灼烧处理对纤蛇纹石反应活性的影响

Impact of Heat-pretreatment on the Reactivity between Ammonium Chloride and Chrysotile

使用可循环的NH4Cl溶液作为中间媒介获取Mg2+用于CO2矿物封存是一种新兴工艺,但是纤蛇纹石在NH4Cl溶液中较低的Mg2+浸出率却是这项工艺发展的瓶颈。针对这一问题,本文采用灼烧处理对纤蛇纹石进行改性。结果表明,灼烧处理可以有效改变纤蛇纹石中Mg2+反应活性。在600℃灼烧后,所得产物与NH4Cl反应的转化率达到55.64%,比灼烧前提高了约43%。600℃灼烧处理脱除了纤蛇纹石外羟基,增大了矿物的反应表面积和具反应活性的Mg2+的量,促进了其与NH4Cl的反应;脱除内羟基后,具反应活性Mg2+减少,与NH4Cl反应的转化率降低。

Using recyclable NH4Cl （ammonium chloride） as medium of CO2 mineral sequestration has become an emerging technology, while the low ammonium chloride leaching rate of chrysotile turn into a bottleneck restricting the development of this process. To solve the problem, this study carried on heat-pretreatment to modify the property of chryattile. Results show that heat- pretreatment can efficiently increase the reactivity of Mg2＋ leached from chryostile. After heated at 600℃, the leaching effuciency of chryostile reacted with NHgCl can reach to 55.64%, increasing about 43%, compared to reaction without heating. Heat- pretreatment at 600℃ can remove the outer hydroxyl group in the layers of chryostile, and greatly increase the reactive surface area of minerals and reactive mg2＋ it concentration, leading to the improvement of reaction rate. But if the roasting temperature was increased above 600℃, the leaching efficiency of chryostile dropped again since the reactive Mg2＋ ot content decreases after removing inner hydroxyl group in the layers of chryostile.