Optimization of Froth Feed Flotation in a Conventional Column for Beneficiation of Oxidized Coal

ABSTRACT

Nowadays, the flotation of oxidized coal attracts more and more attention in China. In this study, a conventional flotation column with a novel of forth feed was used to beneficiate the oxidized coal. Exploratory experiments showed that the froth feed flotation can improve the overall combustible recovery by 22.25% with only 1.19% increase in ash content compared to conventional pulp feed flotation. Box-Behnken design (BBD), a response surface method, was used to design the flotation tests and model the effect of variables on responses. Four operating parameters, including frother concentration, superficial gas velocity, feed height and wash water rate as well as two response factors, namely ash content and combustible recovery were investigated. Meanwhile, their interactions were also described with three-dimensional response surface. Results showed that the models obtained for both ash content and combustible recovery were statistically significant. Additionally, the effect of wash water rate on ash content was found to be more significant than those of other parameters, while the combustible recovery depended more on the frother concentration. At last, the predicted optimal results were obtained within the experimental ranges, which well responded to the verification experiments.

KEYWORDS:

• Conventional flotation column
• froth feed
• oxidized coal
• box-behnken design
• optimization

Acknowledgments

This study was supported by the Fundamental Research Funds for the Central Universities (No. 2017BSCXA16) and the Postgraduate Research & Practice Innovation Program of Jiangsu Province (No. KYCX17_1517). These supports were gratefully acknowledged.