Abstract: Disclosed is a method for selectively separating and recovering silicon from waste silicon sludge generated during a semiconductor manufacturing process. With the method for separating and recovering silicon from the silicon sludge, oil components, iron, silicon carbide that are included in the silicon sludge may be removed and silicon may be selectively separated and recovered. In addition, silicon may be efficiently recovered without injection of an additive for precipitating a specific component or without a separate device such as a magnetic separator, or the like, for removing iron.

Abstract: Kinetically stable halogenated polysilanes include mixture of compounds having respectively at least four silicon atoms bound together, the substituents thereof comprising chlorine, and chlorine and hydrogen, and in the composition thereof, the atomic ratio of substituent to silicon is at least 1:1, wherein a) the kinetically stable halogenated polysilanes have a kinetically high stability in relation to oxidative splitting by chlorine, and the degree of conversion at temperatures of 120° C. within 10 hours with an excess of chlorine gas at 1013 hPa does not exceed 30 mol %, and b) the kinetically stable halogenated polysilanes have a percentage of branching points in the polysilane molecules of more than 8 mol %.

Abstract: This invention relates to a method for the manufacture of monolithic ingot of silicon carbide comprising: i) introducing a mixture comprising polysilicon metal chips and carbon powder into a cylindrical reaction cell having a lid; ii) sealing the cylindrical reaction cell of i); iii) introducing the cylindrical reaction cell of ii) into a vacuum furnace; iv) evacuating the furnace of iii); v) filling the furnace of iv) with a gas mixture which is substantially inert gas to near atmospheric pressure; vi) heating the cylindrical reaction cell in the furnace of v) to a temperature of from 1600 to 2500° C.; vii) reducing the pressure in the cylindrical reaction cell of vi) to less than 50 torr but not less than 0.05 torr; and viii) allowing for substantial sublimation and condensation of the vapors on the inside of the lid of the cylindrical reaction cell of vii).

Abstract: An insulating material for an electrical machine that insulates coiled windings is provided. The insulating material includes a carrier material and adhesive coatings on the front and back of the carrier material. The adhesive coatings are mounted and aligned on the front and back of the carrier material in such a way that in the carrier material in the insulation state a direct frictional connection is developed between the adhesive coatings on the front and back.

Abstract: Methods, systems, and apparatus are disclosed herein for recovery of high-purity silicon, silicon carbide and PEG from a slurry produced during a wafer cutting process. A silicon-containing material can be processed for production of a silicon-rich composition. Silicon carbide and PEG recovered from the silicon-containing material can be used to form a wafer-saw cutting fluid. The silicon-rich composition can be reacted with iodine containing compounds that can be purified and/or used to form deposited silicon of high purity. The produced silicon can be used in the photovoltaic industry or semiconductor industry.

Abstract: A process for production of polysilicon and silicon tetrachloride is provided in which a raw material that is supplied stably and is available at low cost can be used, chlorination reaction can be smoothly promoted, impurities generated after chlorination reaction can be controlled, and production efficiency is superior in a polysilicon producing step. The process includes a step of chlorination in which a granulated body consisting of silicon dioxide and carbon-containing material is chlorinated to generate silicon tetrachloride, a step of reduction in which silicon tetrachloride is reduced by a reducing metal to generate polysilicon, and a step of electrolysis in which chloride of the reducing metal by-produced in the reduction step is molten salt-electrolyzed to generate the reducing metal and chlorine gas.

Abstract: Polycrystalline silicon is prepared by thermally decomposing a reaction gas comprising hydrogen and a silicon-containing gas in a reaction chamber containing heated silicon, depositing additional silicon thereon, and forming an offgas; and separating the offgas into a first fraction comprising trichlorosilane and lower boiling chlorosilanes, and a second offgas fraction comprising components having a higher boiling point than trichlorosilane; recycling the first offgas fraction to the reaction gas of a polycrystalline silicon deposition; and separating the second offgas fraction into tetrachlorosilane and a high boiler fraction of high boilers, optionally also containing some tetrachlorosilane, and supplying the high boiler fraction to the reaction gas of a silicon deposition and heating the reaction gas to a temperature which ensures that the high boiler fraction is present in gaseous form on entry into the reaction chamber of the deposition reactor.

Abstract: A method and apparatus for refining silicon which can remove impurity elements such as phosphorus and antimony as well as impurity elements such as boron and carbon using an electron beam in the same vacuum chamber are provided. Silicon is irradiated and melted with an electron beam in a low vacuum inside a vacuum vessel, a compound-forming substance such as H2O which reacts with boron or the like in the molten silicon and forms a vaporizable oxide is introduced into the vacuum chamber, and impurity elements such as boron having a low vapor pressure in a vacuum are evaporated from the molten silicon as part of the vaporizable compound. Silicon in the vacuum vessel is then irradiated with an electron beam in a high vacuum in the vacuum vessel, and impurity elements contained in the silicon having a high vapor pressure in a vacuum such as phosphorus are removed.

Abstract: A polymer inactivation method for a polycrystalline silicon manufacturing device, wherein humidified gas such as water vapor and humidified nitrogen gas is supplied into a reacting furnace for manufacturing polycrystalline silicon to hydrolyze polymers adhered to an inner surface of the reacting furnace. It is preferable that a furnace wall of the reacting furnace is heated when the humidified gas is supplied.

Abstract: The present invention relates to a plant and a process for the continuous production of monosilane and tetrachlorosilane by catalytic dismutation of trichlorosilane at an operating temperature and a pressure of from 1 to 50 bar abs. in a plant according to claim 1, in which—trichlorosilane (A) is preheated in a heat exchanger (7), and fed to the 10 countercurrent reactor (1) which is provided with catalyst (3),—product mixture formed in the countercurrent reactor (1) is at least partly condensed by means of the condenser (5) at a temperature in the range from ?25 to 50° C. with the condensate flowing back into the countercurrent reactor (1),—the product phase which is not condensed in the condenser (5) is passed to the 15 condensation unit (8) which is operated at a temperature in the range from ?40 to ?110° C.,—the volatile product phase from the condensation unit (8) is fed to the distillation column (9) which is operated at a temperature in the range from ?60 to ?170° C.

Abstract: The method according to the present invention enables to suppress damaging the reaction tubes and the wafer boat made of quarts, when cleaning the reaction vessel after the completion of film forming process for a polysilicon or titanium nitride film, thus the method reduces the running cost. After forming a polysilicon film on the semiconductor wafers, the empty wafer boat is placed in the reaction vessel. The interior atmosphere of the reaction vessel is maintained at temperatures in the range of 700 to 1000° C. A mixed gas prepared by diluting chlorine gas with nitrogen gas is supplied at a predetermined flow rate into the reaction vessel to remove the polysilicon film. A titanium nitride film can also be removed in the same manner.

Abstract: A method for producing silicon tetrafluoride includes combining uranium oxyfluoride and silicon dioxide; heating the combination below the melting point of the uranium oxyfluoride to sufficiently react the uranium oxyfluoride and the silicon dioxide to produce non-radioactive silicon tetrafluoride and an oxide of uranium; and removing the silicon tetrafluoride.

Abstract: High purity silica is obtained by the reaction of impure by-product waste silica with hydrogen fluoride preferably in the presence of water or sulfuric acid, producing silicon tetrafluoride gas and a mother liquor. The silicon tetrafluoride is separated from the mother liquor, which retains the impurities originally contained within the impure silica. The silicon tetrafluoride gas is contacted with high-purity water, in a clean environment, to form a slurry of high purity silica and high-purity hydrofluosilicic acid (FSA). A portion of the silica is filtered from the slurry and washed producing a high purity silica product. The rest of the silica-FSA slurry is preferably reacted with ammonia to form a slurry of ammonium fluoride and silica. The silica is separated from the ammonium fluoride and preferably washed and calcined to remove any remaining ammonium fluoride, leaving additional high purity silica product.

Abstract: The present invention relates to fluorinated surfaces which exhibit sufficient hydrophilicity and sufficient electropositivity to bind DNA from a suspension containing DNA and permit elution of the DNA from the surface. Generally, the hydrophilic and electropositive characteristics are expressed at the fluorinated surface. Preferred fluorinated surfaces of the present invention include fluorinated Al(OH).sub.3, fluorinated SiO.sub.2 and fluorinated Celite. The fluorinated surfaces of the present invention are particularly useful in processes for purification of DNA from other cellular components. In these processes, a suspension of cellular components is placed in contact with the fluorinated surface, the fluorinated surface is washed to remove all cellular components other than DNA which are bound to the surface, and the bound DNA is eluted from the surface. Lower concentrations of chaotrope in the binding buffer are needed to bind DNA to the fluorinated surfaces.

Abstract: Radioactive metal is recovered from solid oxides of the metal by exposing the oxide to a cocurrent flow of a first acid solution in a first contactor to form partially reacted oxides and a solution containing the metal. The first solution containing the metal is drawn off and the partially reacted oxides are passed through a countercurrent flow of a second acid solution in a second contactor to form reaction residues and a second solution containing the metal. The second solution containing the metal is drawn off and the reaction residues are passed through a countercurrent flow of wash water in a third contactor. The reaction residues are then separated from the wash water and dried.

Abstract: A process for hydrofluoric acid digestion of inorganic silica/alumina matrix material for the production of silicon tetrafluoride and aluminum fluoride comprises the initial step of reacting the matrix material with hydrofluoric acid, to form silicon tetrafluoride gas and a solution/slurry containing aluminum fluoride, undigested oxides, and additional soluble and insoluble fluoride materials. The silicon tetrafluoride gas is purified of contaminants by condensing out impurities in cold traps and reacted with aqueous sodium fluoride to form a solution/slurry of fluorosilicate salt which is delivered to a filter press to separate sodium fluorosilicate powder from the solution/slurry. The sodium fluorosilicate powder is dried and delivered to a kiln at a temperature of about 600.degree. C. to 650.degree. C. to form substantially pure silicon tetrafluoride gas and sodium fluoride powder for collection.

Abstract: Titaniferous solid containing titanium (IV) oxide, for example ilmenite, is reacted with silicon tetrafluoride gas at 800.degree. C. or more and at a pressure of at least 1 atmosphere to produce titanium tetrafluoride vapor and silica. The vapor is rapidly removed from the reaction zone, preferably by rapid cooling to solid titanium tetrafluoride, at a sufficient distance from the reaction zone so as not to quench the reaction. The titanium tetrafluoride may be hydrolysed to produce titanium dioxide and hydrogen fluoride which is combined with silica to regenerate silicon tetrafluoride. It is preferred to pretreat the titaniferous solid by grinding and then roasting at 700.degree. C. to 750.degree. C. in air. Products of the reaction may be separated and purified by condensation and resublimation.

Abstract: Disclosed is a method for the processing of the residues that occur in the production of chlorosilane. The processing is performed by the separation of the residual chlorosilanes, followed by hydrolysis of these residues with water vapor. The water vapor used has a temperature between 100.degree. and 300.degree. C. and additionally contains hydrogen chloride. The hydrolysis residues occurring in the present method have an extremely small chloride content and can be transported, if desired, directly to a dump. The hydrogen chloride that is released can be absorbed in water and removed as hydrochloric acid or can be desorbed for further technical use. Preferably it is reused for chlorosilane production.

Abstract: The present application relates to a method for production of trichloromonosilane in a fluidized bed reactor by reaction of silicon powder and HCl at a temperature between 280.degree. and 300.degree. C. wherein silicon powder which has been produced by gas atomization of molten silicon is used. The gas atomized silicon powder has a preferred particle size between 1 and 1000 .mu.m.

Abstract: Disclosed is a recovering method of a catalytic substance and a carrier from a waste catalyst which comprises subjecting the waste catalyst composed of a catalyst prepared by supporting a catalytic substance on a carrier composed of pourous silicon carbide to chlorinating treatment and then recovering the catalytic substance and the carrier in the form of chlorides.

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: A silica-containing material such as silica sand, a carbonized biomass or biomass ash is converted into carbon tetrachloride by reaction with chlorine gas at an elevated temperature in the presence of a carbonaceous material such as coke, and sulfur or a sulfur compound. The reaction may be suitably performed in the further presence of a potassium compound.

Abstract: What is disclosed is a method for treating a reaction residue from the preparation of organochlorosilanes or chlorosilanes from the reaction of metallic silicon with a chlorinated hydrocarbon or hydrogen chloride, said method comprising (A) combining the reaction residue with water, and (B) granulating the mixture of water and silicon from (A).

Abstract: A process for treating solid substantially non-volatile wastes contaminated with a heat sensitive contaminant is disclosed. The wastes are heated to form a liquid slag. The liquid slag is held at elevated temperature until at least a portion of the contaminating components have either decomposed or evolved from the melt as a gas. The slag is subjected to cooling and the contaminating compounds are bound or encapsulated into a solid glassy slag. The process is particularly suitable for handling fluoride and cyanide contaminated aluminum smelting wastes such as spent potliner material. It is advantageous to add silica to such wastes. The residue from the slagging reaction is a glassy solid sodium metal silicate matrix such that the fluoride residues remaining in the wastes are encapsulated. The amount of silicate blended with the feed material is selected to substantially tie up all of the sodium remaining in the residue after slag melting and is typically 7.5 to 50 weight percent of the feed.

Abstract: The invention relates to the preparation of silicon tetrachloride by reacting material containing SiO.sub.2 with chlorine in the presence of carbon and metal halides and especially chlorides of the fifth main or subsidiary group of the Periodic Table at temperatures in the range of from 500.degree. to 1200.degree. C. The material containing SiO.sub.2 has a BET surface area of at least 0.1 m.sup.2 /g and the carbon has a BET surface area of at least 0.5 m.sup.2 /g.

Abstract: A process for the beneficiation of an iron-containing material is carried out by first chlorinating the iron-containing material. Oxidation of ferrous chloride in the effluent gas from the chlorination is carried out under controlled conditions of oxygen supply so that more than 50% but less than 100% of the ferrous chloride is oxidized. In this way chlorine gas is separated from the process stream in a relatively pure form which can be utilized in a continuous process by recycle to another chlorination.

Abstract: A selective chlorination method of a mixture of simple or complex metallic oxides, comprising at least one of the elements to be used, iron, aluminum, titanium and silicon, as well as the impurities accompanying said elements, said method consisting of a grinding, a calcination, a placing in suspension in a bath of melted salts of the mixture of said metallic oxides and of their impurities and of an introduction of chlorinating agents into said bath maintained at a temperature which assures the volatility of at least one of the metallic chlorides formed; characterized by the fact that, in order to selectively extract the metallic chlorides formed from the bath, specific chlorinating mixtures are introduced into this bath by successive steps, said mixtures having increasing chlorinating power, and the introduction is in a number at the most equal to the usuable elements to be chlorinated.

Abstract: A method for separating and recovering substantially pure aluminum, iron and silica from fly ash, a by-product of coal combustion, includes reacting the fly ash with aqueous fluosilicic acid and aqueous hydrogen fluoride at temperatures sufficiently high to form aqueous silicon fluoride vapor and fluorides and fluosilicate of aluminum and iron, separating the aluminum and iron fluorides and fluorosilicates from the aqueous silicon fluoride vapor, hydrolizing the silicon fluoride vapor to form silicon dioxide in substantially pure form and hydrogen fluoride, recovering and recycling the hydrogen fluoride for reuse in the process, and separating the aluminum and iron fluorides and fluosilicates from one another, and recovering substantially pure aluminum fluoride, substantially pure iron and other substantially pure metals, by electroplating or otherwise.

Abstract: Carbonaceous pyropolymers possessing recurring units containing at least carbon and hydrogen atoms may be obtained from compositions of matter comprising carbonaceous pyropolymers possessing recurring units containing at least carbon and hydrogen atoms composited on an inorganic metal oxide support or substrate by treating the composition of matter with a chloride-containing compound at an elevated temperature in the range of from about 400.degree. to about 1000.degree. C. in the vapor phase. The resulting metal chloride such as aluminum chloride is continuously removed from the composite, leaving only the carbonaceous pyropolymer.

Abstract: At least a two stage chlorination system for the production of aluminum trichloride and aluminum monochloride wherein in the gas stream containing the highest percentages of aluminum chloride produced CO.sub.2 is present and the said gas stream is passed through a charcoal or devolatilized coke bed in a preferred temperature range of about 1000.degree. C. to 1600.degree. C. to convert the said CO.sub.2 to CO and cycling at least part of the said CO produced to at least the second chlorination stage.

Abstract: At least a single stage chlorination system for the production of a substantially iron-free alumina-silica product from Bauxites, Bauxitic Clays and Clays wherein at least one chlorination agent is selected from the group consisting of Cl.sub.2, HCl and COCl.sub.2 and at least one chlorination agent from the group consisting of AlCl.sub.3 and SiCl.sub.4.

Abstract: At least a two-stage chlorination system for the production of a substantially iron-free alumina-silica product from Bauxites and Clays wherein in a preferred embodiment of the invention the chlorination agent is selected from the group consisting of Cl.sub.2, HCl and COCl.sub.2 in the first chlorination stage and wherein in the second chlorination stage the chlorination agent is selected from the group consisting of AlCl.sub.3 and SiCl.sub.4.

Abstract: At least a single stage chlorination system for the production of a substantially iron-free alumina-silica product from Bauxites, Bauxitic Clays and Clays wherein at least one chlorination agent is selected from the group consisting of Cl.sub.2, COCl.sub.2, AlCl.sub.2, AlCl, SiCl.sub.4 and SiCl.sub.2 and wherein the said chlorination agent is a limited percentage of the total gas stream.

Abstract: A method for producing alumina from a material containing alumina values via a chlorination step which process comprises the steps of:(A) dehydrating the material, if necessary, at a temperature of between about 500 and about 1300.degree. K.;(B) chlorinating the product of step (A) in the presence of chlorine and carbon at a temperature below about 1200.degree. K. and under conditions which provide chlorination of a majority of the iron present in the clay without substantial chlorination of titania values which may be present therein with concommittant formation of an iron chloride cloud above the surface of the chlorination reaction mixture;(C) introducing oxygen into the iron chloride cloud under conditions to cause oxidation of a majority of the iron chloride contained in the cloud;(D) chlorinating the non-gaseous product of step (B) in the presence of chlorine and carbon at a temperature above about 1300.degree. K.

Abstract: There is described a method for producing alumina from a material containing alumina values via a chlorination step which process comprises the steps of:(A) dehydrating the material, if necessary, at a temperature of between about 500 and about 1300.degree. K;(B) chlorinating the product of step (A) in the presence of chlorine and carbon at a temperature below about 1200.degree. K and under conditions which provide chlorination of a majority of the iron present in the clay without substantial chlorination of titania values which may be present therein with concommittant formation of an iron chloride cloud above the surface of the chlorination reaction mixture;(C) introducing oxygen into the iron chloride cloud under conditions to cause oxidation of a majority of the iron chloride contained in the cloud;(D) chlorinating the non-gaseous product of step (B) in the presence of chlorine and carbon at a temperature above about 1300.degree.

Abstract: A two stage process is described for chlorinating aluminum value containing materials such as bauxite, clay, fly ash, etc. The process comprises the steps of:(A) dehydrating the material, if necessary, at a temperature of between about 500.degree. and about 1300.degree. K.;(B) chlorinating the product of step (A) in the presence of chlorine and carbon at a temperature below about 1200.degree. K. and under conditions which provide chlorination of a majority of the iron present in the clay without substantial chlorination of titania values which may be present therein with concommittant formation of an iron chloride cloud above the surface of the chlorination reaction mixture;(C) introducing oxygen into the iron chloride cloud under conditions to cause oxidation of a majority of the iron chloride contained in the cloud; and(D) chlorinating the non-gaseous product of step (B) in the presence of chlorine and carbon at a temperature above about 1300.degree. K.

Abstract: The process is based on the series of halide-forming affinities. The oxides are passed through a series of zones equal in number to the plurality of halides or mixtures which are to be produced. A halide of an element of lower halide-forming affinity is fed counter-current to the oxides. The halide supply is in stoichiometric equivalent to the total content of halide to be extracted. The oxide of the said fed element is also extracted.

Abstract: A process for recovering aluminum from clays associated with coal or bauxite containing iron, siliceous material and titanium which comprises: (a) chlorinating the clay or bauxite 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 or carbon monoxide and vaporizing the chlorides of aluminum, silicon, titanium, and the residual iron, (c) separating and recovering the formed vaporized chlorides by selective condensation. Silicon tetrachloride may be added to step (b) to suppress the chlorination of silicon. If the clay contains alkali or alkaline earth metals, then the residue of step (b) is treated with sulfuric acid to convert the soluble chlorides, e.g., gypsum, to sulfates and to regenerate a chloridizing and binder solution for pelletizing the clay or bauxite.

Abstract: A continuous process for recovering substantially pure aluminum chloride from chlorination products of aluminum ore. The chlorination products are contacted with a first selective solvent to dissolve a substantial portion of the aluminum chloride and some ferric chloride. The solvent is separated from the chlorides which then are treated to produce a ferric chloride-rich stream and an aluminum chloride-rich stream in which the aluminum chloride to ferric chloride ratio is higher than the ratio prior to solvent separation. The aluminum chloride-rich stream is contacted with a second solvent to dissolve any ferric chloride present and saturate the solution with aluminum chloride. Aluminum chloride in excess of that soluble in the second solvent separates as a substantially pure solid phase. The solution is separated from solid phase and recycled in process to recover additional aluminum chloride.

Abstract: A process for the removal of iron and titanium minerals from aluminum bearing materials in at least one chlorination stage by the use of an excess of aluminum trichloride as at least the major chlorinating agent for the contained iron and titanium minerals, condensing the excess aluminum trichloride to recover the aluminum trichloride in an impure form, and recycling the impure aluminum trichloride to the chlorination stage together with additional aluminum trichloride or starvation amounts of chlorine, or alternately additional amounts of aluminum trichloride and starvation amounts of chlorine.

Abstract: A method of producing aluminum chloride from aluminous materials containing compounds of iron, titanium and silicon comprising reacting the aluminous materials with carbon and a chlorine-containing gas at a temperature of about 900.degree. K. to form a gaseous mixture containing chlorides of aluminum, iron, titanium and silicon and oxides of carbon; cooling the gaseous mixture to a temperature of about 400.degree. K. or lower to condense the aluminum chlorides and iron chlorides while titanium chloride and silicon chloride remain in the gas phase to effect a separation thereof; heating the mixture of iron chlorides and aluminum chlorides to a temperature of about 800.degree. K. to form gaseous aluminum chlorides and iron chlorides; passing the heated gases into intimate contact with aluminum sulfide to precipitate solid iron sulfide and to form additional gaseous aluminum chlorides; and separating the gaseous aluminum chloride from the solid iron sulfide.

Abstract: Aluminum chloride is produced from clay containing aluminum oxide and silicon oxide by chlorinating clay in at least two stages with a mixture consisting of a chlorinating agent, a reducing agent, an alkali metal compound catalyst and silicon tetrachloride in which the proportions and amounts of the feed gases to each stage are separately regulated to suit the needs of the aluminum chloride production reaction in that stage. The effluent gases from the successive stages are collected and the silicon tetrachloride is separated from such gases and recycled back into the reactors to promote chlorination of the aluminum oxide in the clay while suppressing net chlorination of the silicon oxide fraction of the clay.

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: The present invention provides a process for the production of aluminum chloride and alumina of metallurgical grade purity, and valuable by-products from aluminous ores like clay, bauxites and laterites. The process comprises carbo-chlorination of the ore to produce aluminum chloride and other metal chlorides. The aluminum chloride is separated, purified and utilized as such or oxidized to make alumina while the other metal chlorides are processed to recover maximum values.

Abstract: One of the major obstacles toward the needed and economic production of alumina and other values from kaolinitic clay and other ores by chlorination has been the slow reaction rates and low yields of the metal values. The present information provides methods for improving reaction rates and/or yields in the halogenation of various ores which comprises the addition of sulfur and/or functionally equivalent sulfur containing compounds as an ore conditioning agent and/or reaction promoter. These improvements also permit operation at low temperatures with advantage of savings of energy and of equipment and maintenance costs. The invention is applicable to both displacement halogenation and carbo-halogenation processes. The sulfur and/or functionally equivalent sulfur containing compounds can be added to the reaction mass during pre-halogenation steps or to the halogenation step or to combinations of steps ordinarily with additional benefits.

Abstract: Aluminum may be recovered from various raw materials including kaolinite, alunite, coal ash and slag, and both raw and spent oil shale, by contacting such materials with an aqueous solution of hydrofluoric acid, followed by removal of the insoluble residues remaining suspended in solution and the precipitation of hydrated aluminum hydroxide from the clear solution by basification with an alkaline agent.