Flotation test work – from bench scale to modern pilot plant

The flotation test work can be performed in the bench scale and pilot scale. The bench scale test is performed using a single laboratory cell unit, which is a few liters in volume. In the laboratory cell unit, a batch of ore is floated for a certain time and during the test, froth is scraped either manually of automatically from the cell with a froth scraper.

Due to the froth scraping and the test being batch test by nature, it does not fully represent the performance of industrial scale flotation process, which is a continuous process where the froth recovery takes place with froth overflow, instead of scraping.

The pilot plant is a miniature of the real industrial scale flotation circuit, including the different flotation steps and recirculation loads. The pilot plant arrangement is always configured case by case depending on the flotation behavior of the ore and the quality requirements of the concentrate. Therefore, the pilot flotation equipment must provide a high level of flexibility to conform the flowsheet requirements. When done properly, the pilot test can significantly increase the test work accuracy, setting a more reliable basis for the industrial scale process design and equipment selection.

Towards modern pilot flotation plant

Traditionally, the pilot cells are operated and controlled manually with a very low level of instrumentation. This means a lot of manual work sensitive to human errors, slow reaction time to changing process conditions and lack of data collection from the process. This is pretty much opposite to what modern industrial scale flotation plants are nowadays with very high level of instrumentation and sophisticated automated controls for process optimization.

The new pilot cells are taking the pilot plants to a whole new level with high level of instrumentation and automated process control. The cells can be connected to a centralized pilot plant control system to control and monitor air feed, slurry level, reagent dosage, or for example rotor rotation speed - thanks to the integrated frequency converter. Several of these controls can also be performed via the integrated local user interface.

The cells are constructed of durable stainless steel and all the other material selections are done by keeping in mind the tough and variating process conditions. The cells are available in several different sizes from 0.025 m3 to 0.5 m3 and equipped with the state-of-the-art FloatForce® mixing mechanism similarly to well-known Metso Outotec TankCell® and OK-Cell industrial scale flotation cells. In addition to the high level basic instrumentation, the new pilot cells can be equipped with additional sensors for pH-, density- and slurry volumetric flowrate measurement.

Read more

Article: Utilizing plant simulation to design and optimize flotation processes

Press release: Metso Outotec delivers flotation technology to GTK’s pilot plant

Video: GTK Mintec mineral processing pilot plant in Finland