高效分离煤气化细渣中的残碳和矿物是其高值化利用的前提,但气化细渣较差的可浮性成为其浮选分离面临的难题之一。以多喷嘴对置(OMB)水煤浆气化炉的煤气化细渣为对象,研究了油类捕收剂十二烷的浮选效果和气化细渣的难浮机理。通过傅里叶红外光谱测试,发现气化细渣中芳香结构和侧链的含量相比煤炭样品的含量较少,且气化细渣表面存在较多含氧基团;X射线光电子能谱结果表明气化细渣矿物中包含多种亲水的氧化矿物。通过低温氮气吸附和压汞试验测量了气化细渣的孔隙特性,结果表明其孔隙在纳米到微米尺寸内均有大量分布;计算得到原矿样品的BET比表面积为62.03m2/g。通过粉末润湿试验和改进的Lucas-Washburn方程表征了水和十二烷对气化细渣粉末的润湿过程,试验发现气化细渣残碳相比水更易被十二烷润湿,而气化细渣尾矿更易被水润湿,但残碳和尾矿对水的润湿性差异较小;通过低场-H1核磁共振的T2反演图谱证明了油类捕收剂在孔隙中的吸附行为;油类捕收剂用量的增加和油滴粒径的减小导致孔隙药剂吸附量增加。油类捕收剂在气化细渣的浮选过程中大量进入孔隙而难以有效在残碳表面吸附,导致油类捕收剂的浮选作用效果差。

Efficient separation of residual carbon and minerals in the gasification fine slag is the premise of its high-value utilization, butthe poor floatability of the gasification fine slag has become one of the major issues on its flotation separation. In this paper, the flotationeffect and mechanism of the oil collector, dodecane, were studied by using the gasification fine slag from the opposed multi - burner(OMB) coal-water slurry gasifier. Measurements including X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FITR) were applied. It is found that the aromatic structure and side chains on the surface of the gasification fine slag are inpoor content compared to coal samples, and the existence of rich oxygen-containing groups is found. The pore structures of the gasificationfine slag are characterized by low-temperature nitrogen adsorption and mercury intrusion porosimetry measurements. The specific surfacearea of the sample is 62.03 m2 / g, and the pores are widely distributed on nano to micron scale. The liquid-powder wetting measurementand modified Lucas-Washburn equation are applied and wetting processes of gasification fine slag powder by water and dodecane are characterized. It is found that the residual carbon of gasification fine slag is more easily wetted by dodecane than that of water, while the minerals of tailings in gasification fine slag are more easily wetted by water. However, the water wettability of residual carbon and tailings are notin much difference. The adsorption behavior of oil collector in pores is justified by the T2 inversion spectrum of low-field H1 NMR. The adsorption behavior of the oil collector in pores increases with the increase of oil dosage and the decrease of oil droplet size. In fine gasification slag flotation, the oil collector is trapped in the pores in large quantities, which makes it difficult to adsorb on the surface of residue carbon, resulting in poor flotation indexes.

0 引言

1 试验材料

2 试验方法

   2.1 浮选试验

   2.2 气化细渣粉末润湿测试

   2.3 孔隙特性测试

   2.4 低场-H1核磁共振测试

   2.5 气化细渣化学组成测试

   2.6 颗粒和油滴的连续粒径分布测试

3 结果与讨论

   3.1 油类捕收剂对气化细渣浮选效果

   3.2 气化细渣形表面化学特性分析

   3.3 气化细渣粉末润湿特性

   3.4 气化细渣物理结构特性与LF-NMR结果分析

4 结论