Metallurgy
Introduction
Metallurgy is the domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are called alloys. It is a principle element in the field of materials science, often considered a subset of chemical engineering.
History
Metallurgy dates back to 6000 BC, as evidenced by the discovery of copper items from the Fertile Crescent. The extraction of iron from its ore into a workable metal is much more difficult than copper or tin. While iron is not much harder than bronze, iron tools and weapons were far more durable and efficient, leading to the advent of the Iron Age.
Principles of Metallurgy
The production of metals involves the processing of ores to extract the metal they contain, and the mixture of metals, sometimes with other elements, to produce alloys. Metallurgy is distinguished from the craft of metalworking, although metalworking relies on metallurgy, as medicine relies on medical science, for technical advancement.
Extraction
Metals are often extracted from the Earth by means of mining ores that are rich sources of the requisite elements. The process of ore formation is called ore genesis.
Refining
Metals are often purified by pyrometallurgical processes. These processes include distillation, roasting, smelting, and calcination.
Alloy production
To further refine the metal, it can be alloyed with other elements to improve certain properties. An alloy may have a higher strength or corrosion resistance than the pure metal.
Metallurgical Processes
Metallurgical processes can be divided into production processes, which cover the sequence of operations from the delivery of the raw materials to the furnace up to the production of the molten metal, and the casting of the metal or alloy into the required product; and secondary processes, which further refine the metal to give the properties required.
Pyrometallurgy
Pyrometallurgical processes use heat to separate desired metals from other materials. These processes include roasting, smelting, and converting.
Hydrometallurgy
Hydrometallurgical processes use aqueous solutions to extract metals from ores. These processes include leaching, solution concentration and purification, and metal recovery.
Electrometallurgy
Electrometallurgical processes use electrical energy to extract and refine metals. These processes include electrolysis, electrorefining, and electrowinning.
Metallurgical Testing
Metallurgical testing is used to determine the quality of materials and the properties of the metals that are produced. These tests can include hardness testing, tensile testing, impact testing, and fatigue testing.
Applications of Metallurgy
Metallurgy is used in a variety of industries, including the automotive, aerospace, and construction industries. It is also used in the production of a wide range of products, from structural steel to precision instruments.