Abstract: In order to find out the burning loss and activity of dolomite after calcination of a dolomite mine in Henan，the calcination test was carried out to study the different differences of dolomite at different calcination temperatures and time. The decomposition temperature of dolomite was obtained by differential thermal analysis. When the calcination temperature and time of dolomite were 1 100 ℃ and 90 min，the ignition loss and activity after calcination reached the maximum，the ignition loss was 47.36%，and the activ⁃ ity was 225.6 mL. The chemical composition of the calcined product was mainly MgO and CaO，and the content was 40.50% and 55.68%，respectively. The material composition is mainly limestone and peri⁃ clase，and the content is 54% and 41% respectively. The results show that the suitable calcination tempera⁃ ture of dolomite is 1 100~1 150 ℃，and the suitable time is 30~90 min. The main components are limestone and periclase.

Key words: dolomit, calcination system, calcination temperature, reactivity