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Ore processing
Mineral raw materials (ores) extracted from the earth's interior cannot, in most cases, be used in their natural form in the national economy and industry.
Methods of ore processing
Direct metallurgical or chemical processing of mined ores is not economically viable due to the low content of useful components. Therefore, it is necessary to first improve the quality of the mined ore for further processing. It is also necessary to undertake processes to remove impurity elements from the ore.
Beneficiation of minerals is a set of methods and processes of primary processing of mineral raw materials with the aim of concentrating valuable components in quality products by removing waste rock and separating minerals. In this case, the following tasks are solved:
- Increasing the content of useful components in raw materials;
- Removal of the most harmful impurities;
- Obtaining raw materials that are uniform in size and material composition.
The procedures for enriching minerals are carried out at enrichment plants, which are independent structures or are part of mining and processing plants.
The result of enrichment is one or more concentrates and waste (tailings).
Concentrate is a beneficiated product that differs from primary ore by a higher content of useful components and the absence of impurities. The name of the concentrates is characterized by the content of the main metal, for example, copper concentrate, lead, rutile, etc.
Final tailings are enrichment waste consisting mainly of waste rock and have only a small content of useful components.
Processes of mineral raw materials processing are in turn divided into preparatory, main enrichment, auxiliary and production maintenance processes.
1) Preparatory processes include processes such as crushing and grinding, the purpose of which is to reveal minerals as a result of the destruction of intergrowths of useful minerals with gangue (or intergrowths of some minerals with others); as a result of this process, a mechanical mixture of particles and pieces of different mineral composition is formed. This also includes screening and classification processes, which serve to separate the mechanical mixtures obtained after crushing and grinding by size;
2) The main enrichment processes include physical and physicochemical methods, as a result of which useful minerals are separated into concentrates, and waste rock - into tailings . The enrichment processes related to this class are in turn classified depending on what property of minerals is used to obtain concentrates. Let's consider the main methods:
- The method of gravitational enrichment is based on the difference in the density of separated mineral grains in the field of gravitational forces.
- Magnetic enrichment method – based on the difference in magnetic properties of ore components.
- The flotation enrichment method is based on differences in the physical and chemical properties (wettability) of the separated minerals.
- Special enrichment methods – based on combining the properties of the minerals being separated. For example, radiometric and chemical enrichment methods.
- The radiometric enrichment method is based on the difference in radiospectroscopic properties of the minerals being separated. This method is widely used to control the quality of the product circulating along the factory conveyors. This method deserves special attention, as it is the main activity of Technoanalitpribor LLC. The method is implemented in an autonomous operational device that controls the quality of the product at all stages of enrichment - the ARP-1C/2C X-ray fluorescence analyzer.
- The chemical enrichment method is based on the difference in chemical properties (solubility) of the separated minerals or harmful impurities.
- The mechanical enrichment method is based on the differences in the physical and mechanical properties of minerals, such as mechanical strength, friction, etc.
Each enrichment method differs in the wide variety of additional separating forces used, as well as the design of the machines and apparatus.
3) Auxiliary processes. These are mainly processes of dehydration of enrichment products (thickening, filtration and drying), to obtain normal humidity, established by GOST, or to obtain recycled water.
4) Production maintenance processes . This class includes operations responsible for the continuity and stability of technological processes, communication systems, etc.
Thus, the ore processing process includes a huge range of actions and procedures, the main task of which is to obtain a product (concentrate), the further use of which for the production of metals or other raw materials will be economically profitable. These processes are conveniently represented in the form of the so-called ore enrichment process flow chart, which is shown in Fig. 1.
