摘要
采用机械混合法制备电石渣/碳酸镁体系,分别从成分配比、升温速率、气氛3方面对其高温下的热分解行为与机制进行研究.结果表明,不同配比的电石渣/MgCO3体系热分解分成3个阶段,且趋势相同.随样品中Mg含量的增大,第一阶段分解温度由387℃下降到361℃,质量损失率由16.0%增加到18.0%.第二阶段分解温度基本不变,质量损失率由13.2%增加到17.1%,第三阶段分解温度和质量损失率基本不变,形成稳定的金属氧化物.随着升温速率的增大,电石渣/MgCO3体系的热失重曲线逐渐向高温方向移动,其表观活化能随Mg含量的增大而增加.在CO2气氛下电石渣/MgCO3体系的质量先上升后下降,MgCO3分解逸出的CO2会被同一反应温度区间内的Ca(OH)2吸收.制备得到的电石渣/碳酸镁体系具有更发达的孔隙结构,吸附剂表面Ca和Mg分散均匀,有效提高了电石渣/MgCO3体系的抗烧结特性.该研究揭示了电石渣/MgCO3热分解过程中的反应机理,为制备具有较强CO2捕获能力和较强循环稳定性的电石渣吸附剂提供理论支持.
Abstract
A carbide slag/magnesium carbonate system was synthesized by mechanical mixing method.Thermal decomposi-tion behavior and mechanism under high temperature conditions were studied from three aspects of component ratio,heat-ing rate,and pyrolysis atmosphere.The results indicated that the thermal decomposition of this carbide slag/MgCO3 system with different ratios could be divided into three stages and displayed similar trends.As the amount of magnesium in the samples increased,the decomposition temperature of the samples in the first stage was dropped from 387℃to 361℃,while the weight loss rate was increased from 16.0%to 18.0%.The decomposition temperature of the samples in the second stage maintained steady with the weight loss rate increasing from 13.2%to 17.1%.The changes in the third stage of the decompo-sition temperature and weight loss rate of the samples were minimal which could attribute to the formation of stable metal ox-ides.The thermogravimetric curve of the carbide slag/MgCO3 system gradually shifted towards higher temperatures with the increasing heating rate,and its apparent activation energy was increased with the magnitude of magnesium.The weight of the carbide slag/MgCO3 system displayed the tendency of firstly increased and then decreased under CO2 atmosphere.CO2 re-leased from the decomposition of MgCO3 was absorbed by Ca(OH)2 within the same reaction temperature range.The pre-pared carbide slag/magnesium carbonate agent system exhibited a more abundant porous structure with Ca and Mg elements dispersed uniformly on the adsorbent surface,which effectively enhanced the anti-sintering properties of the carbide slag/MgCO3 system.The reaction mechanism during the thermal decomposition process of the carbide slag/MgCO3 system was re-vealed that provided theoretical support for the preparation of calcium carbide slag adsorbents with strong CO2 capture ca-pacity and cycling stability.
基金项目
内蒙古自治区自然科学基金资助项目(2023LHMS05001)
内蒙古自治区直属高校基本科研业务费项目(JY20240052)
内蒙古电力(集团)有限责任公司内蒙古电力科学研究院分公司项目(ZC-2023-05)
NETL
NSTL
万方数据