Bauxite residue from Greece (AoG)

Data provider

Organisation/Data provider's name 
Budapest University of Technology and Economics, Department of Applied Biotechnology and Food Science, Environmental Microbiology and Biotechnology Group
Name of contact 
Dr. Molnár Mónika, Dr. Feigl Viktória

Contact details

Country 
Hungary
Telephone/fax 
+36-1-4632347
Production, treatment and dumping place
Name 
Aluminium of Greece, Metallurgy Business Unit Mytilineos S.A., (AoG)
Activities 
Producing
Waste stockpiling
Waste disposing
General information about the waste or by-product
Denomination of the waste or by-product 
Bauxite residue from Greece (AoG)
Denomination of the waste or by-product in English 
Bauxite residue from Greece (AoG)
Type of the waste or by-product data-sheet 
Characterisation of a particular waste or secondary product
Functional characterisation 
Non-hazardous waste from mining
EWC code of waste 
  • 01 WASTE RESULTING FROM EXPLORATION, MINING, QUARRYING, AND PHYSICAL AND CHEMICAL TREATMENT OF MINERALS
  • 01 04 wastes from physical and chemical processing of non-metalliferous minerals
  • 01 04 12 tailings and other wastes from washing and cleaning of minerals other than those mentioned in 01 04 07 and 01 04 11
Consistency of the waste or by-product 
Sludge (sludgy), pasta
Description of the waste generating technology 

The Bayer process is the primary method by which alumina (Al2O3) is produced from bauxite ore. In this hydrometallurgical process, caustic soda digestion under elevated temperature and pressure is used to leach soluble alumina minerals from the bauxite ore and subsequently precipitate technically pure aluminum hydroxide. From the pregnant leach solution, the residual mineral matrix is removed as a byproduct, commonly termed as bauxite residue or “red mud” (Adamson et al., 2013; Gräfe and Klauber, 2011).
According to Vind, J. et al, 2018, in the process flowsheet of Aluminium of Greece, Metallurgy Business Unit, Mytilineos S.A., (AoG), about 80% of the bauxite feed is from karst bauxite, mainly Greek origin. About 20% of feed is from lateritic bauxite originating from West Africa (Ghana, Awaso) or Brazil (Porto Trombetas). The suspended karst bauxite is digested at a high temperature, and then the lateritic bauxite suspension stream is introduced to the main karst bauxite slurry stream in the appropriate flashing stage. The karst bauxite slurry in AoG is digested at about 255 °C (Balomenos et al., 2009) and a pressure of about 5.8–6.0 MPa.
The current practice in AoG’s plant is to dewater the washed bauxite residue in filter presses and store the filter cake. This datasheet provides the properties of the filter cake, based on Vind, J. et al, 2018.

Any special characteristics of the waste or by-product 
It has been reported that over a 15-year period, the concentration of rare earth elements (REE) as well as Sc in the bauxite residue of AoG has fluctuated only about 8%, indicating a stable and homogeneous occurrence of Sc in this material (Davris et al., 2017).
Is it a hazardous waste? 
no
Generated annual tonnage 
0.7 Mt/year
Dumped tonnage 
5 Mt by 2015
Characterisation of the waste as a chemical substance 
Mixture of chemical substances
Characterisation and concentration of the chemical substances
Chemical substance, Main group|Chemical substance, Subgroup 
  • Metals, semi-metals and their compounds
  • aluminium
Other type of chemical substance 
Al2O3
Is the contained chemical substance main component, component or contaminant of the waste or by-products / biochar? 
Main component
Concentration of the chemical in the waste or by-product / biochar 
20.16 %
Analytical method 

Standardized X-ray fluorescence (XRF),

Chemical substance, Main group|Chemical substance, Subgroup 
  • Metals, semi-metals and their compounds
  • iron
Other type of chemical substance 
Fe2O3
Is the contained chemical substance main component, component or contaminant of the waste or by-products / biochar? 
Main component
Concentration of the chemical in the waste or by-product / biochar 
41.65 %
Analytical method 

standardized X-ray fluorescence (XRF),

Chemical substance, Main group|Chemical substance, Subgroup 
  • Other inorganic chemical compounds
  • silicon
Other type of chemical substance 
SiO2
Is the contained chemical substance main component, component or contaminant of the waste or by-products / biochar? 
Component
Concentration of the chemical in the waste or by-product / biochar 
6.76 %
Analytical method 

Standardized X-ray fluorescence (XRF)

Chemical substance, Main group|Chemical substance, Subgroup 
  • Metals, semi-metals and their compounds
  • titanium
Other type of chemical substance 
TiO2
Is the contained chemical substance main component, component or contaminant of the waste or by-products / biochar? 
Component
Concentration of the chemical in the waste or by-product / biochar 
5.32 %
Chemical substance, Main group|Chemical substance, Subgroup 
  • Other inorganic chemical compounds
  • calcium
Other type of chemical substance 
CaO
Is the contained chemical substance main component, component or contaminant of the waste or by-products / biochar? 
Component
Concentration of the chemical in the waste or by-product / biochar 
10.07 %
Chemical substance, Main group|Chemical substance, Subgroup 
  • Other inorganic chemical compounds
  • sodium
Other type of chemical substance 
Na2O
Is the contained chemical substance main component, component or contaminant of the waste or by-products / biochar? 
Component
Concentration of the chemical in the waste or by-product / biochar 
2.87 %
Chemical substance, Main group|Chemical substance, Subgroup 
  • Metals, semi-metals and their compounds
  • chromium
Is the contained chemical substance main component, component or contaminant of the waste or by-products / biochar? 
Component
Concentration of the chemical in the waste or by-product / biochar 
1429 mg/kg
Analytical method 

Inductively coupled plasma mass spectrometry (ICP-MS) after lithium metaborate/tetraborate fusion

Chemical substance, Main group|Chemical substance, Subgroup 
  • Metals, semi-metals and their compounds
  • vanadium
Is the contained chemical substance main component, component or contaminant of the waste or by-products / biochar? 
Component
Concentration of the chemical in the waste or by-product / biochar 
1029 mg/kg
Analytical method 

Inductively coupled plasma mass spectrometry (ICP-MS) after lithium metaborate/tetraborate fusion

Chemical substance, Main group|Chemical substance, Subgroup 
  • Metals, semi-metals and their compounds
  • other metal
Other type of chemical substance 
Sc
Is the contained chemical substance main component, component or contaminant of the waste or by-products / biochar? 
Component
Concentration of the chemical in the waste or by-product / biochar 
97.6 mg/kg
Analytical method 

Instrumental neutron activation analysis (INAA).

Main characteristics of the waste/ by-product
Name of the waste/by-product 
Bauxite residues from Greece (AoG)
Components of the waste/by-product 

Mineralogical composition of the studied bauxite residue representing XRD-crystalline phases: boehmite: 2%, diaspore: 13%, hematite: 31%, Goethite: 7.5%, anatase: 0.6%, rutile: 0.7%, calcite: 5%, quartz: 5%, chamosite: 3.7%, gibbsite: 2.5% .
Secondary phases formed during the Bayer process: Hydrogarnet:14.5%, cancrinite: 11%, pervskite: 4%, portlandite: 0.8% (Vind et al, 2018)

Other characteristics of the waste/by-product 

Based on various publications that used different analytical techniques, the average concentration of Sc in AoG’s bauxite residue is 121 ± 16 mg/ kg (n=24) (Vind et al, 2018)

Physico-chemical properties of the waste or by-product
Moisture content (%) 
26
Ignition loss (LOI) (%) 
9.17
Homogeneity 
Homogeneous
References 

1) Adamson, A.N., Bloore, E.J., Carr, A.R., 2013. Basic Principles of Bayer Process Design. In: Donaldson, D., Raahauge, B.E. (Eds.), Reprinted in Essential Readings in Light Metals. John Wiley & Sons Inc, pp. 100–117 (2013).
2) Balomenos, E., Giannopoulou, I., Panias, D., Paspaliaris, I., 2009. ENEXAL: Novel technologies for enhanced energy and exergy efficiencies in primary aluminium production industry. MJoM 15, 203–217.
3) Gräfe, M., Klauber, C., 2011. Bauxite residue issues: IV. Old obstacles and new pathways for in situ residue bioremediation. Hydrometallurgy 108, 46 59. http://dx.doi.org/10.1016/j.hydromet.2011.02.005.
4) Davris, P., Balomenos, E., Taxiarchou, M., Panias, D., Paspaliaris, I., 2017. Current and alternative routes in the production of rare earth elements. BHM Berg- Hüttenmänn. Monatshefte 162, 245–251. http://dx.doi.org/10.1007/s00501-017-0610-y.
5) Vind, J., Malfliet, A., Bonomi, C., Paiste, P., Sajó, I.E., Blanpain, B., Tkaczyk, A.H., Vassiliadou, V., Panias, D. (2018) Modes of occurrences of scandium in Greek bauxite and bauxite residue, Minerals Engineering 123, 35–48.

Hazards of the waste or by-product
Hazard characteristics 
No information
Measured harmful effects 
No information