Calcium synthetic carbonate

A synthetic coupled cycle of calcium and carbon through the oxalate-carbonate pathway is shown in Fig. 12.8. Atmospheric CO2 is fixed by the plants through photosynthesis to produce biomass. Inside the plant, oxalate crystals form. In addition, fungal mycelium may also accumulate oxalate. Mainly in the form of calcium oxalate (COM or COD), this carbon pool is used by oxalotrophic bacteria as a carbon, energy and electron source. The transformation of oxalate can occur in the soil... 

Calcite and whitings (RI 1.5-1.7) are naturally occurring calcium carbonate deposits. The lowest cost grades are ground limestone or the mixed calcium magnesium carbonate ore, dolomite. Synthetic calcium carbonate is also used as an extender, but it is more expensive. 

A statistical yearbook of the Furnish industries 16) includes general statistics for the various branches of industry (value of output, number of workers, wages, and motive power), and detailed tables of output and raw material consumption by the different industries. Chemicals for which output figures are given include paints, varnishes, and lacquers, superphosphate, turpentine, explosives, chlorine, caustic soda (solid and solution), hydrochloric acid,. phosphates, trichlorethylene, chlorophenolates, calcium hypochlorite, carbon tetrachloride, calcium carbide, potassium chlorate, carbon dioxide (hquid), sulfuric acid, water glaiss, metasilicate, plastics and synthetic resins, dichloro-ethane, and chloral. For lacquers and varnishes, and plastics and synthetic resins, data are given for individual products. 

The Italian chemical journal, Rassegna Chemica 50), contains articles on technical and industrial developments and on chemical markets in Italy. Monthly statistics on Italian chemical production (quoted from the Ministry of Industry and Commerce) include the following synthetic ammonia, nitric acid, sulfuric acid, sodium carbonate, caustic soda, alumina, trichlorethylene, calcium carbide, carbon disulfide, explosives, superphosphates, ammonium sulfate, calcium cyanamide, calcium nitrate, ammonium nitrate, copper sulfate, dyestuffs, ethyl alcohol, methanol, tanning extracts, tartaric acid, citric acid, wood pulp and cellulose, and sodium nitrate. 

All the resultant polymers have been characterised in detail and used in studies of the crystallisation of calcium carbonate from supersaturated aqueous calcium hydrogen carbonate, as the first step towards synthetic organic/inorganic composites. 

The synthetic pitting solution simulates a potable water composition known to cause cold water pitting [26]. It was prepared by bubbling carbon dioxide through a rapidly stirred suspension of calcium carbonate in distilled water to produce a solution of calcium hydrogen carbonate. Sodium sulfate (133 mg/L) and sodium chloride (49 mg/L) were dissolved in the solution and air then was bubbled through to adjust the pH to within the range of 7.0 to 7.5. 

Abstract A new low density mineral material has been synthesized via a simple, flexible, cheap and easy to control process. This material is a synthetic carbonate produced by carbonation of a solid phase composed of a calcic part and a magnesian part. Typically, its production process includes the calcination of a raw dolomite (general formula CaC03.MgC03) into the oxide form, followed by an at least partial hydration of this oxide and a subsequent carbonation step. This process is thus close to the well-known process used for the production of Precipitated Calcium Carbonate (PCC), a common filler and pigment in plastic, paper and rubber, except that the raw material is a dolomite instead of a limestone. It has to be pointed out that flue gases from different industries can be used as a source of CO2 for the carbonation. 

PCC (Precipitated Calcium Carbonate) is by definition a very fine, high purity processed calcium carbonate with controlled morphology, particle size and particle size distribution. PCC is often used in the production of paper [1], but can also be used in different fields of applications, mainly as fillers (in paints, polymers...). There is therefore a need for Lhoist to further improve its expertise in the field of synthetic carbonates and to develop innovative synthetic carbonates with new properties and especially new morphologies. For this purpose, an area in which Lhoist does not have much experience has been explored, that is the production of synthetic carbonates starting from a natural dolomite (CaC03.MgC03) instead of limestone (CaCOs). 

Historically, soda ash was produced by extracting the ashes of certain plants, such as Spanish barilla, and evaporating the resultant Hquor. The first large scale, commercial synthetic plant employed the LeBlanc (Nicolas LeBlanc (1742—1806)) process (5). In this process, salt (NaCl) reacts with sulfuric acid to produce sodium sulfate and hydrochloric acid. The sodium sulfate is then roasted with limestone and coal and the resulting sodium carbonate—calcium sulfide mixture (black ash) is leached with water to extract the sodium carbonate. The LeBlanc process was last used in 1916—1917 it was expensive and caused significant pollution. 

Synthetic Marble. Synthetic marble-like resin products are prepared by casting or molding a highly filled monomer mixture or monomer—polymer symp. When only one smooth surface is required, a continuous casting process using only one endless stainless steel belt can be used (52,53). Typically on the order of 60 wt % inorganic filler is used. The inorganic fillers, such as aluminum hydroxide, calcium carbonate, etc, are selected on the basis of cost, and such properties as the translucence, chemical and water resistance, and ease of subsequent fabrication (54,55). 

The mbber compound usually requires an inert inorganic filler and small particle sise carbon particle for reinforcement. The mbber polymers vary in inherent tensile strength from very high in the case of natural mbber to almost nonexistent for some synthetic polymers, eg, SBR. The fillers most commonly used for mbber compounds include carbon black, clay, calcium carbonate, siUca, talc (qv), and several other inorganic fillers. 

Calcium carbonate [471-34-1]—Cl Pigment White 18, Cl No. 77220, EEC No. E 170. A fine, white, synthetically prepared powder consisting essentially of precipitated calcium carbonate, CaCO. ... 

Type of dryer tions, extracts, milk, blood, waste liquors, rubber latex, etc. gents, calcium carbonate, bentonite, clay sbp, lead concentrates, etc. trifuged sobds, starch, etc. dry. Examples centrifuged precipitates, pigments, clay, cement. ores, potato strips, synthetic rubber. objects, rayon skeins, lumber. sheets. her sheets. 

Cellulose acetate Silica gel Scoured wool Sawdust Rayon waste Fluorspar Tapioca Breakfast food Asbestos fiber Cotton linters Rayon staple Starch Aluminum hydrate Kaolin Cryolite Lead arsenate Cornstarch Cellulose acetate Dye intermediates Calcium carbonate White lead Lithopone Titanium dioxide Magnesium carbonate Aluminum stearate Zinc stearate Lithopone Zinc yellow Calcium carbonate Magnesium carbonate Soap flakes Soda ash Cornstarch Synthetic rubber... 

Calcium carbonate/marble Calcium oxide Camphor, synthetic Caprolactam dust vapour... 

Many workers (5,6,7,87) have compared various metals for the selective hydrogenation of lower acetylenes to olefins, and it was always found that palladium was by far the most selective. This conclusion concurs with the usual synthetic experience, but under special circumstances other metals, such as platinum, may prove more useful (35,63). The catalyst support may also have an influence (21,65). Carbon, calcium carbonate, and barium sulfate are frequently used supports. Examples of some differences are noted later,... 

Vitamin K is the cofactor for the carboxylation of glutamate residues in the post-synthetic modification of proteins to form the unusual amino acid y-carboxygluta-mate (Gla), which chelates the calcium ion. Initially, vitamin K hydroquinone is oxidized to the epoxide (Figure 45-8), which activates a glutamate residue in the protein substrate to a carbanion, that reacts non-enzymically with carbon dioxide to form y-carboxyglut-amate. Vitamin K epoxide is reduced to the quinone by a warfarin-sensitive reductase, and the quinone is reduced to the active hydroquinone by either the same warfarin-sensitive reductase or a warfarin-insensitive... 

Overview of Calcium Carbonate Crystallization by Synthetic Substrates... 

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