This study proposed a novel process of killing three birds with one stone for valorizing titanium gypsum, which benefits the reduction of CO2 emissions in cement industries, the production of vaterite CaCO3 as potential feedstock of construction materials, and the fabrication of adsorbent for wastewater treatment. The indirect carbonation process of titanium gypsum was optimized considering the extractant type, extractant concentration, liquid-solid ratio, and temperature. Under the optimal conditions of CH3COONH4 6 M, liquid-solid ratio 15, and temperature 60 °C, the weight loss of titanium gypsum reached 75.01 %. The carbonation efficiency was 97.28 %, and the vaterite CaCO3 was produced. The co-carbonization of leaching residue and waste peanut shell produced biochar-based adsorbent with good adsorption performance of organic pollutants. The removal rate of rhodamine B at 60 min was close to 100 %, while the adsorption capacity reached 468.26 mg/g. The adsorption mechanism was discussed based on adsorption kinetics, isotherms, and characterizations. The economic evaluation of the proposed process clarifies the feasibility of the valorization strategy of waste titanium gypsum.