Bauxite residue

Residue Disposal. The major environmental problem in the Bayer process is disposal of bauxite residue which is effected by marine disposal, lagooning, use of underdrain lakes, or semidry disposal. Marine disposal in oceans or rivers, diluting the alkaline residue by large quantities of water, is environmentally unacceptable. Lagooning behind retaining dikes built around clay-sealed ground is commonly used, but there have been isolated leaks into aquifers. This has motivated installation of underdrains between the residue and clay-sealed, plastic-lined, lake bottom. This design removes the hydraulic head from the lake bottom and improves consoHdation of the residue. 

White Hydroxide. Tlie soda sinter process appHed to bauxite or bauxite residue produces a hydroxide that is completely free from organic coloring matter and is very wliite. A value of more than 95% is obtained on the GE brightness scale relative to Ti02 as followed in the paper (qv) industry. Tliis compares to about 70% on the same scale for the nomial Bayer product. Tlie wliite hydroxide is preferred in the paper, toothpaste, and artificial marble industries. 

Summers, R.N. Guise, N.R. Smirk, D.D. Summers, K.J. (1996) Bauxite residue (red mud) improves pasture growth on sandy soils in Western Australia. Aust. J. Soil Res. 34 569-581... 

Other brines and mud suspensions from industrial processes that are currently being considered for carbonation include aqueous red mud flows [27] and mixtures of bauxite and saline waste water [115] from aluminum production. Here, the C02 fixation capacities are of the order of 5-10 g per 100 g red mud as a result of 15wt% Na20 + CaO (dry), while a 90%/10% (v/v) bauxite waste/brine mixture can take up more than 9.5 g C02 per liter of liquid. Worldwide, a total of 200 Mt bauxite residues are stored, mainly in ponds. 

Bacteria associated with bauxite ore have been shown to reductively mobilize significant amounts of the Fe(III) oxides in the bauxite under anaerobic conditions without mobilizing significant amounts of the Al(III) oxides like gibbsite or boehmite as long as the pH of the reaction system was kept above 4.5. The bauxite residue was thus enriched in aluminium (Ehrlich et al., 1995 Ehrlich Wickert, 1997). 

BAUXITE RESIDUE (1309-37-1) Violent reactions with powdered aluminum (thermite reaction), hydrogen peroxide, calcium disilicide (thermite reaction), ethylene oxide (may cause explosive polymerization), calcium hypochlorite, hydrazine, hydrogen trisulfide, powdered magnesium. Incompatible with powdered calcium carbide, carbon monoxide, chlorides, guanidinium perchlorate, metal acetylides. Contact with the explosive hydrazinium diperchlorate or ammonium perchlorate can be made more heat-, shock-, or friction-sensitive. Incompatible with aluminum-magnesium-zinc alloys. 

Synonyms cas 1309-37-1 bauxite residue black oxide of iron blended red oxides of iron Burntisland... 

There are two bulk-waste products from which REEs can be recycled. They are red mud , a bauxite residue generated during the Bayer process for alumina production and phosphogypsum, a residue that is formed during phosphorus production, and contains REE originating from the original phosphorus ore mineral (apatite). 

Borra C, Pontikes Y, Binnemans K, Van Gerven T (2015) Ixaching of rare earths from bauxite residue (red mud). Miner Eng 76 20-27... 

Mamnczyn, M. and Laros, T. J., Bauxite residue disposal at Alcoa of Australia using the Hi-Density thickener . Paper B2.2, AFS Seminar and Expo, System Approach to Separation and Filtration Process Equipment, Chicago, Illinois USA, May 3-6,1993, paper published in Advances in Filtration and Separation Technology, Vol. 7, American Filtration Society, Kingwood, Texas, April, 180-188 (1993)... 

Rai, B., and Pradip. 2009. Development of innovative technologies for the treatment, recycling and utilisation of bauxite residue (Red Mud) in India. Indian Chem. Eng. 51 28. 

Want et al. (1982) reviewed the design of a bauxite residue pipeline for Alcoa Australia. The plant disposed 4.75 Mtpy (million tonnes per year) of alumina. Tests conducted on samples confirmed that the rheology of the slurry at concentrations in excess of 45% by weight could be expressed by the Carson equation ... 

Want, F. M., P. M. Colombera, Q. D. Nguyen, and D. V. Boger. 1982. Pipeline design for the transport of high-density bauxite residue slurries. In Proceedings of the 8th International Conference on the HydrauUc Transport of Solids in Pipes, Johannesburg, South Africa. Cranfield, UK BRHA Group. 

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