What is a humic coal?
Humic coals are banded coals. They are the most abundant type of coal. The bands of coal that comprise a humic coal are divided into four lithotypes (vitrain, clarain, durain, and fusain, Stopes, 1919) based on their general appearance. A single humic coal bed may contain all four lithotypes.
Is humic acid coal?
The humic acid extracted from the lignite type of coal has a high content of carbon, lower oxygen and nitrogen, very few carboxylic groups, and more aromatic groups.
What is leonardite ore?
Leonardite is a soft waxy, black or brown, shiny, vitreous mineraloid that is easily soluble in alkaline solutions. It is an oxidation product of lignite, associated with near-surface mining.
Is coal a bituminous?
Bituminous: Bituminous coal is a middle rank coal between subbituminous and anthracite. Bituminous coal usually has a high heating (Btu) value and is used in electricity generation and steel making in the United States.
What is vitrinite composed of?
Chemically, it is composed of polymers, cellulose and lignin. The vitrinite group, which consists of various individual vitrinite macerals, is the most common component of coals. It is also abundant in kerogens that are derived from the same biogenic precursors as coals, namely land plants and humic peats.
How is humic acid made?
Humic substances are formed by the microbial degradation of dead plant matter, such as lignin and charcoal. Humic acids are precipitated from this solution by adjusting the pH to 1 with hydrochloric acid, leaving the fulvic acids in solution. This is the operational distinction between humic and fulvic acids.
What is sub bituminous coal used for?
Steam-electric power generation
Subbituminous coals are a type of coal whose properties range from those of lignite to those of bituminous coal and are used primarily as fuel for steam-electric power generation.
What is the meaning of sub bituminous coal?
subbituminous coal, also called black lignite, generally dark brown to black coal, intermediate in rank between lignite and bituminous coal according to the coal classification used in the United States and Canada. Some subbituminous coal is macroscopically indistinguishable from bituminous coal.
What is vitrinite reflectance?
Vitrinite reflectance is the proportion of incident light reflected from a polished vitrinite surface. Vitrinite is a maceral (an organic component) of coal. As vitrinite is heated in the earth during burial, it systematically changes its reflective properties.