Copper extractants modern

Cupertino, D. C. Charlton, M. H. Buttar, D. Swart, R. M. Maes, C. J. A study of copper/iron separation in modern solvent extraction plants. Proceedings of the COPPER 99-COBRE 99 International Conference, 4th, Phoenix, Oct. 10-13, 1999, 4, 263-276. 

Copper. In the presence of sulfur dioxide, copper-protein cloudiness may develop in white wines. Only small amounts of copper (about 0.3 to 0.5 mg/liter) cause cloudiness. Widespread use of stainless steel in modern wineries has reduced copper pickup, but many wineries routinely test their wines for copper. Atomic absorption spectrophotometry is the method of choice (51) although reducing sugars and ethanol interfere, and correction tables must be used (107). To reduce this interference, chelating and extracting with ketone is recommended (108). Lacking this equipment colorimetric procedures can be used, especially with di-ethyldithiocarbamate (3, 4, 6, 9,10, 22,109). Neutron activation analysis has been used for determining copper in musts (110). 

In order to ascertain whether or not copper is present in an ore miners will drop a little nitric acid on the mass and, after a while, dip a feather into the acid and draw it over the polished blade of a knife. The presence or absence of copper is immediately indicated. Many modern wet processes for the recovery or extraction of opper from waste products or ores are based on this principle. 

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