Principle of Operation:

Flotation is a physico-chemical process for the separation of hydrophobic particles from the hydrophilic one. Flotation column is a cylindrical vessel varying in diameter 0.2m-4m and height 2m–12m. Slurry is being fed to the unit from about 1/3rd height down from the top. Particles start descending against the raising swarm of air bubbles. Air bubbles of the range 0.5-2mm diameter were dispersed by the diffusers fitted in the bottom region of the unit. The descending particles gets collided with the raising air bubbles as a result attachment of hydrophobic particles takes place. Hence attached particles are lifted to the froth zone and are ultimately recovered in the froth product. The unattached hydrophilic particles are returning back to the pulp zone and are diverted to the non-froth product stream. The unique feature of the column is addition of wash water in the froth zone. The froth washing increases quality of the froth product.

Flowsheet development for flotation circuit and flotation column performance prediction could be made through pilot scale testing. The Institute of Minerals and Materials Technology (formerly RRL), Bhubaneswar is pioneer in flotation column technology.

Tega Industries Limited (TIL) is providing solutions to the mineral sector over the past three decades. Now TIL has decided to give shape to the IMMT’s flotation column technology in terms of

• Product Design for Commercial Applications
• Product Manufacturing
• Product Marketing etc.

Benefits:

Mineral processing techniques like gravity concentration, magnetic separation, electrostatic separation, physico-chemical methods are common in beneficiating ore-minerals. Use of these techniques is largely based on techno-economics of the processing activities.

Increased market demand for the minerals has augmented mining and processing activities many-folds. Superior quality ore has been depleted over the time and to meet the present needs following alternatives are employed.

Increase in production by augmentation in the recovery at the cleaning stage of flotation.

1. Utilization of low-grade fines to extract further recovery.
2. Minimizing processing losses.

Physico-chemical method (FLOTATION) is one of the potential techniques, which give better solutions to the above alternatives 2, 3 and 4.

The development of flotation column is the most significant achievement in the area of mineral processing in the last few decades. Flotation column has a wide range of uses due to

• possibility of beneficiating fine and coarse particles
• high selectivity of separation
• simple process control
• low energy consumption
• effective flotation of heavy loaded slurries
• the absence of moving parts
• low floor space requirements
• simple design

Commercial Installations:

Few commercial installations of the IMMT’s flotation column technology are listed hereunder

• 1998- Installation of commercial flotation column for zinc cleaning at Dariba Plant HZL, Udaipur

• Installation of commercial plant to clean graphite concentrate at Ambatola for M/s Utkal Graphite Ltd., Bhubaneswar.

• Installation of commercial pneumatic cell to clean graphite ore at Harisankar Road for M/s Agnisikha Graphite Pvt. Ltd.