Coal-dust

Coal dust is usually added to green sand for cast iron moulding. It is used to a limited extent in some non-ferrous foundries. Coal dust may be mixed with small amounts of resins and oil products. During casting, the thermal degradation produces lustrous carbon , which improves the casting surface finish and shake-out properties. Coal dust is added for three reasons  

In addition to the black and sticky dust caused by handling, coal dust may contain or generate polycyclic aromatic hydrocarbons (PAH) during pouring. 

As coal is blasted, shredded, and hauled in a mine, large amounts of coal dust are produced. Coal dust is extremely flammable, and if ignited it can be more violently explosive than methane. Miners can reduce the buildup of coal dust by injecting pressurized water into coal beds before the coal is 

In animal experiments the inhalation of soot increased mucus formation (Knauff 1867, Gross 1927). In rabbits and mongrel dogs kept underground in a bituminous coal mine (about 50 mg coal dust/m ) nearly continuously for up to 6 years, Schiller (1958) found a hypertrophy of the bronchial epithelium with a prevalence of goblet cells after 3 years exposure, but an atrophy at 6 years exposure. In the bronchioles, Clara cells showed an increase in apocrine secretion. 

In the female Wistar rat, intratracheal instillation of coal dusts of different rank suspended in saline induced a significant Clara cell hyperplasia as compared with TiOa dust (P 0.05) or pure saline (P 0.03) (Albrecht et al. 2000). Proliferation and hyperplasia by coal dust were independent of the quartz content of the dust samples. 

While Haldane (1918) thought coal dust that was not inhaled in excessive quantities would not do any harm and possible even some good as to help the lungs in eliminating other kinds of harmful particles, such as tubercle bacilh, there is now growing evidence that any dust is harmful. 

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Whereas an explosion from methane tends to be localized, it may start coal dust explosions resulting in more widespread injury and loss of life. AH coal breaking operations result in formation of fine coal particles some are controlled with water during the mining operation. Breakage associated with hauling disperses dust, and dust accumulations can be made safe by rockdusting. Powdered limestone is spread over the mine surfaces to cover the dust. 

The Eederal Coal Mine Health and Safety Act set standards for mine ventilation, roof support, coal dust concentrations levels, mine inspections, and equipment. As a part of this comprehensive act, miners must receive medical examinations at employer expense, and payments are made from the U.S. government to miners who caimot work because of black lung disease. 

Minus 200-mesh coal dust, Mumford, Markson and Ravese... 

Alkylphenols, ammonia, asbestos, chlorinated paraffins, 4-chloroaniline, cyanide, detergents, di- -butyl phthalate, polyaromatic hydrocarbons (PAHs e.g. anthracene, benzopyrene, methylcholanthrene, /i-naphthoflavone), nitrate, nitrite, petroleum oil, phenol, pentachlorophenol, 4-nitrophenol, dinitro-o-cresol, polychlorinated biphenyls (PCBs especially coplanar), polychlorinated dioxins, polybrominated naphthalenes, /i-sitosterol, sulfide, thiourea, urea, acid water, coal dust... 

These motors are suitable for locations prone to dust, coal dust and metal particles etc. and occasional water spray and I ain (Figures 1.19(a) and (b)). 

Special provisions are laid down in lEC 60079-0 and lEC 60079-1 for motors required for such locations in view of fluctuating degrees of humidity and temperature. Such locations are defined with a surface temperature limit of 150°C where coal dust can form a layer, or 450°C where it is not expected to form a layer. Otherwise, other details are generally the same as for flameproof motors type Ex d , according to lEC 60079-1. For variations in length of paths, gaps, widths, creepage and clearance distances, the reader should consult these Standards. 

Failure may be caused by coal dust, fly ash and moisture. Pollution may weaken the insulation, particularly of a protected type motor and result in a failure at some stage. 

The air pollution problems associated with combustion of coal are of major concern. These problems generally occur away from the coal mine. The problems of atmospheric emissions due to mining, cleaning, handling, and transportation of coal from the mine to the user are of lesser sigruficance as far as the overall air pollution problems are concerned. Whenever coal is handled, particulate emission becomes a problem. The emissions can be either coal dust or inorganic inclusions. Control of these emissions can be relatively expensive if the coal storage and transfer facilities are located near residential areas. 

Coke oven charging Hydrocarbons, carbon, coal dust Aspiration systems to draw pollutants into oven, venturi scrubbers... 

Pitch In manufacture of blocks of fuel consisting of coal, coal dust, coke or slurry with pitch as a binding substance... 

Total frequencies of environmental illness are difficult to measure. When causes can be identified, however, scientists observe that frequencies of occurrence of a particular illness vary directly with the severity and extent of exposure. Particularly frequent in the workplace are skin lesions from many different causes and pulmonary diseases related to the inhalation of various dusts, such as coal dust (black lung), cotton dust (brown lung), asbestos fibers (asbestosis), and silica dust (silicosis). Environmental agents can also cause biological effects without overt clinical illness (for example, chromosome damage from irradiation). 

In 1955 it was discovered that mixtures of ammonium nitrate and fine coal dust have satisfactory blasting capabilities in large (9 inch) holes used in open-pit coal mines to remove the rock and soil covering the coal. Polyethylene bags containing this material deform to fit the hole and provide moderate water resistance. ANFO is used in open-pit iron and copper mines and for construction such as road building. The mixture is air blown into 2-inch holes or less m maiiv underground mines. 

Most black pigments are made of carbon black formed by depositing carbon from a smoky flame of natural gas on a metal surface. Lampblack is made similarly by burning oik Bone blacks are made from charred bones. Graphite occurs naturally or can be prepared from coal in electric furnaces. Mineral blacks come from shale, peat, and coal dust. Iron oxide blacks are found in nature or prepared. Blue lead sulfate is a pigment for priming. Of these, carbon black is su[XTinr. 

Klare, /. clearness clarifier clear (clarified) liquid coal dust boneash. klkren, v.t. clear, clarify, purify, defecate. — v.r. clear, clear up. 

Kohlen-karbonit, n. kohlencarbonite (trade name of an explosive), -klein, n. small coal, -klemme,/, (Elec.) carbon terminal, -kom, n. carbon granule, -licht, n. carbon light, -losche, /, coal dust or slack, -mehl, n, coal dust, powdered coal, -meiler, m, charcoal pile, -monoxyd, n, carbon monoxide, -mulm, m, coal dust, slack charcoal dust, -olsaure, /. carbolic acid, -oxycblorid, n. carbon oxychloride, carbonyl chloride,... 

Kohlen-schwarz, n. carbon black charcoal black, -schwefelwasserstoffsaure, /, (tri)-thiocarbonic acid (H2CS1). -spat, m. anthraconite whewellite, -spitze,/. carbon point, -staub, m. coal dust charcoal dust, -stick-stoff, m. cyanogen, -stickstoffsaure, /, car-bazotic acid (picric acid), -stoff, m. carbon,... 

Kohle-rohx, n., -rohre,/. carbon tube, -schwe-lung, /. coal distillation, -stab, m. carbon rod. -Stahl, m. carbon steel, ordinary steel, -staub, m. coal dust charcoal diist. 

Vei y small solid fuel particles such as sawdust, agricultural grains, or coal dust can sustain flames when they are suspended in air. In fact, very serious fires have occurred in grain storage towers and coal mines because of the flammability of suspended dusts. The combustion of the individual particles follows the usual pattern of solid particle burning— devolatization and char burning. The combustion of the whole cloud of particles is similar to spray combustion and its characteristics depend on the nature of the fuel, size of the particles, and the number of particles in a given volume. 

Maximum Charge (Charge Umite in Fr) is the max charge of an expl that can be fired in a coal mine without causing ignition of firedamp and/or coal dust in air Ref Marshall 2, 585 (1917)... 

O Brien Explosives. A series of patents were issued to J.F. O Brien of Chicago, HI, USA between 1913 and 1915 for new commercial expls. Typical formulations included K chlorate 30, Nitrostarch 10, Si dioxide 55, crude petroleum with coal dust 5ps (Ref 1) K chlorate 87, naphthalene 6.5, asphalt 6.5, crude oil distillate 1.5 Si dioxide 44ps (Ref 2) K chlorate with Na nitrate 60, Hq TNT 15 sawdust 25p (Ref 3) and Amm perchlorate 20—65, Na nitrate 55, liq DNT 10—15, sawdust 14-23 free C l-3.5ps (Ref 4)... 

Pettingall. A powder, patented in Engl in 1895, contg crude saltpeter 63, coal dust 20, crude S... 

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