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Line 1: {{for|the tannic for drilling mud|Quebracho tree}} ] (])]] '''Red mud''' or '''red sludge''' is a ] product generated in the industrial producing aluminium. With about 77 million tons produced annually, red mud is one of the most important disposal problems in the mining industry. '''Red mud''' or '''red sludge''' is a ]<ref>{{Cite journal | last1 = Kurniawan | first1 = TA. | last2 = Chan | first2 = GY. | last3 = Lo | first3 = WH. | last4 = Babel | first4 = S. | title = Comparisons of low-cost adsorbents for treating wastewaters laden with heavy metals. | journal = Sci Total Environ | volume = 366 | issue = 2–3 | pages = 409–26 |date=Aug 2006 | doi = 10.1016/j.scitotenv.2005.10.001 | pmid = 16300818 }} </ref> ] product of the ], the principal industrial means of refining ] in order to provide ] as raw material for the ] of ] by the ].<ref name="hand">{{cite book | url = http://books.google.de/books?id=WvT2OEf8DskC&pg=PA18 | pages = 18 | chapter = Red Mud Disposal | title = Handbook of aluminium recycling | isbn = 978-3-8027-2936-2 | author1 = Schmitz, Christoph | year = 2006}}</ref><ref name="waste">{{cite book | url = http://books.google.de/books?id=87_snenwV5MC&pg=PA292 | pages = 292–295 |chapter = Red Mud Utilization | title = Waste materials used in concrete manufacturing | isbn = 978-0-8155-1393-3 | author1 = Chandra, Satish | date = 1996-12-31}}</ref><ref name="indust">{{cite book | url = http://books.google.de/books?id=zNicdkuulE4C&pg=PA258 | pages = 258–259 |chapter = Bauxite | title = Industrial minerals & rocks: commodities, markets, and uses | isbn = 978-0-87335-233-8 | author1 = Mining, Society for | author2 = Metallurgy, | author3 = ), Exploration (U.S | date = 2006-03-05}}</ref> A typical plant produces one to two times as much red mud as alumina.<ref>{{Cite journal | last1 = Mohan | first1 = D. | last2 = Pittman | first2 = CU. | title = Arsenic removal from water/wastewater using adsorbents--A critical review | journal = J Hazard Mater | volume = 142 | issue = 1–2 | pages = 1–53 |date=Apr 2007 | doi = 10.1016/j.jhazmat.2007.01.006 | pmid = 17324507 }}</ref> This ratio is dependent on the type of bauxite used in the refining process.<ref name="waste"></ref>▼   ==Production and storage== Red mud is composed of a mixture of solid and ]lic oxide-bearing impurities, and presents one of the aluminium ]'s most important disposal problems. The ] colour is caused by the ] ] present, which can make up to 60% of the mass of the red mud.<ref name="hand"/><ref name="waste"/><ref name="indust"/> In addition to iron, the other dominant particles include ], unleached residual aluminium, and ].<ref>{{Cite journal | last1 = Babel | first1 = S. | last2 = Kurniawan | first2 = TA. | title = Low-cost adsorbents for heavy metals uptake from contaminated water: a review | journal = J Hazard Mater | volume = 97 | issue = 1–3 | pages = 219–43 |date=Feb 2003 | doi = 10.1016/S0304-3894(02)00263-7 | pmid = 12573840 }}▼ ▲</ref>It ]is a side-product of the ], the principal industrial means of refining ] inen orderroute to provide ]. asThe resulting alumina is raw material for the ] of ] by the ].<ref name="hand">{{cite book | url = http://books.google.de/books?id=WvT2OEf8DskC&pg=PA18 | pages = 18 | chapter = Red Mud Disposal | title = Handbook of aluminium recycling | isbn = 978-3-8027-2936-2 | author1 = Schmitz, Christoph | year = 2006}}</ref><ref name="waste">{{cite book | url = http://books.google.de/books?id=87_snenwV5MC&pg=PA292 | pages = 292–295 |chapter = Red Mud Utilization | title = Waste materials used in concrete manufacturing | isbn = 978-0-8155-1393-3 | author1 = Chandra, Satish | date = 1996-12-31}}</ref><ref name="indust">{{cite book | url = http://books.google.de/books?id=zNicdkuulE4C&pg=PA258 | pages = 258–259 |chapter = Bauxite | title = Industrial minerals & rocks: commodities, markets, and uses | isbn = 978-0-87335-233-8 | author1 = Mining, Society for | author2 = Metallurgy, | author3 = ), Exploration (U.S | date = 2006-03-05}}</ref> A typical plant produces one to two times as much red mud as alumina.<ref>{{Cite journal | last1 = Mohan | first1 = D. | last2 = Pittman | first2 = CU. | title = Arsenic removal from water/wastewater using adsorbents--A critical review | journal = J Hazard Mater | volume = 142 | issue = 1–2 | pages = 1–53 |date=Apr 2007 | doi = 10.1016/j.jhazmat.2007.01.006 | pmid = 17324507 }}</ref> This ratio is dependent on the type of bauxite used in the refining process.<ref name="waste"></ref> The mud is highly ] with a ] ranging from 10 to 13. Several methods are used to lower the ] pH to a less corrosive level . </ref>   Red mud cannot be disposed of easily. In most countries where red mud is produced, it is pumped into ]s.<ref name="hand"/><ref name="waste"/><ref name="indust"/> Red mud presents a problem as it takes up land area and can neither be built on nor farmed, even when dry. As a waste product of the Bayer process the mud is highly ] with a ] ranging from 10 to 13. Several methods are used to lower the ] pH to an acceptable level to decrease the impact on the environment. Research is being performed to find a suitable way to use the mud for other applications,<ref name="hand"/><ref name="waste"/><ref name="indust"/> but drying the mud requires much energy (] for ] ]) and can represent high costs if ]s have to be used in the drying process.   ==Composition== ▲Red mud is composed of a mixture of solid and ]lic oxide-bearing impurities, and presents one of the aluminium ]'s most important disposal problemsoxides. The ] colour isarises caused by thefrom ]iron ] presents, which can makecomprises up to 60% of the mass of the red mud.<ref name="hand"/><ref name="waste"/><ref name="indust"/> In addition to iron, the other dominant particlescomponents include ], unleached residual aluminium, and ].<ref>{{Cite journal | last1 = Babel | first1 = S. | last2 = Kurniawan | first2 = TA. | title = Low-cost adsorbents for heavy metals uptake from contaminated water: a review | journal = J Hazard Mater | volume = 97 | issue = 1–3 | pages = 219–43 |date=Feb 2003 | doi = 10.1016/S0304-3894(02)00263-7 | pmid = 12573840 }}</ref>   ==Use== Research is being performed to find uses for red mud.<ref name="hand"/><ref name="waste"/><ref name="indust"/> One challenge is that drying the mud requires much energy (] for ] ]. Potential applications include the production of low cost concrete.<ref>Liu, W., Yang, J., Xiao, B., "Review on treatment and utilization of bauxite residues in China", Int. J. Miner. Process. 2009, 93, 220.</ref> Vedanta Aluminium Ltd has commissioned a red mud powder producing unit at Lanjigarh refinery in Odisha, describing it as first of its kind in alumina industry tackling major environmental hazards.<ref>{{Cite news | title = Vedanta commissions red mud powder plant in Odisha | url = http://www.thehindubusinessline.com/companies/vedanta-commissions-red-mud-power-plant-in-odisha/article5367292.ece | newspaper = Business Line| date = 19 November 2013}}</ref>▼   == Environmental hazards == Discharge of red mud is hazardousl environmentally because of its alkalinity. In the event of improper disposal or willful discharge of red mud in rivers or lakes, there are fatal environmental hazards. The rain water run off from the red mud ponds increases river and stream water alkalinity which will convert lands into ] when used for irrigation purpose.   In October 2010, approximately one million cubic meters of red mud from an ] plant near ] in ] was accidentally released into the surrounding countryside in the ], killing ten people and contaminating a large area.<ref name=npr100510>, David Gura, NPR, October 5, 2010</ref> All life in the ] river was said to have been "extinguished" by the red mud, and within days the mud had reached the ].<ref>{{Cite news | title = Hungarian chemical sludge spill reaches Danube | url = http://www.bbc.co.uk/news/world-europe-11491412| newspaper = BBC| date = 7 October 2010}}</ref>   == Powder generation == ▲Vedanta Aluminium Ltd has commissioned a red mud powder producing unit at Lanjigarh refinery in Odisha, describing it as first of its kind in alumina industry tackling major environmental hazards.<ref>{{Cite news | title = Vedanta commissions red mud powder plant in Odisha | url = http://www.thehindubusinessline.com/companies/vedanta-commissions-red-mud-power-plant-in-odisha/article5367292.ece | newspaper = Business Line| date = 19 November 2013}}</ref>   ==See also==

Revision as of 16:04, 27 September 2014

For the tannic for drilling mud, see Quebracho tree.
Red mud near Stade (Germany)

Red mud or red sludge is a waste product generated in the industrial producing aluminium. With about 77 million tons produced annually, red mud is one of the most important disposal problems in the mining industry.

Production and storage

It is a side-product of the Bayer process, the principal means of refining bauxite en route to alumina. The resulting alumina is raw material for the electrolysis of aluminium by the Hall–Héroult process. A typical plant produces one to two times as much red mud as alumina. This ratio is dependent on the type of bauxite used in the refining process. The mud is highly basic with a pH ranging from 10 to 13. Several methods are used to lower the alkaline pH to a less corrosive level .

Red mud cannot be disposed of easily. In most countries where red mud is produced, it is pumped into holding ponds. Red mud presents a problem as it takes up land area and can neither be built on nor farmed, even when dry.

Composition

Red mud is composed of a mixture of solid and metallic oxides. The red colour arises from iron oxides, which comprises up to 60% of the mass of the red mud. In addition to iron, the other dominant components include silica, unleached residual aluminium, and titanium oxide.

Use

Research is being performed to find uses for red mud. One challenge is that drying the mud requires much energy (latent heat for water evaporation. Potential applications include the production of low cost concrete. Vedanta Aluminium Ltd has commissioned a red mud powder producing unit at Lanjigarh refinery in Odisha, describing it as first of its kind in alumina industry tackling major environmental hazards.

Environmental hazards

Discharge of red mud is hazardousl environmentally because of its alkalinity.

In October 2010, approximately one million cubic meters of red mud from an alumina plant near Kolontár in Hungary was accidentally released into the surrounding countryside in the Ajka alumina plant accident, killing ten people and contaminating a large area. All life in the Marcal river was said to have been "extinguished" by the red mud, and within days the mud had reached the Danube.

See also

References

  1. ^ Schmitz, Christoph (2006). "Red Mud Disposal". Handbook of aluminium recycling. p. 18. ISBN 978-3-8027-2936-2.
  2. ^ Chandra, Satish (1996-12-31). "Red Mud Utilization". Waste materials used in concrete manufacturing. pp. 292–295. ISBN 978-0-8155-1393-3.
  3. ^ Mining, Society for; Metallurgy,; ), Exploration (U.S (2006-03-05). "Bauxite". Industrial minerals & rocks: commodities, markets, and uses. pp. 258–259. ISBN 978-0-87335-233-8.{{cite book}}: CS1 maint: extra punctuation (link)
  4. Mohan, D.; Pittman, CU. (Apr 2007). "Arsenic removal from water/wastewater using adsorbents--A critical review". J Hazard Mater. 142 (1–2): 1–53. doi:10.1016/j.jhazmat.2007.01.006. PMID 17324507.
  5. Babel, S.; Kurniawan, TA. (Feb 2003). "Low-cost adsorbents for heavy metals uptake from contaminated water: a review". J Hazard Mater. 97 (1–3): 219–43. doi:10.1016/S0304-3894(02)00263-7. PMID 12573840.
  6. Liu, W., Yang, J., Xiao, B., "Review on treatment and utilization of bauxite residues in China", Int. J. Miner. Process. 2009, 93, 220.
  7. "Vedanta commissions red mud powder plant in Odisha". Business Line. 19 November 2013.
  8. "Toxic Red Sludge Spill From Hungarian Aluminum Plant 'An Ecological Disaster'", David Gura, NPR, October 5, 2010
  9. "Hungarian chemical sludge spill reaches Danube". BBC. 7 October 2010.

External links

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