Development of the flotation process

The beginnings of flotation technology date back to the middle of the 19th century, when it was realized that metallic minerals become preferentially wetted by oil and gangue minerals preferentially by water (HAYNES, 1860).

In 1877 BESSEL patented a process that shows already all the essentials of a modern flotation. The process had been developed for the recovery of graphite mined at the Bavarian deposit of Kropfmühl. An aqueous slurry of ground graphite ore with additives of oil or grease was heated to boiling in order to generate steam bubbles. The oily graphite flakes would then get attached to the bubbles and float to the surface where they could be recovered in a graphite rich foam.

The following development of flotation technology took place mainly in Australia and the United States of America. In the twenties of the past century KELLER made use of xanthates as collectors for sulphides. The xanthates are well defined water soluble reagents that replaced the different types of oil with their rather inconsistent properties. Xanthates still remain the most common sulphide collectors.