Determination of silver in ores, concentrates, zinc process solutions, copper metal and copper-base alloys by atomic-absorption spectrophotometry after separation by extraction of the tribenzylamine-silver bromide complex.
A method for determining approximately 0.1 mug/g or more of silver in ores and concentrates and approximately 0.001 mug/ml or more of silver in zinc process solutions is described. Silver is separated from the matrix elements by chloroform extraction of the tribenzylamine-silver bromide ion-association complex from 0.08M potassium bromide-2M sulphuric acid and stripped with 9M hydrobromic acid. This solution is evaporated to dryness and organic material is destroyed with nitric and perchloric acids. Silver is determined by atomic-absorption spectrophotometry in an air-acetylene flame, at 328.1 nm, in a 10% v/v hydrochloric acid-1% v/v diethylenetriamine medium. Cadmium, bismuth and molybdenum are partly co-extracted but do not interfere. The method is also applicable to copper metal and copper-base alloys. Results obtained by this method are compared with those obtained by a fire-assay/atomic-absorption method.
Donaldson
E M
EM
Mineral Sciences Laboratories, Canada Centre for Mineral and Energy Technology, Department of Energy, Mines and Resources, Ottawa, Canada.