摘要
依据赤泥强碱性和钛白废酸呈酸性的特点,利用钛白废酸浸出赤泥脱碱。考察了搅拌速率、液固比、浸出温度和浸出时间对赤泥脱碱效果的影响,同时对赤泥脱碱过程进行了理论分析和动力学研究。结果表明:在浸出温度为70℃,搅拌速率为400 r/min,液固比为5 mL/g和反应时间为60 min的条件下,赤泥脱碱率大于99%,脱碱液pH值为6.2。利用钛白废酸浸出赤泥,赤泥脱碱率高,脱碱渣中铁品位也得到了富集,可以作为提取回收铁的二次矿产资源。钛白废酸能够显著破坏赤泥中钙霞石的晶体结构,使得结构碱几乎全部溶解,脱碱渣中出现硬石膏衍射峰,赤铁矿衍射峰也可明显分辨。该脱碱过程受未反应核收缩模型(USCM)中的内扩散关键步骤控制,线性相关系数大于0.99,脱碱反应速率常数随着温度升高而增加,表观活化能(E a)为13.12 kJ/mol。
Red mud is a tailing produced during alumina smelting of bauxite,in which the content of free alkali and structural alkali is high.Titanium white waste acid is the acid waste liquid produced during the production of titanium white powder by vanadium-titanium magnetite,which contains a large amount of sulfuric acid.According to the strong basicity of red mud and the acidity of titanium dioxide waste acid,the dealkalization from red mud by leaching with titanium white waste acid was put forward.The effect of stirring rate,liquid to solid ratio,leaching temperature and leaching time on dealkalization rate were investigated.Furthermore,the theoretical analysis and leaching kinetics of the process of red mud demineralization were studied with X-ray diffraction(XRD)and the unreacted shrinking core model(USCM).The results show that the dealkalization rate of red mud is higher than 99%and the pH value of the leaching solution is 6.2 under the conditions of leaching temperature of 70℃,stirring rate 400 r/min,liquid to solid ratio 5 mL/g and reaction time 60 min.The leaching process of red mud with titanium white waste acid not only achieves the high demineralization rate,but also enriches the iron grade in the demineralization residue,which is used as a secondary mineral resource for extraction and recovery of iron.The titanium white waste acid significantly destroies the crystal structure of cancrinite in the red mud,which results in complete dissolution of the alkali.The diffraction peaks of anhydrite and hematite are obvious in the demineralization residue according to the analysis of XRD.The leaching process is controlled by the internal diffusion by the analysis of leaching kinetics,and the linear correlation coefficient is more than 0.99.The rate constant increases with the increase of temperature and the apparent activation energy(E a)is 13.12 kJ/mol.
作者
朱晓波
王涛
李望
ZHU Xiaobo;WANG Tao;LI Wang(College of Chemistry and Chemical Engineering,Henan Polytechnic University,Jiaozuo 454000,China;State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,Wuhan University of Science and Technology,Wuhan 430081,China)
出处
《硅酸盐通报》
CAS
北大核心
2020年第12期3918-3923,共6页
Bulletin of the Chinese Ceramic Society
基金
国家自然科学基金(51904097,51804103)
河南省高等学校青年骨干教师培养计划(2019GGJS056)
国家环境保护矿冶资源利用与污染控制重点实验室开放基金(HB201905)。
关键词
脱碱
动力学
表观活化能
浸出
赤泥
钛白废酸
dealkalization
kinetics
apparent activation energy
leaching
red mud
titanium dioxide waste acid
