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Production of high purity silica by microfluidic-inclusion fracture using microwave pre-treatment

Buttress, A.J.; Rodriguez, J.M.; Ure, A.; Ferrari, R.S.; Dodds, C.; Kingman, S.W.

Production of high purity silica by microfluidic-inclusion fracture using microwave pre-treatment Thumbnail


Authors

A. Ure

CHRIS DODDS CHRIS.DODDS@NOTTINGHAM.AC.UK
Professor of Process Engineering

SAM KINGMAN SAM.KINGMAN@NOTTINGHAM.AC.UK
Pro-Vice Chancellor Faculty of Engineering



Abstract

© 2018 Demand for high purity silica used in component manufacture is set to outstrip current supply in the near future. As such, alternative processing routes to feed-stock materials suitable for use in lighting and solar cell fabrication are required, without having to rely on reject material from semi-conductor manufacture. In this work, we report a facile, environmentally friendly method of producing quartz powder with a total residual impurity level of 30 ± 3 ppm from whole pebbles having an initial impurity level of 158 ± 22 ppm. This has been achieved using a metallurgical upgrading process incorporating microwave pre-treatment, crushing and milling, High Intensity Wet Magnetic Separation (HIWMS) and acid leaching. This process yielded a quartz powder having an 80% reduction in residual impurities compared to the untreated quartz pebbles. Pre-treatment of whole quartz pebbles in a multimode microwave cavity for 10 min yielded a reduction of the residual elemental impurity content associated with micro-fluidic inclusion sites containing calcium, potassium and sodium of 84, 78, and 50% respectively. Statistically significant reduction in residual aluminium phases was also observed (83%) compared to the as received material to below the IOTA® specification for Ultra High Pure Quartz produced by Sibleco. Mechanistically, this has been achieved by selectively heating impurity containing micro-fluidic inclusion sites. Resulting in their explosive decrepitation and enabling removal of the impurities in subsequent processing steps. It has been concluded that natural quartz pebbles can be upgraded through a combination of microwave treatment, magnetic and chemical refinement to produce a viable feedstock for the subsequent production of solar grade silicon.

Journal Article Type Article
Acceptance Date Nov 14, 2018
Online Publication Date Dec 6, 2018
Publication Date Jan 15, 2019
Deposit Date Jan 7, 2019
Publicly Available Date Dec 7, 2019
Journal Minerals Engineering
Print ISSN 0892-6875
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 131
Pages 407-419
DOI https://doi.org/10.1016/j.mineng.2018.11.025
Keywords Control and Systems Engineering; Geotechnical Engineering and Engineering Geology; Mechanical Engineering; General Chemistry
Public URL https://nottingham-repository.worktribe.com/output/1409018
Publisher URL https://www.sciencedirect.com/science/article/pii/S0892687518305090

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