Investigation of bivariate particle size-density classification and quality differenti-ation of coal gasification fine slag
SHI Xu
LIU Lili
CHU Mo
GU Suqian
DONG Jianfei
LIU Yanyu
Abstract：Physical separation has inherent limitations in the carbon-ash separation of coal gasification fine slag(CGFS).Strengthening fundamental research on the composition and structural properties of CGFS can enhance separation efficiency.This study investigates the particle size-density classification characteristic of typical GSP entrained-flow coal gasification fine slag.The distribution patterns of resid-ual carbon,macroscopic morphology of ash samples,micro-morphology of particles,and pore structure characteristics are systematically investigated by loss on ignition analysis,XRD mineral analysis,SEM morphology analysis,and N2 gas adsorption.The results indicate that residual carbon in the CGFS primarily exists as two forms:amorphous carbon and porous carbon.Amorphous carbon accounts for approx-imately 8-14%of the total fine slag,while porous carbon constitutes about 10%.A clear correlation is observed between the macroscopic morphology of ash samples and their mineral compositions:ash colors ranging from deep red to light red to black correspond to mineral assemblages of hematite/iron-bearing mica,anorthite/cristobalite,and wüstite,respectively.This finding provides a basis for mineral iden-tification in CGFS using visual features.Combining residual carbon content,micro-morphology,and pore structure of classified fractions,we traced the formation pathways of CGFS particles and categorized them into three typical groups:"Amorphous carbon":Primarily found in fine-sized(0.074-0.25 mm)and low-density(<1.9 g/cm3)fractions,featuring interwoven carbon-ash fusion and a moderate specific sur-face area."Porous carbon":Present in medium-coarse size fractions(0.074-0.25 mm)and medium-high density fractions(1.9-2.3 g/cm3),with well-developed internal pores and a large specific surface area."Slag particles":Predominantly in coarse size fractions(>0.25 mm)and high-density fractions(>2.5 g/cm3),possessing the smallest specific surface area.Separation and recovery methods should be tailored to the characteristics of the two residual carbon types.Recovered amorphous carbon can serve as a fuel supplement,porous carbon is suit-able for adsorption applications,and slag particles can be purposed in construction materials.
Keywords：coal gasification fine slagparticle size classificationdensity classificationcarbon-ash distributionphysical characteristics
Publication Date：2025-06-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：9( 202-210 )