1. School of Chemical Engineering & Technology,China University of Mining and Technology,Xuzhou　 221116,China; 2. National Engineering Research Center of Coal Preparation and Purification,Xuzhou　 221116,China

为增加石英与褐煤的可浮性差异,提出了采用低温空气等离子体改性的思路。采用扫描电镜(SEM)、能谱分析(EDS)、X射线光电子能谱分析(XPS)、接触角、浮选试验研究了等离子体处理对石英表面性质、可浮性的影响。SEM结果显示改性后表面形貌变化不大,新生了1~5μm的硅酸盐矿物颗粒;XPS分析表明C—C/C—H含量逐渐降低,C—O含量逐渐增大,C O,COO含量基本不变;接触角及浮选试验结果表明处理1~5 min石英与褐煤接触角差值增大了2.5~3.2倍。单独浮选时处理后石英浮出率基本不变,褐煤浮出率显著降低。混合浮选时,采用等离子体预处理获得了精煤灰分8.32%、产率37.8%的良好指标。等离子体改性显著扩大了石英与褐煤可浮性差异,利用其抑制褐煤反浮选石英是可行的。

In this study,the feasibility of quartz reverse flotation by depressing lignite using low-temperature air plasma pre-treatment was investigated. SEM,EDS,XPS and contact angle were carried out to measure the surface property of pure quartz before and after plasma treatment. SEM detected the new product of 1-5 μm metal silicate mineral grains on the quartz surface after plasma treatment,but the surface change was little. XPS results show that the content of C—C / C—H groups decreased gradually,and the content of C—O group increased. However,the contents of C O and COO groups did not change. The contact angle and flotation test results indicate that the difference of contact angle be- tween quartz and lignite treated for 1-5 minutes increased by 2. 5-3. 2 times. The rate of quartz floatation was almost constant when treated with flotation alone,and the rate of lignite was significantly reduced. At the time of mixed flota- tion,the plasma pretreatment was used to obtain the good index of 8. 32% of concentrate ash and 37. 8% of yield. The plasma modification significantly expanded the difference between quartz and lignite,and it was feasible to inhibit the reverse flotation of lignite.

“十二五”国家科技支撑计划资助项目(2014BAB01B02)；国家自然科学基金资助项目(51704290)；江苏省自然科学基金资助项目(BK20170285)；

WANG Dapeng,XU Meng,JIN Wei,et al. Modification of quartz in a low-temperature air plasma[J]. Journal of China Coal Society,2017, 42(10):2752-2757.