关键词: 环形套筒窑, 煤粉, 氧化镁, 碳热还原

Abstract: A coal combustion annular shaft kiln（ASK） was firstly operated China′s limekiln industry successfully.The lime activity was 383.8 mL and the CaO mass fraction was 93.08%.Clean and high efficiency coal combustion was achieved in the ASK. For the MgO imbalances of the raw materials and product in the project commissioning，reduction of MgO in the kiln was validated，based on thermodynamic analysis，experimental，and data analysis.And the mass balance，reduction，and volatilization process of MgO were analyzed.The results indicated that MgO was reduced in the high Ca/Mg ratio condition.The ash contents of the kiln bottom，received flue，and combustion chamber indicated that the reduced MgO content was significantly enriched in the combustion chamber and the kiln bottom.

Key words: annular shaft kiln, coal ash, MgO, carbothermal reduction