Sequence the following steps involved generally in the extraction of a metal in pure form from its ore. (1) The metal obtained from its oxide requires further purification for end use. (2) The ore should be converted to its oxide form. (3) The ore is beneficial to us if it is hand-picked then metal crushed and ground, and later subjected to pulverization as per the requirement. (4) The ore in the form of oxide is required to be reduced. (5) Dressed ore is required for it to be concentrated. (a) 53241 (b) 35241 (c) 35214 (d) 35421

Extracting a metal from its ore starts with the 'dressing' or 'ore preparation' step. This involves crushing, grinding, and separating useful minerals from the rest of the rocks or materials. It's all about increasing the metal concentration before the main extraction process begins.

For example, if we're working with a copper ore, the valuable copper minerals need to be separated from the waste rock particles. It's akin to sifting flour to eliminate lumps for a smooth batter – you want to isolate the useful ingredient. This is typically achieved through a combination of mechanical processes including hand-picking, crushing, and grinding, followed by methods like gravity separation, magnetic separation, or flotation.

Magnetic Separation

One common method of ore concentration is magnetic separation. If the ore particles or the gangue can be attracted by a magnet, this method can be used. It's a fairly straightforward technique and can be highly effective for certain types of ores.

After the initial preparation, the concentrated ore must go through a chemical transformation to make metal extraction easier. This phase is known as the 'conversion to oxide'. Most metals exist in nature as oxides, and those that don't are converted to oxides at this stage.

This conversion is primarily done through two processes: roasting and calcination. Both involve heating the ore, but with different outcomes. Roasting is when the ore is heated in the presence of excess air or oxygen, while calcination involves heating in limited air or oxygen supply. Both methods drive off other components like carbon dioxide or water vapor, leaving behind the desired oxide state that's more amendable to reduction.

The main act in the metal extraction concert is 'reduction of oxide'. This is where the actual separation of metal from its oxide takes place. The method of reduction largely depends on the metal being extracted. For example, iron is typically reduced in a blast furnace, while aluminum oxide is reduced via the Hall-Héroult process.

Taking iron as an instance, carbon monoxide produced within a blast furnace reacts with the iron oxide, stripping away the oxygen atoms and leaving behind pure iron. The immense heat and series of chemical reactions are tailored to ensure that oxygen is effectively removed to yield the most metal possible.

Even after metal is extracted from its ore, the job isn't done. There's still the crucial 'purification of metal' stage. This could involve a variety of processes, depending on the metal and the form of impurities present. Some common methods include electrolysis, zone refining, and the use of chemical agents.

Electrolysis, for instance, is particularly useful for metals like copper and aluminum, purifying them by driving an electric current through the metal, causing pure metal to accumulate at the cathode and impurities to fall away. It's the equivalent to filtering water through a sieve, ensuring only pure water gets through and leaving behind any sediments.

Ore concentration, also known as 'beneficiation', is all about increasing the ore's metal content. Think of it as a treasure hunt where you want to find more gold with less digging. There's no one-size-fits-all approach to this: different ores and metals may require different techniques like froth flotation, hydrometallurgy, or pyrometallurgy.

Take froth flotation, which is frequently used in the mining industry. Here, the ore is ground into fine particles and mixed with water and chemicals, creating a slurry. Air is then bubbled through the liquid, and thanks to the added chemicals, valuable metal particles stick to the bubbles and can be skimmed off while the rest sinks to the bottom. The result is a higher concentration of desired metal, ready for the next step in the extraction process.