To investigate potassium (K) migration and to mitigate its slagging tendency during biomass gasification, the transformation mechanisms of K in biomass (sunflower stalk (SS) , Rapeseed Straw (RS) ash and the effects of aluminosilicate-rich solid wastes (coal gangue, and Pharmaceutical wastewater sludge (PWS)) were explored under a reducing atmosphere. The potassium transformation behavior and aluminosilicate structural evolution were characterized by XRD, ICP OES, Raman spectroscopy, SEM EDX, and FactSage simulations. With increasing temperature, K in SS ash, mainly existing as KCl, was gradually released into the gas phase. The addition of aluminosilicate rich wastes redirected potassium transformation toward stable potassium aluminosilicate phases, resulting in the increase of potassium content after high temperature treatment. However, at high additive dosages, K+ in silicate phases may have been partially substituted by Ca²⁺, which promoting potassium release and the formation of low melting-point akermanite. Thermodynamic analysis suggested that potassium aluminosilicate generationwas thermodynamically more favorable than potassium volatilization. This study reveals K migration and ash fusion mechanisms during biomass gasification.
 

Biomass gasification; Potassium migration; Aluminosilicate formation; Regulation