Combined morphology and dissociation characteristics of carbon-ash in fine slag of entrained flow gasification

The separation of carbon-ash in coal gasification fine slag is the key to realize its efficient utilization, and it is a prerequisite to explore the combined form of carbon-ash and dissociate the two effectively. In this paper, the fine slag produced by the Siemens GSP pulverized coal gasification process in Ningdong was classified into three particle classes, which were < 0.074 mm, 0. 074~0. 250 mm and >0. 250 mm, and Raman spectroscopy, XRF and SEM were used to investigate the carbon-ash binding morphology and to study the dissociation characteristics under ultrasonic treatment and grinding treatment. The results show that the ash content of <C0. 074 mm grain level is 81. 37%, and the fine ash is fused to the dense carbon matrix in an amorphous form; the carbon content of 0. 074 ~ 0. 250 mm grain level is up to 49. 09%, and the spherical ash is filled in the pores of porous carbon; the ash content of > 0. 250 mm grain level is up to 87. 76%, and a small amount of debris carbon is attached to the spherical ash particles. Ultrasonic treatment can strip the ash particles from the porous carbon pores, which is conducive to the recovery of porous carbon from the higb carbon fraction (0. OZi^O. 250 mm), grinding treatment can achieve the full dissociation of carbon-ash from the high ash fraction (<C0. 074 mm and !> 0. 250 mm), which helps the separation and utilization of carbon-ash. The above results can provide a basis for the treatment of GSP fine slag. © 2023 China University of Mining and Technology. All rights reserved.