Copper extraction chemistry

The diluent in a sol van t extraction system does not serve simply as an inert carrier for the extractant and its metal compounds, it has been found repeatedly that the choice of diluent can affect significantly the perfomience of various extractants, presumably through both chemical and physical interactions with the solute species. For example. Mutiny and Bouboulis9 reported the effects of systematically varying the aromatic content of cha diluent on a copper extraction process, and Akiba aud F reiser5 demonstrated solvent effects on system chemistry. Ritcey and Ashbrook10 review the various solvent properties that influence extractant performance. 

The extraction of copper from acid leachates has been studied most extensively, especially by Cahn et al. and Igawa et al. The chemistry of copper extraction is illustrated below ... 

LIX 64N has been used to separate nickel ions as well as copper. The chemistry of extraction in the two cases is the same [see Eqs. (19.4-3) and (19.4-4)]. However, data on transport tiirougb supported liquid membranes suggest that the copper flux across the membrane is four times that of nickd and selective extraction of copper can be achiev. The compound di-(2-ethylhexyl) phoqrhoric acid also has been proposed for the extraction of nickel II using liquid membranes. ... 

Arsonium salts have found considerable use in analytical chemistry. One such use involves the extraction of a metal complex in aqueous solution with tetraphenyiarsonium chloride in an organic solvent. Titanium(IV) thiocyanate [35787-79-2] (157) and copper(II) thiocyanate [15192-76-4] (158) in hydrochloric acid solution have been extracted using tetraphenyiarsonium chloride in chloroform solution in this manner, and the Ti(IV) and Cu(II) thiocyanates deterrnined spectrophotometricaHy. Cobalt, palladium, tungsten, niobium, and molybdenum have been deterrnined in a similar manner. In addition to their use for the deterrnination of metals, anions such as perchlorate and perrhenate have been deterrnined as arsonium salts. Tetraphenyiarsonium permanganate is the only known insoluble salt of this anion. 

The platinum metals are valuable by-products from the extraction of common metals such as copper and nickel. The anodic residue that results from copper refining is a particularly important source. The chemistry involved in their purification is too complicated to describe here, except to note that the final reduction step involves reaction of molecular hydrogen with metal halide complexes. 

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. 

The development of hydrometallurgical processes for the extraction of copper from ores and concentrates has been a widespread major research activity for the past 20 years. Coordination chemistry has been applied in many ingenious ways in attempts to devise novel and energy-efficient processes to replace the conventional smelting—electrorefining approach. Several of these processes... 

Although the study of materials chemistry is a relatively new entry in both undergraduate and graduate curricula, it has always been an important part of chemistry. An interesting timeline of materials developments from Prehistoric times to the present may be found in Appendix A. By most accounts. Neolithic man (10,000-300 B.C.) was the first to realize that certain materials such as limestone, wood, shells, and clay were most easily shaped into materials used as utensils, tools, and weaponry. Applications for metallic materials date back to the Chalcolithic Age (4,000-1,500 B.C.), where copper was used for a variety of ornamental, functional, and protective applications. This civilization was the first to realize fundamental properties of metals, such as malleability and thermal conductivity. More importantly, Chalcolithic man was the first to practice top-down materials synthesis (see later), as they developed techniques to extract copper from oxide ores such as malachite, for subsequent use in various applications. 

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