the mineralogy of bauxite for producing smelter-grade alumina | springerlink
Aluminum-producing companies rely on low-cost, high-purity, smelter-grade alumina (aluminum oxide), and alumina production utilizes the bulk of bauxites mined world-wide. The mineralogy of the bauxites has a significant impact on the operation of the Bayer process for alumina production. Typically, the Bayer process produces smelter-grade alumina of 99.5% Al2O3, starting from bauxite containing 30% to 60% Al2O3. The main objective of the Bayer process is to extract the maximum amount of aluminum from the bauxite at as high an aluminate concentration in solution as possible, while limiting any troublesome side reactions. Only with a better understanding of the chemistry of the mineral species and a strict control of the operating/processing conditions can the Bayer process produce efficiently, a low cost, high-quality alumina with minimum detrimental environmental impact.
R. Calalo and Tam Tran, Effects of Sodium Oxalate on the Precipitation of Alumina from Synthetic Sodium Aluminate Liquors, Light Metals 1993, ed. Subodh K. Das (Warrendale, PA: TMS, 1993), pp. 125133.
Raw Materials R&D Coordinator,
Bayer Consultant (retired),
Senior Research Scientist,
the Arvida Research and Development Centre, Alcan Int. Limited, Canada
bauxite mining process analytical solutions | malvern panalytical
Available alumina and reactive silica define ore grade and conditions for bauxite refining. Malvern Panalytical s predictive solutions help to efficiently sort and blend bauxite, ensure optimal and profitable extraction of available alumina, and support sustainable and safe waste management (red mud).
Our expertise and solutions range from direct conveyor belt analysis to laboratory analysis and complete automated quality control. We deliver tailored analytical solutions for exploration geologists, mine planners, process engineers, laboratory and quality managers as well as geometallurgists.
Our solutions for real-time monitoring on conveyor belts (elemental and mineralogical) with its fast feedback loops, enable fast counteractions on changing bauxite composition directly in the mine and effective ore sorting.
Optimal bauxite blends with constant composition secure optimal use of caustic soda and other reagents during refining and avoid costly processing of waste material. Control of the moisture content on the conveyor belt using near-infrared (NIR) technology, together with accurate monitoring of the composition of iron ore before shipment, guaranties constant ore quality to avoids penalties.
Our laboratory solutions, tailored to the specific requirements of your mine, provide accurate and fast information whether it is benchtop or stand-alone equipment or completely automated laboratories.
Our expertise in XRF sample preparation, especially to produce high quality glass disks using fusion machines, are the basis for accurate elemental analysis according to international norms. The use of modern technologies such as X-ray diffraction (XRD) to predict available alumina and reactive silica, reduces the need for costly, time intense and unsafe wet chemistry.
Efficiency of alumina refineries, minimal use of energy per ton alumina and highest recovery rates depend on bauxite composition, impurity level of the process liquor and optimal caustic soda consumption. Our portable and flexible elemental analysers are perfectly suitable to monitor impurity levels of bauxite and process liquors directs in the refinery even in remote areas.
Particle size and distribution as well as the crystallographic modification are key variables that define quality of alumina and directly impact the rate of dissolution of alumina in the aluminium smelters. To meet the required alumina specifications our on-line particle size analyzers are designed to operate in rough process environments. Economic benefits are: