Xue Zhonghua, Dong Lianping, Fan Xiaoting, Ren Zhenyang, Liu Xiaodong, Fan Panpan, Fan Minqiang, Bao Weiren, Wang Jiancheng
College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China.
State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China.
ACS Omega. 2022 May 4;7(19):16484-16493. doi: 10.1021/acsomega.2c00484. eCollection 2022 May 17.
Coal gasification fine slag is a kind of solid waste with low resource utilization rate. The complex embedding of residual carbon and inorganic minerals (ash materials) is the main reason restricting the efficient resource separation and utilization of residual carbon or ash materials. Hydrophobic-hydrophilic separation (HHS) is a separation technology in which mineral particles with different surface hydrophobicity values are enriched in the water phase and oil phase under the action of mechanical stirring. The water on the surface of hydrophobic particles is replaced by the oil phase to form flocs, which are enriched in the hydrophobic liquid phase, while hydrophilic particles are dispersed into the aqueous phase. In this study, the HHS process was used to separate the carbon/ash from the fine gasification slag produced by a Shenning gasifier, Texaco gasifier, and GSP gasifier of Ningxia Coal Industry Co., Ltd. The physicochemical properties of the original sample and the residual carbon products obtained by hydrophobic-hydrophilic separation were analyzed. The results show that HHS can separate the carbon/ash in the three kinds of fine slag to varying degrees. The carbon element is enriched into the hydrophobic phase to form the concentrates, while the silicon element, oxygen element, and metal element enter the tailings. The spherical ash with different particle sizes distributed on the surface of residual carbon and the gap of the matrix is basically removed, while the ash in the carbon-ash melt is difficult to remove. The ash contents of the concentrate and tailings of fine slag of the Shenning gasifier are 22.58 and 96.28%, respectively, which reach the best ash index compared with that of the other two gasifiers. From the change of mineral surface properties after HHS, the distribution of oxygen-containing groups, benzene rings, Si-O, and clay minerals or carbonate minerals in the three kinds of fine slag residual carbon products is basically similar. Compared with the other two gasifier products, the GSP gasifier concentrate has a larger specific surface area and less ash material, more amorphous carbon structures (less graphitic), and more active sites, resulting in a stronger combustion activity.
煤气化细渣是一种资源利用率较低的固体废弃物。残余碳与无机矿物质（灰分物质）的复杂嵌布是制约残余碳或灰分物质高效资源分离与利用的主要原因。疏水-亲水分离（HHS）是一种利用机械搅拌作用，使具有不同表面疏水性值的矿物颗粒在水相和油相中富集的分离技术。疏水颗粒表面的水被油相取代形成絮体，在疏水液相中富集，而亲水颗粒则分散于水相中。本研究采用疏水-亲水分离工艺对宁夏煤业有限公司神宁气化炉、德士古气化炉和GSP气化炉产生的细气化渣进行碳/灰分离。分析了原始样品及通过疏水-亲水分离得到的残余碳产物的物理化学性质。结果表明，疏水-亲水分离能够不同程度地分离三种细渣中的碳/灰。碳元素富集进入疏水相形成精矿，而硅元素、氧元素和金属元素进入尾矿。分布在残余碳表面及基体间隙的不同粒径的球形灰分基本被去除，而碳-灰熔体中的灰分难以去除。神宁气化炉细渣精矿和尾矿的灰分含量分别为22.58%和96.28%，与其他两种气化炉相比达到了最佳的灰分指标。从疏水-亲水分离后矿物表面性质的变化来看，三种细渣残余碳产物中含氧基团、苯环、Si-O以及黏土矿物或碳酸盐矿物的分布基本相似。与其他两种气化炉产物相比，GSP气化炉精矿具有更大的比表面积和更少的灰分物质，更多的无定形碳结构（石墨化程度低）以及更多的活性位点，因而具有更强的燃烧活性。
