A brick can “eat” waste residue and absorb carbon dioxide. This magical brick has been put on the production line. On December 28, it was learned that the industry’s first “automatic production line for brick making by CO2 absorption of cement kiln flue gas” was successfully put into operation in Hubei, which was jointly developed by Huaxin Cement Co.Ltd(600801) and Hunan University.
At present, non fired autoclaved concrete lime sand brick has been widely used in the construction industry to replace the traditional fired clay solid brick. However, lime sand brick is mainly made of river sand and other raw materials by burning natural gas and other high-temperature and high-pressure steam curing. The brick making process still consumes a lot of energy and resources.
Since 2018, Li Yeqing, President of Huaxin Cement Co.Ltd(600801) and director of the technology center, has established a production line for making bricks with cement-based materials and mine waste earth rock slag without burning steam, realizing the comprehensive utilization of resources. After long-term research, the team of Professor Shi Caijun of Hunan University put forward the collaborative theory of “water regulation – gas migration – carbonization reaction”, which broke through the scientific bottleneck that carbon dioxide can not quickly enter the interior of concrete products for migration and reaction.
It is reported that after treatment, the temperature of the tail gas discharged from the cement kiln producing cement is still about 70 ℃, and the carbon dioxide concentration is 20-30%. After using the new technology, concrete bricks do not need to be steam cured at high temperature and high pressure in the production process, but directly cured with cement kiln tail gas. The raw materials for brick making react quickly with the carbon dioxide in the tail gas, that is, “carbon absorption” carbonization, and then incarnate into finished bricks.
Since the beginning of this year, the two sides have jointly designed and prepared relevant pilot production lines and obtained stable production process and technical parameters. The operation results of the automatic production line in the base of Huaxin Wuxue Industrial Park for many days show that the average compressive strength of “carbon absorbing” brick is more than 15 MPa, which meets the requirements of relevant national building materials standards. The cost and time of brick making are equivalent to those of similar products in the market. With the passage of time and the deepening of carbonization reaction, the strength of brick will continue to increase.
Energy conservation and emission reduction in the cement industry is the focus of China’s realization of the “double carbon” goal. Huaxin Cement Co.Ltd(600801) the relevant person in charge said that based on the calculation of the production line with an annual output of 100 million concrete bricks, 26000 tons of carbon dioxide can be absorbed and utilized every year. In addition, if the corresponding waste heat steam saved by canceling the high-temperature steam compression link is used for power generation, the annual power generation can reach 3.79 million kwh. The popularization and application of this achievement may become an important driving force for energy conservation and emission reduction in the building materials industry.
(Hubei Daily)
