Preparation of Bio-Based Microemulsion Collector and Its Flotation Performance for Coal Slime

Cardanol polyoxyethylene ether (CPE) is a green bio-degradable surfactant. Herein, we used CPE as an emulsifier to prepare a new environmentally friendly and high-efficiency bio-based microemulsion collector (HE-BMC) for coal slime flotation. The phase behavior studies showed that the single-phase microemulsion (SPM) area proportion was the largest at the mass ratio of CPE-12 to n-pentanol of 1.2. The dilution integrity study results demonstrated that the microemulsion collector average particle size was stabilized at nearly 30 nm when the mass ratio of SACS to n-dodecane was greater than 6: 4, with water content higher than 20 %. Based on the above research, the relationship model between the microemulsion collector size and the component contents was constructed using the mixture design method. Consequently, the optimal formulation for HE-BMC was obtained and consisted of 24.75 % CPE-12, 20.62 % n-pentanol, 27.69 % n-dodecane, and 26.94 % water, with an average size of 25.83 nm. The physical properties study results elucidated that HE-BMC has good daily storage and transportation as well as better dispersibility in water. The particle size in water was 2.28 μm when the cumulative particle size distribution reached 90 %. The flotation test results revealed that the HE-BMC yielded 3.91 % more clean coal than n-dodecane while maintaining a similar clean coal ash content. However, the dosage of HE-BMC was only 41.67 % of that required for n-dodecane. Furthermore, long flame coal slime flotation utilizing HE-BMC could be achieved without the need for adding frother.