Abstract:

Extraction and separation of carbon from coal gasification slag is the key to realize its reduction, harmless and resource utilization. This paper takes Yulin gasification coarse slag as raw material and uses the self-developed waterflow classifier, to study the carbon extraction and separation from coarse slag combined with direct waterflow classification and first wet screening and then waterflow classifier. The results showed that the waterflow classifier can effectively achieve the separation of carbon and ash in the coarse slag. By adjusting the water flow velocity and impeller speed, the highest loss on ignition of the floating slag can reach 43.16%, and the loss on ignition of the tail slag can be as low as 6.63%. The combination of wet screening and waterflow classifier can further improve the recovery of carbon in coarse slag, especially for 0.5—0.18mm medium-size samples, the loss on ignition can be increased to 70.05%, this method was significantly higher than the direct waterflow classifier combustible recovery and comprehensive efficiency. The microstructure analysis of products obtained from coarse slag and waterflow classifier showed that the residual carbon particles were mostly irregular in shape, with rough surface and developed pores, while the ash particles were mainly molten spheres of different sizes and irregular smooth and dense particles. The density measurements showed that the higher the residual carbon content of the product, the lower its density.

Key words: coal gasification slag, coarse slag, waterflow classifier, screening, carbon residue, density

摘要：

煤气化渣提炭分质是实现其减量化、无害化、资源化利用的关键。本文以榆林地区气化粗渣为原料，利用自研的水流分级装置，研究了粗渣直接水流分级与先湿法筛分再水流分级组合的提炭分质特性。结果表明：水流分级能够高效实现粗渣中的炭灰分离，通过调整水流速和叶轮转速，所得浮渣烧失量最高可达43.16%，尾渣烧失量则低至6.63%。先湿法筛分再水流分级组合能够进一步提高粗渣中炭的回收，尤其是对于0.5~0.18mm粒级样品，其烧失量可提高至70.05%，该方法相对于直接水流分级其可燃体回收率和综合效率均显著提高。对粗渣及水流分级所得样品微观结构分析发现，残炭颗粒多呈不规则形状，表面粗糙且孔隙发达，灰颗粒则主要为大小不一的熔融球体和不规则的表面光滑且致密的颗粒。密度测定结果表明，分级样品的残炭含量越高，其密度越小。

关键词: 煤气化渣, 粗渣, 水流分级, 筛分, 残炭, 密度