Skip to main content Skip to Search Box

Definition: coke from The Hutchinson Dictionary of Scientific Biography

Subject: rocks and minerals, technology and manufacturing

Solid, porous material produced from the carbonization of coal, all the volatile material having been driven off. It is used in the production of steel.


Summary Article: coke
from The Columbia Encyclopedia

substance obtained by the destructive distillation of bituminous coal. Coke bears the same relation to coal as does charcoal to wood. A hard, gray, massive, porous fuel, coke is the solid residue remaining after bituminous coal is heated to a high temperature out of contact with air until substantially all components that easily vaporize have been driven off. The residue is chiefly carbon, with minor amounts of hydrogen, nitrogen, sulfur, and oxygen. Also present in coke is the mineral matter in the original coal, chemically altered and decomposed.

Since the vapor-producing constituents are driven off during coke production, coke is an ideal fuel for stoves and furnaces in which the environment is unsuitable for the complete burning of bituminous coal itself. In the form of oven coke it is primarily used when a porous fuel with few impurities and high carbon content is desired, as in the blast furnace to make iron. Coke is also used in other metallurgical processes, such as the manufacture of ferro-alloys, lead, and zinc, and in kilns to make lime and magnesium. Exceptionally large strong coke is known as foundry coke and is used in foundry cupolas to smelt iron ores. The smallest sizes of coke are used to heat buildings.

The majority of coke produced in the United States comes from byproduct coke ovens. The coke is prepared in retorts or furnaces of silica brick, and the byproducts (chiefly ammonia, coal tar, and gaseous compounds) are saved. These volatile gases are collected and sent to the byproduct plant where various byproducts are recovered. In nonrecovery coke plants, originally referred to as beehive ovens, the coal is carbonized in large oven chambers; the partially combusted gases collect in a common tunnel and exit via a stack. In recovery coke plants the waste gas exits into a waste heat recovery boiler which converts the excess heat into steam for power generation.

Petroleum coke is the solid residue left by the cracking process of oil refining. Natural coke, or carbonite, is formed by metamorphism from bituminous coal when intrusive igneous rock cuts across a vein of coal.

The Columbia Encyclopedia, © Columbia University Press 2017

Related Articles


Full text Article coke
The Macmillan Encyclopedia

A fuel consisting mainly of carbon. It is made by heating coal in the absence of air and is produced as a by-product of coal gas . Coke is...

Full text Article coke
Hawley's Condensed Chemical Dictionary

The carbonaceous residue of the destructive distillation (carbonization) of bituminous coal, petroleum, and coal tar pitch. The principal type is th

Full text Article Pingxiang
The Columbia Encyclopedia

or Pingsiang both: pĭng-shyäng, city (1994 est. pop. 451,700), W Jiangxi prov., China. It is a major coal-mining center, producing quality coking coa

See more from Credo