Tag: concentration of ores

Froth flotation commences by comminution (that is, crushing and grinding), which is used to increase the surface area of the ore for subsequent processing and break the rocks into the desired mineral and gangue in a process known as liberation, which then has to be separated from the desired mineral. The ore is ground into a fine powder and mixed with water to form a slurry. The desired mineral is rendered hydrophobic by the addition of a surfactant or collector chemical. The particular chemical depends on which mineral is being refined. As an example, pine oil is used to extract copper. This slurry (more properly called the pulp) of hydrophobic mineral-bearing ore and hydrophilic gangue is then introduced to a water bath which is aerated, creating bubbles. The hydrophobic grains of mineral-bearing ore escape the water by attaching to the air bubbles, which rise to the surface, forming a foam or a scum (more properly called a froth). The froth is removed and the concentrated mineral is further refined.

Iron ores are concentrated by magnetic separation method.
In  magnetic separation method, ferromagnetic and nonmagnetic particles in the ore are separated by an electromagnetic separator.

Leaching is a chemical method of concentration of ores. It involves the treatment of the ore with a suitable reagent so as to make it soluble while impurities remain insoluble. The ore is recovered from the solution by suitable chemical method. Copper is recovered from chemical solutions by leaching processes such as solvent extraction.

Bayer's process is used for the concentration of aluminium ore, bauxite. In this process, the impurities like iron oxide and silica are removed.

Concentration of ore is also k/a enrichment of ore or one dressing. All the method depend on some difference in physical or chemical properties of gangue.

Bayer's process is the industrial refining process to refine bauxite to produce alumina. In this process, the crushed ore is treated with hot concentrated caustic soda (NaOH).

Sodium bicarbonate, also called sodium hydrogen carbonate, or bicarbonate of soda, $NaHCO _3$, is a source of carbon dioxide and so is used as an ingredient in baking powders, in effervescent salts and beverages, and as the main constituent of dry-chemical fire extinguishers. Its slight alkalinity.

Stellite is an alloy of Co, Cr, W & F and is extremely hard, which is used in drill bits for rock drilling.

Chemical separation is one of the methods employed in concentration of ore.