Usually, the term metallurgy refers to the commercial production and use of metals and it affects industries such as healthcare, transportation, defence, and entertainment through the creation and refinement of metals.
History
Early humans took an essential step toward the Metal Age when they discovered that metals such as copper could be melted and casted in moulds to form new shapes. Additionally, they made the discovery that metals could be separated from metal-bearing minerals. Eventually, our ancestors figured out they needed to add iron oxide to the process of melting copper to maintain the element's separation from the other associated minerals. Thus, they discovered flux, which is defined by Lexico as “a substance mixed with a solid to lower its melting point, used especially in soldering and brazing metals or to promote vitrification in glass or ceramics.”
These early stages of metallurgy primarily involved working with copper, gold, bronze, iron, brass, and other precious metals. These materials allowed early men to fashion weapons and even jewellery and such allowed successive peoples to create the civilisations we know today.
In more recent decades, metallurgy has evolved to primarily focus on the production of metals for commercial use. Metal production starts with extracting metals from ores through mineral processing, and oftentimes involves mixing metals in order to create alloys.
Types of metallurgy
Metallurgy can be separated into two categories, extractive and physical metallurgy. After metals have been extracted and processed, they can be used for production.
Extractive
Extractive metallurgy involves separating metal from ore or other chemical compound forms, allowing the metals to be processed and purified.
Extractive metallurgy consists of two main methods:
- Pyrometallurgy involves the use of heat, or thermal treatment, of minerals and ores. The heat causes a physical or chemical transformation of the materials allowing for metals to be extracted. The most common pyrometallurgical processes are roasting, smelting, and converting.
- Hydrometallurgy involves the use of water in processes to extract metals or compounds from their ores. This can be done through leaching, precipitation of insoluble compounds, and pressure reduction.
Physical
Physical metallurgy deals with processes of making useful products from and developing metallic alloys for manufacturing and construction. Physical metallurgy examines the metallic crystal structures, mechanical properties, electrical properties, magnetic properties, and chemical properties of metals.
Major components of physical metallurgy include:
- Powder metallurgy describes the processes in which materials or components are made from metal powders. Powder metallurgy enables operations to reduce the need to use metal removal processes and often results in lower costs.
- Alloying is the process of mixing several elements. Such mixtures, or alloys, can have properties superior to pure metals. Operations use alloying as a means to increase strength, increase corrosion resistance, and often reduce costs.
Production
In terms of production, metallurgy focuses on metallic components that are necessary for consumer or engineering products. Metal production can be divided into subsections of ferrous metallurgy and non-ferrous metallurgy. The difference between ferrous and non-ferrous metallurgy centres on the metals used in processes and alloys, with ferrous involving iron and non-ferrous involving other metals. According to USGS, ferrous metal production accounts for 95 percent of world metal production.
Production of metals may involve:
- Metalworking processes
- Heat treatment
- Plating
- Shot peening
- Thermal spraying
- Surface Treatment
Metallurgy in Mining
Metallurgical Coal
Metallurgical coal is an essential ingredient in blast-furnace steel production and accounts for around 70% of global steel output. Also known as coking coal, this carbon-rich form of coal is used to make coke which is the primary source of carbon used in steel-making. The coal is sourced through mining.
Mineral Processing
Mining and mineral processing go hand in hand. Mineral processing starts with mining mineral products from the earth’s crust and then processing them in order to provide a more concentrated material for extractive metallurgy.
The operation of processing involves comminution, concentration, sampling, analysis and dewatering.
Metallurgical testing
Metallurgical testing is essential for verifying quality and adequacy of materials. Industries such as Oil & Gas, Desalination, and Nuclear rely on metallurgical testing as the materials used must be durable over sustained periods of time and hold up in the toughest conditions.
It typically consists of microscopic examination of a metal or alloy sample to determine the structure, grade, elasticity, tensile strength, grain size, hardness, or the presence of any defects.
A few types of metallurgical testing include:
- Chemical analysis
- Hardness testing
- Tensile Testing
- Fatigue Testing
- Impact Testing
- Microstructural analysis
This science of metals, discovered by early man, allows for many of our modern comforts, affecting everything from the buildings we live in to the gas we put in our cars. Modern metallurgists today work alongside engineers and scientists across varying industries and with varying materials. Meet the difference makers working in mining operations at Anglo American, who are helping to maintain and aid the furtherment of this essential technology by providing necessary ores and metals.
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