Copper ore

Of economically workable copper deposits in the world, about 90% are sulfide ores, 

9% are oxide ores and less than 1% is native copper. Considerable amounts of native copper were found on the Kewenaw Point peninsula in Lake Superior in Michigan. 

That copper was extracted economically from the 1840s. Nowadays mining has ended. 

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The examples in the preceding section, of the flotation of lead and copper ores by xanthates, was one in which chemical forces predominated in the adsorption of the collector. Flotation processes have been applied to a number of other minerals that are either ionic in type, such as potassium chloride, or are insoluble oxides such as quartz and iron oxide, or ink pigments [needed to be removed in waste paper processing [92]]. In the case of quartz, surfactants such as alkyl amines are used, and the situation is complicated by micelle formation (see next section), which can also occur in the adsorbed layer [93, 94]. 

Large copper ore deposits are found in the U.S., Chile, Zambia, Zaire, Peru, and Canada. The most important copper ores are the sulfides, the oxides, and carbonates. From these, copper is obtained by smelting, leaching, and by electrolysis. 

Indium is most frequently associated with zinc materials, and it is from these that most commercial indium is now obtained however, it is also found in iron, lead, and copper ores. 

Fig. 12. Complex copper ore concentration flow sheet. Courtesy of Denver Equipment Co.

Fig. 1. Average yield of copper ores mined in the United States.

Before scmbbing procedures were estabUshed for copper ore, most of the rhenium was lost as the volatile (Re202). A small portion, perhaps 10%, was retained in flue dust, which was processed to give the metal. A commercial flotation (qv) process for the recovery of the molybdenite by-product is available that permits a high recovery of molybdenum and rhenium. This process is used at the Caridad copper mine in Mexico. 

Arsenic is widely distributed about the earth and has a terrestrial abundance of approximately 5 g/t (4). Over 150 arsenic-bearing minerals are known (1). Table 2 fists the most common minerals. The most important commercial source of arsenic, however, is as a by-product from the treatment of copper, lead, cobalt, and gold ores. The quantity of arsenic usually associated with lead and copper ores may range from a trace to 2 —3%, whereas the gold ores found in Sweden contain 7—11% arsenic. Small quantities of elemental arsenic have been found in a number of localities. 

Bismuth is referred to as a minor metal. It is not generally mined for its own intrinsic value, rather it is mined primarily as a by-product of lead or copper ores. In China, however, bismuth can be found ia tungsten ores. In BoHvia the metal has been mined for its own value, but this has not happened on a consistent basis over the years because fluctuations ia the bismuth price have at times made it uneconomical to recover. 

Developments in the metallurgy of copper or its alloys were mentioned in 1556 in De MetalBca where the process of copper ore was described by Agricola (see also Copper alloys). About that time, smelting operations commenced at Mansfield, Germany, and at the Swansea smelter in Wales. Both smelters employed successive oxidations and reductions to eliminate iron and sulfur. The process used in the Swansea smelter is similar to modern techniques. 

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). 

Tyrone Grant, N.M. Phelps Dodge Corp. and Burro Chief Copper Co. copper ore, concentrated and leached 160... 

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