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Hydrogen fluoride (HF), is a colourless fuming liquid or gas with a strong irritating odour. As a solution in water it is called hydrofluoric acid which is highly corrosive to tissue.

Hydrogen fluoride is used in the etching of glass, as a catalyst at petroleum refineries (to produce high octane petrol blendstock from the gases generated in cat crackers). Overseas there have been reports of major problems of corrosion in alkylation units based on hydrogen fluoride and there have been moves to use alternatives such sulfuric acid.

Other uses of hydrofluoric acid, though not used in Australia, are to make inorganic and organic fluoride chemicals, to separate uranium isotopes, to produce fluorine-containing plastics and dyes.

Hydrofluoric acid is important for analytical analysis at laboratories to dissolve silica from sample rock for which it would be particularly costly to replace and for some nearly impossible for some applications.

Trade

During 1995, some 390 tonnes of hydrofluoric acid valued at $0.8m were imported.

Manufacture

Hydrofluoric acid is simply produced by reacting the fluoride mineral (fluorspar or fluorite) with sulfuric acid. Transport costs is seen as the impediment to their exploitation.

In Australia, hydrogen fluoride is only manufactured as a fortuitous by-product in the manufacture of superphosphate fertilisers and represents a cost in disposal as waste. Hydrofluoric acid is readily produced by reacting naturally occurring fluoride minerals with sulfuric acid. The limited and distributed market in Australia precludes its competitive production though it would probably require a small (say 50 per cent) price increase to render production competitive. It is believed to be more economic than its extraction from phosphate fertiliser operations though environmental concerns could reverse this in the future.

Outlook

Australia could readily become self sufficient in hydrofluoric acid and even an exporter as it has large deposits of the key raw material calcium fluoride. Presently only remoteness from markets preclude their development although the subject of on-going interest and feasibility studies.

 


Chemlink Pty Ltd ABN 71 007 034 022. Publications 1997. All contents Copyright © 1997. All rights reserved. Information in this document is subject to change without notice. Products and companies referred to are trademarks or registered trademarks of their respective companies or mark holders. URL: www.chemlink.com.au/

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