An Introduction to Mineral Processing: Learn the Basics of Extractive Metallurgy

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Picture frames, dental crowns for teeth, astronaut helmets, cell phones and jewellery. What do all of these items have in common? They all use gold in some shape or form. Gold is one of many precious metals that is obtained through the mining of ore. Ore is the rock that contains many minerals. Those minerals have important elements such as metals. Along with gold; nickel, copper, platinum and palladium are some of the more commonly known metals that are obtained through the mining of ore. The process of separating out the metal from the minerals in the ore is called extractive metallurgy.

How Does the Process Start?

Before any work is done, it is necessary to determine if the worth of the precious metal contained in the rock is going to outweigh the costs of mining and extracting that metal. The rock is typically given a grade and this mineral analysis will help determine if the rock is worth mining. The metal ores found through mining are typically not found in high concentrations in the crust of the Earth. If it is determined that the rock is worth mining, once enough rock has been removed it is crushed so that the ore can be separated out from the waste rock.

Hydrometallurgy

One method for separating minerals from ore is called hydrometallurgy. This process not only separates the minerals from the ore, but it can also refine those minerals into a more pure form. The minerals are chemical compounds that contain the precious metals mentioned earlier. Leaching is one method that can separate the precious metals into a more pure form. This involves dissolving the metals into a solution. The solution is then purified and concentrated before the precious metals can be recovered. The metal is typically recovered in its pure metallic state or as a chemical compound.

Pyrometallurgy and Electrometallurgy

Another method for separating out precious metals is pyrometallurgy. In this method, the rock is superheated to temperatures near one thousand degrees Celsius. This takes a solid rock that contains valuable metal and turns it into a molten form which will result in the metallic state or elemental form. This roasting process is typically referred to as smelting. A third method for extracting precious metals is called electrometallurgy. This process usually follows either the hydro or pyro processes already mentioned. An electrolysis process can further refine the metals that may not have separated out into a pure enough form.

As advancements in electronics, transportation systems, and machines continue to evolve at a rapid pace, the need for raw materials to create all of these new devices and systems is great. Extractive metallurgy is the process that allows people to study the properties of various precious metals. The process also allows engineers to figure out new and innovative ways to use metals in the production of consumer products. Minerals and metals are ever present in society. From trains, ships, planes, medical devices to cutlery, cookware, coins and jewellery, the work of metallurgy is extremely important.