Abstract: The invention provides a complete set of treatment system and method for deep utilization of dolomite resources. The system includes a primary calcination device, a carbon dioxide capture device, a digestion device, a carbonization separation device, a pyrolysis device and a secondary calcination device; the primary calcination device includes a dolomite calciner, a plurality of hoardings and an exhaust pipe, and an exhaust chamber is formed between the hoardings, the top of the dolomite calciner and the outer wall of the blanking bin; the exhaust chamber is in communication with the carbon dioxide capture device through the exhaust pipe; the carbonization separation device includes a carbonization reaction tank whose gas inlet is in communication with the gas outlet of the carbon dioxide capture device; and the pyrolysis device includes a pyrolysis kettle and a vacuum pump which maintains a negative pressure state in the pyrolysis kettle.

Abstract: A method for producing a double sulfate of potassium and magnesium by dry mechanical attrition of potassium sulfate and magnesium sulfate hexahydrate, comprising obtaining potassium sulfate by sulfatation of potash to bisulfate of potassium and disproportionation of the bisulfate of potassium to potassium sulfate in a water-methanol solution, and obtaining magnesium sulfate hexahydrate by sonic-assisted partial sulfatation of calcined serpentinic silicate.

Abstract: This invention refers to a novel process for obtaining high purity magnesium hydroxide from a solid starting material containing magnesium in the form of, and/or combined with, carbonates, oxides and/or hydroxides, either natural or synthetic. The process comprises leaching the starting material to dissolve the magnesium; the solution is treated with alkali to precipitate the high purity magnesium hydroxide, and the remaining mother liquor is fed to a regeneration step of both the alkali used in the precipitation of high purity magnesium hydroxide, and the acid for leaching. The process of the invention is characterized by recycling reactants (acid and alkali) regenerated in the same process.

Abstract: An air pollution control system 10A according to the present invention includes: a boiler 11 that burns fuel; NOx removal equipment 12 that decomposes nitrogen oxides in flue gas 25 discharged from the boiler 11; a desulfurizer 15 that causes sulfur oxides in the flue gas 25 having passed through the NOx removal equipment 12 to be absorbed by an absorbent, thereby reducing sulfur oxides in the flue gas 25, a waste-water treatment device 16 including a solid-liquid separating unit 31 that separates desulfurized waste water 28 discharged from the desulfurizer 15 into a solid fraction and a liquid fraction, and a mercury removing unit 32 that removes mercury in the desulfurized waste water 28; and a treated waste-water returning unit (a makeup water line) 17 that returns at least a part of treated waste water 40 treated by the waste-water treatment device 16 to the desulfurizer 15.

Abstract: A novel process for complete utilization of olivine is based on purification of brine by oxidation and precipitation of iron and nickel compounds.

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: Method and apparatus for treating the atmosphere to lower the concentration of pollutants therein in which ambient air is passed into operative contact with a stationary substrate having at least one ambient air contacting surface having a pollutant treating material thereon.

Abstract: In the method for the humid treatment of effluents containing a compound selected from the group consisting of H.sub.2 SO.sub.4, free SO.sub.2, SO.sub.3.sup.-, or SO.sub.4.sup.= and having a pH lower than 5, the effluents are reacted with a basic compound. Particles selected from the group consisting of CaCO.sub.3.MgCO.sub.3, MgCO.sub.3 and a mixture of these, are used for treating the said effluents, the said particles having a particle size such that at least 95% of the particles selected from the group consisting of CaCO.sub.3.MgCO.sub.3 and MgCO.sub.3 have a particle size smaller than 75 .mu.m. After treatment magnesium sulfate in the form of a solution or brine is recovered.

Abstract: A process for producing anhydrous magnesium chloride comprising steps of selective calcination of Mg-containing minerals, selective leaching of magnesium, separation of insoluble impurities, precipitation of magnesium chloride hexammoniate and thermal decomposition of the magnesium chloride hexammoniate crystals into magnesium chloride and ammonia.

Abstract: A method of separating calcium from mixtures of metal oxides, sulfides, nitrates and carbonates. Particulate calcium containing mixtures are leached with nitric acid to form calcium nitrate and metal nitrates, which are heated to dryness and to form metal oxides, while not affecting the calcium nitrate. The resulting mixture is then leached with water to obtain a calcium nitrate containing leachate and a residue of low solubility metal oxides and insoluble metal oxides. If desired, the calcium nitrate can be decomposed to form a lime product.

Abstract: Process for dissolving unwanted magnesium from phosphate ores by leaching with dilute sulfuric acid at automatically controlled pH. Minerals so treated are more easily converted by the conventional "wet" process into phosphoric acid, and yield better quality phosphoric acid. Magnesium So leached is precipitated with lime or dolime in a second conventional processing step to make byproduct magnesium hydroxide. An anion such as nitrate, acetate or formate is maintained in the recirculating leach solution in concentration sufficient that calcium sulfate does not precipitate with product magnesium hydroxide. Nearly pure carbon dioxide can be recovered as a second byproduct.

Abstract: Fermentors, reactors and processes for preparing magnesium enriched calcium magnesium acetate (CMA) (Mg:Ca mole ratios of 1:1 to 20:1) by reacting a dolomitic lime product with a Mg:Ca mole ratio less than one with dilute acetic acid, such as in fermentation broths. A process to prepare a mildly aklaline mineral product by calcining the dolomite under conditions to convert only the MgCO.sub.3 to MgO and treating the selectively calcined dolomite with acidic solutions to dissolve largely the MgO, leaving the original CaCO.sub.3 matrix intact. The mildly alkaline mineral product includes a highly porous structure derived from dolomite, consisting of a matrix of CaCO.sub.3 with smaller amounts of MgO and interspersed with a regular array of voids on a molecular scale.

Abstract: A process for improving a purity and/or whiteness degree of a talc powder is disclosed. A talc powder with a particle size of about 0.8 mm or less containing impurities such as asbestos, etc. is treated with a phosphoric acid agent under heating at from 70.degree. to 250.degree. C. to remove impurities such as asbestos, etc. by utilizing the difference in the rate of dissolution as between the talc and the impurities. The phosphoric acid agent is one selected from the group consisting of phosphoric acid, pyrophosphoric acid, sodium phosphate, ammonium phosphate, calcium phosphate, sodium tripolyphosphate, sodium pyrophosphate, sodium hexametaphosphate and mixtures thereof. Thus, asbestos, which is considered to be carcinogenic, can be effectively removed from talc.

Abstract: A process for producing magnesium oxide and/or hydrates thereof from predominantly magnesium or magnesium-calcium raw materials, and optionally producing calcium carbonate, whereby the raw material is roasted if necessary to form a mixture of magnesium oxide and calcium oxide. The calcium oxide is then dissolved from the mixture using an aqueous solution containing an organic amine and a salt of an organic amine with an acid capable of forming a soluble calcium salt with said organic amine. Separating the solution from the undissolved magnesium oxide and treating the solution with carbon dioxide will cause the dissolved calcium to be precipitated and calcium carbide.

Abstract: A process is provided for the recovery of one or more useful products including fertilizer, animal feed supplements, iron oxide, magnesia, salt, purified brine, and purified water from brines. The source of the brines can be oil and gas field wastes, seawater or effluent from a seawater desalination plant, or other inland brine sources. Iron and magnesium are initially precipitated from the brine. Then phosphoric acid is added to the brine followed by an alkaline agent to produce precipitates useful as fertilizer and animal feed supplements. The remaining salt in the brine may then be removed and recovered along with purified water.

Abstract: A process for the recovery of magnesium from sea water, brine or impure magnesium salt solutions using an extraction technique with solvents to obtain a concentrate and pure magnesium salt solution or a high purity crystallized magnesium salt. The process consists of two basic stages, high selectivity magnesium extraction and re-extraction with an organic phase as an intermediate vehicle.

Abstract: A wet scrubbing process for desulfurization of waste gas which employs calcium carbonate reactant in the presence of a magnesium compound wherein the magnesium compound is obtained from partially calcined, magnesium-containing limestone.

Abstract: A process of making a calcium acetate-containing solution having a pH value at room temperature between about 7 and about 8 is provided comprising reacting acetic acid with a carbonate compound, adding calcined limestone, and optionally finishing off the acid-base reaction with an amount of an alkali metal hydroxide comprising from about 2% to about 5% of the total stoichiometric complement to the amount of acetic acid. Further process options which may be used in the preparation of deicing agents include adding coarse limestone to the above-prepared calcium acetate-containing solution in amounts up to 10% by weight and converting the solution into solid flakes. The calcium acetate salt product can be mixed with an inert solid material having good anti-slip properties.

Abstract: A process of making a calcium acetate-containing solution having a pH value at room temperature between about 7 and about 8 is provided comprising reacting acetic acid with a carbonate compound, adding calcined limestone, and optionally finishing off the acid-base reaction with an amount of an alkali metal hydroxide comprising from about 2% to about 5% of the total stoichiometric complement to the amount of acetic acid. Further process options which may be used in the preparation of deicing agents include adding coarse limestone to the above-prepared calcium acetate-containing solution in amounts up to 10% by weight and converting the solution into solid flakes.

Abstract: A process of making a calcium acetate-containing solution having a pH value at room temperature between about 7 and about 8 is provided comprising reacting acetic acid with a carbonate compound, adding calcined limestone, and optionally finishing off the acid-base reaction with an amount of an alkali metal hydroxide comprising from about 2% to about 5% of the total stoichiometric complement to the amount of acetic acid. Further process options which may be used in the preparation of deicing agents include adding coarse limestone to the above-prepared calcium acetate-containing solution in amounts up to 10% by weight and converting the solution into solid flakes.

Abstract: A method for recovering a magnesium carbonate of high purity from an aqueous magnesium hydroxide slurry is disclosed. The slurry contains at least 1 percent of magnesium hydroxide and consists of water, magnesium hydroxide and impurities normally associated with magnesium hydroxide slurries. The method involves carbonating the slurry with sufficient carbon dioxide to dissolve a substantial proportion of the magnesium hydroxide therein as magnesium bicarbonate, continuing carbonation until a solution saturated with magnesium bicarbonate is formed, a portion of the magnesium bicarbonate is converted to a crystalline magnesium carbonate and substantially all dissolved calcium is precipitated, so that the slurry contains dissolved magnesium bicarbonate, a crystalline magnesium carbonate precipitate and a calcium carbonate precipitate.