Investigations on Wollastonite Beneficiation Using Physical Methods of Separation
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Authors
Owusu-Addo, Gloria Adjubi
Date
2024-05-30
Type
thesis
Language
eng
Keyword
Wollastonite , Beneficiation , Physical separation , Wilfley table , Air separator
Alternative Title
Abstract
Wollastonite (CaSiO3) is a fibrous silicate industrial mineral experiencing rapid growth in demand, yet it remains underrepresented in the literature. Its unique properties make it valuable in industrial, ecological, and agricultural applications, including its potential to sequester CO2, thereby mitigating global warming, and its use in wastewater treatment. Wollastonite has also replaced asbestos in many applications due to its fibrous nature, anti-carcinogenic properties, and high aspect ratio. However, wollastonite deposits are relatively scarce, with notable occurrences in China, the United States, Finland, Mexico, India, and Canada. The aqueous processing of wollastonite from its gangue presents challenges due to the limited differences in their silicate anions and common calcium cations, which complicates beneficiation using a single technique. Consequently, processing flowsheets typically incorporate multiple techniques. While flotation as a physicochemical method of wollastonite beneficiation is well-documented, other potential methods remain underexplored.
This thesis investigated gravity and air separation processing techniques aimed at improving the grade and recovery of wollastonite. A traditional wet Wilfley table was used in a CCD-DOE approach with varying parameters, achieving a grade of 60.4% and a recovery of 50.8%. Modifications to the Wilfley table included the use of emery papers and white paper board, the latter showing some potential for separation, though not efficiently. Pre-treatment of wollastonite minerals with DDA.HCl and TA before running on the Wilfley table significantly affected the -180+106 µm fraction of pure diopside, increasing its concentrate recovery by 13.9% and decreasing its tailing recovery by 19.9%. Conversely, the -106+45 µm pure wollastonite fraction saw the highest increase in tailing recovery by 7% and a reduction in concentrate by 10.0%. Additionally, air separation tests on wollastonite ore indicated that diopside particles travelled shorter distances with decreasing grade as distance increased, whereas wollastonite particles exhibited higher grades at longer distances under a pressure of 20 psi. Despite some improvements, the separation efficiency observed on the physical methods of separation investigated remained suboptimal, requiring further research.
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ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.