Calcia

Calcia [1305-78-8] Calci-Bind Calcimar Calcimycin [52665-69-7] Calcination Calcined gypsum Calcined limestone... 

The CO2 Acceptor process, also developed under AGA/DOE sponsorship, by the ConsoHdation Coal Co., uses steam to gasify lignitic coal. Heat is supphed by the exothermic reaction between CO2 and calciaed dolomite [17069-72-6]. The dolomite is calciaed ia a separate fluidized bed. This process operates ia a 40 t/d pilot plant, but there are no plans for commercialization as of this writing. 

Precipitated magnesium carbonate and basic magnesium carbonates are calciaed to produce magaesia having surface areas of ca 200 /g. These... 

In the calciaation process, a mixture of corresponding oxides and an optional modifier, eg, molybdic acid, are milled together to achieve a homogenous mixture. The mixture is calciaed at 750—950°C and milled to a desired particle size. Wet milling ia an alkaline medium is recommended to remove any unreacted vanadium salts that ate beheved to degrade the pigmentary properties of bismuth vanadate (39). 

Potassium alum is manufactured by treating bauxite with sulfuric acid and then potassium sulfate. Alternatively, aluminum sulfate is reacted with potassium sulfate, or the mineral alum stone, alunite, can be calciaed and leached with sulfuric acid. Alunite is a basic potassium aluminum sulfate... 

The coarse calciae cooler operates at 300°C, while the waste-heat boiler cools the gas to 350°C. The tubes ia the boilers have a chain-shaking arrangement operated by paeumatic hammers. Steam productioa is 0.78 kg/kg of dry coaceatrate. The only trouble with dust reported is ia the connection betweea the reactor and waste-heat boiler. It is necessary to cool the gas stream quickly to avoid sulfation, but even so the carry-over calciae coataias oa the order of four times more sulfate than the coarse overflow. In this plant, the composite calciae is 0.1% sulfide and 2.2% sulfate sulfur. 

Similarly, fusion of milled zircon with dolomite or lime forms CaSiO and MgZrO [12032-31 -4] CaZrO [12013-47-7] and CaO Ca2SiO or CaSiO and Zr02, and is used to prepare zirconium oxide, usually as calcia-stabiUzed cubic zirconia because of the calcia left in soHd solution in the zirconia (27-29). 

The ziac concentrate is first roasted ia a fluid-bed roaster to convert the ziac sulfide to the oxide and a small amount of sulfate. Normally, roasting is carried out with an excess of oxygen below 1000°C so that comparatively Htfle cadmium is eliminated from the calciaed material ia this operation (3). Siace the advent of the Imperial Smelting Ziac Furnace, the preliminary roasting processes for ziac and ziac-lead concentrates result ia cadmium recovery as precipitates from solution or as cadmium—lead fume, respectively, as shown ia Figure 1. 

The primary constituent is calciaed anthracite coal particles. 

The success of preheater kiln systems led to precalciaer kiln systems. These units utilize a second burner to carry out calciaation ia a separate vessel attached to the preheater. The flash furnace (57), eg, utilizes preheated combustion air drawn from the clinker cooler and kiln exit gases and is equipped with an oil burner that bums about 60% of the total kiln fuel. The raw material is calciaed almost 95%, and the gases continue their upward movement through successive preheater stages ia the same manner as ia an ordinary preheater. 

Po22olans iaclude natural materials such as diatomaceous earths (see Diatomite), opaline cherts, and shales, tuffs, and volcanic ashes or pumicites, and calciaed materials such as some clays and shales. By-products such as fly ashes and siUca fume are also employed. In the United States the proportion of po22olan iaterground with clinker has varied from 15 to over 30%, whereas ia Italy, cements with a 30—40% po22olan content are produced. 

Types of Kaolin. As can be seen from Table 4, kaolins for use in polymers may be subdivided iato the categories of air-floated, water-washed, and calciaed. The processiag of each of these types is similar to that for use ia the paper iadustry. 

The calciaed or meta kaolin is used almost exclusively ia poly(vinyl chloride) wire iasulation because it enhances the electrical resistivity of the compound. 

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