Base metal ores and their metallurgical treatment

In early days of mining ores could be enriched only by hand picking and gravity concentration. These simple techniques limited the ores that could be used by mankind to a few types. Those were all fairly coarse and easy to separate from barren gangue. Most of the base metal sulphides mined today would have been useless because of their fine and complex nature. Only after the invention of a new technology called flotation the development of a new type of base metal deposits became possible.

Flotation works well with most sulphide ores and is definitely the most widespread recovery method for base metal ores. Of course it is no remedy for all types of ores. There is a series of oxides and sulphates that possess high metal contents. In deposits where they represent the main ore other recovery methods may have to be applied (many important porphyry copper deposits e.g. contain such minerals as Antlerite or Brochantite which are best recovered by leaching and precipitation with scrap iron).

In recent years hydrometallurgy has gained a growing importance in mineral beneficiation. Hydrometallurgical methods permit the utilization of low grade or mineralogically complex material whose conventional treatment would be uneconomic or technically difficult.

Flotation

Flotation is a technology for the separation of fine particles of different materials. It is widely used in a variety of fields such as recycling of plastics, paper, etc. At present flotation is the only process available that permits the production of ore concentrates from those fine grained base metal sulphides mined today at the majority of deposits.