annual report 2015 - School of Chemical Engineering · Chief Technologist, Rio Tinto Bauxite and Alumina Steve Healy’s industrial research and development expertise developed over

annual report 2015

UQ RT Bauxite & Alumina Technology Centre

Contents

Message from the Director 2

Aims of the Centre 3

Board of Directors 4

Centre staff 6

Centre students 8

Projects and outcomes 12

Capabilities 19

Research output 22

Communications 24

Financial report 25

2 3

Efficient alumina refinery operation is essential to ensure profitability in the current

business climate. Since the Bayer process is a mature technology, the “low-

hanging fruit” of technical improvements has already been made. To achieve further

gains requires a deep understanding of the process fundamentals combined with

carefully targeted applied development.

The University of Queensland-Rio Tinto Bauxite & Alumina Technology Centre is

a team of dedicated staff and students working with industry advisors from Rio

Tinto’s Queensland Research and Development Centre to identify and progress

high value opportunities that can proceed from the laboratory to industry. Our

core capability is hydrometallurgy and we collaborate with experts from other

disciplines such as minerals processing or pyrometallurgy as required.

2015 was a transition year for the centre with three PhD’s finalised and new

projects established. Hong Peng presented at the 10th Alumina Quality Workshop

on desilication and was recently awarded the Advance Queensland Fellowship to

develop a new process option for high silica bauxite. Our international links were

strengthened with my two-month secondment to Rio Tinto’s Bauxite & Alumina

Group at the Arvida Research & Development Centre which included on-site

exposure to the Vaudreuil refinery and interactions with the solid-liquid separation

specialists at Université de Québec à Chicoutimi.

The recent investment in the Amrun bauxite project in north Queensland will lead

to increased exports and ensure a reliable supply to Rio Tinto alumina refineries.

New centre projects will support technical aspects of processing of this ore with a

research theme of impurity management.

This report summarises centre activities and achievements up to and including

2015. Please feel free to contact me for further information about the centre.

Sincerely,

James Vaughan

Director – UQ RT Bauxite & Alumina Technology Centre

The University of Queensland | School of Chemical Engineering

Message from the Director

UQ RT BAUXITE & ALUMINA TECHNOLOGY CENTRE ANNUAL REPORT 2015

Aims of the Centre

Centre Inauguration in 2012. Back row L-R: Professor Graham Schaffer, Professor Gordon Dunlop and Steve Healy Front row L-R: Professor Peter Hayes, Dr Denis Audet, Francois Tremblay and David Holmyard.

The aim of the Centre is to provide strategic support for Rio

Tinto’s technical and process development, strengthening their

fundamental and applied research capabilities. The Centre’s

activities also result in educational and professional development

pathways for current and future Rio Tinto employees.

4 5

Board of DirectorsThe Centre is governed by a Board of Directors that meets bi-annually with the Director to provide guidance on

activities and strategy. The Board consists of Professor Peter Hayes Leader of the Metallurgical Engineering

Program at UQ, Professor Peter Halley Head of the School of Chemical Engineering, Mr. Nigel Backhouse

General Manager Rio Tinto Technology and Mr. Steve Healy Rio Tinto Chief Technologist.

PROF. PETER HAYES

BSc/MSc (Metallurgy) Newcastle on Tyne (UK) 1972 Ph.D. (Metallurgy) Strathclyde University (Scotland) 1974

Prof. Hayes is Metallurgical Engineering program leader at The University of Queensland. He was founding Director of PYROSEARCH, the Pyrometallurgy Research Centre. The focus of PYROSEARCH is high temperature smelting and processing of metals, specialising in slag chemistry, and high temperature chemical reaction kinetics and mechanisms in ferrous and non-ferrous metallurgy. Dr Hayes is the author of over 240 research publications in international journals and conference proceedings.

PROF. PETER HALLEY

BEng (Chem) The University of Queensland (Australia) 1987 PhD (Chem) The University of Queensland (Australia) 1993

Prof. Halley is the Head of the School of Chemical Engineering, the Director of the Centre for High Performance Polymers, a leader in the Australian Institute for Bioengineering and Nanotechnology, a chief investigator in the Advanced Materials Processing and Manufacturing Centre and also works at the translational research interface between universities and industry. He is a fellow of the Institute of Chemical Engineers and a fellow of the Royal Australian Chemical Institute.

STEVE HEALY

Chief Technologist, Rio Tinto Bauxite and Alumina Research and Development

Steve Healy’s industrial research and development expertise developed over 25 years in the alumina industry (Alcoa, Worsley Alumina, Nabalco, Rio Tinto), and 5 years in the coal industry. He has had a long working relationship with academic and institutional research through his involvement in projects as an industry representative in organisations such as Australian Mineral Industry Research Association, the Parker Centre and the International Aluminium Institute; where he is presently a co-chair of the Bauxite and Alumina Committee. As inaugural Manager, he established Rio Tinto’s Queensland Research and Development Centre (QRDC) at the Queensland Centre for Advanced Technologies site at Pullenvale. In his present role, he is responsible for the ongoing development of alumina technology.

NIGEL BACKHOUSE

B.E Hons (Chem Eng) University of Newcastle Australia 1995

Nigel Backhouse commenced in the Aluminium industry in 1995 as a process engineer at Tomago Aluminium Company, New South Wales, Australia. In 1998, he was seconded to Aluminium Péchiney’s research centre, located in the Savoie region of France where he worked as a research development engineer on projects for clients in France, the Netherlands, Greece, South Africa, Australia and the Middle East. In 2002, he returned to Tomago Aluminium Company working in project and operations management on the AP22 brownfield expansion and as a leader in the Rodded Anodes business unit. In 2008, he joined Rio Tinto as Carbon Research and Development domain director based at the Arvida Research and Development Centre, leading teams in Canada, France and Australia. In 2013, he returned to Australia to take up a role as Strategic Planning Director within Rio Tinto Bauxite and Alumina Technology and was appointed General Manager at the Bauxite and Alumina Technology, Research and Development in 2014, covering activities from fundamental research, applied technology development and technology packaging and engineering for a complete refinery installation.


6 7

DR HONG “MARCO” PENG

BEng (Minerals) Central South University (China) 2003; MSc (Bio-hydrometallurgy) Central South University (China) 2006; PhD (Flotation) The University of Queensland (Australia) 2013

Research Fellow

Hong brings over 10 years of experience in the field of metallurgy and minerals processing which include bauxite flotation and novel industrial crystallisation processes. He joined the Centre in 2014, after obtaining his PhD degree on fundamental aspects of nanobubble formation using a combination of atomic force microscopy and molecular simulation. Hong was recently awarded the Advance Queensland Fellowship to develop a new process for high silica bauxite.

DR WILLIAM HAWKER

BEng (Chem/Met) The University of Queensland (Australia) 2009; GCResComm The University of Queensland (Australia) 2012; PhD (Metallurgy) The University of Queensland (Australia) 2015

Associate Lecturer in Hydrometallurgy

Will has been in a range of projects with the hydrometallurgy research group including investigating scale formation in Bayer precipitation tanks and cross disciplinary hydro- and pyrometallurgical process development through his research investigating hydroxide precipitation and smelting of primary copper. Other current research areas include gold pressure oxidation and cyanide leaching, nickel and cobalt refining and scandium extraction.

DR JAMES VAUGHAN

BEng (Metallurgy) McGill (Canada) 2001; MASc (Material) University of British Columbia (Canada) 2003; PhD (Materials) University of British Columbia (Canada) 2007

Centre Director

James is Senior Lecturer in Hydrometallurgy at The University of Queens-land. Over the past seven years at the University, he has made contributions in precipitation and crystallisation, ion exchange and leaching. He has taught undergraduate courses including “Aqueous Solution Processing and Electrometallurgy”. Before joining the University, James gained experience in industrial research and development with Placer Dome Mines and BHP Billiton.

DR LIGUANG WANG

BEng (Mineral Processing) Central South University (China) 1998; MEng (Mineral Processing) Central South University (China) 2001; PhD (Mining and Minerals Engineering) Virginia Polytechnic Institute and State University (USA) 2006

Minerals Processing Expert

Liguang joined The University of Queensland as a lecturer in November 2006. His current research interests are froth flotation, solid/liquid separation, and gas hydrates. His research program is supported by the Australian Research Council, Australian Coal Association Research Program and other industrial partners. He is currently advisor on oxalate morphology modification, physical beneficiation of bauxite, and bauxite residue treatment projects.

Centre staff


JAMES GUDGEON

BEng (Chem/Met) The University of Queensland (Australia) 2010

Research Officer

Prior to joining the Centre, James spent two years at the Rio Tinto Queensland Research and Development Centre contributing to projects on Bayer organics control and residue management working at both the laboratory and pilot plant. He provides research support, coordinates maintenance of research equipment as well as documenting procedures for the generation of quality data. He is also skilled in the development of customised programs for data processing and analysis.

VALENTINA URRUTIA GUADA

Biology) Universidad Simón Bolívar (Venezuela) 2007; MEnvMng The University of Queensland (Australia) 2012; GDipBus The University of Queensland (Australia) 2013; PhD Candidate (EnvMng) The University of Queensland (Australia)

Laboratory Manager

Valentina joined the hydrometallurgy research group in 2012, managing lab operations with a focus on improving safety and laboratory systems, some of which are being deployed in other parts of the University such as the pyrometallurgy laboratories. Valentina also contributes to Centre communications and grant applications.

KELLY BYRNE

BEng (Chem) The University of Queensland (Australia) 2014

Research Assistant

Kelly brings industrial experience to the team from her placements at the laboratories at Rio Tinto’s Yarwun alumina refinery. Her project experience includes digestion, clarification and environmental issues. Kelly currently provides support through mercury assays, solution silicate assays and Bayer liquor analyses.

8 9

DILINI SENEVIRATNE

BEng (Chemical)/ BSc (Microbiology) The University of Melbourne (Australia) 2007

PhD Candidate

Dilini has over 7 years of experience as a process engineer with Rio Tinto Copper and Coal, focusing on primary copper heap leaching, and Rio Tinto Technology and Innovation, working on technical improvement projects. She joined the centre in July 2015 and her current research aims to manipulate Bayer desilication product crystallisation to enable separation of a concentrate.

Centre students

IMAN “NICK” GHANE GHANAD

BSc (Materials) Sharif University of Technology (Iran) 2008; MASc (Materials) The University of British Columbia (Canada) 2011

PhD Candidate

Nick has more than 6 years of research and engineering experience in the mining industry in Canada and Australia. As a process engineer / metallurgist at SNC-Lavalin Australia in Perth, he was involved in numerous engineering design projects. Prior to this, Nick undertook his master’s studies at the University of British Columbia where his research resulted in a novel catalysed leaching method for treating enargite deposits.

HARRISON HODGE


PhD Candidate

Before starting his PhD, Harrison completed two research internships on physical minerals processing at the Julius Kruttschnitt Mineral Research Centre at The University of Queensland. His current research looks at the recovery of key reagents, such as sodium and aluminium, from Bayer process desilication product. This will be done by using a combined pyro-hydrometallurgical process.


STEFAN LAKEMOND


MPhil Student

Stefan joined the Centre after working in the hydrometallurgy group as research assistant, developing a novel method for recycling platinum and palladium from automotive exhaust catalyst and improving cyanidation of gold flotation concentrates. His current project focuses on oxalate mor-phology modification.

CHRIS STAUN

BSc (IndChem) Central Queensland University (Australia) 2012

MPhil Student

Chris brings industry experience to his research which includes a term at Queensland Alumina as well as servicing the technical and research and development needs for bituminous formulations. He has significant analytical experience, including method development and validation. His current project focuses on stabilisation of mercury during the digestion process.

MAHENDRAN CHOKKANATHAN

BTech (ChemEng) Madras University (India) 2003

MPhil Student

Mahendran has more than 10 years of experience as a process engineer in various alumina and aluminium engineering projects. He has been extensively involved in mathematical modelling and simulation of various facilities within the Bayer circuit for process and energy optimisation. Mahendran has hands on experience in alumina refinery commissioning. His current research focuses on silica management in the Bayer process.

10 11

Centre students

The Centre also facilitates Masters of Engineering industry placements and research projects in conjunction with Queensland Alumina Limited (QAL), the Queensland Research and Development Centre (QRDC) and Rio Tinto’s Yarwun alumina refinery. Additionally, the Centre hosts undergraduate Summer Research Scholars; promoting the advancement of the students towards a career in the bauxite and alumina industry.

For instance, Calvin Chandra joined Queensland Alumina as a graduate engineer, after graduating from the combined bachelor and master of engineering (BE/ME) program which involved a six month placement at Queensland Alumina and a research project “Quantification of Bayer liquor organics using ultra-violet spectroscopy”.

Students who have participated in learning programs through the Centre are as follows:

2015

Neetu Bansal (PhD Project)

Calvin Chandra (UQ BE/ME Research Project at UQ RT Centre)

Wenting (Wendy) Du (UQ BE/ME Industry Placement at QAL)

Benjamin Foster (UQ Summer Research Scholar (UQ BE Chem. Eng. Student))

Weng Fu (PhD Project)

David Johnson (UQ BE/ ME Industry Placement at QRDC)

Reza Salimi (PhD Project)

Rico de Villiers (UQ BE/ME Industry Placement at QRDC)

Benjamin Worley (UQ BE/ME Industry Placement at QAL)

Chua Zhen Yee (UQ Summer Research Scholar (UQ BE Chem. Eng. Student))


2014

Michael Booth (UQ Summer Research Scholar (UQ BE Chem. Eng. Student))

Calvin Chandra (UQ BE/ME Industry Placement at QAL)

Jack Edwards (UQ Summer Research Scholar (UQ BE Chem. Eng. Student))

Chelsea Hayward (UQ BE/ ME Industry Placement at QRDC)

Georgina Lehmann (UQ BE/ ME Industry Placement at QRDC)

Damien Naidu (UQ BE/ME Industry Placement at QAL)

William Shipperley (UQ Summer Research Scholar (UQ BE Chem. Eng. Student))

Avanti Venkatesh (UQ BE/ ME Industry Placement at QRDC)

Shay White (UQ Summer Research Scholar (UQ BE Chem. Eng. Student))

2013

Nabilah Mohamed Aroff (UQ Summer Research Scholar (UQ BE Chem. Eng. Student))

Adam Han Onn (UQ BE/ ME Industry Placement at QRDC)

Michael Hart (UQ BE/ME Industry Placement at Yarwun)

Llyza Mendoza (UQ BE/ME Industry Placement at QRDC)

Jackson Moore (UQ BE/ME Industry Placement at QAL)

Luisa Prasetyo (UQ Summer Research Scholar (UQ BE Chem. Eng. Student))

Sue Ying Tang (UQ Summer Research Scholar (U. Melbourne ME Chem. Eng. Student))

L–R: Hong “Marco” Peng, Ambrosia Maria Ivana, Harrison Hodge, Dilini Seneviratne, James Vaughan, Kelly Byrne, James Gudgeon, William Hawker, Chris Staun, Rhiannon Webb, Benjamin Foster, Eka Setiyawan and Valentina Urrutia Guada.

1312

Achievements to dateA technical report was prepared for Rio Tinto titled “Processing High Silica Bauxite- Phase I”.

Achievements to dateDSP precipitation tests under varying aluminium and sodium hydroxide conditions have led to the identification of desilication product crystal morphology and size changes. Designed scoping test work for various organic additives and crystal modifiers were assessed with the help of a summer research student.

INTEGRATION OF A MODIFIED PRE-DESILICATION PROCESS ROUTE FOR BAYER PROCES

Dr. Hong “Marco” Peng

Advisors: Mike Zeiba (Rio Tinto), Warren

Staker (Rio Tinto), Liguang Wang (The

University of Queensland), James Vaughan

(The University of Queensland)

Industry challengeProcessing high silica bauxite is costly to the Bayer refinery. This is due firstly to loss of caustic soda for re-precipitation of dissolved silicates; secondly, higher neutralisation costs due to the presence of sodalite in the bauxite residue; and third, the precipitation of desilication product on surfaces of heat exchanging units resulting in higher process energy requirements and unwanted process downtime.

Technical ObjectivesThe overall aim of this project is to explore alternatives for the effective removal of silicates from the circuit, or to prevent these from entering the process. The objectives are to critically review solid and aqueous phase silicate thermodynamic data and apply this data to understand and predict Bayer relevant silicate reactions. Also to establish the key parameters influencing separation of reactive silica from bauxite and the formation of conventional and unconventional desilication products.

Skills developedChemical thermodynamic measurement, calculations and predictions. Advanced solid and solution phase characterisation.

NUCLEATION AND GROWTH OF BAYER PROCESS DESILICATION PRODUCTS

Dilini Seneviratne, PhD Candidate

Advisors: Warren Staker (Rio Tinto), James

Vaughan (The University of Queensland), Hong

Peng (The University of Queensland)

Industry challengeReactive silica in bauxite can cause unwanted scale formation on heat exchangers and contamination of alumina product due to high levels of silicate in the Bayer liquor. The pre-desilication step, through the formation of crystalline aluminosilicates known as desilication product, is therefore an important step in silica control. However, the desilication product is discarded along with the bauxite residue, leading to the loss of soda and aluminium, increasing neutralisation costs and leading to inefficient solid-liquid separation. If a concentrated desilication product stream can be separated from red mud or pre-digestion solids, it can be economically recycled to recover lost soda and aluminium through a sinter leach process. If it is possible to control crystallisation of this product in the pre-desilication and/or digestion stages to enable separation using existing methodologies, a commercially viable treatment circuit can be developed.

Technical ObjectivesThis project aims to study the mechanisms (nucleation, growth and agglomeration) of desilication product crystallisation and levers for control of its size, morphology and composition, for obtaining a product with sufficient sodium to silica ratio and alumina to silica ratio to financially warrant reprocessing and be efficiently separated at high selectivity from red mud or pre-digestion slurry. Seeding and the impact of additives of the formation of desilication product will also be investigated.

Skills developedAnalytical techniques such as scanning electron microscopy, Bayer liquor titrations and AccuSizer characterisation. Shaker and continuously stirred tank reactor crystallisation experiments and autoclave preparation of synthetic Bayer liquors.


Projects and outcomes

SILICATES PROJECT 1 (IN PROGRESS)

SILICATES PROJECT 2 (IN PROGRESS)

14 15

THE CO-PRECIPITATION OF GIBBSITE AND SODIUM OXALATE UNDER BAYER CONDITIONS

Dr. Weng Fu

Industry challengeSodium oxalate is generally present in bauxite, but most of the oxalate that is found in the process is produced by degradation of organic impurities in bauxite during the digestion stage of the Bayer proc-ess. The limited solubility of oxalate in the Bayer solu-tion results in co-precipitation of sodium oxalate and gibbsite during the precipitation stage leading to a wide array of operational, maintenance and produc-tion problems.

Technical ObjectivesThe main objective of this research is to understand, at the molecular level, the nature of the co-precipita-tion occurring between gibbsite and sodium oxalate in the Bayer process. This project consists of three distinct focus areas: (1) the precipitation mechanism of sodium oxalate under Bayer conditions; (2) the interaction mechanism between gibbsite and sodium oxalate under Bayer conditions; (3) sodium oxalate-induced gibbsite secondary nucleation under Bayer conditions.

Skills developedTechnical communication skills, knowledge of opera-tional practice, development of technical/experimen-tal capabilities within the lab, e.g., crystallisation methods, electron microscopy, in situ optical microscopy and atomic force microscopy.

Achievements to date PhD thesis, five journal and two conference papers published. Oxalate management strategies have been proposed to Rio Tinto based on the research findings.

OXALATE CRYSTAL MORPHOLOGY MODIFICATION FOR THE BAYER PROCESS

Stefan Lakemond, MPhil Project

Advisors: Alistair Gillespie (Rio Tinto), Liguang

Wang (The University of Queensland), James

Vaughan (The University of Queensland)

Industry challengeOrganic matter in the bauxite feed for alumina plants introduces a range of process complications. As organics are degraded during digestion, sodium oxalate is generated which is of particular concern as it can have substantial impacts on product quality and forms a scale during the precipitation section of a Bayer process if the concentration becomes sufficiently elevated. Managing sodium oxalate formation often limits the caustic strength and temperature profile in the precipitation circuit, reducing productivity in order to maintain product quality.

Technical ObjectivesSpecific technical objectives of this project include: (1) developing experimental methods for studying oxalate nucleation and crystallisation processes at simulated industrial conditions, and (2) assessing process parameters that affect oxalate morphology and how this might be advantageously modified.

Skills developedOptical and electron microscopy techniques for studying oxalate morphology. Bottle roll, batch and continuous reactor crystallisation experiments. Methods to monitor particle formation in-situ.

Achievements to dateDevelopment of continuous stirred reactor experiment set-up and methodology which allowed sodium oxalate concentration to be increased in a supersaturated solution while other liquor components remained constant. Particle nucleation and evolution were monitored in-situ using the focused beam reflectance measurement probe. Using this approach, conditions were identified to produce large, homogenous robust sodium oxalate particles from industrial liquor.



OXALATES PROJECT 1 (COMPLETE)

OXALATES PROJECT 2 (IN PROGRESS)

1716

DETERMINATION OF MERCURY DEPORTMENT IN BAYER PROCESS & OPPORTUNITIES FOR ITS REMOVAL

Dr. Neetu Bansal

Industry challengeMercury is a toxic element present in bauxite ore. In the Bayer process, a portion of the mercury is extracted from the solid phase and exits the refinery at multiple points in different forms. The industry is seeking a safe, effective and cost efficient method to isolate the mercury from the circuit.

Technical objectivesThe primary objective was to develop methods to accurately determine the mercury content in the Bayer process streams to improve mass balancing efforts and to identify opportunities for recovery.

An additional objective was to study the electrochemical behaviour of mercury in strongly alkaline solution and combine this with thermodynamic predictions to assess the pre-dominant state throughout the circuit.

Skills developedRisk assessment and safety practice. Statistical analysis of experimental data. Technical presentation skills. Analytical method development techniques. Electro-analytical chemistry. Experience gained by interaction with industry advisors and site visits.

Achievements to dateDevelopment of an accurate, sensitive and robust method to assay mercury in Bayer process solids resulting in preliminary refinery mercury mass balances and insight into the variation in the concentration of the toxic element.


STABILISATION OF MERCURY DURING BAYER PROCESS DIGESTION.

Chris Staun, MPhil Candidate

Advisors: Helen Morrison (Queensland

Research and Development Centre), William

Clarke (The University of Queensland), James

Vaughan (The University of Queensland)

Technical ObjectivesThe primary objective is to develop an additive which stabilises mercury to the solid phase in digestion, preventing the deportment of mercury to condensate. Mercury would instead exit the circuit with the bauxite residue stream and enter dam storage. Additives are to be evaluated for effectiveness and optimal dose rates determined. Effectiveness is to be determined initially via two phase liquor/residue analysis, then validated via gas phase sampling during autoclave digestion. A secondary objective is method development and validation of a Milestone’s Direct Mercury Analyser. This instrument utilises a thermal desorption methodology, which allows for reduced sample preparation time and analysis of alkaline process liquor.

Skills developedInstrumental analytical and development techniques. Thermodynamics and kinetics of aqueous systems. Digestion mineralogy and mass balance. Academic writing and presentation.

Achievements to dateDevelopment and validation of a Milestone’s Direct Mercury Analyser. Demonstration of effectiveness and optimal dose of mercury stabilising additives via a two phase liquor/residue analysis. Preparation of a conference paper detailing additive effectiveness, solubilisation of mercury as thiomercurate and complexation of oxidised mercury by organics.


MERCURY PROJECT 1 (COMPLETE)

MERCURY PROJECT 2 (IN PROGRESS)

18 19

TRICALCIUM ALUMINATE PROJECT (COMPLETE)

CRYSTALLISATION OF TRICALCIUM ALUMINATE (TRICALCIUM ALUMINATE) AS FILTER AID

Dr. Reza Salimi

Industry challengeThe generation of tricalcium aluminate as the Bayer liquor filter aid and operation of filters constitutes a major operating expense for the Alumina refinery. Inconsistent filter aid quality can dramatically increase the frequency of filter cleaning, reduce filter productivity and can even compromise alumina product quality if certain insoluble impurities (calcium, vanadium, iron, silica) are able to pass through the filters. While many empirical optimisation studies have been completed, the fundamental basis for selection of conditions is not always apparent and the approach can vary widely across refineries.

Technical ObjectivesDetermine the solubility of tricalcium aluminate over a range of industrially relevant conditions. Develop a mechanistic model of the crystallisation process from batch experiments by studying the changes in both the solution and solid phases. Relate the batch crystallisation process to the continuous crystallisation using chemical engineering theory. Generate well defined tricalcium aluminate from the continuous re-actor at select conditions. The new information on solubility, metastability, nucleation and crystal growth mechanisms will provide guidance on improved design and control of the tricalcium aluminate crystallisation process which ultimately controls liquor filtration performance.

Skills developedMaterial characterisation, experimental design, fundamentals of thermodynamics and statistics, attention to detail, managing risks to work safely, experimental troubleshooting skills, technical presentation and writing skills.

AchievementsDevelopment of methods to assay trace levels of calcium in solution and accurately determine particle size distribution from kinetic and lime conversion from kinetic samples. Tricalcium aluminate solubility as well as batch and continuous crystallisation reveal the particle formation reaction pathway and effects of key process parameters.


The Centre capabilities encompass laboratory and pilot scale equipment and experimental methodologies, solution and particle analysis and thermodynamic and process modelling. A key aspect of the Centre is the close collaboration with the Queensland Research and Development Centre, described as benchmark regarding industry-university collaboration. This results in seamless application of the research outcomes, infrastructure and knowledge sharing. Furthermore, the Centre’s activities build on the extensive research infrastructure of The University of Queensland such as the Centre for Microscopy and Microanalysis and the Australian National Nanofabrication Facility.

Capabilities

This year saw the commissioning of new research equipment and PC and operating system upgrades on older instruments to maintain security, operability and data integrity.


20

This is complemented by a new optical microscope to allow data comparison in final or time series observations. This technology has been used to observe nucleation of growth of oxalate crystals in Bayer liquor, and can now be expanded for application in other systems.

To expand the application of existing instruments, an initial investigation into determining organics levels in Bayer liquors by UV-Visible Spectroscopy has yielded promising results. For instance, silica in liquor analysis through this technique has also been implemented to reduce the previous reliance on external analysis. When combined with the liquor titration, this allows the majority of sample analysis for new silica work to be undertaken in-house.

The Centre recently acquired a rotating block heater donated by Queensland Alumina. This will provide the capacity to run up to 16 separate 45ml digestion tests in parallel at refinery conditions, making it particularly suitable for scoping and optimisation studies.

CapabilitiesCentre staff were involved in the commissioning of a new Direct Mercury Analyser at the Queensland Research and Development Centre which complements the Microwave Digest-Flow Injection Mercury System assay. The two methods provide maximum flexibility in obtaining accurate mercury assays from solids, solutions, Bayer liquor and gas. Experimental equipment and methodologies for autoclave gas sampling are being established.

The Focused Beam Reflectance Measurement probe jointly-purchased in late 2014 has been commissioned and successfully utilised in plant Bayer liquors at elevated temperatures. This hardware provides an in-situ measurement of particle chord-length distribution, allowing kinetic studies of precipitation/dissolution systems under a wide range of conditions.

21UQ RT BAUXITE & ALUMINA TECHNOLOGY CENTRE ANNUAL REPORT 2015

22 23

Research outputJournal Publications

Bansal N., Vaughan J., Boullemant A., Leong T. Determination of total mercury in bauxite and bauxite residue by flow injection cold vapour atomic absorption spectrometry. Microchemical Journal, 113, 36‐41 (2014).

Fu W., Vaughan J., Gillespie, A. Effects of Inorganic Anions on the Morphology of Sodium Oxalate Crystallized from Highly Alkaline Solutions. Crystal Growth & Design 14 (4), 1972-1980 (2014).

Fu W., Vaughan J., Gillespie, A. Aspects of the Mechanism of Nucleation and Intergrowth of Gibbsite Crystals on Sodium Oxalate Surfaces in Concentrated Alkaline Solutions. Crystal Growth and Design 15, 374-383 (2015).

Fu W., Vaughan J., Gillespie, A. In situ AFM investigation of heterogeneous nucleation and growth of sodium oxalate on industrial gibbsite surfaces in concentrated alkaline solution. Chemical Engineering Science, 126, 399-405 (2015).

Fu W., Vaughan J., Gillespie A., Aroff N. Mechanisms of polyacrylate modified sodium oxalate crystallization from highly alkaline solutions. Crystal Growth & Design (2016).

Fu W., Vaughan J., Gillespie A. In situ AFM investigation of gibbsite growth in high ionic strength, highly alkaline, aqueous media. Hydrometallurgy (2016).

Salimi R., Vaughan J., Peng H. Solubility of tricalcium aluminate in synthetic spent Bayer liquor. Industrial & Engineering Chemistry Research (2014).

Salimi R. and Vaughan J. Crystallisation of tricalcium aluminate from sodium aluminate solution using slaked lime. Powder Technology (2016).


Conference Publications

Bansal N., Vaughan J., Boullemant A., Leong T. The determination of mercury in environmental samples: a review. Chemeca 2013 : challenging tomorrow, 29 Sep – 2 Oct, Brisbane Australia (2013).

Bansal N., Vaughan J., Tam Wai Yin P., Boullemant A., Leong T. Chemical thermodynamics of mercury in the Bayer process. Proceedings of the Hydrometallurgy 2014 Conference, CIM, Victoria, Canada, June 22‐25 (2014).

Fu W. and Vaughan J. Morphological investigation of sodium oxalate crystals grown in aqueous sodium hydroxide solution. Light Metals 2013, Ed.: B. Sadler, 191‐194 (2013).

Fu W. and Vaughan J. A study of sodium oxalate growth on industrial gibbsite with in situ optical microscopy. Proceedings of the Hydrometallurgy 2014 Conference, CIM, Victoria, Canada, June 22‐25 (2014).

Salimi R. and Vaughan J. Batch tricalcium aluminate crystallisation and particle morphology. Proceedings of the Hydrometallurgy 2014 Conference, CIM, Victoria, Canada, June 22‐25 (2014).

Peng H., Vaughan J., Zieba M., The thermodynamic approach to predicting silicate solubility. Accepted for publication in: Proceedings of the 10th International Alumina Quality Workshop, April 19-23 Perth, Australia (2015).

Theses

Bansal N. Mercury deportment in the Bayer process and highly alkaline solution electrochemistry. PhD Thesis, The University of Queensland (2015)

Fu W. Oxalate/gibbsite co-precipitation in the Bayer process. PhD Thesis, The University of Queensland (2015)

Salimi R. Crystallisation of tricalcium aluminate for use as a Bayer liquor filter aid. PhD Thesis, The University of Queensland (2015)

L–R: Stefan Lakemond, Valentina Urrutia Guada, James Gudgeon, Weng Fu, James Vaughan, Hong “Marco” Peng, William Hawker and Reza Salimi.

24 25

CommunicationsCentre activities and research outcomes are routinely reported through presentations, knowledge exchange events, quarterly updates, annual report and the website.

In the second half of the year, the new Centre projects were discussed and selected following a Rio Tinto strategic review. Yearly timelines summarising key events are shown below.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

QRDC students’ presentations Hydro 2014 Board Meeting

Annual Report 2013 RTA Tech Review

Centre website launch PhD Outcome Presentations to QRDC

Centre Planning Workshop

Gladstone refinery tour

Board Meeting RTA Tech Review Centre Update Centre Update

Centre Update ICHM 2014

ICSOBA 2014

2014


Board Meeting Board Meeting

RTA Tech Review

TMS Conference Centre Update CHEMECA Conference Centre Update

2013


PhD Outcomes presentation to RT

10th Alumina Quality Workshop

Centre Update Gladstone refinery tour

Annual Report 2014 Visit from RT delegates Alumina plant design workshop

Centre projects workshop

Centre Update Board MeetingBoard Meeting

2015

Rio Tinto Delegates visit to the UQ Rio Tinto Centre

L-R Nigel Backhouse, Claude Vanvoren, Stefan Lakemond.

Expenditure2013$’000

2014 $’000

2015 $’000

2016 $’000

2017 $’000

2018 $’000

Staff 156 341 358 272 288 TBD

Admin 15 16 17 18 19 TBD

Travel 6 12 13 14 15 TBD

Projects 0 90 180 370 370 315

Contingency 0 0 - 27 29 TBD

Capability Development 19 19 25 TBD TBD TBD

Total 196 478 593 701 721 315

Revenue2013 $’000

2014 $’000

2015 $’000

2016 $’000

2017 $’000

2018 $’000

Total Centre Funds 294 314 336 360 385

RT Projects Funds 0 90 180 237 237 182

UQ/State Government - 133 133 133

Carry Over 97 24 -53 -24

Total 294 501 540 677 731 315

Surplus (Rev. - Exp.) 98 23 -53 -24 10 0

Financial Report


UQ RT BAUXITE AND ALUMINA TECHNOLOGY CENTRE

The University of Queensland | School of Chemical Engineering

Chemical Engineering Building (74), College Road St Lucia QLD Australia 4068

[email protected] | +61 7 3365 3850

http://www.chemeng.uq.edu.au/rt

Documents

annual report 2015 - School of Chemical Engineering · Chief Technologist, Rio Tinto Bauxite and Alumina Steve Healy’s industrial research and development expertise developed over