Different methods of concentration of ores

Ores are solid materials that can be used to produce pure metals. Concentration, dressing, or beneficiation of ores is the process of removing undesirable particles from ore. There are various steps to it. The variations in physical characteristics of the existing metal complex and that of the gangue are used to separate the needed material from the ore. Gangue is a mineral that contains undesirable elements. Ore is the only useful material. The ore is extracted by removing the gangue from the mineral.

Minerals can be found in ores. To harvest the mineral’s ore, we must first dig it up. Impurities must be removed from an ore before the metal can be extracted. Minerals include impurities or undesirable elements. The ores are concentrated according to the type of impurities and their percentage proportion to remove the unwanted compounds. We can get a concentrated ore with a high metal content by eliminating these impurities. The removal of gangue particles from ore, also known as ore concentration, increases the quantity of metal in the ore. The differences in physical or chemical qualities of the ores determine the procedures needed to eliminate contaminants.

Different Techniques for Ore Concentration:

The following processes are used for the concentration of various types of ores.

• Hydraulic Washing

The difference in gravity of the gangue and ore particles is the basis for it. As a result, it is categorised as a gravity separation method. The powdered ore is washed using an upward stream of flowing water. The heavier ore particles are left after the lighter gangue particles are washed away. Because tin and lead ores are heavier than gangue, hydraulic washing is used to remove them.

• Magnetic Separation method

It works based on the ore components’ magnetic properties. Magnetic separation can be employed if either the ore particles or the gangue can be drawn to a magnetic field. The ore is kept in a conveyor that passes through a magnetic roller. To separate the ore and gangue, the magnetic properties of either the ore or the gangue are used. The ore is meticulously treated before being transported on a conveyor belt that passes past a magnetic roller. The gangue slides away while the magnetic ore stays on the belt. By eliminating non-magnetic impurities, this method is used to concentrate magnetic iron ores such as magnetite, chromite, and manganese (pyrolusite). A magnetic separator is utilised in this process.

• Froth flotation process

Separating gangue from sulphide ores is done using this approach. Sulphide ores of Cu, Pb, and Zn are processed. Water is used to make a suspension of powdered ore. Collectors and froth stabilisers are incorporated into this solution. In order to improve the non-wettability of mineral particles, pine oils and fatty acids are utilised as collectors. To stabilise the froth, froth stabilisers such as cresols and aniline are used. The mixture is agitated and drawn into by a spinning paddle. As a result, froth forms, carrying the mineral particles. The froth is light and is removed with a scanner. The ore particles are then dried off for recovery. By changing the percentage of oil, depressants are occasionally employed to separate the sulphide ores.

• Flotation begins with roughing. The most valuable material is extracted during this procedure. Before roughing, it is sometimes necessary to do a pre-flotation phase. It is done to get rid of organic carbon and other contaminants.
• The next step in the flotation process is to clean. Unwanted materials are deleted during this process. Cleaner concentration is the finished result of this process.
• The flotation process concludes with scavenging. It is done to retrieve any missed critical items during the roughing process.

Conclusion

The most common product of metal ore mining is ore concentrate, sometimes known as dressed ore or simply concentrate. In most comminution operations, the raw ore is finely crushed, and gangue (trash) is eliminated, concentrating the metal component. The concentrate is then transferred to hydrometallurgy, pyrometallurgy smelters, and electrometallurgy, where it is processed to make usable metals through physical or chemical processes. When an ore contains only a low percentage of the desired metal, physical concentration is required before the extraction process can begin. One approach involves crushing the ore and placing it in a machine, where gravity separates the heavier metal-bearing particles from the lighter rock particles. The flotation technique, which is often used for copper sulphide ores, is another option. Mechanical or ore dressing methods alone are sufficient to obtain the relatively pure metal in some cases (such as when gold, silver, or occasionally copper occur free, i.e., uncombined chemically in sand or rock). Waste material is washed away or separated by gravity and screening; the concentrated ore is processed chemically.