Ground coal

ASTM D5377 provides a classification system of ground coal for use in rubber. This classification system is based on average particle size. 

Ground coal is mainly used as a black economic diluent in rubber compounding. Most of the ground coal use in rubber occurs in the United States. 

Of course, only a minute amount of the available coal is used in rubber compounding. The rubber grades of ground coal are mostly used in rubber and not in other material. 

Other economic diluent fillers, such as clay, whiting, and talc, are available for use in rubber. 

Tight Supply Situations in the Past and Future Supply Outlook 

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Oxidative Desulfurization Process. Oxidative desulfurization of finely ground coal, originally developed by The Chemical Constmction Co. (27,28), is achieved by converting the sulfur to a water-soluble form with air oxidation at 150—220°C under 1.5—10.3 MPa (220—1500 psi) pressure. More than 95% of the pyritic sulfur and up to 40% of the organic sulfur can be removed by this process. 

A small sample of ground coal is introduced into the top of a column of water 30 cm high, and the time required for the particles to settle out is measured. If it takes 26 s for the first particle to reach the bottom and 18 hr for all particles to settle, what is the range of particle sizes in the sample (T = 60°F, SGcoa = 1.4.)... 

At the beginning of the 1990s, Houston Industries developed an enzymatic process ( Enzymatic Coal Desulfurization ) protected in Canada and US [83,84], Although, the application was focused to coal desulfurization it may also be applicable to crude oil and fossil fuel-derived liquids. The processes claim the removal of both, organic as well as inorganic sulfur species. The process was described as using ground coal (10-50 p,m) slurried with water, while the oil was treated in an aqueous emulsion. 

Not all suspensions will exhibit wall slip. Concentrated suspensions of finely ground coal in water have been found to exhibit wall slip [Fitzgerald (1990)]. This is to be expected because the coal suspension has a much higher apparent viscosity than the water. In contrast, when the liquid is a very viscous gum, the addition of solids may have a relatively small effect. In this case, the layer at the wall will behave only marginally differently from the material in the bulk. 

Previously the py.-f.i.m.s. of coals and their pyridine extracts has already been described (14) using this novel technique. About 100 micrograms of ground coal sample was heated in the high vacuum of a combined... 

AN 53.5, NaNOg 16.1 and water 16.9 parts were mixed heated and the pH adjusted to 5.4— 6.0 by NH4OH or HOAc. Separately blended NaHCOg 0.0 25, NaNOa 0.025, ground coal 1.2, and guar gum 1.2 parts were mixed with Si or Al (amt not shown in CA)... 

Hie coal was ground in the laboratory and sized to pass 200 mesh. Ash determinations on tne ground coal sample were made, and an average value of 5.2% was used to correct for the ash content of the extracted coals. 

For the first step, 12 g. of ground coal and 120 ml. of alkaline solution were mixed and placed in a 300-ml. stainless steel autoclave equipped with a turbine agitator. The system was flushed with nitrogen and then heated to the desired temperature while the mixture was stirred continuously. After a period of treatment at constant temperature and pressure, the autoclave was cooled quickly, and the contents were filtered to recover the coal. The filter cake was washed with 400 ml. of distilled water, dried at 90 C for 4 hr., weighed, and analyzed for total sulfur and ash. A portion of the alkali-treated coal (usually 2.5-3.0 g) was leached for an additional... 

Approximately two thirds of airborne acids in the Northeast are sulfate with wet or dry deposition contributing equally to sulfates reaching the ground ( ). Coal combustion in the industrial Midwest produces most of the S02 (sulfate precursor) emitted east of the Mississippi River. Indeed, eight coal-burning midwestern states (Illinois, Indiana, Kentucky, Michigan, Ohio, Pennsylvania,... 

Steric FFF (mainly in the form Sd/StFFF) has been applied to the separation of a number of large-particle samples, including chromatographic support material, fine-ground coal, and human and animal cells. Separation can be accomplished rapidly despite the normal sluggishness of large-particle transport (28). An example is shown in Figure 9.12. 

The ground coals were stored in glass bottles under nitrogen. 

Direct coal liquefaction (DCL) refers to the process of converting coal to liquid products by mixing ground coal with a recycled process solvent and/or petroleum-derived residual oil and reacting the slurry in a hydrogen atmosphere at 750-850°F (400-450°C) and 1000-2500 psig (7-17 MPa). Under these conditions, the coal structure breaks down into... 

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