'Arribapedia'
Brief infomation packages with references
This page is intended as a free-form reference source for industry practitioners, suppliers, researchers, students - in fact anyone with an interest in 'bauxite to alumina' and beyond. It will be an organic, evolving page. We at Arriba will add content - brief articles, reference sources, etc from time to time, and we invite others to submit contributions by email. he idea is to create a repository of informative, rigorously factual, current information in an easily readable and informal format for all to share, . The references are key - this page gives you easy access to public domain documents that may be hard to find elsewhere, all grouped according to the subject that interests you. And we will have other pages with more detail on specific topics - again, just follow the links.
Organic Evils
Organic compounds are an ever-present nuisance in the Bayer process. We all know that they cost heaps through reduced liquor yield, and that they mostly come from the bauxite.
For more detail click here:
Operators also have to be very careful what else we add to the liquor. Starch is a good example - It does a great job of clarifying liquor, but it breaks down to hydrate active organics (HAOs), the worst kind of yield inhibitor. Modern polymer flocculants have largely solved that problem.
We have recently completed a comprehensive review of the effects of organics. Here is a brief summary:
The biggest single impact of organics is usually the formation of carbonate in Digestion. The effect is mitigated by lime causticisation, but at considerable cost.
Organics don't just affect yield. They impact alumina quality by increasing impurities, particularly soda, and by reducing particle strength and forming fines. Where hydrate is the product, they are really bad for colour. And they emit odours that can be extremely troublesome (Galbally et al). See Power et al 2012 for more detail.
Here are some useful articles you can download immediately:
'Soda in alumina': Grocott & Rosenberg 1988
'Identification of HAOs': Picard et al 2002
'Macromolecules in the Bayer process': Whelan et al 2003
'Poisons, polyols and precipitation': Owen et al 1999
'Testing Bayer process additives': Gotsis, Harrison et al 1999
'Influences of Bayer process impurities': Kelly 1962
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And here is a selection from academic journals:
'Origins of organics in the Bayer process': Power & Loh 2010
'Origins of organics...Addendum': Power, Loh & Niemla 2011
'Effects of organics in the Bayer process Power et al 2012
'Determination of organics in Bayer liquor': Power, Loh et al 2011
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AQW Treasure Trove
The Proceedings of the Alumina Quality Workshops are a great source of specialist information generally not captured by even the best academic search engines. But don't despair! The full texts of all AQW papers since the first Conference in Gladstone in 1988 are now just a click away, at: http://www.aqw.com.au/pastconferences.html. Definitely worth a browse, and expect individual articles to crop up quite a bit on this page!
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Bauxite:
From craggy rock to universal ore
The Bayer process story begins with bauxite; so much so that: "all the alumina produced today comes from bauxite" is a practical tautology.
But there was bauxite before Bayer. Until the coinciding dawns of the twentieth century and the aluminium industry, aluminium hydroxide was in demand as a dye mordant and bauxite was the preferred ore.
But why is bauxite so called, and what's so special about it?
Find out on on our 'Bauxite' page: