Calcination material balance

SO2 removal experiments with CEB were performed in a thermogravimetric analysis (TGA) set-up to simulate the process during its combustion. The sample was first heated in a mixture of 70% CO2 in N2 to produce CaCOj, followed by the decomposition of CaCOj to CaO under N2 and O2. This calcined material was sulfated using a mixture containing 3000 ppm SO2, 12% O2, and the balance N2. 

Table 9.16 covers the sensible heat of the components of the output gas. Table 9.17 covers the lime product output sensible heat. Table 9.18 covers the sensible heat from the dust. Table 9.19 covers the heat releases from the combustion reaction. Table 9.20 covers the heat consumed by calcinations. Table 9.21 covers the material and energy balance for the dolomitic lime process. Table 9.22 gives a summary and analysis, including the material balance and the heat balance. 

Cementstone is an impure (usually argillaceous) limestone, possessing the ideal balance of siUca, alumina, and calcium carbonate for Portiand cement (qv) manufacture. When calcined it produces a hydrauHc cementing material. 

Flow Measurements Measurement of flow rates of clean gases presents no problem. Flow measurement of gas streams containing solids is almost always avoided. The flow of solids is usually controlled but not measured except solids flows added to or taken from the system. Solids flows in the system are usually adjusted on an inferential basis (temperature, pressure level, catalyst activity, gas analysis, heat balance, etc.). In many roasting operations, the color of the calcine discharge material indicates whether the solids feed rate is too high or too low. 

Since in the acid mesophase product the surfactant cationic charge is exactly balanced by a chloride anion, the ion-pair surfactants are removable by extraction without providing an exchangeable cation as required for the anionic framework of MCM-41. It was found that most of the surfactant could be removed from the as-synthesized material by stirring it in pure ethanol at room temperature or by overnight reflux. Removal of the surfactant was also possible by calcination. Calcined SBA-3 has similar stability and absorption-desorption properties as has MCM-41. 

Western-world bauxite production in 1988 totaled about 90 x 10 t, approximately 90% of which was refined to aluminum hydroxide by the Bayer process. Most of the hydroxide was then calcined to alumina and consumed in making aluminum metal. The balance, which constituted about 2.3 x 10 t in 1988 (Table 2), was consumed in production of abrasives (qv) adhesives (qv) calcium aluminate cement used in binding ceramics (qv) and refractories (qv) catalysts used in petrochemical processes and automobile catalytic converter systems (see Petroleum Exhaust control, automotive) ceramics that insulate electronic components such as semiconductors and spark plugs chemicals such as alum, aluminum halides, and zeoHte countertop materials for kitchens and baths cultured marble fire-retardant filler for acryhc and plastic materials used in automobile seats, carpet backing, and insulation wrap for wire and cable (see Flame retardants) paper (qv) cosmetics (qv) toothpaste manufacture refractory linings for furnaces and kilns and separation systems that remove impurities from Hquids and gases. 

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