活性炭辅助微波协同活化煤矸石过程

Microwave Activation of Coal Gangue with Synergistic Granular Activated Carbon

选择颗粒活性炭作为微波场中煤矸石活化的传热介质,将70目活性炭与10.00 g 200目煤矸粉以2.0:1的质量配比充分混合后在800 W微波功率下活化20 min,铝铁浸出率可达750℃焙烧2 h方法的1.714倍。在680 W功率下,活性炭的微波附着速率常数ka为0.334 min-1,微波脱附速率常数k'a为0.050 min-1,煤矸粉的微波附着速率常数kb为0.262 min-1。在528,680和800 W三个功率水平下,升温动力学模型的计算值与实验值吻合很好,且各动力学参数与颗粒活性炭及煤矸粉的粒径均无关。在以上三种功率下,活性炭经两次循环后活性炭极限温升ΔTA max比新炭分别提高33,16和7 K,表明该过程为协同活化。得铝铁相对浸出率α与煤矸粉温升ΔTB成正比,比例系数为1.246×10-3K-1,得到了以α为目标的动力学方程。

Granular activated carbon （GAC） was selected as the heat transfer medium in microwave-activation of coal gangue. For the mixture of 70 mesh GAC and 10.00 g 200 mesh gangue powders with the mass ratio of 2.0：1, after it was activated for 20 min under 800 W microwave power, the A1/Fe relative leaching rate was 1.714 times of that being calcined for 2 h at 750 ℃. Under 680 W microwave power, the microwave adsorption rate constant k,, of GAC was measured as 0.334 min1, the microwave resorption rate constant k＂ of GAC was measured as 0.050 min＂1. and the microwave adsorption rate constant kh of gangue powder was measured as 0.262 min. A rising temperature kinetic model fit well with the experimental data for microwave power of 528 W, 680 W and 800 W, with a correlation coefficient more than 0.999. Moreover, the particle size of GAC and gangue powder did not affect the kinetics. Compared with fresh GAC, after two cycles under above three microwave powers, the maximum temperature rise ATAmaof GAC was up 33 K, 16 K and 7 K, respectively, therefore, the process was proved to be the synergistic activation. The A1/Fe relative leaching rate a was proportional to the temperature rise ATB of the gangue powder, and the coefficient was 1.246 10-3 Kl. A kinetics aiming at the A1/Fe relative leaching rate a was finally established.