Experimental study of dissolution rates of fluorite in HCl-H2O solutions

doi:10.1007/s10498-005-3658-3

	Experimental study of dissolution rates of fluorite in HCl-H2O solutions
	Zhang, RH; Hu, SM; Zhang, XT
刊名	AQUATIC GEOCHEMISTRY
	2006
卷号	12 期号:2 页码:123-159
关键词	dissolution rates kinetics proton adsorption surface modifications
ISSN号	1380-6165
DOI	10.1007/s10498-005-3658-3
英文摘要	The experiments of the dissolution kinetics of fluorite were performed in aqueous HCl solutions over the temperature range of 25 - 100 degrees C using a flow-through experimental apparatus. With a constant input of aqueous HCl solution through the reactor, output concentrations of the dissolved species Ca, F, Cl vary with flow rate, as well as with the surface compositions. Measured output concentrations of dissolved species and the pH can be used to determine a rate law for fluorite dissolution. Fluorite dissolution rates are found to be pH dependent. Usually, dissolution rates of fluorite decreases with increasing dissolved Ca in the output solution at 25 and 100 degrees C. Dissolution rate can be expressed as;-r = k(((a(H)(+))2/(a(Ca)(2+)))(alpha) (1a);where k is the rate constant and alpha is the order with respect to the hydrogen ion activity vs. the activity of dissolved Ca. The alpha was obtained from kinetic experiments. For the fluorite sample passed through 18 - 35 mesh, alpha = 1.198 at 100 degrees C and k = 10(-0.983), while fluorite dissolved in HCl-H2O solution at pH 2.57 of input solution. Adsorption of a proton and Cl-1 onto the fluorite surface, surface cation exchange and the formation of the surface complex Ca( F, Cl) 2 and/or (H-2x, Ca1-x) F, Cl)(2) control dissolution rates. Investigation of the fluorite surface before and after dissolution by using X-ray photoelectron spectroscopy (XPS) indicate that surface modi. cations affect reaction rates.
学科主题	岩矿鉴定与测试
WOS关键词	MINERAL-WATER REACTIONS ; KAOLINITE DISSOLUTION ; AQUEOUS-SOLUTIONS ; COORDINATION CHEMISTRY ; ELEVATED-TEMPERATURES ; SILICATE DISSOLUTION ; KINETIC CONSTRAINTS ; SURFACE SPECIATION ; ACTIVATION-ENERGY ; RATE ; CONSTANTS
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	SPRINGER
WOS记录号	WOS:000237500000002
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/38199]
专题	中国地质科学院地质研究所
作者单位	Chinese Acad Geol Sci, Open Res Lab Geochem Kinet, Inst Mineral Deposits, Beijing 100037, Peoples R China.
推荐引用方式 GB/T 7714	Zhang, RH,Hu, SM,Zhang, XT. Experimental study of dissolution rates of fluorite in HCl-H2O solutions[J]. AQUATIC GEOCHEMISTRY,2006,12(2):123-159.
APA	Zhang, RH,Hu, SM,&Zhang, XT.(2006).Experimental study of dissolution rates of fluorite in HCl-H2O solutions.AQUATIC GEOCHEMISTRY,12(2),123-159.
MLA	Zhang, RH,et al."Experimental study of dissolution rates of fluorite in HCl-H2O solutions".AQUATIC GEOCHEMISTRY 12.2(2006):123-159.