Byproducts calcium carbonate

Byproducts of this rearrangement are cyclobutenes, cyclopropane derivatives and allenic alcohols. The ratio of these products depends on the substitution of the substrate and on the reaction conditions. For example, 3-methyl-5-tosyloxypenta-l,2-diene (3) gives 75% of 1-methyl-2-methylenecyclobutanol (4) upon hydrolysis with water and calcium carbonate at 100 °C, while acetolysis with acetic acid/sodium acetate at 80 °C, and subsequent treatment with lithium aluminum hydride, provides only 37% of the cyclobutanol.12... 

Precipitated calcium carbonate, precipitated chalk, Aero-matt, Albacar, Purecai. Commercial CaCOj produced by chemical means. It is 98-99% pure. The byproduct process, the car bona ti on process, and the calcium chloride process of manuf from limestone are outlined in Kirk-Othmer Encyclopedia of Chemical Technology, vol. 4 (Interscience, New... 

Carbon dioxide is obtained commercially as the byproduct of a number of industrial reactions. For example, when calcium carbonate is heated to produce lime (CaO), carbon dioxide is released and captured as a by-product. The steam reforming (refining) of petroleum results in the production of a mixture of gases known as synthesis gas, consisting of carbon dioxide, carbon monoxide, hydrogen, and nitrogen. Carbon dioxide can be separated from the other components of synthesis gas for commercial uses. Carbon dioxide also produces as a by-product of the manufacture of ammonia (NH3) by the Haber-Bosch process. 

The acid solution is neutralized by adding calcium carbonate, and the precipitated gypsum produced from the excess sulfuric acid is filtered off. The nitrated product remains in the filtrate and is reduced by iron chippings to T acid (1-aminonaphthalene-3,6,8-trisulfonic acid). The remaining calcium ions are removed as calcium carbonate together with the iron oxide by adding sodium carbonate solution, and the T acid is isolated as an intermediate by acidification of the filtrate, so that the various byproducts can be removed with the mother liquor. 

Chalk, precipitated n. Obtained as a byproduct in water softening by sodium carbonate. It consists chiefly of calcium carbonate, but is often contaminated by appreciable quantities of calcium sulfate. 

The calcium hydroxide byproduct is traditionally converted to calcium chloride for which there is a market. However, a significant market is developing for precipitated calcium carbonate (PCC) in several industries. Demand in the US paper industry for PCC is projected to rise to 1.8 million tonnes per annum by 1996, up from only 175 000 tonnes in 1974. Use in the plastics, adhesives, paints and coatings industries is also increasing dramatically. The first acetylene plant producing PCC has recently been successfully commissioned in Dessau, Germany [18]. 

Calcium carbide, CaC2, is die raw material for the production of acetylene (used in welding torches). Calcium carbide is produced by reacting calcium oxide with carbon, producing carbon monoxide as a byproduct. When one mole of calcium carbide is formed, 464.8 kj is absorbed. 

About 95% of the sodium carbonate used in the U.S. is mined, primarily in Wyoming. The ore is known as trona and needs only to be heated to produce commercial soda ash. Elsewhere in the world it is made by the Solvay process, which uses limestone and salt as raw materials. Calcium chloride is a byproduct of the Solvay process. 

CASH CBM CBO CBPC CC CCB CCM CCP CDB CEC CFBC CFC CFR CMM COP CSH CT Calcium aluminosilicate hydrate Coal bed methane Carbon burn-out Chemically-bonded phosphate ceramics Carbonate carbon Coal combustion byproducts Constant capacitance model Coal combustion product Citrate-dithionate-bicarbonate Cation exchange capacity Circulating fluidized bed combustion Chlorofluorocarbon Cumulative fraction Coal mine methane Coefficient of performance Calcium silicate hydrate Collision theory... 

Hydrogen and calcium phosphite are formed as byproducts. Excess calcium hydroxide is precipitated by passing carbon dioxide through the solution and is filtered off together with the poorly soluble calcium phosphite. Upon addition of sodium carbonate and subsequent filtration a solution of sodium hypopho.sphite is obtained, which can be converted into phosphinic acid by passing over an ion exchanger. 

In other processes similar to the Solvay process (see Section 3.1.1.3.3), potassium carbonate is produced directly from potassium chloride with amines such as isopropylamine via a potassium hydrogen carbonate step, but contaminated calcium chloride brine is produced as a byproduct whose disposal poses environmental problems. In the former States of the USSR potassium carbonate is also produced from alkali aluminosilicate deposits (e.g. nepheline) together with aluminum oxide, cement and sodium carbonate. 

Phosphogypsum is the major byproduct of wet-process phosphoric acid production. Phosphate rock, which is composed of apatite minerals (4], (calcium phosphates containing varying amounts of carbonate and fluoride), is digested with sulfuric acid and water to produce phosphoric acid, phosphogypsum, and minor quantities of hydrofluoric acid. 

The product of this reaction is a dark ashy material that contains sodium carbonate, calcium sulfide, carbon dioxide, and other byproducts ... 

The principal commercial source of rubidium is accumulated stocks of a mixed carbonate produced as a byproduct in the extraction of lithium salts from lepidohte. Primarily a potassium carbonate, the byproduct also contains ca. 23 wt.% rubidium and 3 wt.% cesium carbonates. The primary difficulty associated with the production of either pure rubidium or pure cesium is that these two elements are always found together in nature and also are mixed with other alkali metals because these elements have very close ionic radii, their chemical separation encounters numerous issues. Before the development of procedures based on thermochemical reduction and fractional distillation, the elements were purified in the salt form through laborious fractional crystallization techniques. Once pure salts have been prepared by precipitation methods, it is a relatively simple task to convert them to the free metal. This is ordinarily accomplished by metallothermic reduction with calcium metal in a high-temperature vacuum system in which the highly volatile alkali metal is distilled from the solid reaction mixture. Today, direct reduction of the mixed carbonates from lepidolite purification, followed by fractional distillation, is perhaps the most important of the commercial methods for producing rubidium. The mixed carbonate is treated with excess sodium at ca. 650 C, and much of the rubidium and cesium passes into the metal phase. The resulting crude alloy is vacuum distilled to form a second alloy considerably richer in rubidium and cesium. This product is then refined by fractional distillation in a tower to produce elemental rubidium more than 99.5 wt.% pure. 

Charcoai. Charcoal is a porous form of carbon obtained by the destructive distillation of an organic material in the eibsence of air. Byproducts such as wood tar, wood spirit, acetone, and gaseous compounds are usually recovered.I I A common precursor is coconut shell which produces excellent charcoal. Charcoal is cilso obtained by heating animal bones and dissolving the calcium phosphate and other mineral compounds with acid. The material is known cis l)one black . 

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