Bauxite residues,a large volume solid waste,are in urgent need of effective disposal and management.Especially,strategies to alleviate the high alkalinity of bauxite residue remain a big challenge.Here,we developed a synergistic pyrolysis to neutralize the alkalinity of bauxite residue and upgrade the structure of biomass simultaneously.By cooperating the catalytic feature from bauxite residue,rice straw,a cellulose-enriched biomass,could prefer to produce acidic components under a hypothermal pyrolysis temperature (below 250 ℃) and partial oxygen-contained atmosphere as evidenced by the synchronous TGA-FTIR analysis.In return,these in-situ produced acidic components neutralized the bauxite residue profoundly (pH decreased from 11.5 to 7.2) to obtain a neutral product with long-term water leaching stability.Also,a higher pyrolysis temperature led to neutral biochar-based products with well-defined carbonization characteristics.Thus,the biomass-driven pyrolysis strategy provides a potential to dispose the alkalinity issue of bauxite residue and further opportunities for the sustainable reuse and continuing management of bauxite residue.