Factors governing formation of todorokite at atmospheric pressure  

作　　者：CUI Haojie1, FENG Xionghan1, LIU Fan1, TAN Wenfeng1 & HE Jizheng2 1. College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China 2. Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 

出　　处：《Science China Earth Sciences》2005年第10期1678-1689,共12页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.40403009);by the Research Fund for the Doctoral Program of Higher Education(Grant No.2002050411).

摘　　要：Todorokite commonly occurs in Earth surface environments. The factors governing formation of todorokite, such as reaction temperature, metal ions, dissolved O2 and pH, were investigated in this paper. Results showed that the forming rate of todorokite and its crystallinity decreased with falling reaction temperature, and the effect of temperature was more significant than that of other parameters. Nature of metal ions in the interlayer of buserite precursor and the structure of the buserite precursor obviously affected buserite transformation into todorokite. Weak bonding between the metal ions and MnO6 layer of buserite was favorable to todorokite formation. The rate of todorokite formation was promoted at a lower temperature with appropriate bubbling of O2. The pH in the system slightly influenced the todorokite formation, and todorokite could also be formed in a weak alkali medium or in a slightly acidic medium. Aged buserite pre-cursor more easily form todorokite than the unaged one.Todorokite commonly occurs in Earth surface environments. The factors governing formation of todorokite, such as reaction temperature, metal ions, dissolved O2 and pH, were investigated in this paper. Results showed that the forming rate of todorokite and its crystallinity decreased with falling reaction temperature, and the effect of temperature was more significant than that of other parameters. Nature of metal ions in the interlayer of buserite precursor and the structure of the buserite precursor obviously affected buserite transformation into todorokite. Weak bonding between the metal ions and MnO6 layer of buserite was favorable to todorokite formation. The rate of todorokite formation was promoted at a lower temperature with appropriate bubbling of O2. The pH in the system slightly influenced the todorokite formation, and todorokite could also be formed in a weak alkali medium or in a slightly acidic medium. Aged buserite pre-cursor more easily form todorokite than the unaged one.

关 键 词：todorokite  buserite  MANGANESE OXIDE mineral  ATMOSPHERIC pressure  transformation. 

分 类 号：P618.3[天文地球—矿床学]