A Design of an Inclined Froth Zone in Column Flotation Device to Reduce Ash Content in Clean Coal

Abstract

A modified column flotation was designed based on the cyclonic microbubble flotation column (FCMC). In the modified flotation column, the froth zone was designed with an inclined arrangement to enhance the gravity settling of coarse middling particles, which were collected as a third product. The modified flotation column was referred as S-FCMC. In this study, the effects of process parameters (collector dosage, frother dosage, superficial gas velocity, and froth layer height) on the performance of the S-FCMC were investigated. For comparison purposes, tests were also conducted using the standard FCMC. The results showed that clean coal obtained using the S-FCMC had lower ash content than that obtained with the FCMC. Under the optimized operating conditions, the decrease in clean coal ash content and clean coal yield was 1.29% and 3.93%, respectively. The increase in tailings ash content and flotation efficiency index was 6.77% and 1.57%, respectively. About 64.55% of the settled (third) product in the inclined zone consisted of −0.045 mm sized particles and the ash content of this size fraction was 58.04%.

Keywords:

• Flotation column
• Inclined froth zone
• Gravity sedimentation
• Mechanical entrainment
• Process parameters