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Study on decomposition mechanism of tuff in Zaofanshan Mine, Zhenfeng County, Guizhou Province |
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DOI:10.3969/j.issn.1671-4172.2020.01.009 |
KeyWord:Zaofanshan; tuff; mineral composition; microstructure; dissolution |
Author | Institution |
ZHENG Mingxiong 1 |
(1. 昆明理工大学 计算中心,昆明
2. 昆明理工大学 国土资源工程学院,昆明 ) |
SHEN Yuelong2 |
(1. 昆明理工大学 计算中心,昆明
2. 昆明理工大学 国土资源工程学院,昆明 ) |
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Abstract: |
The tuff which is rapidly decomposed by water, is unfavorable to the exploration and drilling of the mining area. Therefore, it is necessary to study the related properties and causes of tuff’s rapid decomposition, further to provide reference for the application of tuff engineering. In this paper, the decomposition mechanism of Zaofanshan tuff in Zhenfeng County, Guizhou Province was studied by XRF, XRD, SEM, ICP-MS and chemical experiments. The results indicated that: 1) The main mineral components of tuff were quartz, muscovite, pyrite, phlogopite and kaolinite. The material factors that caused the tuff to decompose rapidly with water were mica and kaolinite. 2) Micro-lamellar structures widely existed in tuff, which were just the typical microstructures of highly hydrophilic clays. Pores and fissures were well developed in tuff. The micro-lamellar structure and pore cracks were conducive to the diffusion and movement of water in tuff, which was also an important reason for the rapid decomposition of tuff. 3) Pyrite in tuff was oxidized to sulfuric acid and sulfate. ICP-MS test indicated that a large number of ions dissolve rapidly in water, and dissolution also promotes the decomposition of tuff. 4) Potassium salt, ammonium salt and silicate had remarkable ion exchange modification and stabilization effect on Zaofanshan tuff. Carbonate or bicarbonatepresented a significant decomposition promotion effect. The ion exchange stability of cations such as potassium ions was less than the promoting decomposition of carbonate anion. Rich in highly hydrophilic silicate minerals with micro-lamellar structure and sulfate dissolution were the main reasons for rapid decomposition of Zaofanshan tuff. |
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