The MEA (ethanolamine) chemisorption technology commonly used for the capture and purification of CO₂ gas in industrial kiln exhaust gas was introduced, including the process flow of external heating rotary kiln and vertical kiln direct capture and purification technology, main equipment and research and development process. The key points focus on comparing the application status of chemical adsorption technology and externally heated rotary kiln capture technology in the domestic cement industry. For chemical adsorption technology captures and purifies CO₂ gas, the quality of the product is poor and the production cost is higher with the payback period >10 years. Comparably, for externally heated rotary kiln capture technology, it can directly capture CO₂ produced by thermal decomposition of carbonates, the product is of high quality with low energy consumption and short payback period of only 3~4 years. A externally heated rotary kiln capture technology was applied in a cement production line, where the specifications of rotary kiln ?(2.2~2.8)m×65.8m. It can capture and purify food-grade liquid CO₂ more than 6.0×10⁴t per year, at the same time, it can produce lime powder (CaO) more than 15.3×10⁴t per year, achieving a higher payback on investment and bring a broad  promotion and application prospect.