<p>To investigate the feasibility of applying electrolytic manganese residue (EMR) in cementitious materials, an approach combining high-temperature activation (200, 400, 600, 800 and 1 000 °C) and mechanical grinding (5 min) was adopted to stimulate the EMR activity. We analyzed the effect of calcination temperature on the performance of EMR with the aid of X-ray diffraction (XRD), specific surface area test (BET) and pozzolanic activity test, explored the effects of EMR activation temperature and content (0%, 10%, 15% and 20%) on the setting time, soundness, drying shrinkage, compressive strength, hydration products of cement-EMR mixed slurry, and assessed the effect of cement hydration on the solidification of harmful NH₄⁺-N and Mn²⁺ in EMR. The research results show that high-temperature calcination can lead to the dehydration, decomposition or crystalline phase transformation of the inert sulfate and other substances in EMR, mechanical grinding can improve its particle distribution, and the coupling of the two can effectively enhance the pozzolanic activity of EMR. The decomposition and recombination of aluminum-silica phase at 800 C optimized the EMR activity, and the strength activity index (SAI) of EMR at 28 d reached up to 95%. Appropriate calcination temperature and EMR content can ensure the workability of the mixed slurry, and when the EMR calcination temperature was 400 – 1 000 °C, the setting time of the mixed slurry under different EMR contents satisfied the specification requirements. When the calcination temperature was 600 – 1 000 °C and EMR content was less than 20%, the soundness of the mixed slurry satisfied the specification requirements. The compressive strength of the mixed slurry increased and then decreased with the increase of activated EMR content, when the EMR content was 10%, the compressive strength of all specimens was optimal and higher than the baseline group; when the activation temperature was 800 °C, the C-S-H gel in the mixed slurry interconnected with the rod-like Aft and blocked Ca(OH)₂, and the 28 d compressive strength was increased by 14% compared with that of the baseline group. The solidification rate of Mn²⁺ in EMR by cement hydration was higher than 99%, and that of NH₄⁺-N was higher than 97%. The leaching toxicity after solidification can meet the requirements of toxic emission. The results of the study may provide theoretical basis for the feasibility of the application of EMR in cementitious materials.</p>