本文已被：浏览 429次 下载 332次
投稿时间：2022-11-07 修订日期：2022-11-07
投稿时间：2022-11-07 修订日期：2022-11-07
中文摘要: 粉煤灰中有价元素提取是实现粉煤灰高值化资源的有效途径。氯化法因处理速率快、产物分离操作简单、处理过程渣减量化程度大等优点而受到研究者重视，但粉煤灰中SiO2含量大，且氯化速度较其它氧化物小，影响到氯化法在粉煤灰处理中的应用。本研究采用基于第一性原理的从头计算方法，对Cl原子、Cl2和COCl化合物与C原子在β-SiO2（101）面的协同吸附行为进行了分析。分析结果表明，在无C原子存在下，Cl原子和COCl化合物可与β-SiO2（101）面发生化学吸附，而Cl2与β-SiO2（101）面的吸附键类型与其吸附方法有关。经过吸附能计算结果可知，该情况下氯化剂在β-SiO2（101）面的化学吸附趋势为Cl原子 > COCl化合物 > Cl2，Cl原子吸附于β-SiO2（101）面的吸附能为-4.80 eV。在C原子存在下，上述三种氯化剂在β-SiO2（101）面的吸附能不仅与氯化剂吸附方式有关，还与C原子出现位点有关。总体而言，该情况下氯化剂在β-SiO2（101）面的化学吸附趋势为Cl原子 > COCl化合物 > Cl2，当C原子出现在OA位置时，Cl原子在β-SiO2（101）面的吸附能最小，为-9.74 eV。其电子分布和态密度分析结果表明，C原子和Cl原子在β-SiO2（101）面的协同吸附作用，有利于电子向Cl原子转移，同时促使β-SiO2（101）面整体稳定性下降，有助于后续晶面吸附结构的解离或氯化剂的吸附。
Abstract:The extraction of valuable elements from fly ash is an effective way to realize the high valuably utilization of fly ash. Increasing attention has been paid to the chlorination method due to its high reaction rate, simply products separation operation and high reducing quantity of residue. However, SiO2, that has a smaller chlorination rate than other oxides in fly ash, has a large mass in fly ash. It is affects the chlorination ratio of fly ash in treatment. In this study, the cooperative adsorption behavior of chlorinating agents, including Cl, Cl2 and COCl molecule and C on β-SiO2(101) surface are evaluated, based on the first principle. The results show that Cl and COCl can chemically absorbing on the β-SiO2(101) surface in the absence of C, while the absorption behavior of Cl2 on the β-SiO2(101) surface is related on its adsorption manner. The results of the adsorption energy reveal that the chemical adsorbing trend of the chlorinating agents in the absence of C on the β-SiO2(101) surface is Cl > COCl > Cl2. The absorption energy of Cl on the β-SiO2(101) surface is -4.80 eV. The cooperative absorption behaviors of chlorinating agents and C on the β-SiO2(101) surface are also discussed. It reveals that the cooperative absorption behaviors is not only related to the adsorbing manner of chlorinating agents, but also related to the C atom absorption site on the β-SiO2(101) surface. In general, the cooperative absorption energy of chlorinating agents and C on the β-SiO2(101) surface is Cl > COCl > Cl2. The cooperative absorption has a minimum value, -9.74 eV, when Cl absorbs on β-SiO2(101) surface and C atom absorbs at OA atom. The analysis of electron distribution and density of states demonstrate that the electron it is conducive to the electron transfer from β-SiO2(101) surface to Cl atom when Cl and C cooperative absorb on the surface. In the meanwhile, the absorption behavior will lead to the decrease of β-SiO2(101) surface stability, which is conducive to the subsequent dissociation of adsorption structure or the adsorption of chlorination agent.
文章编号：20221107002 中图分类号： 文献标志码：
基金项目:国家重点研发计划(2018YFC1903806)；北京市自然科学基金(2212021)；国家自然科学基金(52004262)*通信作者：陈思明,男,湖南湘潭人,副研究员,主要从事固废资源氯化处理技术开发并产业化应用;E-mail : smchen@ipe.ac.cn ,2*,段东平1,2,李燕江1,2,刘艳1,2,胡凯1,2,周娥1,2,董昌吉3,李鹏业3
引用文本：
陈思明,段东平,李燕江,刘艳,胡凯,周娥,董昌吉,李鹏业.碳热氯化过程中氯化剂在SiO2(101)面吸附反应模拟[J].矿冶,2023,32(2):.
陈思明,段东平,李燕江,刘艳,胡凯,周娥,董昌吉,李鹏业.碳热氯化过程中氯化剂在SiO2(101)面吸附反应模拟[J].矿冶,2023,32(2):.
关注微信公众号