不同粒度煤气化粗渣物化特性及战略性金属赋存形态研究OA

Gasification coarse slag is a primary solid waste generated during the coal gasification process.During gasification,coarse slag residues particles of different particle sizes exhibit significant differences in heat transfer efficiency,residence time,and cooling rate,resulting in distinct physical and chemical properties and occurrence forms of strategic metals.Investigating the physicochemical structural characteristics of gasification coarse slag and the correlation between the occurrence modes of strategic metals and particle size distribution can provide a theoretical basis for achieving graded resource utilization of the slag and targeted recovery of strategic metals.This study focuses on Shendong coal gasification coarse slag(CGCS)as the research subject.Through wet sieving,the CGCS was fractionated into five particle-size fractions.The physicochemical characteristics of these fractions were systematically characterized using scanning electron microscopy(SEM),nitrogen adsorption,X-ray diffraction(XRD),and Raman spectroscopy.Additionally,the occurrence modes and distribution patterns of strategic metals(Li,Ga,Ge,and In)in different particle-size fractions were investigated through sequential chemical extraction.The results demonstrate that the medium-fine fraction of CGCS(75 μm‒120 μm)exhibits a lower degree of gasification,the highest residual carbon content,and a higher graphitization degree of residual carbon,along with a higher specific surface area and the most developed pore structure.In contrast,these characteristics show an inverse trend in the coarse fraction(>425 μm).Statistical analysis reveals significant positive correlations between the content of strategic metals(Li,Ga,Ge,and In)and major elements(Si and Al),while negative correlations are observed with Fe,Ti,S,and Ca contents.With decreasing particle size,the occurrence forms of these strategic metals in CGCS progressively shift from aluminosilicate-bound phases toward more mobile fractions,including metal oxide phases and organic/sulfate-associated species.