Abstract: The present invention provides methods and apparatus for treating flue gas containing sulfur dioxide using a scrubber, and more particularly relates to recovering gypsum and magnesium hydroxide products from the scrubber blowdown. The gypsum and magnesium hydroxide products are created using two separate precipitation reactions. Gypsum is crystallized when magnesium sulfate reacts with calcium chloride. Magnesium hydroxide is precipitated when magnesium chloride from the gypsum crystallization process reacts with calcium hydroxide. The process produces a high quality gypsum with a controllable pH and particle size distribution, as well as high quality magnesium hydroxide.

Abstract: The present invention relates to a method for preparing barium titanate based powder. More particularly, the present invention provides a method for preparing barium titanate powder comprising the following steps of precipitation of barium titanyl oxalate (BaTiO(C2O4)2.4H2O) with spraying a mixture of an aqueous barium chloride (BaCl2.2H2O) and titanium tetrachloride (TiCl4) to an aqueous solution of oxalic acid, via a nozzle; wet pulverization by using a beads mill after adding an additive such as an amine; dry; pyrolysis; and re-pulverization.

Abstract: A production process for an oxide magnetic material comprising the steps of blending raw material powder so as to take the composition of a hexagonal ferrite including: at least one kind of an element A selected from the group consisting of Ba, Sr and Ca; Co and Cu; Fe; and O; and sintering said blended powder at a temperature lower than 1000° C.

Abstract: Disclosed herein is a small particle oxide powder for dielectrics. The oxide powder has a perovskite structure, an average particle diameter [D50(?m)] of 0.3 ?m or less, a particle size distribution of the average particle diameter within 3%, a particle size distribution satisfying a condition D99/D50<2.5, a content of OH? groups of 0.2 wt % and a C/A axial ratio of 1.006 or more. A method of manufacturing the oxide powder comprises the steps of mixing TiO2 particles and a compound solved with at least one element represented by A of the perovskite structure of ABO3; drying and pulverizing the mixture of TiO2 and the compound; calcining the pulverized mixture; adding the oxide containing the elements of the site A to the coated TiO2 particles and wet-mixing, drying and pulverizing; primarily calcining and pulverizing the pulverized powder under vacuum; and secondarily calcining and pulverizing the powder.

Abstract: The present invention provides a process for producing particles, such as oxide nanoparticles, in a substantially water-free environment. The process involves mixing at least one metal compound of the formula MX(m?n) with at least one surfactant and at least one solvent, wherein M is an electropositive element of Groups 1–15; each X is independently selected from the group consisting of O1/2, F, Cl, Br, I, OR, O2CR, NR2, and R; each R is independently a hydrocarbyl group; n is equal to ½ the oxidation state of the metal M in the product particle; and m is equal to the oxidation state of the element M. The components are typically combined to form a mixture which is thermally treated for a time period sufficient to convert the metal compound into particles of the corresponding oxide, having sizes in a range between about 0.5 nanometer and about 1000 nanometers.

Abstract: A method of synthesis of alkali metal ferrates and alkaline earth metal ferrates, in which a trivalent iron compound is mixed with potash and optionally persulphate, and the mixture is heated at a temperature in the range of about 250 to about 500° C. for about 1 to 10 hours. The invention also relates to the use of the ferrates obtained by this method.

Abstract: The present invention relates to the macroporous manganese oxide material having ferromagnetic property and a method of preparing the same, more particularly to the macroporous ferromagnetic manganese oxide having three-dimensionally ordered nanopores, which is prepared by aligning colloidal polymer particles with an average diameter of a few hundred nanometers in 3D, infiltrating a solution of the precursor compound capable of forming manganese oxide represented by the following Chemical Formula 1 into interstices of the colloidal template and heating in an oxygen atmosphere to decompose and remove the polymer template, and a method for preparing the same: La1-xCax-ySryMnO3 ??(1) wherein 0.25<x<0.35 and 0<y?0.35.

Abstract: A process for purifying a stock Sr-90 solution containing stable and radioactive impurities, holding the purified Sr-90 solution for Y-90 ingrowth, and subsequently extracting the Y-90 from the Sr-90/Y-90 solution. The stock solution is sequentially passed through two thermoxide-type sorbents (T-3 and T-5), which hold the impurities while passing the Sr-90 solution. After ingrowth of Y-90, the Sr-90/Y-90 solution is passed through sorbent T-3, which preferentially sorbs the Y-90 while passing the Sr-90 solution. The Y-90 is then eluted from the T-3 sorbent. The T-3 and T-5 sorbents are specially prepared compounds of zirconium dioxide and titanium dioxide, respectively, that preferentially sorb Y-90 under predetermined conditions of solution pH and NaCl concentration.

Abstract: The present invention is focused on a revolutionary, low-cost (highly-scaleable) approach for the mass production of three-dimensional microcomponents: the biological reproduction of naturally-derived, biocatalytically-derived, and/or genetically-tailored three-dimensional microtemplates (e.g., frustules of diatoms, microskeletons of radiolarians, shells of mollusks) with desired dimensional features, followed by reactive conversion of such microtemplates into microcomponents with desired compositions that differ from the starting microtemplate and with dimensional features that are similar to those of the starting microtemplate. Because the shapes of such microcomponents may be tailored through genetic engineering of the shapes of the microtemplates, such microcomposites are considered to be Genetically-Engineered Materials (GEMs).

Abstract: Tellurium-containing nanocrystallites are produced by injection of a precursor into a hot coordinating solvent, followed by controlled growth and annealing. Nanocrystallites may include CdTe, ZnTe, MgTe, HgTe, or alloys thereof. The nanocrystallites can photoluminesce with quantum efficiencies as high as 70%.

Abstract: The present development is a silica additive for use in rubbers and similar cross-linked materials having a silicon atom intercalated within an oxygenated framework. The additive may be prepared starting with crystalline, fused or amorphous silica powder, thereby reducing the cost of the additive as compared to using precipitated silica.

Abstract: The invention relates to a nickel mixed hydroxide with Ni as the main element and with a layer structure, comprising at least one element Ma from the group comprising Fe, Cr, Co, Ti, Zr and Cu which is present in two different oxidation states which differ by one electron in terms of the number of outer electrons; at least one element Mb from the group comprising B, Al, Ga, In and RE (rare earth metals) present in the trivalent oxidation state; optionally at least one element Mc from the group comprising Mg, Ca, Sr, Ba and Zn present in the divalent oxidation state; apart from the hydroxide, at least one additional anion from the group comprising halides, carbonate, sulfate, oxalate, acetate, borate and phosphate in a quantity sufficient to preserve the electroneutrality of the mixed hydroxide; and water of hydration in a quantity which stabilizes the relevant structure of the mixed hydroxide.

Abstract: An aqueous coating liquid for forming a magnesium oxide film comprising (a) a magnesium carboxylate derived from a carboxylic acid having 1 to 6 carbon atoms, (b) a surfactant, (c) a polyhydric alcohol compound, and (d) a solvent made substantially of water, wherein the magnesium carboxylate is contained in a ratio of 5 wt % or more and 50 wt % or less. The surfactant is contained in a ratio of 0.01 wt % or more and 2.5 wt % or less, and the polyhydric alcohol compound is contained in a ratio of 0.05 wt % or more and 40 wt % or less, based on a weight of the entire coating liquid. The magnesium carboxylate content is the same with or larger than that of the polyhydric alcohol compound, and a total weight of the magnesium carboxylate and the polyhydric alcohol compound is 80 wt % or less of the weight of the entire coating liquid; and wherein the magnesium carboxylate, the surfactant, and the polyhydric alcohol compound are dissolved in the solvent.

Abstract: A new process for recovery of common salt, potassium chloride, concentrated magnesium chloride with enriched bromide, and high purity magnesia from brine in an integrated manner, said process comprises preparation of calcium chloride by reaction of hydrochloric acid generated in the process with limestone, desulfatation of brine with calcium chloride, production of sodium chloride of superior quality in solar pans, solar evaporation of bittern thereby producing carnallite and end bittern, processing carnallite through established processes to produce potassium chloride, recovering end bittern containing highly concentrated magnesium chloride and enriched bromide and calcination of a part of the end bittern after solidification to produce high purity magnesia and hydrochloric acid utilizable in the process.

Abstract: Novel iron sulfides having excellent durability and excellent treating properties of heavy metals, processes for producing the iron sulfides, iron sulfide mixture, a heavy metal treating agent containing either of these novel iron sulfides as an effective component, and a method by which wastes containing various heavy metals are treated with the heavy metal treating agent are disclosed. The iron sulfide having a mackinawite structure which contains FeMxNySz wherein M represents an alkaline earth metal, N represents an alkali metal, and x, y and z, indicating the molar proportions of the respective elements, represent numbers satisfying 0.01<x≦0.5, y≦0.2 and 0.7≦z≦1.4, as an essential component.

Abstract: A catalyst active in ammonia synthesis with improved activity and a process for the recovery of useful components from the catalyst.

Abstract: Doped, nanosize metal oxide particles have been shown to exhibit stimulated emission and continuous-wave laser action when energized appropriately, for example by electron beams. The doped particles are useful as solid state lasing devices and “laser paints”. Particles containing homogeneously distributed dopant atoms in concentrations greater than the thermodynamic solubility in the metal oxide matrix, and having in some circumstances, unusual oxidation states, have been produced.

Abstract: The invention encompasses methods of forming titanium-based mixed-metal materials and zirconium-based mixed-metal materials utilizing one or more of a reduction process, electrolysis process and iodide process. The invention also encompasses a sputtering target comprising zirconium and one or more elements selected from the group consisting of Al, B, Ba, Be, Ca, Ce, Co, Cs, Dy, Er, Fe, Gd, Hf, Ho, La, Mg, Mn, Mo, Nb, Nd, Ni, Pr, Sc, Sm, Sr, Ta, Ti, V, W, Y, and Yb. The invention also encompasses a sputtering target comprising titanium and boron.

Abstract: A high-melting-point conductive oxide includes a mixture of a powdered Sr compound and Ru compound and/or Ru metal. The mixture is sintered at a primary temperature of 900° C. to 1300° C. in an atmosphere containing oxygen to form a sintered body that is pulverized back to a powder. The powder is given a desired shape that is again sintered, this time at a secondary temperature of 1000° C. to 1500° C. higher than the primary temperature, again in an atmosphere containing oxygen. The high-melting point conductive oxide is used as a heating element for high-temperature use, an electrode material for high-temperature use, a material for high-temperature thermocouple use and a light-emitting material for high-temperature use.

Abstract: A method for separating metal ions, which comprises adding a selective capturing agent to an aqueous solution containing plural types of metal ions, said selective capturing agent being a cyclic compound and forming a complex with metal ions having ion radii suitable for the size of the ring alone, so that unnecessary metal ions are held by the selective capturing agent in the aqueous solution, and bringing said aqueous solution into contact with an ion exchange solid phase so as to transport desired metal ions alone to the solid phase.

Abstract: A method of producing an electronic device including a dielectric layer includes a dielectric ceramic composition containing a main component expressed by a formula of {(Sr1−xCax)O}m.(Ti1−yZry)O2, wherein x fulfills 0≦x≦1.00 and y fulfills 0≦y≦0.20, and producing said dielectric ceramic composition by using a material expressed by a formula of {(Sr1−xCax)O}m′.(Ti1−yZry)O2 wherein the mole ratio m′ fulfills m′<m. It is possible to produce an electronic device, such as a chip capacitor, having excellent resistance to reducing during firing and excellent capacity-temperature characteristics after firing, wherein the insulation resistance is hard to be deteriorated particularly when made to be a thin layer and defect rate of the initial insulation resistance is low.

Abstract: There is provided a process for producing high-purity magnesium hydroxide by reaction of magnesium or reactive magnesium compounds with hydroxy compounds yielding magnesium alkoxides, followed by hydrolysis to form magnesium hydroxide, or a process for producing magnesium oxide by calcination of magnesium hydroxide.

Abstract: A method of treating metal-contaminated spent foundry sand, or other industrial waste, by combining the sand with a sulfite to produce insoluble metal sulfur oxide complexes that do not leach from the sand. The treated waste may also be processed to reducing “clumping,” thereby rendering the treated waste appropriate for use in another industrial process.

Abstract: This patent describes economical and environment-friendly processes for the synthesis of Mg-containing non-Al anionic clays. It involves a one-step process wherein a suspension comprising a trivalent metal source and at least a magnesium containing source as a divalent metal source is reacted to obtain a magnesium-containing non-Al anionic clay. The anionic clay has interlayers containing anions comprising hydroxycarbonate, carbonate, bicarbonate, acetate, hydroxyacetate, oxalate, nitrate, hydroxyl, and/or formate or mixtures thereof. There is no necessity to wash or filter the product. It can be spray dried directly to form microspheres or can be extruded to form shaped bodies. The product can be combined with other ingredients in the manufacture of catalysts, absorbents, pharmaceuticals, cosmetics, detergents, and other commodity products that contain anionic clays.

Abstract: A process of preparing superconducting magnesium diboride powder by heating an admixture of solid magnesium and amorphous boron powder or pellet under an inert atmosphere in a Mg:B ratio of greater than about 0.6:1 at temperatures and for time sufficient to form said superconducting magnesium diboride. The process can further include exposure to residual oxygen at high synthesis temperatures followed by slow cooling. In the cooling process oxygen atoms dissolved into MgB2 segregated to form nanometer-sized coherent Mg(B,O) precipitates in the MgB2 matrix, which can act as flux pinning centers.

Abstract: This invention concerns catalysts comprising a molybdenum compound of formula I, II, III, IV or V I VqMoAyOz II NiMoxByOz′ III VNiwMoxCy′Oz″ IV CoNiwMoxDyOz′″ V VNiwCorMoxEyOz″″ wherein: A is at least one cation selected from the group consisting of cations of: Cr, Sb, Co, Ce and Pb; B is at least one cation selected from the group consisting of cations of: Sb, Al and W; C is at least one cation selected from the group consisting of cations of: Fe, Zn, Al, Sb, Bi, W, Li, Ba, Nb and Sn; D is at least one cation selected from the group consisting of cations of: Ba, Mn, Al, Sb, Sn, and W; E is at least one cation selected from the group consisting of cations of: Fe, Ca, Mn, Sr, Eu, La, Zr, Ga, Sn and Pb; q, r, w, x and y are each independently a number from 0.1 to 10 and y′ is a number from 0 to 10, z, z′, z″, z′″, and z″″ are determined using the amounts and oxidation states of all cations present in each formula.

Abstract: The ferrite magnet powder of the present invention is magnet powder having, as the major phase, a La—Co magnetoplumbite ferrite where La and Co are substituted for Sr and Fe, respectively, represented by (1−x)SrO.(x/2)La2O3.(n−y/2)Fe2O3.yMO wherein x, y, and n represent mole ratios and satisfy 0.22−0.02≦x≦0.22+0.02, 0.18−0.02≦y≦0.18+0.02, and 5.2≦n≦6.0, where x>y.

Abstract: A method of treating metal-contaminated spent foundry sand, or other industrial waste, by combining the sand with a sulfite to produce insoluble metal sulfur oxide complexes that do not leach from the sand. The treated waste may also be processed to reduce “clumping,” thereby rendering the treated waste appropriate for use in another industrial process.

Abstract: A method of removing from a metal salt ionic species contained therein involves contacting the metal salt with an ionic liquid to dissolve the metal salt, the ionic species or both. At least in the case where both the metal salt and the ionic species are dissolved, the resultant ionic liquid composition is treated to separate the ionic species therefrom and subsequently processed to recover the metal salt.

Abstract: The present invention provides a clathrate compound which can be used as a thermoelectric material, a hard material, or a semiconductor material. Silicon or carbon are formed into a clathrate lattice, and a clathrate compound is then formed in which specified doping atoms are encapsulated within the clathrate lattice, and a portion of the atoms of the clathrate lattice are substituted with specified substitution atoms. The clathrate lattice is, for example, a silicon clathrate 34 (Si34) mixed lattice of a Si20 cluster including a dodecahedron of Si atoms, and a Si28 cluster including a hexahedron of Si atoms. Suitable doping atoms are atoms from group 1A, group 2A, group 3A, group 1B, group 2B, group 3B, group 4A, group 5A, group 6A, and group 8, and suitable substitution atoms are atoms from group 1A, group 2A, group 3A, group 1B, group 2B, group 3B, group 5A, group 6A, group 7A, group 5B, group 6B, group 7B, and group 8 of the periodic table.

Abstract: A method of treating solid containing material derived from effluent or sludge from a plant for de-inking paper, the material containing calcium in the form of one or more insoluble calcium compounds, the method including the steps of treating the material with an acid to cause dissolution of the calcium thereby forming a calcium ion-containing solution in which insoluble solids are suspended, separating the solution from the insoluble solids and incinerating the separated solids. The solution containing calcium ions may be treated by adding one or more reagents to form a calcium compound precipitate, eg calcium carbonate. The particulate solids produced following the incineration step and following the precipitate formation may be employed as pigments or fillers in paper making or paper coating.

Abstract: Process and apparatus for recovering magnesium from foundry sludge and cell bleed electrolytes includes structure and/or steps for: (i) dissolving, in a water slurry, soluble chloride compounds in the magnesium-containing material; (ii) acidifying the water slurry to between substantially pH 4 and substantially pH 6; (iii) further acidifying the water slurry to between substantially pH 1 and substantially pH 0, and providing a magnesium chloride solution; (iv) precipitating calcium from the magnesium chloride solution; (v) separating solids from the magnesium chloride solution; (vi) stripping SO2 from the magnesium chloride solution; and (vii) precipitating NaCl from the magnesium chloride solution to provide a concentrated magnesium chloride solution.

Abstract: A process for removing impurities contained in the crystal lattice of minerals, comprising the steps of forming a mixture of a mineral capable of structurally reorganizing its crystal lattice which contains an impurity in its crystal lattice and a halogen anion, and water; heating the mixture to the mineral's structural reorganization transition temperature; holding the mixture at the structural reorganization transition temperature for a sufficient period of time to allow the impurity to freely migrate from the lattice to combine with the halogen anion; and separating the combined impurity and anion from the mixture to render the mineral essentially free of the impurity. The process is applicable to numerous minerals and impurities, but is especially useful to remove arsenic from fluorspar. Numerous halogen anions can be employed, such as chlorides, fluorides, bromides and iodides, but the preferred halogen anion is a metal chloride such as calcium chloride.

Abstract: The present invention relates to calcium double salts having good preservative properties. Said salts can be used in foods, feeds, pet food, cosmetics and pharmaceuticals, food-contact items, silage, brewers' spent grains, pomace, food wastes, brewers' yeast, distillation residues and other wastes from the food industry or for leather treatment. These substances exhibit a considerably extended shelf life after addition of, or treatment with, one of the calcium double salts.

Abstract: A process for the flocculation of impurities from clays in which the following steps are performed: blunging the clay with a dispersing agent or combination of dispersing agents in water to form an aqueous dispersion, treating the aqueous dispersion with at least one aliphatic or aromatic hydroxamic acid or salt conditioning agent, flocculating the conditioned dispersion with a water soluble or water dispersible organic polymer containing hydroxamic acid groups or salts thereof, and removing the flocculated impurities to form a purified clay dispersion.

Abstract: A process is provided for preparing ammonium metavanadate from the combustion ashes resulting from the combustion of petroleum fuels in a boiler by using the ammonium sulfate and vanadium components in the combustion ash. Water is added to the combustion ash to form a slurry. The solids are removed from the slurry. Ammonia and an oxidizing gas, such as air, oxygen or ozone, are added to the aqueous solution obtained from the slurry to oxidize the vanadium, thereby producing an aqueous solution containing ammonium metavanadate. The ammonium metavanadate is crystallized and recovered from the aqueous solution. Calcium hydroxide or calcium oxide is injected into the aqueous solution and reacts with the ammonium sulfate to produce gypsum and ammonia. This gypsum and ammonia containing solution is flowed down a packed column, where it is counter-currently contacted with air or steam which strips the ammonia out of the solution.

Abstract: The present invention relates to a process for treating fly ash/APC residues chlorides, sulphates, earth alkali metals selected from the group consisting of calcium, potassium, and sodium, and heavy metals selected from the group consisting of lead, which residues are obtained from air pollution control processes that utilize dry/semi-dry line injection, such that said residues may be disposed of as non-hazardous materials. The process comprises the sequential steps of: (a) washing and agitating the fly ash/APC residue (20) with water (50) to form a residue slurry containing solubilized lead salts and calcium chloride; (b) filtering (42) the residue slurry to remove a filtrate (46) having a pH of higher than about 11.8 and containing the solubilized lead salts and calcium chloride; and (c) recovering a first calcium enriched filter cake (44).

Abstract: High yields of vanadium containing virtually no nickel or magnesium are obtained from natural bitumen ash consisting of up to 5% carbon, more than 95% of water-soluble compounds of vanadium, nickel and magnesium by mixing the ash with water to produce a 20% solids slurry of pH below 6.5 and temperature of 80-85° C. oxidizing any reduced vanadium in the slurry and then separating and removing the resulting polyvanadate precipitate from the liquid phase containing substantially all the nickel and magnesium values of the ash.

Abstract: A process for preparing an alkaline earth metal hydroxide which comprises reacting particulate alkaline earth metal oxide having a particle size in the range from about 100 &mgr;m to about 10,000 &mgr;m with a sufficient quantity of water for a sufficient time and at a sufficient temperature to carry out the reaction effectively thereby the alkaline earth metal hydroxide is prepared.

Abstract: Novel compositions containing at least one biologically active component derived from peat or similar composition, methods for their preparation and therapeutic uses for a variety of diseases, injuries, and conditions, including wound healing, pain, itch, inflammation, abnormal cell proliferation, or infections caused by fungal, bacterial, rickettsial or viral agents, psoriasis, allergic and other dermatitis, pruritis, eczema, actinic keratosis and similar conditions. In addition, the compositions can be used as diuretics, antiarrhythmics, and cardiac-stimulating agents, as well as for the treatment of mammalian diseases and disorders, including multiple drug resistance, cancers, asthma, rheumatoid arthritis, pain, wound healing, fungal disorders, and other inflammatory disorders. The compositions are derivable from peat or peat-related substances and may alternatively be synthetically produced.

Abstract: A non-metallic product (NMP) substantially free of metallic aluminum and aluminum nitride which is utilized for making calcium aluminate.

Abstract: A process for treating thickened phosphatic clay suspensions, waste clay and phosphogypsum produced in the processing of phosphate ore by water beneficiation and chemical processing, the thickened phosphatic clay suspension having a solid content of from about 4 to about 40 percent by weight, includes mixing a sufficient amount of deflocculating agent with a thickened phosphatic clay suspension to cause deflocculation of the suspension to an extent sufficient to reduce the viscosity thereof to a value enabling the deflocculated suspension to be readily pumped from one location to another, the deflocculating agent comprising an alkali compound of a phosphorus oxide. The deflocculated suspension of reduced viscosity is pumped from one location to another and separated into a clay suspension and a phosphatic mineral and sand suspension.

Abstract: Method of recovering calcium carbonate from waste material or contained natural calcic material. Calcium is recovered by prepariag an aqueous suspension the material containing calcium to be recovered and by lowering the pH of the suspension to pH<6, preferably pH<4, for providing a spension including an acidic liquid phase containing the calcium compounds in soluble form. Thereafter the pH of the liquid is raised to pH>6, preferably pH>7, by mixing a base therein, for precipitating the main portion of aluminium therein. Thereafter the neutral or basic liquid phase is carbonized by introducing Na2CO3 or NaHCO3 therein, for precipitation of the calcium compounds as CaCO3.

Abstract: The present invention relates to a compound based on an alkaline-earth metal, on sulphur and on aluminium, on gallium or indium, to its process of preparation and to its use as luminophore. The compound of the invention corresponds to the formula AB2S4, in which A represents an alkaline-earth metal and B aluminum, gallium, or indium and it is characterized in that it is provided in the form of a powder with a residual oxygen content of not more that 1.5% and composed of particles with a mean size of not more than 10 &mgr;m. This compound is obtained by a process which contains the following stages: a solution or a suspension comprising salts of the elements A and B is formed, the solution or the suspension is dried by atomization and the product obtained in the preceding stages is reacted with carbon disulphide or with a mixture of hydrogen sulphide and or carbon disulphide. The compound of the invention can be used as a luminophore, in particular in cathodoluminescence.

Abstract: This invention relates to a low energy hydrometallurgical process for the production of strontium carbonate of chemical and glass grade from carbonate rich celestite ores typically having around 28% combined strontianite, calcite, dolomite and other carbonates. This process avoids negative environmental impact usually associated to calcining technology and involves fewer processing stages than prior art hydrometallurgical processes. Thus, in two stages which provide: (1) the acid wash of the celestite ore in an acid medium to eliminate carbonates present other than strontium carbonates and (2) the conversion of the thus enriched celestite to strontium carbonate in an air/vapor-lift loop reactor using a sodium carbonate aqueous medium, a step permitting recovery of sodium sulfate as a by-product. Thus, an almost complete conversion of the strontium sulfate present in the enriched ore is achieved.

Abstract: A method for the manufacture of precipitated calcium carbonate from impure calcium oxide of improved color is disclosed. The method comprises admixing impure calcium oxide with an aqueous solution consisting essentially of a salt of at least one compound selected from the group consisting of organic amines of the formula RNH.sub.2 and alkanolamines of the formula NH.sub.2 (R.sup.1 OH), where R and R.sup.1 are alkyl groups of 1-4 carbon atoms, and hydrochloric or nitric acid. The solution obtained is treated with a reducing agent e.g. sodium hydrosulphite, separated from insoluble matter and then treated with carbon dioxide or the carbonate of the amine or alkanolamine at a temperature of at least 50.degree. C. Preferably, the amine of the salt and of the carbonate are the same, and the salt is used in at least the stoichiometric amount to dissolve the lime.

Abstract: A process for recovering SF.sub.6 from a gas is provided. The process includes the step of contacting a gas stream comprising SF.sub.6 and at least one of N.sub.2, O.sub.2, CO.sub.2, and H.sub.2 O with a membrane in at least one membrane separation unit at conditions effective to obtain a retentate stream rich in SF.sub.6 and a permeate stream rich in at least one of N.sub.2, O.sub.2, CO.sub.2, and H.sub.2 O. A process for forming solidified Mg metal is also provided. The process includes recovering and/or recycling of SF.sub.6 and/or CO.sub.2.

Abstract: A process for removing impurities contained in the crystal lattice of minerals, comprising the steps of forming a mixture of a mineral capable of structurally reorganizing its crystal lattice which contains an impurity in its crystal lattice and a halogen anion, and water; heating the mixture to the mineral's structural reorganization transition temperature; holding the mixture at the structural reorganization transition temperature for a sufficient period of time to allow the impurity to freely migrate from the lattice to combine with the halogen anion; and separating the combined impurity and anion from the mixture to render the mineral essentially free of the impurity. The process is applicable to numerous minerals and impurities, but is especially useful to remove arsenic from fluorspar. Numerous halogen anions can be employed, such as chlorides, fluorides, bromides and iodides, but the preferred halogen anion is a metal chloride such as calcium chloride.

Abstract: A method for purifying a phosphorus containing scheelite ore is described wherein the calcite phase is selectively dissolved prior to dissolution of the apatite phase. Selective dissolution of the calcite produces several benefits: (1) a usable calcium solution, (2) enhanced apatite dissolution, and (3) lower volumes of toxic acid solution for disposal.

Abstract: A process which uses selective flocculation with hydroxamates for the beneficiation of mixtures of mineral particles (such as kaolin clays). The increased selectivity of hydroxamates for certain mineral phases within kaolin clays and other mixtures of mineral particles improves the process over selective flocculation processes utilizing other activators.