Calcium carbonate/hydroxide/oxide

Anticaking agents commonly used include calcium carbonate, phosphate, silicate, and stearate cellulose (microcrystalline) kaolin magnesium carbonate, hydroxide, oxide, silicate, and stearate myristates palmitates phosphates silica (silicon dioxide) sodium ferrocyanide sodium silicoa-lummale and starches. 

A substance is considered soluble if more than three grams of the substance dissolves in 100 ml of water. The more common rules are listed below. 1. All common salts of the group 1A elements and ammonium ions are soluble. 2. All common acetates and nitrates are soluble. 3. All binary compounds of group 7A elements (other than F) with metals are soluble except those of silver, mercury(l), and lead. 4. All sulfates are soluble except those of barium, strontium, lead, calcium, silver, and mercury(l). 5. Except for those in Rule 1, carbonates, hydroxides, oxides, sulfides, and phosphates are insoluble. ... 

However, certain corrosion inhibitors, such as y-alumina, calcium carbonate, zinc oxide, sodium oxalate, etc., show insufficient corrosion inhibition. For some corrosion inhibitors, the mechanical strength of the PAS resin is deteriorated. More satisfactory corrosion inhibitors are nickel compounds, such as nickel carbonate, nickel hydroxide, and nickel cit-rate. The anticorrosive effect is already satisfactory when the corrosion inhibitor is added in amounts of 0.1 %. 

Surface layers may be calcium carbonate, hydroxide or, in freshly broken crystals, possibly calcium oxide. It is now well established that coccoliths in chalk are coated with very thin aluminosilicates (smectites and other clay minerals) and organic matter (humates, etc) [6]. During comminution, compaction or metamorphosis, these coatings may be disrupted or may still adhere to the calcite surface. Aluminium silicates have been identified in pure limestones and pure marbles, and have been shown to be unattached to calcite fragments. 

After a few weeks of service at a temperature between 60 and 70 °C, a reddish-brown deposit becomes incrusted it is made up of a mixture of calcium carbonate, iron oxide (Fe ) and aluminium hydroxide (Al(OH)3) [41]. The iron oxide stems from the superficial corrosion of steel pipes. This deposit protects aluminium against possible attack of copper ions [42]. When pitting occurs, its depth is approximately 0.5 mm and does not increase after a few months of operation [43]. 

Heavy metals often can be removed effectively by chemical precipitation in the form of carbonates, hydroxides, or sulfides. Sodium carbonate, sodium bisulfite, sodium hydroxide, and calcium oxide are all used as precipitation agents. The solids precipitate as a floe containing a large amount of water in the structure. The precipitated solids need to be separated by thickening or filtration and recycled if possible. If recycling is not possible, then the solids are usually disposed of to a landfill. 

Some carbonates are important industrial chemicals. Calcium carbonate occurs naturally in several forms, including limestone, and is used in the production of quicklime, calcium oxide CaO, slaked (or hydrated) lime, calcium hydroxide Ca(OH)2 and cement. 

Magnesium sulfate heptahydrate may be prepared by neutralization of sulfuric acid with magnesium carbonate or oxide, or it can be obtained directly from natural sources. It occurs abundantly as a double salt and can also be obtained from the magnesium salts that occur in brines used for the extraction of bromine (qv). The brine is treated with calcium hydroxide to precipitate magnesium hydroxide. Sulfur dioxide and air are passed through the suspension to yield magnesium sulfate (see Chemicals frombrine). Magnesium sulfate is a saline cathartic. 

The polymerization is carried out at temperatures of 0—80°C in 1—5 h at a soHds concentration of 6—12%. The polymerization is terminated by neutralizing agents such as calcium hydroxide, calcium oxide, calcium carbonate, or lithium hydroxide. Inherent viscosities of 2-4 dL/g are obtained at 3,4 -dianiinodiphenyl ether contents of 35—50 mol %. Because of the introduction of nonlinearity into the PPT chain by the inclusion of 3,4 -dianiinodiphenyl ether kinks, the copolymer shows improved tractabiUty and may be wet or dry jet-wet spun from the polymerization solvent. The fibers are best coagulated in an aqueous equiUbrium bath containing less than 50 vol % of polymerization solvent and from 35 to 50% of calcium chloride or magnesium chloride. 

Detergents are metal salts of organic acids used primarily in crankcase lubricants. Alkylbenzenesulfonic acids, alkylphenols, sulfur- and methjiene-coupled alkyl phenols, carboxyUc acids, and alkylphosphonic acids are commonly used as their calcium, sodium, and magnesium salts. Calcium sulfonates, overbased with excess calcium hydroxide or calcium carbonate to neutralize acidic combustion and oxidation products, constitute 65% of the total detergent market. These are followed by calcium phenates at 31% (22). 

In spite of widespread usage of these compounds, the stmctures of only the calcium, barium, and strontium compounds are reasonably weU-estabhshed. The materials are generally made by trituratiag the oxides, or hydroxides, with aqueous hydrogen peroxide and dryiag the soHd products. The commercial products are typically mixtures of the peroxides with varyiag amounts of hydroxides, oxides, carbonates, hydrates, and peroxohydrates. 

At room temperature, the bisulfite pH inflection poiat occurs at pH 4.5 and the monosulfite at pH 9. Analogous equations can be written for magnesium, calcium, and ammonia. The starting raw materials, ia addition to sulfur, are sodium hydroxide, magnesium oxide, calcium carbonate, or ammonia, depending on the base used. The four commercial bases used ia the sulfite process are compared ia Table 4. 

Calcium Oxide. Also called lime or quicklime (4,5), calcium oxide [1305-78-8] (Class 1, nonregenerative), is relatively iaexpensive. It is prepared by roasting calcium carbonate (limestone) and is available ia a soft and a hard form according to the way ia which it was burned. For desiccant service, soft-burned lime should always be used. Calcium oxide is most commonly used to dehydrate Hquids and is most efficient when it can be heated to speed the reaction rate. The reaction product is calcium hydroxide, which cmmbles as it picks up moisture. 

Calcium hydroxide//i05-62-0y M 74.1, m loses H2O on heating, pK 12.7 (for Ca " "). Heat analytical grade calcium carbonate at 1000 during Ih. Allow the resulting oxide to cool and add slowly to... 

Alkali Ammonia Biocides Sodium hydroxide (caustic soda) Potassium hydroxide (caustic potash) Calcium oxide (lime) Calcium hydroxide Sodium, potassium and calcium carbonates Ammonia (q.v.)... 

Calcium Oxide (lime, Quicklime, Burnt Lime, Calx, Unslaked Lime, Fluxing Lime). CaO, mw 56.08, white or greyish-white lumps or powd, mp 2580°, bp 2850°, d 3.25-3.40g/cc. SI sol in w with formation of calcium hydroxide and evolution of large amts of heat sol in acids, and insol in ethanol. Coml prepn consists of heating calcium carbonate in kilns at 1000—1100° until all of the C02 is driven off. Lab prepn is by burning calcium carbonate or calcium oxalate at about 800° using a quartz crucible in an electric furnace... 

Recently, several metal oxides apart from silica have been investigated and reported for mbber-based nanocomposites. Some important and commercially meaningful oxides used in rubber are zinc oxide (ZnO), magnesium hydroxide (MH), calcium carbonate, zirconate, iron oxide, etc. 

Many metal hydroxides are insoluble. For example, when MgO is made into a slurry, the white suspension is known as milk of magnesia. Calcium oxide (lime) is produced by heating limestone (calcium carbonate) at high temperature. 

Lime is the old-fashioned name for calcium oxide. As a root, it is also found in lime stone (calcium carbonate), lime pits (burial sites for the poor, which were lined with CaO) and quick lime (calcium hydroxide). 

The inorganic ash from the recovery furnace is then dissolved in water, and calcium hydroxide is added to precipitate out calcium carbonate and to convert the sodium carbonate to sodium hydroxide for reuse. The calcium carbonate is then separated out by sedimentation and is combusted to give calcium oxide which provides the calcium hydroxide which is used in the precipitation process. 

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