Calcium phosphate-silicates

At times, failures in processing may introduce such materials as carbon adsorbent particles, filter aid, or inorganic compounds. In the last category, iron oxides and sulfides and sodium and ammonium salts have frequently been reported to be factors in the color problem,60 not only because of their own color but also because of their catalytic effect on the formation of coloring materials from sugars. Turbidity may also result from presence of traces of such salts as calcium phosphate, silicate, or sulfate. 

Solubilities of the Glasses of Calcium Phosphate-Silicates in Water in the Presence of Ion-Exchange Resin (36)... 

The average chain lengths of polyphosphates produced by dissolving the glasses of calcium phosphate-silicates were determined by the pH titration method. As shown in Table III, the average chain length decreases with an increase of the silicon dioxide in the glass. 

Valentinite, see Antimony(III) oxide Verdigris, see Copper acetate hydrate Vermillion, see Mercury(II) sulflde Villiaumite, see Sodium fluoride Vitamin B3, see Calcium (+)pantothenate Washing soda, see Sodium carbonate 10-water Whitlockite, see Calcium phosphate Willemite, see Zinc silicate(4—)... 

Woods contain from 0-2 to 4% of mineral ash. This consists largely of calcium, potassium and magnesium as carbonate, phosphate, silicate and sulphate. Aluminium, iron, sodium and chloride are also present. Sulphate contributes 1 to 10% by weight, usually 2 to 4%, and chloride 01 to 5%. 

Elemental phosphorus is prepared by the reduction of calcium phosphate, Ca3(P04)o, with coke in the presence of sand, SiO>. The products are phosphorus, calcium silicate, CaSiOa, and carbon monoxide. 

Other anticaking ingredients include ferric ammonium citrate, silicon dioxide, sodium ferrocyanide, magnesium silicate, magnesium carbonate, propylene glycol, aluminum calcium silicate, sodium aluminosilicate (also called sodium silicoaluminate), and calcium phosphate. 

Modem production of elemental phosphoras uses a technique similar to the metallurgical processes described in Chapter 20. Apatite is mixed with silica and coke and then heated strongly in the absence of oxygen. Under these conditions, coke reduces phosphate to elemental phosphoms, the silica forms liquid calcium silicate, and the fluoride ions in apatite dissolve In the liquid calcium silicate. The reactions are not fully understood, but the stoichiometry for the calcium phosphate part of apatite is as follows ... 

Silver white, relatively soft metal that is only applied in alloys. Oxygen and water attack pure Ca. The most prominent compound is the oxide (CaO) = burnt calcium, which hardens to calcium carbonate in mortar. Annual production of about 120 million tons. Burnt gypsum (CaS04 0.5 H20) hardens with water. A great step in evolution was the replacement of hard shells of brittle calcium carbonate by an internal skeleton of tough calcium phosphate (hydroxylapatite)-protein composite. Calcium is essential for all life forms. The daily requirement is 0.7-1.0 g. Humans (70 kg) contain 1 kg of calcium. Calcium silicate is the main component of cement. Marble is calcium carbonate in polycrystalline form and the favorite material of sculptors. 

Both humic acids and fulvic acids have a strong affinity for particulate and crystalline substances possessing oxygen atoms at their surfaces and they have been reported to bring about the dissolution of iron phosphate, calcium phosphate (61), uranium dioxide (65), hydrated magnesium alumino-silicates (66) and limonite, a complex mixture of hydrated ferric oxides (67). 

From a theoretical point of view, the gel layer is a barrier that reduces further hydrolysis of the silicate network, and is supposed to be more stable than the glass matrix, thus reducing the overall rate of corrosion. However, gel exfoliation may momentarily re-activate corrosion, at least locally. No clear trend was observed for the presence of the crystalline secondary phases identified at the surface of the corroded HT samples. The most abundant minerals are aluminosilicates, calcium phosphates, Fe- and Mg-rich minerals, and zeolites their role in the scavenging or release of metals remains ambiguous, although many mineral phases identified bear traces of metals. 

A biodegradation accelerant increases or accelerates the rate of biodegradation in the environment. For example, calcium carbonate, calcium hydroxide, calcium oxide, barium oxide, barium hydroxide, sodium silicate, calcium phosphate, magnesium oxide, may accelerate the biodegradation process. These compounds may also act as processing aids. A commonly used compound is calcium carbonate (20). 

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. 

Anticaking agents include carbonates, phosphates, silicates, and fatty acid salts of calcium and magnesium. Levels of anticaking agents in food products are determined by manufacturing, based on good practices. 

Meldrum, 2002), the elaborately shaped spicules in ascidians, and finely the sculpted coccolith shells in coccolithophores (Mann, 2001). For silica structure, the diatoms produce the most exquisite siliceous cell wall (Sumper and Brunner, 2006). Also the calcium phosphate in bone shows a highly regulated organization and arrangement. Interestingly, avians have two main biomineralization systems, one produces calcium carbonate for egg shell and the other produces calcium phosphate for bone (Bauerlein, 2000 Mann, 2001). 

Sodium chloride Sodium bromide Sodium iodide Sodium sulphate Sodium silicate Sodium bicarbonate Potassium sulphate Lithium chloride. Calcium carbonate. Calcium phosphate. Magnesium carbonate Manganous carbonate Ferrous carbonate. Aluminium phosphate Ammonium bicarbonate Organic matter... 

Bark contains 2-5% inorganic solids of the dry bark weight (determined as ash). The metals are present as various salts including oxalates, phosphates, silicates, etc. Some of them are bound to the carboxylic acid groups of the bark substance. Calcium and potassium are the predominating metals. Most of the calcium occurs as calcium oxalate crystals deposited in the axial parenchyma cells. Bark also contains trace elements, such as boron, copper, and manganese. 

The lithosphere consists primarily of rocks and minerals. Some of the important classes of metal compounds found in the lithosphere are oxides, sulfides, silicates, phosphates, and carbonates. The atmosphere surrounding the earth contains oxygen, so several metals such as iron, aluminum, tin, magnesium, and chromium are found in nature as the oxides. Sulfur is found in many places in the earth s crust (particularly in regions where there is volcanic activity), so some metals are found combined with sulfur as metal sulfides. Metals found as sulfides include copper, silver, nickel, mercury, zinc, and lead. A few metals, especially sodium, potassium, and magnesium, are found as the chlorides. Several carbonates and phosphates occur in the lithosphere, and calcium carbonate and calcium phosphate are particularly important minerals. 

Pigmentation can range from "inert types, such as barium sulphate, magnesium and calcium silicates together with a primary coloured pigment such as iron oxide, to anticorrosive pigments such as red lead, zinc chromate, zinc or calcium phosphate, etc. Others, which may be included to... 

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