关键词: 煤气化渣, 粗渣, 水流分级, 筛分, 残炭, 密度

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