Copper base metal recovery

Deposits. Selenium forms natural compounds with 16 other elements. It is a main constituent of 39 mineral species and a minor component of 37 others, chiefly sulfides. The minerals are finely disseminated and do not form a selenium ore. Because there are no deposits that can be worked for selenium recovery alone, there are no mine reserves. Nevertheless, the 1995 world reserves, chiefly in nonferrous metals sulfide deposits, are ca 70,000 metric tons and total resources are ca 130,000 t (24). The principal resources of the world are in the base metal sulfide deposits that are mined primarily for copper, zinc, nickel, and silver, and to a lesser extent, lead and mercury, where selenium recovery is secondary. 

Like selenium, tellurium minerals, although widely disseminated, do not form ore bodies. Hence, there are no deposits that can be mined for tellurium alone, and there are no formally stated reserves. Large resources however, are present in the base-metal sulfide deposits mined for copper, nickel, gold, silver, and lead, where the recovery of tellurium, like that of selenium, is incidental. 

There are an estimated 800 plants in the U.S. involved in the primary or secondary recovery of nonferrous metals. These plants represent 61 subcategories. However, many of these subcategories are small, represented by only one or two plants, or do not discharge any wastewater. This chapter focuses on 296 facilities that produce the major nonferrous metals [aluminum, columbium (niobium), tantalum, copper, lead, silver, tungsten, and zinc]. The volume of wastewater discharged in this industry varies from 0 to 540 m3/T (0 to 160,000 gal/t) of metal produced.13 The global size of the industry is reflected in Table 3.1 (reported in 1000 USD) for the top 20 export countries for nonferrous base metal waste and scrap.4 Here T = metric ton = 1000 kg = 2204.6 lb, t = 2000 lb. 

In the case of a copper-zinc and copper-lead-zinc ore, gold collects in the copper concentrate. During the treatment of lead-zinc ores, the gold tends to report to the lead concentrate. Information regarding gold recovery from base metal ores is sparse. 

The use of organophosphorus acids, such as di(2-ethylhexyl)phosphoric acid (D2EHPA di(2-ethylhexyl) monohydrogen phosphate 2 R = C4H9CH(Et)CH2), is now well established in the recovery of base metals. This reagent has found commercial application in the separation of cobalt from nickel,67 68 the separation of zinc from impurities such as copper and cadmium,69 the recovery of uranium,68 beryllium70 and vanadium,71 and in separations involving yttrium and the rare-earth metals.72 73... 

Most base-metal sulfides are very insoluble compounds and, in principle, processes based on the differences in their solubilities can be used in the selective precipitation of sulfides. For example, the strong affinity of copper ions for sulfide ion is used to good effect in the removal of traces of copper from leach liquors in the recovery of nickel,406 cobalt407 and manganese.408 For manganese, other impurity metal ions such as cobalt, nickel and zinc are also selectively precipitated by the use of sulfide ions. 

The waste streams in standard metallurgical processing are good potential sources of important elements. The U.S. Bureau of Mines has developed processes for the recovery of elemental sulfur from stack gases discharged by base metal smelters (G4) and for the recovery and production of alumina from waste solutions of mining operations (G6). A potential of 1,750,000 tons of sulfur per year and an estimated 2000 tons of alumina per day are recoverable just from 14 copper mines included in the study. 

Methane sulfonic acid is used as an electrolyte for electroplating of tin onto sheet steel, for plating tin and tin/lead alloy onto nickel or other base metal substrates in the manufacture of lead frames and bump-contacts for microelectronic devices.It can also be used for copper deposition during the manufacture of microprocessors. Other alkanesulfonic acids have also found use in electroplating applications. Disodium methanedisulfonate and other alkanedisulfonate salts are used in chrome plating.As discussed previously, several processes for the recovery and recycle of alkanesulfonic acids from spent metal plating baths have been described. 

Among metals, consumption of Cu is exceeded only by steel and Al. The recovery of Cu from scrap metal is an essential part of copper-based industries, e.g. in 2005 in the US, recycled metal constituted of the Cu supply. World-... 

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