황화광의 컬럼부선에서 가스분산특성 및 바이어스의 제어

Abstract

Abstract

Control of gas dispersion characteristics and bias in column flotation of sulfide minerals

By An, Ki-Seon Advisor : Prof. Park, Chul-Hyun Dept. of Energy & Resource Engineering Graduate School, Chosun University

The development of a separation technique that can recover low grade ores as well as solve tailings problems is a growing necessity. Column flotation has many advantages over conventional flotation owing to its ability to effectively reduce entrainment of fine gangue minerals due to less turbulence in the pulp, having a deep froth bed and using wash water to drain back the entrained gangue. Hence, flotation column has been installed at diverse plants and extensively released in the world. The purpose of this study is to establish systematically the relationships of main parameters, and mechanisms of flotation column for improving separation efficiency of korean low grade ores. So gas dispersion characteristic such as superficial gas velocity (Jg), bubble size (db), gas holdup () and bubble surface area flux (Sb) have been investigated in gas-liquid 2 phase and then carrying rate and water bias for improving flotation efficiency of gold bearing sulfide ore have been evaluated in gas-slurry 3 phase, using flotation columns equipped with porous, cavitation and inline-mixer sparger. The gas dispersion characteristic in gas-liquid 2 phase showed that surface tension was the lowest at MIBC among different frothers and bubble size decreased as frother concentration increased. Also mean bubble size (0.613mm) was the smallest at cavitation among porous, inline mixer and cavitation spargers. Measured versus calculated bubble size (db) could satisfy ±15 ~ 20% of error ranges in the literatures. From this method the empirical relationship to control the bubble size has been developed. The results of estimation of carrying rate and water bias in 3 phase seemed that grade and recovery of Au can be improved with controlling a superficial gas rate related upstream and a wash water rate related downstream because the carrying rate increased as superficial gas rate and gas holdup increased, however the bias reversed. From the results of column flotation for improving grade of gold bearing sulfide ore, we could product the concentrate of Au 150g/t grade with 81% recovery from Au 60g/t concentrate of conventional flotation. Also, a high grade of Au 250g/t was obtained at water recovery (RW) of approximately 40% although the Au recovery was decreased to 68%. In the future work, based on the systematic approach presented in this study, we will extend it to mixing models, carrying capacity and column scale-up which can be used in process control.