Steps in Metallurgical Process
The various processes involved in extracting metals from their ores and refining them for use are referred to as metallurgy.
The various steps in the metal extraction or metallurgical process:
- Crushing and grinding the ore.
- The concentration of ore, is also known as ore enrichment.
- Metal extraction from concentrated ore.
- Impure metals are refined or purified.
Principles of Metallurgy:
The metallurgical process can be classified as the following:
1. Crushing and grinding: The first process in metallurgy is crushing of ores into a fine powder in a crusher or ball mill. This process is known as pulverization.
2. The concentration of ores: The process of removing impurities from ore is known as a concentration of minerals or ore dressing. In metallurgy, we concentrate the ores mainly by the following methods.
3. Hydrolytic method: In this method, we pour the ore over a sloping, vibrating corrugated table with grooves. A jet of water is allowed to flow over the surface. The denser ore particles settle in the grooves, and the impurities are washed away by water.
4. Magnetic separation: In this case, the crushed ore is placed on a conveyor belt. This belt rotates around two wheels in which one of the wheels is magnetic, and therefore the magnetic particles get attracted to the magnetic wheel and fall apart from the non-magnetic particles.
5. Froth floatation: In this process, we take the crushed ore in a large tank which contains oil and water. A current of compressed air is passed through it. The ore gets wet by oil and is separated from the impurities in the form of froth. Ore is lighter, and so it comes on the surface and impurities are left behind.
6. Roasting and calcination: In metallurgy, the process of heating a concentrated ore in the presence of oxygen is known as roasting. This process is applied in the case of sulfide ores. For ores containing carbonate or hydrated oxides, heating is done in the absence of air to melt the ores, and this process is known as calcination.