碱性固废湿法碳酸化是一种矿化固定CO2的有效方式。为探究电石渣废弃物直接湿法碳酸化固定CO2的反应特性，基于高压反应釜试验装置，在常温环境下研究液固比（5～20）、碳酸化时间（0～4 h）和反应压力（0.1～1.0 MPa）对电石渣碳酸化速率和CO2固定能力的影响。结果表明，电石渣具备良好的CO2固定能力，1 h内整体碳酸化反应基本完成，CO2固定能力会随液固比和反应压力的增加而提升。反应时间4 h，最优工况（1 MPa、液固比20）下电石渣的CO2固定量达9.26 mmol/g，而在0.1 MPa、液固比5时，电石渣的CO2固定量仅3.58 mmol/g。电子扫描显微镜和热重分析证明了电石渣碳酸化反应后生成了大量CaCO3，且碳酸化产物的粒径显著减小。因此，在反应釜中常温加压条件下，电石渣直接液相碳酸化即具备较好的CO2固定能力和较高的碳酸化效率。本研究结果能为电石渣加速矿化固定CO2的技术应用提供基础理论支撑。

Direct liquid-phase carbonation of alkaline solid waste is an effective way to fix CO2. In this paper, the reaction characteristics of direct liquid phase carbonation of carbide slag waste to fix CO2 were studied. Based on a high-pressure reactor at room temperature, the effects of liquid-solid ratio (5-20), carbonation time (0-4 h) and reaction pressure (0.1-1.0 MPa) on carbonation rate and CO2 fixation capacity of carbide slag were studied. The results show that carbide slag has good CO2 fixation ability, and the whole carbonation reaction is basically completed within 1 h. The CO2 fixation ability increases with the increase of liquid-solid ratio and reaction pressure. The CO2 fixation amount of calcium carbide slag is 9.26 mmol/g under the optimal operating condition (1 MPa, liquid-solid ratio 20) for 4 h reaction time, while the CO2 fixation amount of calcium carbide slag is only 3.58 mmol/g under the condition of 0.1 MPa and liquid-solid ratio 5. It is proved by SEM and TGA that a large amount of CaCO3 is formed after carbonation of carbide slag, and the particle size of the carbonated product is significantly reduced. Therefore, the direct liquid phase carbonation of carbide slag has better CO2 fixation ability and higher carbonation efficiency under the condition of normal temperature and pressure in the reactor. The results of this study can provide basic theoretical support for the application of calcium carbide slag accelerated mineralization to fix CO2.

0 引言

1 试验

   1.1 直接液相碳酸化试验

   1.2 数据分析方法

2 结果与讨论

   2.1 原样分析

   2.2 CO2压力对碳酸化效率的影响

   2.3 液固比对碳酸化效率的影响

   2.4 碳酸化产物表征分析

   2.5 碳酸化机理分析

3 结论