Abstract: Very pure magnesium oxide is obtained from ore containing magnesium, more particularly ore containing magnesium carbonate, by calcining the ore and leaching the resulting magnesium oxide with carbon dioxide and calcium chloride solution to produce magnesium chloride solution. Carbon dioxide and ammonia are added, so as to precipitate magnesium carbonate trihydrate, which is decomposed to magnesium oxide.

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: Mineral filler such as calcium carbonate, having at most 15% by weight of particles which are smaller than 0.2 .mu.m with a corresponding spherical diameter, method of preparation, and use thereof are provided.

Abstract: A process is described for treating an exhaust gas containing NO.sub.x and SO.sub.x in which NO.sub.x and SO.sub.x are effectively converted into industrially useful products of NH.sub.3, or sulfur by use of an aqueous absorbing solution containing at least iron chelate salt and potassium sulfite.

Abstract: This invention relates to an improved barium carbonate prepared by precipitating barium carbonate on an inert core to effectively increase its sulfate scavenging utility by providing enhanced reactivity and dispersibility. This invention is especially useful in the prevention of efflorescence and scumming of bricks or ceramic tile caused by the migration of soluble sulfates during their manufacture.

Abstract: A method for converting calcium sulfoxy compounds selected from the group consisting of CaSO.sub.x and Ca(HSO.sub.x).sub.2 and their hydrates wherein x is 3 or 4 into calcium carbonate, the method consisting essentially of; converting the Ca(HSO.sub.x).sub.2 compounds into CaSO.sub.x compounds by reacting the Ca(HSO.sub.x).sub.2 compounds with calcium carbonate in the presence of water, thereafter reacting the CaSO.sub.x compounds with ammonia and carbon dioxide in the presence of water to produce NH.sub.4 (HSO.sub.x) wherein x is 3 or 4 and calcium carbonate, thereafter separating the NH.sub.4 (HSO.sub.x) and calcium carbonate and reacting the NH.sub.4 (HSO.sub.x) with carbon to produce ammonia, hydrogen sulfide and carbon oxides.

Abstract: In methods for combusting carbonaceous sulfur-containing fuels in a fluidized bed wherein the fluidized bed contains at least one calcium compound selected from the group consisting of calcium oxide, calcium hydroxide, calcium carbonate and calcium bicarbonate to absorb sulfur oxides formed during the combustion of the carbonaceous fuel thereby producing calcium sulfoxy compounds having the formula CaSO.sub.x wherein x is 3 or 4, an improvement comprising (a) withdrawing a stream of fluidized bed solids containing said calcium sulfoxy compounds and mixing the fluidized bed solids and said calcium sulfoxy compounds with water to produce a slurry; (b) reacting the CaSO.sub.x compounds with NH.sub.3, H.sub.2 O and CO.sub.2 to produce water-soluble ammonium sulfoxy compounds such as NH.sub.4 (HSO.sub.x) where x is 3 or 4 and CaCO.sub.3 ; and (c) separating the ammonium sulfoxy compounds from the fluidized bed solids and CaCO.sub.3.

Abstract: A method for converting calcium sulfoxy compounds selected from the group consisting of CaSO.sub.x and Ca(HSO.sub.x).sub.2 where x is 3 or 4, into calcium carbonate by a method consisting essentially of: (a) converting the Ca(HSO.sub.x).sub.2 compounds into CaSO.sub.x compounds by reacting the CA(HSO.sub.x).sub.2 compounds with CaCO.sub.3 in the presence of water; (b) reacting the CaSO.sub.x compounds with NH.sub.3 and CO.sub.2 in the presence of water to produce NH.sub.4 HSO.sub.x and CaCO.sub.3 ; (c) separating the NH.sub.4 HSO.sub.x and CaCO.sub.3 ; (d) reacting the NH.sub.4 HSO.sub.x with H.sub.2 S to produce ammonium polysulfide (NH.sub.4).sub.2 S.sub..omega. wherein .omega. is from 1 to about 4; (e) decomposing the ammonium polysulfide to produce NH.sub.3, H.sub.2 S, elemental sulfur and water; and (f) recovering the elemental sulfur from the NH.sub.3, H.sub.2 S and water.

Abstract: A method of producing finely-divided phosphor grade calcium carbonate having a calcite crystalline structure and a very low sodium content. The calcium carbonate is produced from calcium chloride having a high sodium impurity content, such as calcium chloride which is a by-product of the Solvay process for producing soda ash.

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

Abstract: Sulfur-containing compounds, particularly sulfur dioxide, are removed from stack gas streams by wet scrubbing the gases wherein an alkaline earth metal sulfate and/or sulfite are formed. Example processes are lime/limestone and Double Alkali scrubbing processes. These processes produce sludge material containing primarily the alkaline earth metal sulfate which is disposed of only with significant difficulty. An improvement is described herein whereby the aqueous sludge is reduced in contact with sufficient coal to produce the corresponding sulfide and effluent gases from the reduction step having a sufficient heating value to be used to dry the mixture of sludge and coal prior to the reducing step. The alkaline earth metal carbonate and elemental sulfur are recovered from the sulfide.

Abstract: The disclosed process provides for the production of a desulfurized fuel gas from a sulfur-containing fuel oil by absorption, in a first reaction zone, of the sulfur contaminants with a calcium oxide-containing material, which material is then further treated to render it environmentally stable without producing a sulfur-rich gas process stream. The spent limestone from the oil gasifier is reacted with an oxygen-containing gas in a second reaction zone for conversion of the calcium sulfide to calcium sulfate and the sulfated material is then transferred to a third reaction zone wherein it is reacted with carbon dioxide for conversion of the calcium oxide to calcium carbonate.