Classes of Coal and Usage Flashcards
What is the primary origin of coal?
Altered remains of lush vegetation.
What geological stage involves initial peat formation?
Microbial Stage.
Which stage of coal formation is characterized by the conversion of peat to coal?
Biochemical Stage.
What is the term for the process that transforms peat into higher ranks of coal?
Coalification
What are the two main factors affecting coalification?
Heat and pressure.
Define “coal rank.”
The degree of coalification.
What does “coal grade” refer to?
The quantity of impurities in coal.
Which type of coal has the highest heating value?
Anthracite.
What is the maximum volatile matter percentage in subbituminous coal?
40%.
Identify one characteristic of lignite coal.
Light brown to black color.
Which classification system is primarily used in the United States for coal?
ASTM classification system.
What is the primary use of coking coal?
Steel production.
What does Hilts’ rule state regarding volatile matter content?
Volatile matter decreases with increasing depth.
What are macerals in coal?
Microscopic constituents derived from plant material.
Which maceral constitutes 80% or more of U.S. coal?
Vitrinite
Identify one property that distinguishes inertinite from other macerals.
Low volatile matter content.
What does reflectance measure in coal petrography?
The proportion of light reflected from a polished surface, indicating rank.
What are lithotypes in relation to coal?
Megascopic constituents visible to the naked eye.
Name one lithotype that appears bright and glassy.
Vitrain
Which lithotype is characterized by a dull, greasy luster and granular texture?
Durain
Identify a common impurity found in U.S. coals classified as silicates.
Kaolinite
What type of impurity is described as being intimately mixed with coal?
Inherent impurities.
Which mineral group includes sulfides commonly found in coals?
Sulfide minerals.
Name one method used to analyze macerals in coal samples.
Microscopy (transmitted or reflected light).
What is the significance of the Gray-King test in coal classification?
It determines coking properties based on heating behavior.
Identify one environmental impact associated with coal mining operations.
Land degradation or water pollution.
In which country was an international coal classification system developed after World War II?
United Nations (UN).
What does “caking property” refer to in coals?
The ability of coal to form a coherent mass when heated.
Which maceral group is primarily responsible for coking properties in coals?
Vitrinite
What is fusinite characterized by in terms of reflectance and carbon content?
Very bright under reflected light; highest carbon content among macerals.
Define “volatile matter” in the context of coal analysis.
The portion of coal that can be released as gas or vapor when heated.
Which type of mining method typically results in higher environmental impact, surface or underground mining?
Surface mining.
Name one factor that influences the heating value of different types of coal.
Moisture content.
What is the primary chemical component found in all coals?
Carbon.
Identify one health risk associated with exposure to coal dust during mining operations.
Respiratory diseases (e.g., pneumoconiosis).
Which type of coal has less than 8% volatile matter?
Anthracite.
Name one characteristic feature of clarain lithotype in coals.
Bright to semi-bright laminated bands with silky luster.
What does ASTM stand for in relation to coal classification standards?
American Society for Testing and Materials.
Which digit in the UN international classification system indicates volatile matter content?
First digit.
Identify a mineral commonly associated with ash content in coals from the carbonate group.
Calcite (CaCO3).
In terms of reflectance, what indicates higher rank coals?
Increased reflectance values correlate with higher rank coals.
What does “segregated impurity” mean regarding its association with coal?
Discrete particles that exist separately from the coal matrix.
Name one technological advancement that has improved efficiency in coal utilization processes recently.
Carbon capture and storage (CCS).
Which country is known for its lignite reserves and extensive lignite mining operations?
Germany.
Define “coal liquefaction” and its primary purpose in energy production
A process that converts solid coal into liquid hydrocarbons for fuel production.
