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Alumina Market Research

AMIRA P266E "Improving Thickener Technology” Project Website

INTRODUCTION

 

 

Australia is the world's largest producer of alumina (aluminium oxide). In 2006-2007, 18.5 million  tonnes of alumina were produced from Australia’s seven refineries using the Bayer process. This represents around 23% of world production. Australia exported A$6.2 billion worth of alumina (15.1 million tonnes) in 2006-2007 (Australian Commodities, ABARE, September 2007).                                                                                

 

The Parker Centre has strong support from the alumina industry and allied companies. Alumina producers and engineering companies/industry supplie r s make up 12 of the Centre’s 19 Industry Participants.

 

The five principal alumina companies in Australia – Alcan International, Alcoa World Alumina, Billiton Aluminium Australia, Rio Tinto Aluminium and Queensland Alumina – are all Industry Participants in the Parker Centre. Overseas alumina producers Aughinish Alumina and Norsk Hydro are also Industry Participants. Collectively these seven companies produce approximately 55% of the world’s alumina.

The Bayer process for extracting alumina (aluminium oxide) from bauxite ore produces the majority of the world’s alumina. The Bayer process involves the dissolution of the aluminium oxy-hydroxide minerals in bauxite ore using hot concentrated caustic solutions. The aluminium-laden liquor is separated from the waste solids (primarily iron oxides and silicates) before the aluminium is recovered as gibbsite (aluminium hydroxide, also called alumina trihydrate) by seeding and cooling the liquor. The final step in the process is calcination of the gibbsite (Al2O3.3H2O) to alumina (Al2O3) by heating.

Being a mature industry, there is an on-going need for process improvements and new technologies. The alumina industry had considerable input into the Parker Centre’s current alumina project portfolio, which was designed to address six of the 12 areas identified by the industry in the Alumina Technology Roadmap as priority areas for R&D to 2020.

The Centre’s alumina research includes CRC-funded research projects; pre-competitive, multi-sponsored AMIRA projects (the P266E "Improving Thickener Technology" project, the P507C “Thermodynamic Characterisation of Organics in Bayer Liquor” project and the P521C “Developing a Mathematical Model of the Effect of Solid Phase Oxalate on Gibbsite Secondary Nucleation” project) and one-to-one company-specific projects.

This research involves around 40 full-time equivalent research staff, drawn from all four of the Centre’s Research Participants and a range of disciplines. These researchers include chemists, fluid dynamicists, chemical engineers, process engineers and physicists. They are supported by a unique array of Bayer-specific and general research equipment.

ALUMINA RESEARCH CAPABILITIES 

• Characterisation of bauxite mineralogy
• Bauxite processing assessments
• Impurity removal technologies
• Bayer process chemistry
• Studies of solution properties and solution chemical species
• Flocculation
• Characterisation of surface processes: surface properties, adsorption behaviour and inter-particle forces
• Thickener design and performance issues
• Alumina product strength and quality
• Precipitation technology
• Computer modelling: molecular modelling, modelling using computational fluid dynamics and process models
• Environmental issues, including residue treatment.

 

 

 

ALUMINA RESEARCH AREAS

The Centre’s alumina research includes CRC-funded projects covering the red-side and the white-side of an alumina refinery, solid-liquid separation, impurity issues, fluoride speciation, scale and environmental issues (follow the links below for further details on each project):

Research in the Bayer Red-Side Technology project include:

- bauxite characterisation
- bauxite beneficiation
- predicting bauxite processing behaviour
- desilication and digestion of bauxite ore, flashing and lime chemistry
- process options for high-silica bauxites, including acid routes
- thermodynamics of acidic aluminium/iron solutions relevant to acid processing routes.

The Bayer White-Side Technology project focuses on:

- options for increasing gibbsite precipitation yield
- precipitation kinetics models describing the relationship between precipitation rates and process variables
- modelling inhomogeneously mixed industrial precipitators
- secondary nucleation and management of fines
- alumina strength and breakage behaviour (product quality)
- simulation of a precipitation circuit.

The Solid-Liquid Handling project involves research on:

- aggregation processes
- thickening of residue
- relating suspension properties, solution properties and reagent    adsorption to inter-particle interactions and hence dewatering behaviour
- modelling of all aspects of the thickening process
- dewatering issues in other markets.

The Impurity Issues project focuses on:

- sodium oxalate crystallisation and stability
- removal strategies for organic impurities
- removal strategies for inorganic impurities
- fluoride speciation in Bayer liquors
- scale prevention or minimisation.

 

 

Research in the Bayer Environmental Issues project includes:

- bauxite residue disposal and re-use options
- understanding causes of emissions (eg odours, trace metals and dust) and formulation of options to control such emissions.

The Framework for New Technologies project focuses on:

- factors affecting community reaction to the proposed introduction of new hydrometallurgical processes
- communication with the community about new processes.

The Centre also undertakes a wide range of other projects with companies in the alumina industry, many of which are confidential projects.

INDUSTRY BENEFITS

The potential benefits to the minerals industry of the Centre’s alumina research include:

Benefits Arising from Breakthrough

Technologies Research Benefits Arising from Process Fundamentals Research

innovative processing technologies for extracting alumina from bauxite ores containing high levels of silica, which would potentially convert vast untapped bauxite deposits into valuable assets processes for removing inorganic and organic impurities from Bayer liquors, leading to improved efficiency of Australian alumina refineries improved technologies for reducing the rate of scale formation on refinery processing equipment technical solutions for decreasing the release of volatile organic compounds (cause odours) into the air during alumina processing strategies to remove minor elements (trace heavy metals) from the Bayer process and from residues decreased dust formation in bauxite residue storage areas economic options for bauxite residue re-use.

improved digestion and desilication procedures, including procedures better tailored to the properties of the bauxite ore being processed better strategies for seeding alumina refinery precipitators with seed crystals of gibbsite to promote gibbsite crystal growth increased gibbsite yields from precipitation in the Bayer process improved design and operation of industrial gibbsite precipitators better quality smelter grade alumina product with improved properties, such as greater strength improved performance of gravity thickeners (resulting from increased fundamental knowledge and computer modelling), allowing processing plants to increase throughput, save water, reduce capital and running costs and obtain a purer mineral slurry for the next processing stage a greater capacity to select flocculants for specific process outcomes (eg clarity, throughput, paste disposal) in solid-liquid separation improved recovery of water from tailings treatment, thereby reducing overall water consumption reduced environmental impact from tailings disposal through improved utilisation of paste technologies an enhanced industry skill base achieved through technology transfer and education & training activities.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Centre's alumina researchers work in:

CSIRO Minerals' Alumina Production Program
Murdoch University's School of Electrical, Energy and Process Engineering
Murdoch University's School of Chemical and Mathematical Sciences
Nanochemistry Research Institute (Curtin University)
Curtin University's Department of Applied Chemistry
Centre for Social Responsibility in Mining (University of Queensland).


ALUMINA MARKET LEADER: DR CHRIS VERNON