Mineral Processing Technology

The main objective of mining industry is to satisfy the requirement to metals, and this trend is growing each time more and more in such grade that treating of rich ores is not enough. So the treating of ore deposits of low grade is more common. Perhaps, most of metals are extracted from low grade ores by using complex systems of concentration. Considering this aspect, researches and manufacturers have been trying to improve the performance of the equipments and the processes to be used.

Improvement of mineral processing techniques can markedly conserve primary sources of materials. As ore reserves become more difficult to treat, losses of tailings increase. The emphasis must be to improve the efficiency of existing processes, optimize their performance, and seek new techniques that not only reduce losses, but more economical, and considering environmental aspects.

The essential operations to treat ores are liberation and concentration. Both can be present in any particular case. The Liberation is done by operations of crushing and grinding with only one limit, the economical performance. The concentration processes depend on the type of ore and have for objective to obtain a product which is sold to the highest price but with the less possible cost. This product is called concentrate.

Liberate particles imply to break the particles consecutively so that the resistance between particles can be minimum. Also the machine must work in the best mechanical conditions assuring a good performance and wear. Selective reduction requires employing different machines each time or perhaps any modification of the initial work. Break particles has a cost which depends of the power draw, and number of reduction steps employed. So, the cost increases with the necessity of better liberation.

The concentration is done considering different characteristics of particles. Thus concentration by gravimetric devices is based on the particles movement in a system under influence of gravity forces. By other way, gravity concentration involves simultaneous classification by sizes and types. The concentration base on electric properties is done considering the different behaviour of particles across an electric field. Some times, it is necessary to give special conditions to have an effective separation, this is the case of froth flotation because the valuable mineral requires be hydrophobic by adding an special reagent called collector, but also it’s necessary to modify the superficial tension by the addition of other reagent called frother. Simply, froth flotation is a separation process based on wettability behaviour.

It is important to point out that all concentration processes are only approximations to the reality because perfect separation is impossible and only the operator’s skill and machine performance can make possible the best operative parameters. Machines are very important at the moment of considering the economical performance of any process. Thus, the space around the machine is as important as the operator. When can be possible, control and work of any machine must be automatic in order to reduce certain mistakes made by the human been.

So, the mineral processing technology involves: minerals, machines, and people. To learn how to harmonize the three elements is the key of any treatment process.