改性白云石制备CO<sub>2</sub>吸收剂的活化条件优化
摘要
To further clarify the preparation techniques of the CO<sub>2</sub> absorbent of MgO-CaCO<sub>3</sub> using NaNO<sub>3</sub> modified dolomites, the effects of activation conditions on the activation degree of the calcium and magnesium double salts and on the CO<sub>2</sub> absorption ability of the activated absorbents were investigated using the thermogravimetric analysis. The results indicated that the weight loss of the prepared calcium and magnesium double salts was bigger during the activation, when the activation temperature was higher, the activation time was longer, and the activation atmosphere was air instead of N<sub>2</sub>. However, the CO<sub>2</sub> absorption ability of the activated absorbent was not proportional to its weight loss during the activation. The affecting mechanism of the activation conditions on the CO<sub>2</sub> absorption ability of the activated absorbent was analyzed combined the decomposition mechanism of MgCO<sub>3</sub>-CaCO<sub>3</sub> double salts, and the promoting mechanism of molten NaNO<sub>3</sub> on the diffusion of ions by providing ionic liquid channel. The too intense activation process would result in a long distance between the CaCO<sub>3</sub> grains and the MgO grains, and weaken the promoting effect of CaCO<sub>3</sub> on the CO<sub>2</sub> absorption ability of MgO-based absorbent, and then obtain the separate MgO absorbent with almost no CO<sub>2</sub> absorbent ability under high temperature.