Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Résumé Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Peterson, R. C. Articles by Grant, A. H. Search for Related Content GeoRef GeoRef Citation

DEHYDRATION AND CRYSTALLIZATION REACTIONS OF SECONDARY SULFATE MINERALS FOUND IN MINE WASTE: IN SITU POWDER-DIFFRACTION EXPERIMENTS

Ronald C. Peterson and Alan H. Grant

Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada

E-mail address: peterson{at}geol.queensu.ca

A sample stage and a control system have been developed to vary the humidity and temperature of the atmosphere surrounding a powder sample during an X-ray-diffraction experiment. The use of this stage and a position-sensitive detector creates the opportunity to conduct experiments that determine the stability fields and reaction mechanisms of related sulfates of different states of hydration, such as melanterite, siderotil and rozenite. The sample is dusted onto a zero-background plate, and this small amount of dispersed sample ensures maximum interaction among all of the crystallites of the sample and the atmosphere. Determination of the phase boundary for the dehydration of melanterite to rozenite is compared to that determined by Chou et al.(2002). The rate of dehydration of cuprian melanterite to cuprian siderotil is shown to depend on the relative humidity in the chamber, which is consistent with a diffusion-controlled process. Rozenite is observed to form by very rapid dehydration of cuprian melanterite. The crystallization of melanterite from liquid under controlled humidity is demonstrated.

Keywords: powder X-ray diffraction, melanterite, siderotil, rozenite, relative humidity, dehydration.

This article has been cited by other articles:

				J. L. Anderson, R. C. Peterson, and I. P. Swainson THE ATOMIC STRUCTURE AND HYDROGEN BONDING OF DEUTERATED MELANTERITE, FeSO4{middle dot}7D2O Can Mineral, June 1, 2007; 45(3): 457 - 469. [Abstract] [Full Text] [PDF]