碳热氯化过程中氯化剂在SiO_(2)(101)面吸附模拟  

Absorption of chlorinating agents and C on SiO_(2)(101)surface based on the first principles calculation

作　　者：陈思明[1,2] 段东平 李燕江[1,2] 刘艳 胡凯 周娥[1,2] 董昌吉 李鹏业 CHEN Si-ming;DUAN Dong-ping;LI Yan-jiang;LIU Yan;HU Kai;ZHOU E;DONG Chang-ji;LI Peng-ye(National Engineering Research Center of Green Recycling for Strategic Metal Resources,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;School of Chemical Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;Qinghai Salt Lake Industry Co.Ltd.,Golmud 816000,Qinghai,China;Qinghai Salt Lake Magnesium Industry Co.Ltd.,Golmud 816000,Qinghai,China)

机构地区：[1]中国科学院过程工程研究所战略金属资源绿色循环利用国家工程研究中心,北京100190 [2]中国科学院大学化学工程学院,北京100049 [3]青海盐湖工业股份有限公司,青海格尔木816000 [4]青海盐湖镁业有限公司,青海格尔木816000

出　　处：《矿冶》2023年第2期92-101,124,共11页Mining And Metallurgy

基　　金：国家重点研发计划项目(2018YFC1903806);北京市自然科学基金资助项目(2212021);国家自然科学基金资助项目(52004262)。

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SiO_(2)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。基于第一性原理的从头计算方法,对Cl原子、Cl_(2)和COCl化合物与C原子在β-SiO_(2)(101)面的协同吸附行为进行了分析。结果表明,在无C原子存在时,Cl原子和COCl化合物可与β-SiO_(2)(101)面发生化学吸附,而Cl2与β-SiO_(2)(101)面的吸附键类型与其吸附方法有关。吸附能计算结果显示,无C原子存在情况下,氯化剂在β-SiO_(2)(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-SiO_(2)(101)面的吸附能为-4.80 eV。在C原子存在时,上述三种氯化剂在β-SiO_(2)(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,C原子存在情况下,氯化剂在β-SiO_(2)(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-SiO_(2)(101)面的吸附能最小,为-9.74 eV。电子分布和态密度分析结果表明,C原子和Cl原子在β-SiO_(2)(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-SiO_(2)(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。The extraction of valuable elements from fly ash is an effective way to realize the high valuable utilization of fly ash.Increasing attention has been paid to the chlorination method due to its high reaction rate,simple products separation operation and high reducing quantity of residue.However,SiO_(2),which has a smaller chlorination rate than other oxides in fly ash,has a large mass in fly ash.It affects the chlorination ratio of fly ash in treatment.In this study,the cooperative adsorption behavior of chlorinating agents,including Cl,Cl_(2)and COCl molecule and C onβ-SiO_(2)(101)surface are evaluated based on the first principle.The results show that Cl and COCl can be chemically absorbed on theβ-SiO_(2)(101)surface in the absence of C,while the absorption behavior of Cl_(2)on theβ-SiO_(2)(101)surface is related to 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 theβ-SiO_(2)(101)surface is Cl>COCl>Cl_(2).The absorption energy of Cl on theβ-SiO_(2)(101)surface is-4.80 eV.The cooperative absorption behaviors of chlorinating agents and C on theβ-SiO_(2)(101)surface are also discussed.It reveals that the cooperative absorption behaviors are not only related to the adsorbing manner of chlorinating agents,but also related to the C atom absorption site on theβ-SiO_(2)(101)surface.In general,the cooperative absorption energy of chlorinating agents and C on theβ-SiO_(2)(101)surface is Cl>COCl>Cl_(2).The cooperative absorption has a minimum value of-9.74 eV when Cl absorbs onβ-SiO_(2)(101)surface and C atom absorbs at O A atom.The analysis of electron distribution and density of states demonstrate that the electron is conducive to the electron transfering fromβ-SiO_(2)(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 ofβ-SiO_(2)(101)surface stability,which is conducive to the subsequent dissociation of adsorption structur

关 键 词：二氧化硅 碳热氯化 吸附 第一性原理 β-SiO_(2)(101)面 

分 类 号：TF1[冶金工程—冶金物理化学] TF8[理学—物理化学] TF9[理学—化学] O641O647.3