Chapter 3 - Concentrating Copper Ores

Abstract

This chapter describes concentrating copper ores and emphasizes the sulfide minerals because they account for almost all copper concentration. Concentration of copper ores consists of isolating an ore's copper minerals into a high copper concentrate. It entails two basic steps: (1) crushing and grinding of the ore to a certain size and (2) physical separation of copper minerals from non-copper minerals. Copper sulfide ores must be concentrated before they can be economically transported and smelted. The universal technique for the concentration is froth flotation of finely-ground ore. It entails attaching fine copper sulfide mineral particles to bubbles and floating them out of a water-ore mixture. The flotation is made selective by using reagents that make the copper sulfide minerals water-repellant, while leaving the other minerals “wetted.” Copper sulfide usually recovers approximately 90% concentrate. Modern concentrators are automatically controlled to give maximum copper recovery, maximum percentage copper in concentrate, and maximum ore throughput rate at minimum cost. These maxima are obtained with the help of expert control systems. On-stream particle size and X-ray fluorescence analyses are the key components of automatic control systems.