Harold Ellingham
Encyclopedia
Harold Johann Thomas Ellingham, OBE
, (1897–1975) was a British physical chemist, best known for his Ellingham diagram
s, which summarize a large amount of information concerning extractive metallurgy
.
Ellingham studied at the Royal College of Science
from 1914 to 1916.Although the Royal College of Science
had been formally merged with the Royal School of Mines
and the City and Guilds Central Technical College in 1907 to form the Imperial College of Science and Technology, it retained an independent identity as a constituent college until 2002. He became a demonstrator at the college in 1919 and reader in physical chemistry in 1937. He was secretary of the Royal College of Science 1940–44 and of the Royal Institute of Chemistry
1944–63. He was made a fellow of Imperial College in 1949 and an Officer of the Order of the British Empire (OBE) in 1962.
Ellingham is best known for his eponymous diagrams plotting the Gibbs energy change for the reaction
against temperature. By normalizing the thermodynamic functions to the reaction with one mole of oxygen
, Ellingham was able to compare the temperature stability of many different oxide
s on the same diagram. In particular, he could show graphically that carbon
becomes a stronger reducing agent as the temperature increases. The reduction of metal oxides with carbon (or carbon monoxide
) to form the free metals is of immense industrial importance (e.g., the manufacture of iron
in a blast furnace
), and Ellingham diagram
s show the lowest temperature at which the reaction will occur for each metal.
Order of the British Empire
The Most Excellent Order of the British Empire is an order of chivalry established on 4 June 1917 by George V of the United Kingdom. The Order comprises five classes in civil and military divisions...
, (1897–1975) was a British physical chemist, best known for his Ellingham diagram
Ellingham diagram
An Ellingham diagram is a graph showing the temperature dependence of the stability for compounds. This analysis is usually used to evaluate the ease of reduction of metal oxides and sulphides. These diagrams were first constructed by Harold Ellingham in 1944...
s, which summarize a large amount of information concerning extractive metallurgy
Metallurgy
Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. It is also the technology of metals: the way in which science is applied to their practical use...
.
Ellingham studied at the Royal College of Science
Royal College of Science
The Royal College of Science was a higher education institution located in South Kensington; it was a constituent college of Imperial College London from 1907 until it was wholly absorbed by Imperial in 2002. Alumni include H. G. Wells and Brian May and are distinguishable by the letters ARCS ...
from 1914 to 1916.Although the Royal College of Science
Royal College of Science
The Royal College of Science was a higher education institution located in South Kensington; it was a constituent college of Imperial College London from 1907 until it was wholly absorbed by Imperial in 2002. Alumni include H. G. Wells and Brian May and are distinguishable by the letters ARCS ...
had been formally merged with the Royal School of Mines
Royal School of Mines
Royal School of Mines comprises the departments of Earth Science and Engineering, and Materials at Imperial College London.- History :The Royal School of Mines was established in 1851, as the Government School of Mines and Science Applied to the Arts...
and the City and Guilds Central Technical College in 1907 to form the Imperial College of Science and Technology, it retained an independent identity as a constituent college until 2002. He became a demonstrator at the college in 1919 and reader in physical chemistry in 1937. He was secretary of the Royal College of Science 1940–44 and of the Royal Institute of Chemistry
Royal Institute of Chemistry
The Royal Institute of Chemistry was a British scientific organisation.Founded in 1877 as the Institute of Chemistry of Great Britain, its role was to focus on qualifications and the professional status of chemists, and its aim was to ensure that consulting and analytical chemists were properly...
1944–63. He was made a fellow of Imperial College in 1949 and an Officer of the Order of the British Empire (OBE) in 1962.
Ellingham is best known for his eponymous diagrams plotting the Gibbs energy change for the reaction
- M + O2
against temperature. By normalizing the thermodynamic functions to the reaction with one mole of oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, Ellingham was able to compare the temperature stability of many different oxide
Oxide
An oxide is a chemical compound that contains at least one oxygen atom in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2....
s on the same diagram. In particular, he could show graphically that carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
becomes a stronger reducing agent as the temperature increases. The reduction of metal oxides with carbon (or carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
) to form the free metals is of immense industrial importance (e.g., the manufacture of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
in a blast furnace
Blast furnace
A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally iron.In a blast furnace, fuel and ore and flux are continuously supplied through the top of the furnace, while air is blown into the bottom of the chamber, so that the chemical reactions...
), and Ellingham diagram
Ellingham diagram
An Ellingham diagram is a graph showing the temperature dependence of the stability for compounds. This analysis is usually used to evaluate the ease of reduction of metal oxides and sulphides. These diagrams were first constructed by Harold Ellingham in 1944...
s show the lowest temperature at which the reaction will occur for each metal.