Abstract: The present invention relates to a process for decomposing calcium sulfide (CaS) into calcium oxide (CaO) and sulfur dioxide (SO2), comprising:—providing a reactor containing calcium sulfide and a source of carbon,—oxidizing the source of carbon so as to generate carbon dioxide (CO2),—reacting the calcium sulfide with said carbon dioxide so as to produce carbon oxide (CaO), sulfur dioxide (SO2) and carbon monoxide (CO) according to the following reaction: CaS+3CO2˜CaO+SO2+3CO wherein the oxygen and carbon contents in the oxidation step are chosen such that: (i) the mass ratio C/CaS is comprised between 0.15 and 0.35 and (ii) the mass ratio O2/C is comprised between 5 and 25.

Abstract: The present invention relates to a process for decomposing calcium sulfate (CaSO4) present in phosphogypsum (PG), comprising the following steps: a) providing a reactor containing phosphogypsum (PG) and a solid source of carbon (C), b) reacting a flow of dioxygen (Oz) with the source of carbon (C) so as to generate carbon oxide (CO), c) reacting carbon oxide (CO) obtained in step a) with calcium sulfate (CaSO4) of the phosphogypsum to produce calcium oxide (CaO) and sulfoxide (SO2) according to the following reaction: CaSO4+CO?CaO+SO2+CO2 wherein the mass ratio C/PG is between 0.2 and DA, and the mass ratio 15 O2/PG is between 0.5 and 1.5.

Abstract: The present invention teaches the method to use the sulfate or sulfites based raw materials, such as magnesium, calcium and other alkative earth sulfates or sulfites to produce the respective oxides in a carbon five basis, by using sulfur as the fuel and the reductant. The invention also utilizes renewable energy such as solar thermal or green electricity wherever possible. This approach provides a green process, of ultra-low carbon dioxide emission, for the production of magnesium, other alkaline earth metals and other material which requires alkaline earth oxide, such as in the production of carbon free Portland cement requiring lime. The invention also provides a useful outlet for waste streams leading to sustainable processes. The cost of the production of these precursors are kept low by concurrently producing a saleable by-product—sulfuric-acid.

Abstract: A method for manufacturing a cathode active material for a lithium rechargeable battery, including: selecting a first metal compound from a group consisting of a halide, a phosphate, a hydrogen phosphate and a sulfate of Mg or Al; selecting a second metal compound from a group consisting of an oxide, a hydroxide and a carbonate of Mg or Al; combining the first metal compound and the second metal compound to obtain a metal compound, the metal compound containing either Mg or Al atoms; mixing a lithium compound, a transition metal compound and the metal compound to obtain a mixture; and sintering the mixture.

Abstract: The present invention refers to a method to prepare nanometric magnesium hydroxide particles. These particles have an average diameter that ranges from 90 to 110 nm, and that could range from 20 to 160 nm, with monodisperse and stable characteristics for greater than 12 month in a wide range of concentrations. This process includes 3 stages: one reaction stage performed in two steps, one of maturation and one of purification. The first step of the reaction is developed in micro blending zone, and the second one is the stabilization of suspension. During the second stage, the particles maturation is developed through a chemical-mechanic treatment. The last stage is designed to purify and concentrate the material, as well as its preparation to integrate it to the desired form.

Abstract: A process of producing a ceramic powder including providing a plurality of precursor materials in solution, wherein each of the plurality of precursor materials in solution further comprises at least one constituent ionic species of a ceramic powder, combining the plurality of precursor materials in solution with an onium dicarboxylate precipitant solution to cause co-precipitation of the ceramic powder precursor in a combined solution; and separating the ceramic powder precursor from the combined solution. The process may further include calcining the ceramic powder precursor.

Abstract: A method for calcining gypsum in a pressurized reactor by injecting combustion gases and air into the pressurized reactor to create a fluidized bed of gypsum, and heating the fluidized bed of gypsum in the pressurized reactor sufficiently to form a calcined hemihydrate.

Abstract: Multi-step metal compound oxidation process to produce compounds and enhanced metal oxides from various source materials, e.g. metal sulfides, carbides, nitrides and other metal containing materials with metal oxides from secondary reaction steps being utilized as an oxidation agent in the first reactions.

Abstract: A body pigment with a good skin feel for cosmetics is provided which has an appropriate crumbling property and combines slipping property and adhesiveness without compromising oil absorption. The body pigment is comprised of a metal-containing compound and has a structure in which leaf-shaped flakes are combined and/or intersected.

Abstract: A method of producing fine particles of an oxide of a metal, comprising the steps of: preparing an acidic solution which contains ions of the metal; precipitating fine particles of a hydroxide of the metal by adding an alkaline solution to the acidic solution; collecting the fine particles of the hydroxide of the metal precipitated in a mixed solution of the acidic solution and the alkaline solution; mixing fine particles of a carbon with the collected fine particles of the hydroxide of the metal; and heat-treating a mixture of the fine particles of the hydroxide of the metal and the fine particles of the carbon at a predetermined temperature in a non-reducing atmosphere, whereby the fine particles of the oxide of the metal are produced.

Abstract: The present invention relates to the improvement of a replenishment method of a magnesium-based compound and to the improvement of a double decomposition method, which can be used in a magnesium hydroxide desulfurization method. In the improved replenishment method, the magnesium-based compound is supplemented with water and the ratio of Mg/H2O is adjusted to the total Mg/H2O in the desulfurization system. In the improved double decomposition method, a tank for use is provided with an inner cylinder which partitions the tank into an inner part and an outer part, but does not reach the bottom of the tank, and a part of the slurry drawn through the bottom of the tank is fed to the outer upper position in the tank.

Abstract: Magnesium oxychloride and magnesium oxysulfate materials and methods of making the same are disclosed. The materials are cured reaction products of a magnesium oxide, and an aqueous magnesium salt solution. The aqueous salt solution preferably has a specific gravity of about 1.18 to about 1.4. The magnesium oxide has a platelet or flake structure, a bulk density of about 30 lbs/ft3 (about 0.48 g/cm3) to about 70 lbs/ft3 (about 1.12 g/cm3), and a particle density of about 215 lbs/ft3 (about 3.45 g/cm3) or less. The platelet/flake magnesium oxide is prepared, preferably from particles of magnesium oxide ore or brucite ore, using brine-free methods.

Abstract: A process and apparatus for producing calcium sulfide is provided comprising a container housing one or more drums, each drum having a substantially horizontal longitudinal center axis and containing one or more screw conveyors therein. Multiple drums are connected by passageways, and passages are provided for passing material into and out of the container and the drum(s). A heater is provided for supplying heat to the material within the drum(s). The process comprises passing the reactants, gypsum and charcoal, into the container and drum(s), heating the reactants within the drum(s) thereby initiating a chemical reaction converting reactants to products (including calcium sulfide), moving the reactants and products substantially horizontally in the drum(s) through the use of the screw conveyor(s) contained therein, and passing the products out of the drum(s) and the container.

Abstract: Magnesium hydroxide of high purity, having a fine particle size suitable for use in flame retardants and other high-end uses, is produced by utilizing flue gas desulfurization system process slurry as feedstock; the production process is absent energy-intensive steps as well as high-cost chemical usage.

Abstract: Calcium sulfide particles in mixtures with carbon particles, as in coal gasifier waste, are converted to calcium oxide by repeated cycles of oxidation and reduction by utilizing the carbon as a source of the reducing gas required for the treatment. The treatment can be conducted in a two zone fluidized bed reactor by limiting the amount and concentration of oxygen supplied to a lower reducing zone and by supplying excess oxygen to an upper oxidizing zone. Alternatively, for particles less than 0.5 mm in size, the treatment can be conducted by utilizing either two transport reactors or two circulating fluidized bed reactors in series whereby the first reactor in the series is maintained in a reducing state and the second reactor is maintained in an oxidizing state. The particles are transported sequentially through both reactors and recycled several times.

Abstract: A clear solution and a method for preparing the solution which has a pH in the range of from 10 to 13.9 and containing sulfate ions in a concentration range less than 500 parts per million. The solution is prepared by mixing two solutions in which one solution has one equivalent of magnesium sulfate and an equivalent of sulfuric acid and the second solution has an equivalent of Ca (OH).sub.2 and two equivalents of K.sub.2 OH. It is believed that CaSO.sub.4 precipitates in the mixed solution and causes coprecipitation of potassium, perhaps as double salt with the Ca leaving OH stabilized by hydration and magnesium ions.

Abstract: An improved process for converting particles containing calcium sulfide into calcium oxide by subjecting the particles to repeated cycles of oxidation and reduction. The impenetrable layer of calcium sulfate which forms during the oxidation phase of each cycle is destroyed by the subsequent reducing phase. By repeating the cycle many times, the particles are converted completely into calcium oxide at a reasonable temperature of about 1000.degree. C. The process can be carried out in either fixed bed, moving bed, or fluidized bed reactors by varying the composition of the gas supplied to the reactors in a periodic manner. Alternatively, the process can be conducted in fluidized bed reactors which have separate oxidizing and reducing zones located one above the other. In one design air is supplied through a gas distributor at the bottom of the fluidized bed to create an oxidizing zone in the lower part of the bed.

Abstract: In a process for removing sulfur dioxide from a gas stream using an aqueous solution of magnesium scrubbing components and subsequent oxidation of the magnesium sulfite produced which is regenerated by addition of lime, a pure magnesium hydroxide product is produced using less oxidation energy requirements by passing a further portion of solution from the oxidizing unit to a further oxidizing unit, oxidizing the same to produce an aqueous solution containing less than 130 ppm sulfite, treating the further portion with lime and separating purified magnesium hydroxide therefrom.

Abstract: A plate barium sulfate is described, which has a particle size of from 1 to 100 .mu.m or from 5 to 150 .mu.m, wherein neither a sulfide nor a soluble barium salt is detected by an analysis method based on the Japanese Cosmetics Material Standard. The process of the plate barium sulfate is also described.

Abstract: A method is provided for the regeneration of a scavenging compound that has been reacted with hydrogen sulfide. Regeneration is accomplished through the use of calcium oxides and sodium hydroxide. Sodium sulfide is recovered from the regeneration process in a commercially useful form. Calcium oxides are also regenerated in the process, allowing for minimal or no chemical waste.

Abstract: A cyclic process of subjecting calcium sulfide particles to alternating oxidizing and reducing conditions. The impenetrable shell of calcium sulfate which forms during the oxidation phase of the cycle is destroyed by the subsequent reducing phase. By repeating the cycle many times the particles are converted completely into calcium oxide at a reasonable temperature of about 1000.degree. C. The process can be carried out in a fluidized bed reactor either by maintaining both oxidizing and reducing zones within the same fluidized bed or by varying the gas phase throughout the fluidized bed in a periodic manner.

Abstract: A fibrous composite metal hydroxide containing a small amount of hexagonal-plate-like magnesium hydroxide and being therefore advantageously useful as a reinforcing material for resins and rubbers. The crystal water elimination temperature thereof can be set at any point between the crystal water elimination temperature of magnesium hydroxide and that of aluminum hydroxide. This fibrous composite metal hydroxide is excellent in flame retardancy and acid resistance. The fibrous composite metal hydroxide has an aspect ratio of about 10 or more, an average diameter of approximately 0.1 to 10 .mu.m and an average length of approximately 2 to 1,000 .mu.m, and having the formula (1),M.sup.2+.sub.x Mg.sub.1-x (OH).sub.2 (1)wherein M is at least one member selected from Mn, Fe, Co, Ni, Cu and Zn and x is defined by 0.005<x<0.5.

Abstract: Disclosed is a novel basic magnesium carbonate represented by the following general formula:nMgCO.sub.3.Mg(OH).sub.2.mH.sub.2 Owherein n is a number of from 3 to 5 and m is a number of from 3 to 5,which consists of porous particles composed of an aggregate of plate crystals having an average particle size of 1 to 50 .mu.m and a specific surface area of 10 to 70 m.sup.2 /g, wherein in the fine pore size distribution of the particles, the volume of fine pores having a radius smaller than 100 .ANG. is at least 0.02 cc/g and the volume of fine pores having a radius smaller than 75,000 .ANG. is at least 0.8 cc/g.This novel basic magnesium carbonate is highly improved over conventional basic magnesium carbonate in such properties as filling property, dispersibility and flowability.

Abstract: Barium sulfate having a specific crystal structure and optical characteristics is disclosed. The crystals have a plate-like structure of which the aspect ratio is 5-100 and the ratio of the square of the circumference of the plate and the area of the orthogonal projection plane is 20:1-150:1. In a preferred embodiment, a thin film of 25 .mu.m thickness with 20% by weight of the barium sulfate powder concentration has a scattering transmittance of 70% or greater and a total transmittance of 85% or greater. The cosmetic compositions to which the barium sulfate is incorporated exhibits excellent extendibility and adhesion to the skin and can effectively hide the spots or freckles on the skin. The cosmetic composition satisfies both the fine naked skin feeling and the skin covering effect, which have never been satisfied by conventional cosmetic compositions.

Abstract: Novel magnesium hydroxide having a fine, plate-like crystalline structure, a median particle size of up to about 1 micron and a particle size distribution in which about 90% of said magnesium hydroxide particles are less than about 3.5 microns is prepared by a flash precipitation process in which less than or greater than an equivalent amount of alkaline material is reacted with a magnesium salt in a concentrated aqueous mixture thereof. Ultrasonic mixing means is used to combine heated aqueous streams of an alkaline material and a magnesium containing solution followed by a post heat treatment. The magnesium hydroxide is especially useful in providing flame retardancy in admixture with thermoplastic resins.

Abstract: A process for the production of a magnesium oxide having high hydrolysis resistance and high fluidity, which comprises:(A) a step of reacting a water-soluble magnesium salt with an alkaline substance in such an amount that is not more than 0.95 equivalent weight based on 1 equivalent weight of the water-soluble magnesium salt, at a temperature of not more than 40.degree. C.,(B) a step of heating the resultant reaction product and its reaction mother liquor at about 50.degree. to 120.degree. C. to form a magnesium hydroxide,(C) a step of forming particles having an average secondary particle diameter of about 5 to 500 .mu.m by using a spray drier,(D) a step of firing the particles at about 1,100.degree. to 1,600.degree. C., and(E) a step of pulverizing the resultant fired product under conditions which do not substantially destroy the average secondary particle diameter obtained in the above step (C).

Abstract: A process for producing NH.sub.3 and SO.sub.2 from ammonium sulfate, which comprises(i) reacting ammonium sulfate with a metal oxide or hydroxide at a temperature of not more than 200.degree. C. to form NH.sub.3, water and a metal sulfate and recovering NH.sub.3,(ii) decomposing the metal sulfate in the presence of a reducing agent to form a metal oxide and SO.sub.2 and recovering SO.sub.2, and(iii) recycling the metal oxide to step (i) as such or after it is converted to a metal hydroxide.

Abstract: A lightweight magnesia clinker containing magnesium oxide in an amount of more than 85 wt. % and having an apparent porosity of more than 40 vol. % and a bulk specific gravity of less than 2.0 g/cm.sup.3 is disclosed. In the lightweight magnesia clinker, the amount of magnesia clinker particles having a particle diameter of smaller than 3 mm is more than 90 wt. % of the amount of all magnesia clinker particles, and the amount of pores formed in the magnesia clicker particles having a pore size of smaller than 50 .mu.m is more than 90 vol. % of the amount of all pores. A process for the preparation of said lightweight magnesia clinker is also disclosed.

Abstract: The invention relates to a process for removing sulfur oxides, particularly sulfur dioxide, contained in gases such as industrial fumes, characterized in that the gas is contacted with a solid absorbent containing magnesium oxide, in such conditions that sulfur oxides are fixed mainly as magnesium sulfate and then the used solid absorbent is contacted with a gas stream containing elemental sulfur in such conditions that magnesium oxide is regenerated with the production of an effluent of sulfur dioxide-containing gas.

Abstract: The invention concerns a process for removing sulfur oxides and particularly sulfur dioxide contained in such gases as industrial fumes, wherein said gas is contacted with a solid absorbent containing magnesium oxide and at least one group VIII noble metal, in such conditions that the sulfur oxides are mainly fixed as magnesium sulfate, and then the used solid absorbent is regenerated by contact with a hydrogen sulfide-containing reducing gas.

Abstract: A continuous process for the manufacture of a metal salt solution is described which provides more economical products with higher quality than current processes. The process is safer, both to operating personnel and to the environment, than currently used processes. The process comprises feeding an aqueous metal compound slurry, e.g., a metal oxide/hydroxide slurry and a mineral acid, e.g., nitric acid, and water to a reactor which includes a zone of extreme mixing and agitation, most preferably a cross-pipe reactor provided with an optional static in-line mixer. A cross-pipe reactor provides complete and efficient reaction by providing greater surface area, high agitation and a long reaction time.

Abstract: Magnesium hydroxide of a substantially spherical particle form having an average particle size of from 5 to 500 .mu.m and a specific surface area of from 25 to 1 m.sup.2 /g.

Abstract: Magnesium hydroxide of a fine plate-like particle form having an average particle size (d) of from 0.2 to 0.8 .mu.m as measured by a light transmission type liquid phase sedimentation method, wherein the proportion of particles having a particle size of d+0.5 .mu.m or larger is not higher than 50% by weight based on the weight of the total particles, and the particle thickness distribution is such that the proportion of particles having a thickness of 0.05 .mu.m or less is not higher than 5% by number and the proportion of particles having a thickness of 0.2 .mu.m or more is not higher than 20% by number.

Abstract: A process for producing highly pure magnesium hydroxide, which comprises reacting magnesium hydroxide starting material containing impurities, with an aqueous solution containing a water-soluble calcium salt and carbon dioxide to form an aqueous solution containing a magnesium salt and calcium carbonate precipitates whereby said impurities are transferred to the precipitates, filtering off the precipitates, then reacting the aqueous solution containing the magnesium salt, with ammonia to form a slurry comprising magnesium hydroxide solid and an aqueous solution containing an ammonium salt, and filtering the slurry to obtain highly pure magnesium hydroxide solid and an aqueous solution containing the ammonium salt.

Abstract: A method of calcining in a fluidized reactor wherein fluid petroleum coke is utilized as the reactor fuel. The method of the present invention utilizes fluid coke as the fuel for a calcining reactor. The fluid coke is introduced into the pneumatic stream with the lime feed material, ahead of the reactor feed header, to achieve an intimate mixing of the fuel and the feed material. This facilitates calcination of the calcium carbonate and results in more efficient utilization of fuel than in methods of the prior art. Advantages of using fluid coke as the fuel include that it is of a size fine enough to provide efficient utilization as a fuel but not so large that inefficient utilization, unstable temperatures, and carry-over into the final product result. Another advantage is that the fluid coke typically contains 5-7% by weight sulphur, a necessary ingredient in proper calcination of calcium carbonate in a fluidized reactor and one that has been required to be added in methods of the prior art.

Abstract: An improved method for the recovery of elemental sulfur(S) from a coal-gas containing hydrogen sulfide (H.sub.2 S) wherein hot lime (CaO) is used and then regenerated according to the following chemistry:CaO+H.sub.2 S=CaS+H.sub.2 OCaS+3/2 O.sub.2 =CaO+SO.sub.2SO.sub.2 +C=S+CO.sub.2These chemical reactions are conducted in-situ while the supply of carbon (C) for the formation of the elemental sulfur(S) is derived from a component of the coal-gas itself to increase the overall efficiency of desulfurization, increase the uniformity of the carbon deposit into the hot lime (CaO), and eliminate the extra and cumbersome steps of physically moving the spent lime (CaO) for regeneration and returning it after regeneration, and the step of adding coal to react with the sulfur dioxide (SO.sub.2) formed as an off-gas during regeneration.

Abstract: The present invention relates to the discovery of a method by which elemental sulfur may be delivered to a reaction zone, for gas-solids reaction, in the form of a concentrated, coherent, diffusion-resistant gas thereby permitting gas-solid reactions of greatly enhanced reaction rates. It has been found that sulfur, which is first vaporized at approximately 1 atmosphere pressure, and then super heated to at least 1270.degree. F. while in transit through a confined space, such as a transfer line, will debouch from said confined space into a reaction zone as a coherent gas which resist diffusion throughout the free space of the reaction zone. This coherent form of sulfur gas exhibits a dark reddish-violet color. The coherent form of sulfur gas, since it resists diffusion throughout the free space of the reaction zone, flows into concentrated contact with, and remains concentrated at, the solids surface, thereby producing a gas-solids reaction of greatly enhanced reaction rate.

Abstract: A magnesium oxide having a cubic system needle-like crystal structure and a length-to-diameter ratio, determined by an electron microscope at a magnification of 10,000, of at least about 5; and a process for producing a magnesium oxide having a cubic system needle-like crystal structure, which comprises calcining a basic magnesium compound having a needle-like crystal structure expressed by the following formulaMg(OH).sub.2-nx A.sub.x.sup.n-.mH.sub.2 Owherein A.sup.n- represents a monovalent (n=1) to tetravalent (n=4) anion, x is 0.2.ltoreq.x.ltoreq.0.5, and m is 0<m.ltoreq.2,or a magnesium hydroxide having a needle-like crystal structure, at a temperature of not less than about 400.degree. C. to convert it to the magnesium oxide.

Abstract: Phosphogypsum is mixed with fine coal, balled, and charged to a travelling grate where the charge is heated under reducing conditions to evolve sulfur and/or sulfur dioxide for conversion into sulfuric acid.

Abstract: A process and apparatus for producing a low sulfur content hot reducing gas by desulfurizing hot reducing gas by contacting the sulfur-bearing hot reducing gas or carbonaceous material with a particulate calcium oxide desulfurizing agent to thereby produce a product gas stream and a byproduct calcium sulfide composition, and then recovering sulfur from the calcium sulfide composition by contacting the calcium sulfide composition with hot liquid water at a temperature and corresponding pressure sufficient to maintain steam in the system and wherein a major portion of the calcium sulfide composition has a particle size of less than about 6 mesh to thereby convert the sulfide to calcium hydroxide and hydrogen sulfide. A preferred process uses this low sulfur content gas to reduce iron ore, and especially wherein ore, calcium oxide and carbonaceous material are reacted in a shaft furnace.

Abstract: A method for leaching magnesium from a magnesium hydroxide-containing composition, especially a mineral, which comprises contacting said composition with an aqueous solution of an ammonium salt whose corresponding magnesium salt is soluble in said aqueous solution to thereby produce said soluble magnesium salt; separating said aqueous solution from said composition; and transforming the magnesium of said soluble magnesium salt into an insoluble magnesium compound. The method is particularly useful for leaching magnesium from brucite-containing chrysotile asbestos fibers, to yield both a magnesium compound and brucite-free, dispersed chrysotile fibers.

Abstract: A process and apparatus for producing a low sulfur content, hot reducing gas by desulfurizing hot reducing gas by contacting the sulfur-bearing hot reducing gas with a bed of a particulate calcium oxide desulfurizing agent to thereby produce a product gas stream and a byproduct calcium sulfide composition, and then recovering sulfur from the calcium sulfide composition by contacting the calcium sulfide composition with hot liquid water at a temperature and corresponding pressure sufficient to maintain steam in the system and to thereby convert the sulfide to calcium hydroxide and hydrogen sulfide and to produce a liquid water stream containing sulfur, and then combining the sulfur-containing water stream with a fresh water stream and recycling this water stream for contacting the calcium sulfide composition. Preferably water vapor produced in the contacting step is condensed and returned to the system in the final stage of contacting the calcium sulfide composition with hot liquid water.

Abstract: Disclosed is a process for refining a magnesium and nickel containing ore, comprising the steps of grinding the ore; preparing a slurry of the ground ore in sulfuric acid containing less than ten percent of water; adding water to the acid-ore slurry in an amount which is effective to initiate a sulfation reaction; allowing the sulfation reaction to continue, utilizing the heat of the sulfation reaction to heat the acid-ore slurry, whereby water-soluble metal sulfates and insoluble residue are formed; leaching the sulfation product with water to extract the water-soluble metal sulfates in solution; separating the metal sulfates solution from the insoluble residue; precipitating from the solution metals other than Mg as hydroxides; separating the solution from the metal hydroxide precipitate; concentrating the solution sufficiently to precipitate CaSO.sub.4 ; separating the concentrated solution from the precipitate; recovering dehydrated MgSO.sub.

Abstract: Sulfur-containing fuels are converted to substantially sulfur-free combustible gas in an integrated process involving part combustion in a dense phase fluidized conversion bed of particles comprising alkaline earth metal oxides. An oxygen-containing gas is passed into the base of the bed to maintain a relatively high fuel/air ratio. Sulfur is chemically fixed in the particles by reaction to form alkaline earth metal sulfide. Particles containing alkaline earth metal sulfide are circulated from one region of the conversion bed to one region of a dense phase fluidized regeneration bed operated at a higher temperature and fluidized by passing into the base thereof an oxygen-containing gas which exothermically regenerates chemically active alkaline earth metal oxide from the sulfide liberating gases which have a low oxygen content and a relatively high content of sulfur moieties (e.g. SO.sub.2).

Abstract: Fibrous magnesium hydroxide having a hexagonal needle-like crystal structure. The fibrous magnesium hydroxide can be produced by drying a basic magnesium compound having a needle like crystal structure expressed by the following formulaMg(OH).sub.2-nx.A.sub.x.sup.n-.mH.sub.2 Owherein n is 1 or 2, A.sup.n- represents a monovalent or divalent anion, x is 0.2.ltoreq.x.ltoreq.0.5, and m is O<m.ltoreq.2,under conditions which do not cause a loss of its needle-like crystal form so that a part of the water of crystallization is liberated from the magnesium compound; and contacting the dried magnesium compound with an alkali in a liquid medium which is inert to the magnesium compound and does not dissolve the magnesium compound.

Abstract: A process for converting magnesium sulfate into magnesium oxide comprising calcining the magnesium sulfate in the presence of lignite coke or soot as a reducing agent.

Abstract: Lime utilization for sulfurous oxides absorption in fluidized combustion of carbonaceous fuels is improved by impregnation of porous lime particulates with iron oxide. The impregnation is achieved by spraying an aqueous solution of mixed iron sulfate and sulfite on the limestone before transfer to the fluidized bed combustor, whereby the iron compounds react with the limestone substrate to form iron oxide at the limestone surface. It is found that iron oxide present in the spent limestone acts as a catalyst to regenerate the spent limestone in a reducing environment. With only small quantities of iron oxide the calcium can be recycled at a significantly increased rate.

Abstract: CaS is converted to CaO with increased production of SO.sub.2 and decreased production of CaSO.sub.4 by passing CaS-containing particles into one region of a conversion bed wherein they are fluidized at an elevated temperature by an upwardly-passing oxygen-containing fluidizing gas, removing particles of increased CaO content from a second region of the bed, and providing a reducing agent (e.g. a hydrocarbon gas, liquid or carbonaceous solid) in the bed between the first and second regions, preferably nearer the latter, to produce a mildly reducing atmosphere which reduces any CaSO.sub.4 and increases the yield of SO.sub.2. The removed particles may be circulated to a fluidized gasification bed wherein a sulphur-containing fuel is converted to substantially sulphur-free fuel gas and wherein the sulphur is fixed as CaS in the particles, which particles are thereafter recirculated to the conversion bed.

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: Dolomite which has been used to remove sulfur and/or sulfur-containing compounds from gases by chemical reactions therewith is regenerated by passing through the spent dolomite an oxidizing gas selected from oxygen, CO.sub.2 and H.sub.2 O at temperatures between about 1500.degree. F. and the temperature at which the dolomite becomes unreactive.