarbon free retorted aluminiferous oil shale is useful as the source of the alumina in the above chemical reaction.

Abstract: A method for disposing of tracer ammunition pyrotechnic material containing trontium nitrate, magnesium, strontium peroxide, polyvinyl chloride, calcium resinate, barium peroxide, oxamide, zinc stearate, polyethylene, strontium oxalate and lead dioxide, with strontium nitrate and magnesium accounting for about 60 percent of the total material. Strontium nitrate is first removed from the material by dissolving in cold water, and the water solution of strontium nitrate is filtered and evaporated to reclaim the strontium nitrate. The remaining material are given successive washes in hot water, ethyl alcohol and methylene chloride to remove all the other materials except magnesium. The magnesium is dried and reclaimed.