Lignite
Lignite combustion produces less heat for the amount of carbon dioxide and sulfur released than other ranks of coal.
[3] Depending on the source, various toxic heavy metals, including naturally occurring radioactive materials, may be present in lignite and left over in the coal fly ash produced from its combustion, further increasing health risks.
[6] The energy content of lignite consumed in Victoria, Australia, averages 8.6 MJ/kg (7.4 million BTU/short ton) on a net wet basis.
[7] Lignite has a high content of volatile matter which makes it easier to convert into gas and liquid petroleum products than higher-ranking coals.
[12] The operation of traditional brown-coal plants, particularly in combination with strip mining, is politically contentious due to environmental concerns.
[19][20][21][22] Greece has confirmed that the last coal plant will be shut in 2025 after receiving pressure from the European Union[23] and plans to heavily invest in renewable energy.
[25][26] Due to the smell it gives off when burned, lignite was often seen as a fuel for poor people compared to higher value hard coals.
The carbon increases the organic matter in the soil while the biological control microbes provide an alternative to chemical pesticides.
[36] Leonardite is a soil conditioner rich in humic acids that is formed by natural oxidation when lignite comes in contact with air.
Anaerobic bacteria may contribute to the degradation of peat, but this process takes a long time, particularly in acidic water.
Burial by other sediments further slows biological degradation, and subsequent transformations are a result of increased temperatures and pressures underground.
This includes the process of humification, in which microorganisms extract hydrocarbons from peat and form humic acids, which decrease the rate of bacterial decay.
[47] The most characteristic chemical change in the organic material during formation of lignite is the sharp reduction in the number of C=O and C-O-R functional groups.
Topsoil and subsoil must be properly removed and either used to reclaim previously mined-out areas or stored for future reclamation.
These are broken up using specially equipped tractors (coal ripping) and then loaded into bottom dump trucks using front loaders.
[56] A partnership led by Kawasaki Heavy Industries and backed by the governments of Japan and Australia has begun extracting hydrogen from brown coal.
Although xyloid lignite may sometimes have the tenacity and the appearance of ordinary wood, it can be seen that the combustible woody tissue has experienced a great modification.
It is reducible to a fine powder by trituration, and if submitted to the action of a weak solution of potash, it yields a considerable quantity of humic acid.
