A new separation flowsheet for resources recovery from waste coal gasification fine slag black water and its benefits analysis

The gasification fine slag black water (GFSBW) is a kind of slurry including fine gasification fine slag particles produced in the coal gasification process and ineffective disposal process causes environmental pollution and resources waste. The aim of this study is to recover combustible matters, high silica-aluminum minerals and water resources via reprocessing GFSBW by innovative separation process of “flotation-agitator-ceramic membrane vacuum (CMV) dewatering”. The physicochemical properties of samples are characterized and at least 6 kinds of carbon-ash occurrence modes of gasification fine slag were found. The flotation process could be a useful method to separate residual carbon and tailing ash. The dewatering processes of flotation slurries are then achieved by the ceramic membrane vacuum filtration, followed by dewatering combustible matters, high silica-aluminum minerals and industrial-water-grade filtrate will be recovered. It is worth noting that the components separation of GFS eliminates their synergistic water holding effect and the average dewatering effect after flotation is improved by 11.67%, and the fixed carbon content of combustible matters is elevated from 22.74% to 44.64%, while the tailing ash including high silica-aluminum minerals is purified to 97.25%. A novel flotation-agitator-ceramic membrane vacuum (CMV) dewatering flowsheet is developed, and useful resources could be recovered to realize waste comprehensive utilization. The proposed GFSBW processing flowsheet could bring 9.82 million US$ per year which is benefit.