Mineral Processing

Mineral processing has as objective to prepare the ore for the extraction of the valuable minerals (metallic ores) but also produces commercial final products of non-metallic ores. Apart from regulating the size particle, it is a process treating to separate the valuable minerals from the no useful mineral (gangue) so that can be produced a rich product called concentrate which has most of the valuable minerals. The importance of mineral processing is very important nowadays due to the lack of mineral deposits of high grade and easy treatment. So, treat a low grade ore is many times a challenge. A mineral deposit is mined if the ore is found in a large enough deposit to be extracted economically, usually in an underground or open pit mine. Mineral processing separates minerals and gangue (undesirable minerals). Key steps in mineral processing are comminution and separation.

The comminution processes involve crushing and grinding and are highly capital intensive and contribute the most to total operating costs at ore processing plants. They are also sometimes inefficient at converting energy into work as particle size is reduced. As a result the ancient art of comminution can spark heated debates among specialists over how best to break the mechanical bonds that lock useful minerals to a host rock so that valuable minerals can be exposed to recovery systems. The progress on this are has been slow since the time of the stamp mills.

To recover and concentrate valuable minerals, the final product from the size reduction step is sent to the concentration section which separates that product into two product products: valuable mineral (concentrate), and gangue (tailings). The main concentration processes are flotation, electric and magnetic systems, and gravimetric methods. When the concentrate is obtained, there are two possible routes for its treatment which depends of the ore treated. Thus, polymetallic ores usually produce a copper, lead or zinc concentrate which are sent to the smelter for the final treatment. But, the situation can be different in the treatment of precious metals because many times the concentrate is treated at the same mill by combined operations of pyrometallurgy, hydrometallurgy, and electrometallurgy.

An aspect very important in the two decades is related to the advances in process control which has been responsible for the most significant recent increases in mill productivity. Combined with computer based control systems, on stream analysis has revolutionized mill operations, cutting operation costs and more importantly, increasing recoveries, grades, and throughputs. Thus, an operator does not have to work blind and pit his skills against the whims of the ore. So without considering the type of ore or process treatment employed, a fundamental achievement obtained is the called control policy. Then, It is clear that the control system has to maintain the best metallurgical efficiency although many times, there is a dilemma between quality and throughput, this relationship trends to change from mill to mill.

Consequently, mineral processing is a complex art that most time is influenced by the nature of the ore and the devices implanted in the plant. Understand the principles can be any times no clear, and when it happens, our experience is the best source to solve any problem.