Volatile matter is any substance that has a tendency to vaporize given the right conditions. A substance’s volatility is measured by its vapor pressure, the point at which a substance turns from a solid to a gas, or vice versa. Unlike temperature-based measurements, like boiling point, vapor pressure is not directly related to heat or cold and instead relies on the pressure placed on a substance. While both vapor pressure and volatile matter are common in many form physics and chemistry, one of its main industrial uses is in determining the properties of coal.
Vapor pressure is the main determination of the volatility of matter. A substance with a high vapor pressure will vaporize easily while one with a low one requires a lot more energy. In this case, the high or low designation refers to how easily the substance will become vapor.
When applied to a material, the vapor pressure determines its volatility. This often comes up when discussing flammability, since a volatile substance has a tendency to be more flammable than a non-volatile one. For this reason, it is important to study the volatility in a fuel source to determine its overall usefulness.
The volatile matter test for coal is generally a very strict operation. Different regions have their own methods, but they all involve heating a specific amount of coal to a specific temperature for a specific amount of time. This test is typically performed in a vacuum, and studies the amount and type of gasses given off by the piece of coal.
The analyzing of these gasses is one of the major ways people determine the best uses for coal from different areas. Some types have higher concentrations of certain materials, and that allows that particular coal to perform better in certain ways. For instance, lignite has a very high-volatile matter content along with high moisture. The moisture and volatility analysis shows that it burns for a long time with a low heat and a lot of smoke.
A volatile organic compound (VOC) is a specific type of matter that originates from the life cycle or processing of organic materials. These compounds are literally everywhere, as materials are diverse as propane fumes and the smells from flowers fall into this category. This category of substances often has a very high volatility, resulting in the ability it smell them when they are nearby. VOCs are a major source of allergens and respiratory health risks.