Cement dust

FIG. 17-73 Normal (perpendicular) rapping efficiency for various precipitated dust layers having about 0.03 g diist/cm (0.2 g diist/in ) as a function of maximum acceleration in multiples of g, Curve 1, fly ash, 200 or 300°F, power off. Curve 2, fly ash, 70°F, power off also 200 or 300°F, power on. Curve 3, fly ash, 70°F, power on. Curve 4, cement-ldln feed, 300°F, power off. Curve 5, cement dust, 300°F, power off. Curve 6, same as 5, except power on. Curve 7, cement-ldln feed, 300°F, power on. Curve 8, cement dust, 200°F, power off. Curve 9, same as 8, except power on. Curve 10, cement-ldln feed, 200°F, power off. Curve 11, same as 10, except at 70°F. Curve 12, cement-ldln feed, 200°F, power on. Curve L3, cement-ldln feed, 70°F, power on. °C = (°F — 32) x %. [Spioull, Air Polliit. Control Assoc. J., i.5, 50 (1965).]... 

Gas-solid Fume Metal oxides, cement dust... 

Seals Seals are normally transparent, quick-drying, highly penetrating materials that are used to stop cement dusting and contamination by oils, etc. The moisture-cured urethanes are particularly suitable, since they penetrate to produce a hard-wearing surface. However, if safety factors preclude their use there are also epoxy and even oleo-resinous products available. 

Remember that outside influence (for example, new building work in the vicinity of the installation) can increase air-based pollution, such as cement dust entering the tower at air inlet levels or via the forced-draft fan. 

Gas Gas-vapour Gas-liquid Gas-solid Gas-liquid-solid Mist Fume SO2 NOxI HCI CO hydrocarbons Acid mist carryover chromic acid oil mists tar fog Metal oxides, cement dust Paint spray... 

Particulate Pollutants. Smoke, ash, viruses, pollen, sand, and in contemporary industrial society also coal and cement dust, are generally known as particulate pollutants (they occur as extremely small solid particles suspended in the atmosphere). The combination of air, pollutant gases, small liquid droplets, and particulate matter constitutes what is known as smog, which, since the second half of the eighteenth century, has beset antiquities, damaging and disintegrating even those made of stone and metals. 

Heavy or moist Lead dust with small chips, moist cement dust, asbestos chunks from machines, sticky buffing lint >4500 >23... 

The relation between exposure to Portland cement dust and cancer was examined in a population of 546 workers who had been exposed at some time before 1974 for 1 or more years. No increased risk of overall cancer, respiratory cancer, or stomach cancer was found among the cement workers compared with a referent population. ... 

Vestbo J, Knudsen KM, Raffn E, et al Exposure to cement dust at a Portland cement factory and risk of cancer. Br J Ind Med 48 803-807, 1991... 

Dust. Relatively large particles about 100 xm in diameter that come directly from substances being used (e.g., coal dust, ash, sawdust, cement dust, grain dust). 

No information was found that indicated other environmental impacts for the cement industry as a result of using whole tires or TDF. Often, cement dust is ducted back into the kiln, except in cases where the alkali content of the dust would cause a problem for the quality of the finished cement. In those cases, the dust from the fabric filter or ESP is landfilled. This situation does not change with tire use. At Holnam, plant personnel have experimented with briquetting ESP dust.19... 

Ammonium chloride + — Cement dust fume I. Sulfuric I I concentrator mist... 

A portland cement plant ball mill emits particulate matter (PM) emissions that must be controlled to meet state air pollution regulations. Three PM control devices, each of which can control these emissions to the same level, are being evaluated (1) a high-energy wet scrubber (scrubber), (2) an electrostatic precipitator (ESP), and (3) a fabric filter (baghouse). Unlike the wet scrubber, the ESP and the baghouse each recover salable cement dust, and, accordingly, revenue can be attributed to those two options. Two scenarios are visualized, with after-tax hurdle rates of 6% and 18%, respectively. The economic specifications for the three devices are as follows ... 

AmmoiXum ddrirJe-. Cement dust-fume 1 Sulfuric Icc... 

Pylev LN, Kogan FM, Kulagina TF. 1988. [Carcinogenic activity of asbestos cement dust.] Gig Tr Prof Zabol (July) 55-57 (Russian)... 

Particle size range of cement dust = 2.5-50.0 pm Specific gravity of the cement dust = 1.96 Wind speed = 3.0 miles/h... 

This describes the specific curing behavior of fly ash, cement dusts, and certain steel works byproducts, is based on the reaction of silicate and aluminous materials with quick lime. Here too, as with the above-mentioned additives, a higher pH causes the precipitation of metal hydroxides and carbonates. The British SEALOSAFE-Process uses fly-ash plus Portland cement, or alkali silicate glass and Fe/Al hydroxides to solidify a broad spectrum of wastes. In the POZ-O-TEC-Process, the wastes from flue gas scrubbers are solidified together with grate ash and fly-ash. The pozzolanic processes have the advantage of excellent longterm stability however, the products solidify rather slowly and are susceptible to acids. 

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