Recycling of copper

Gokcay, C. F. Onerci, S. (1994). Recycling of copper Dotation tailings and bioremediation of copper-laden dump sites. In Emerging Technology for Bioremediation of Metals, ed. J. L. Means R. E. Hinchee, pp. 61-73. London Lewis Publishers. 

Reker M, Lenart M, Hamsberger S. Treatment and water recycling of copper CMP slurry waste streams to achieve environmental compliance for copper and suspended solids. 8th Ed. Semiconductor Fabtech (www.fabtech.org) 2005. p 141-150. 

Copper electrorefining plays a major role in the production and recycling of copper. In the production of copper, copper-bearing sulfide concentrates are first smelted to copper matte. The molten matte is oxidized to blister copper by a Peirce-Smith converter and the blister copper is fire refined and cast to copper anodes. Blister copper contains about 99% copper and impurities such as arsenic, bismuth, iron, nickel, lead, antimony, selenium, tellurium, and precious metals. It is cast into flat anodes, most often on a rotating horizontal wheel. The mold shape includes lugs by which the anodes are... 

The equihbrium constants for these reactions are such that copper is not appreciably oxidi2ed by oxygen until most sulfur has been removed. This makes possible the production of bHster copper, 98.6—99.5% Cu that is low in both sulfur (0.02—0.1%) and oxygen (0.5—0.8%). The converter slag, however, contains a significant amount of copper and must be recycled to the smelting stage. 

Fig. 1. Recycling of the nonferrous metals ( ) lead, ( ) nickel (stainless steel), (U) copper, (S) aluminum, and ( ) 2iac from secondary sources from 1989...

Copper. Domestic mine production of copper metal in 1994 was over 1,800,000 t. Whereas U.S. copper production increased in the 1980s and 1990s, world supply declined in 1994. There are eight primary and five secondary smelters, nine electrolytic and six fire refiners, and fifteen solvent extraction—electro winning (SX—EW) plants. Almost 540,000 t/yr of old scrap copper and alloy are recycled in the United States accounting for - 24% of total U.S. consumption (11). New scrap accounted for 825,000 t of contained copper. Almost 80% of the new scrap was consumed by brass mills. The ratio of new-to-old scrap is about 60 40% representing 38% of U.S. supply. 

The output from brass mills in the United States is spHt nearly equally between copper and the alloys of copper. Copper and dilute copper alloy wrought products are melted and processed from electrically refined copper so as to maintain low impurity content. Copper alloys are commonly made from either refined copper plus elemental additions or from recycled alloy scrap. Copper alloys can be readily manufactured from remelted scrap while maintaining low levels of nonalloy impurities. A greater proportion of the copper alloys used as engineering materials are recycled than are other commercial materials. 

Alkyl chlorides. Olefins are chlorinated to alkyl chlorides in a single fluidized bed. HCl reacts with O9 over a copper chloride catalyst to form chlorine. The chlorine reacts with the olefin to form the alkyl chloride. The process developed by the Shell Development Co. uses a recycle of cat yst fines in aqueous HCl to control the temperature [Chem. Proc., 16, 42 (1953)]. 

Slides Map of World (to illustrate strategic factors) open-cast copper mine (to emphasise energy needed to extract ores) recycling of scrap metals, glass, building materials, etc. 

Reuse of waste metals generated from metal fabrication and from discarded products (scrap) can save large amounts of energy, particularly for metals that have high energy use in production, such as aluminum. The low fractions of energy used to produce metals from scrap for aluminum, certain sources of copper, and nickel show the value of recycling these metals. 

The purity ot the scrap mainly determines the fraction of energy needed to produce metal from it, and the value of recycling. Clean copper scrap need only be remelted and cast to form recycled copper if the copper is contaminated with organic materials and other metals, more complex separation processes are needed that are similar to production from ores. It is easier to remelt the steel of a car driven in Arizona compared to one rusted by the road salt in snowy areas. Scrap that is produced as a by-product of metal processing can be easily recycled, and it can be collected from relatively few locations. There has been a strong effort to educate both householders and industrial users to separate scrap and return it to waste collectors, leading to a supply of reasonably separated scrap. 

Recycled condensate often is of higher quality than FW, although in facilities with extremely long runs of steam and condensate lines, or where amine treatments are not used (e.g., some food processors, hospitals, drug manufacturers, etc.) and in high heat-flux power boiler plants, there is a tendency for the condensate to be contaminated by iron and smaller levels of copper. 

Silver, Ag, is rarely found as the metal. Most is obtained as a by-product of the refining of copper and lead, and a considerable amount is recycled through the photographic industry. Silver has a positive standard potential, and so it does not... 

The last reaction cited above as shown is very effectively catalyzed by bacterial action but is very slow chemically by recycling the spent ferrous liquors and regenerating ferric iron bacterially, the amount of iron which must be derived from pyrite oxidation is limited to that needed to make up losses from the system, principally in the uranium product stream. This is important if the slow step in the overall process is the oxidation of pyrite. The situation is different in the case of bacterial leaching of copper sulfides where all the sulfide must be attacked to obtain copper with a high efficiency. A fourth reaction which may occur is the hydrolysis of ferric sulfate in solution, thus regenerating more sulfuric acid the ferrous-ferric oxidation consumes acid. 

Subsequently, the enantioselective variant of this reaction202 was carried out in a biphasic medium (water + diethylene glycol) by using a mixture of amino acids and copper complexes (Eq. 3.54). When the reaction was carried out under an argon atmosphere, the recycling of the catalyst was also possible. The enantiomeric excess decreased slightly... 

The pollutants of concern are the same as in wet basic oxygen furnaces, but the concentration of metals (primarily lead and zinc, but also arsenic, cadmium, copper, chromium, and selenium) in wastewater is higher because of the higher percentage of scrap charged. Wastewater treatment operations are similar to those for the wet basic oxygen furnaces, including sedimentation in clarifiers or thickeners and recycle of the water.14... 

Recycling of plastic-sheathed cables Electrical cables are sent to cable recycling plants that separate the plastic and copper components. 

The Commission is working on establishing end-of-waste criteria for a number of specific recyclable materials including metal scrap of copper, aluminum and iron, waste paper, waste glass, compost, and plastics. Based on the results of two frontrunner studies, ferrous scrap and aluminum scrap in 2010, the first... 

In 1986, domestic consumption of copper in the United States was 2.14 million metric tons, and mine production was 1.14 million metric tons, mostly from mines in Arizona, New Mexico, and Michigan. The major copper deposits in the United States are of hydrothermal origin and are uniformly distributed in fractures or veins (ATSDR 1990). Copper is the major toxic component in streams impacted by active placer mines (Buhl and Hamilton 1990). About 60% of copper metal is eventually recycled in 1986, smelting of scrap copper produced an additional 0.9 million metric tons of copper. Also in 1986, 1.1 million tons of copper were imported into the United States, mostly from Canada, Chile, Peru, and Mexico (ATSDR 1990). 

---