Abstract: In order to achieve the goal of temperature control of 1.5℃ proposed by IPCC, mineral sequestration has been widely studied due to its long-term stability and safety. This paper selects magnesium-based tailings as the raw material for further research. Magnesium-based tailings, as waste of potassium salt production in the salt lake, have been plaguing the local industry due to limited application. If used as a raw material for sequestration of carbon dioxide, it will have great storage potential. In this experiment, two core processes of CO₂ absorption and carbonate precipitation were studied to investigate the reaction rate and path of CO₂ in MgCl₂-NH₃-NH₄Cl system under four different reaction temperatures (0, 20, 50, 80℃ ). It was found that the kinetic reaction rate constant of CO₂ at the gas-liquid interface is an important factor limiting CO₂ mass transfer. Modeling temperature and reaction rate constant and their relationship was found to  k_app=1.4857×10⁵ exp(-1974/T) . In addition, for the CO₂ absorption rate and carbon precipitation rate of the magnesium carbonate precipitation process, the optimal experimental temperature conditions are proposed, indicating the potential for large-scale application.

Key words: carbon dioxide, mineral sequestration, absorption rate, temperature