Coal is a combustible rock that forms from the accumulation of organic debris such as spores, leaves, and wood. It forms within swampy deposits known as peat bogs. As peat bogs are buried and deepened with layers of sediment, the remains of organic material undergo a chemical process. This process produces coal, which holds a range of chemical constituents and physical characteristics, including its density.
When coal is measured on the basis of weight per volume, its density is estimated to be roughly around 1.35 grams per cubic centimeter. Coal density may change as a result of recent or prolonged exposure to moisture and oxygen, or through specific treatments that alter the density of the coal.
The density of a coal sample can be quite useful in providing an indication of the degree of decayed material, as denser coal has a higher carbon content and less energy content than the original organic matter. Thus, the density of coal may provide an insight into the quality of the coal. Also, the density of coal can be used to assess the compressibility of coal, a factor which is particularly important for industries employing subsurface mining.
The variability in the density of coal can be attributed to other characteristics of the coal such as particle size and mineral content. These variations can create changes in the degree of decayed material that is present. For example, as coal becomes more compressed, its density increases. As a result, denser coal has a greater percentage of concentrated carbon and less intrinsic energy content. Additionally, particles of bituminous coal contain more highly combustible constituents than anthracite. Because the density of coal is related to combustibility, it can be used to estimate the total energy available from burning one unit of coal.
The density of coal can also be impacted by various treatments such as screening or washing. Through screening and washing, specific fractions of coal are removed. As a result, the density of the remaining coal is altered as its composition changes. For example, when coal is processed by removing unwanted material and clumps, its density is reduced, as less material is present per volume. Conversely, when the concentration of coal matter is increased, which can occur through processes such as briquetting or submerging, coal density is raised.
The density of coal is an important characteristic that can influence its usage. This is an area of research that has been well studied and since more is understood about coal density, greater advancements in the coal industry can be made. By examining the methodology for measuring the density of coal and understanding how coal density can be used to predict coal characteristics and qualities, the consumption of coal can be more efficiently managed in the future.
