Metallurgy refers to the science and technology of metals. Metallurgical reactions take place either at high temperatures or in aqueous solutions. Reactions take place more rapidly at a higher temperature, and thus large-scale metal production is mostly done through high-temperature processes. Most metallurgical reactions occurring at high temperatures involve an interaction between a gas phase and condensed phases, which may be molten liquids or solids. In some cases, interactions between immiscible molten phases are important (Watch Metallurgical Process Video to learn more).
High-temperature metallurgical reactions involving molten phases are often carried out under the conditions of near equilibria among all the phases; other such reactions proceed under the control of interphase mass transfer with equilibria at interphase boundaries. Reactions involving gas±solid contact also often take place under the rate control of mass transfer with chemical equilibrium at the interface, but the chemical kinetics of the heterogeneous reactions are more often important in this case than those involving molten phases. Even in this case, mass transfer becomes increasingly dominant as temperature increases.
The solid phases undergo undesirable structural changes, such as fusion, sintering, and excessive reduction of internal porosity and surface area, as temperature becomes too high. Thus, gas±solid interactions are carried out in practice at the highest possible temperatures before these undesirable changes in the solid structure become damaging. In the case of high temperature oxidation, the structure of the product oxide determines the mass transport of gases and ions.
The treatment of metals in their molten state, e.g. refining and alloying, involves reactions between the melt and a gas phase or a molten slag. Interfacial reaction kinetics, mass transport in the molten or gaseous phase becomes important. The production of metals and alloys almost always involves solidification, the rate of which is often controlled by the rate of heat transfer through the mold.
Metallurgical Process Video
Useful for CBSE, ICSE, NCERT & International Students
Grade : 8
Subject : Chemistry
Lesson : Metals and Non Metals
Topic: Metallurgical Process Video
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