Improving the recovery of coarse coal particles by froth feed in the conventional flotation column

ABSTRACT

Many studies have shown that the mineral cleaning by feeding directly into the froth phase is much more efficient than feeding into the pulp phase in the flotation column, especially for the coarse particles and low-hydrophobicity particles. In this research, the weathered coal particles (0.125–2 mm), which were a combination of coarse and low-hydrophobicity properties, were used to conduct the tests in a conventional flotation column. The results indicated that the froth feed flotation had a higher combustible matter recovery of 43.67% compared with that of the pulp feed flotation of 32.07%. For the +0.5 mm size fraction, the combustible matter recovery increased by 3.33%. The fine particles could improve the froth stability in the flotation system and further improve the recovery of the coarse coal particles. Froth feed flotation with the addition of fine intermediate-hydrophobicity coal particles showed that the combustible matter recovery increased by 6.27%, while the concentrate ash decreased by 0.58% in the same operating conditions. For the +0.5 mm size fraction, the combustible matter recovery increased by 2.55%. The mechanism of fine coal particles to enhance the recovery of coarse coal particles was analyzed.

KEYWORDS:

• Coarse coal
• flotation column
• froth feed
• froth stability
• premineralization

Funding

This study was supported by the Fundamental Research Funds for the Central Universities (No. 2017BSCXA16) and Scientific Innovation Research of College Graduate in Jiangsu Province of China (No. KYCX17_1517). The support is gratefully acknowledged.