The crucial role of flotation in mineral processing
Flotation has been a cornerstone of modern mineral processing since the early 20th Century. The first patent for froth flotation was granted in 1905 to the Elmore brothers, Francis Edward and Alexander, who used a mixture of oil and air to separate sulphide ores. By the 1920s, froth flotation had become the dominant mineral separation method as larger and more efficient cells replaced earlier gravity-based jigs and shaking tables. Subsequent decades saw the introduction of reagents such as frothers and collectors, allowing improved recovery and selectivity.
Flotation works by passing air through a mineral slurry via a rotating rotor-stator. This creates bubbles that attach to hydrophilic mineral particles. Bubble-attached particles float to the froth zone at the top of the tank, where they are removed. Non-floated particles are rejected as waste. There are two main types of flotation. A forced-flotation cell uses an external air blower to introduce air into the slurry through a hollow shaft and holes in the rotor. In contrast, in self-aspirating flotation, air is drawn naturally into the slurry under suction created by the rotor’s motion.
Flotation remains indispensable in mineral processing today. However, traditional flotation systems face limitations, including high energy consumption, suboptimal recovery rates of coarser and finer particles, and throughput constraints. Modern innovations from FLS, such as WEMCO II self-aspirated flotation and nextSTEP forced-air flotation, tackle these issues through optimised equipment designs. At the same time, smart flotation solutions bring the era of digital optimisation to the flotation cell. Such innovations address the industry’s growing need to process increasing ore quantities cost-effectively while reducing environmental impact.
