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Methods of processing and extraction of copper ore
After quarrying of ore, primary crushing and sorting, the resulting product is transported to mining and processing plants for subsequent processing and extraction of valuable and secondary elements.
The efficiency of extraction directly depends on how completely the extraction of minerals and the preferential distribution of their grains according to those size classes, the extraction of which by gravity, flotation and other methods occurs most completely, were ensured during ore preparation (grinding).
To apply the basic flotation method of ore enrichment, the grain size must satisfy two basic requirements:
- The grains of the mineral being floated must not exceed the upper limit in size, and must not be less than the lower limit;
- It is necessary that the processes of crushing and screening ensure the complete disclosure of minerals, i.e. they must be freed from intergrowths with other rocks, intergrowths with each other, etc.
Of course, in most cases, it is a priori impossible to achieve full disclosure of intergrowths. During flotation, it is necessary to separate particles more saturated with inclusions of the extracted mineral from less saturated grains. Full disclosure of intergrowths requires too fine grinding of the ore, accompanied by strong overgrinding of minerals, which is not economically advantageous. Based on these factors, each ore has its own, economically advantageous degree of grinding.
Copper ore is a complex of sulphides of copper, zinc, iron, nickel and minerals of host rocks. For more complete disclosure of copper ore aggregates, it is subjected to grinding to 70% (0.074 mm) at the first stage, obtaining the first copper concentrate ("copper head"), then it is further ground to 90% to a size of 0.043 mm, for subsequent enrichment.
In the context of the constant deterioration of the quality of non-ferrous metal ores and the need for their comprehensive use, the importance of the enrichment stage is continuously increasing, which primarily affects the need to introduce new technologies, principles and methods for enriching non-ferrous metal ores.
The most popular and widespread enrichment methods are gravity methods, based on the separation of grains in heavy suspensions and sediments; table concentration methods and others are used less frequently.
Separation in heavy suspensions is used for preliminary enrichment (pre-concentration) of the original ore or rock mass after coarse or medium crushing.
Magnetic enrichment methods are used in the processing of copper-magnetite ores, for the extraction of monoclinic pyrrhotite from copper-nickel ores, the regeneration of heavy suspensions, and the additional extraction of iron-containing and other weakly magnetic minerals from ores or tailings.
The copper content in the ore usually does not exceed 10%, but generally ranges from 0.5% to 3%, based on this, the most applicable enrichment method for such ores is the method with preliminary collective flotation of all extracted valuable components.
Schemes with separate reagent treatment of sand and sludge parts of the initial feed of enrichment products and their subsequent separate or combined flotation have become widely used in the enrichment of copper and nickel ores. A significant increase in the selectivity and efficiency of flotation is achieved by modifying existing and using new flotation reagents. The following main areas are distinguished:
- Replacement of toxic reagents with non-toxic or less toxic ones;
- The use of more selectively acting collectors, foaming agents, and modifying reagents;
- Search for reagents that are easily destroyed by chemical or thermal treatment, effective reagents and reagent modes for the depression of sphalerite, pyrite and copper sulfides, reagents and reagent modes for the flotation of oxidized copper and zinc minerals.
One of the methods allowing to perform ore enrichment, as well as to conduct concentration elemental control of the obtained enrichment product, is the X-ray method , based on measuring the radiation intensities of ore components excited by an external X-ray source. This method provides enrichers with timely information on the qualitative and quantitative composition of the ore, allowing them to make balanced and correct decisions on the amount of reagents added in flotation processes. The method can be used both for rough (primary) sorting of ore and for monitoring the main enrichment process. Over time, the method received a complete hardware and technical solution, which resulted in the emergence of devices and installations created specifically for use in the metallurgical and mining industries.
One of such devices is the ARP-1C flow ore analyzer , which allows for qualitative and quantitative analysis of ore in the element range from Ca to U. For more detailed information, follow the link ARP-1C.
