Copper mineral processing

Flotation or froth flotation is a physicochemical property-based separation process. It is widely utilised in the area of mineral processing also known as ore dressing and mineral beneftciation for mineral concentration. In addition to the mining and metallurgical industries, flotation also finds appHcations in sewage treatment, water purification, bitumen recovery from tar sands, and coal desulfurization. Nearly one biUion tons of ore are treated by this process aimuaHy in the world. Phosphate rock, precious metals, lead, zinc, copper, molybdenum, and tin-containing ores as well as coal are treated routinely by this process some flotation plants treat 200,000 tons of ore per day (see Mineral recovery and processing). Various aspects of flotation theory and practice have been treated in books and reviews (1 9). 

Iron [7439-89-6J, Fe, from the Latin ferrum, atomic number 26, is the fourth most abundant element in the earth s cmst, outranked only by aluminum, sihcon, and oxygen. It is the world s least expensive and most useful metal. Although gold, silver, copper, brass, and bron2e were in common use before iron, it was not until humans discovered how to extract iron from its ores that civilization developed rapidly (see Mineral processing and recovery). 

Both sodium sulfide and the bisulfide are used in the flotation process for copper minerals and as a depilatory for animal liides (see Copper Copper ALLOYS Leather). Also, sodium polysulfide can be produced from Na2S, and elemental sulfur can be produced if H2S is generated as an intemiediate. 

Copper ore minerals maybe classified as primary, secondary, oxidized, and native copper. Primaryrninerals were concentrated in ore bodies by hydrothermal processes secondary minerals formed when copper sulfide deposits exposed at the surface were leached by weathering and groundwater, and the copper reprecipitated near the water table (see Metallurgy, extractive). The important copper minerals are Hsted in Table 1. Of the sulfide ores, bornite, chalcopyrite, and tetrahedrite—teimantite are primary minerals and coveUite, chalcocite, and digenite are more commonly secondary minerals. The oxide minerals, such as chrysocoUa, malachite, and azurite, were formed by oxidation of surface sulfides. Native copper is usually found in the oxidized zone. However, the principal native copper deposits in Michigan are considered primary (5). 

The technologies involved in the minerals processing industry can be broken down into those where the desired metal component is in high concentration, such as scrap iron, iron ore, phosphate ore, and bauxite, and those where the concentration of the valuable constituent is low, such as gold and silver ore, lean copper ore, and certain types of scrap and wastes. 

V. H. Aprahamian and D. G. Demopoulos, The Solution Chemistry and Solvent Extraction Behaviour of copper, iron, nickel, zinc, lead, tin, Ag, arsenic, antimony, bismuth, selenium and tellurium in Acid Chloride Solutions Reviewed from the Standpoint of PGM Refining, Mineral Processing and Extractive Metallurgy Review, Vol. 14, p. 143,1995. 

Duyvesteyn, W. P. C. Sabacky, B. J. Ammonia Leaching Process for Escondida Copper Concentrates (Reprinted from Extractive Metallurgy of Copper, Nickel, and Cobalt. Vol. 1, 1993). Trans. Inst. Min. Metall. Sect. C-Miner. Process. Extr. Metall. 1995, 104, C125-C140. 

In most cases, oxide copper ores contain more than one copper oxide mineral, and also contain mixtures of sulphide and oxide copper minerals. From a processing point of view, the oxide copper ores can be divided into the following five groups ... 

The gangue constituents and their nature are sometimes determining factors in selection of a treatment process for beneficiation of oxide copper ores. Highly weathered ores usually contain a fairly large amount of slimes, which has a negative effect on the floatability of oxide copper minerals. Also, there is an appreciable difference in floatability between oxide minerals from carbonaceous and siliceous ores. 

In the deposits where oxide cobalt is present, it is common to have oxide copper minerals. The cobalt is, therefore, recovered in a bulk copper-cobalt concentrate that is processed using a hydrometallurgical technique to produce separate copper and cobalt metals. Oxide... 

Miner. Process Extra. Metall. Rev., 2 203 - 234 Hayes, R. A. and Ralston, J., 1988. The collectorless flotation and separation of sulphide minerals by control. Inter. J. Miner. Process, 23 55 - 84 Hepel, T. and Pomianowski, A., 1977. Diagrams of electrochemical equilibria of the system copper-potassium ethyl xanthate-water at 25°C. Int. J. Miner. Process, 4 345 - 361 Heyes, G. W. and Trahar, W. J., 1977. The natural floatability of chalcopyrite. Int. J. Miner. Process, 4 317-344... 

Woods, R., 1996. Chemisorption of thiols on metal and metal sulphide. In J. O M Bockris, B. E. Conway, R. E. White (eds.). Modem Aspects of Electrochemistry. 29 401 - 453 Woods, R., Young, C. A., Yoon, R. H., 1990. Ethyl xanthate chemisorption isotherms andEh-pH diagrams for the copper/water/xanthate and chalcocite/water/xanthate systems. Inter. J. Miner. Process, 30 17 - 33... 

Zhao Jing et al., 1988. Research on the mechanism of chalcopyrite depressed by sodium mercaptoacetic. Nonferrous Metals (part of mineral processing), (3) 42 - 45 Zhuo Chen and Yoon, R. H., 2000. Electrochemistry of copper activation of sphalerite. Inter. J. Miner. Process, 58 57 - 66... 

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