79:
374:
1.7–3.3 tonnes (3,800–7,200 lb) of bauxite (corresponding to about 90% of the alumina content of the bauxite) is required to produce 0.91 tonnes (2,000 lb) of aluminium oxide. This is due to a majority of the aluminium in the ore being dissolved in the process. Energy consumption is between
390:
is the waste product that is produced in the digestion of bauxite with sodium hydroxide. It has high calcium and sodium hydroxide content with a complex chemical composition, and accordingly is very caustic and a potential source of pollution. The amount of red mud produced is considerable, and this
489:
in dyeing cotton), Bayer discovered in 1887 that the aluminium hydroxide that precipitated from alkaline solution was crystalline and could be easily filtered and washed, while that precipitated from acid medium by neutralization was gelatinous and difficult to wash. The industrial success of this
363:
Organic impurities that accumulate during the precipitation of gibbsite may cause various problems, for example high levels of undesirable materials in the gibbsite, discoloration of the liquor and of the gibbsite, losses of the caustic material, and increased viscosity and density of the working
424:
where the western dam of its red mud reservoir collapsed. The reservoir was filled with 700,000 cubic metres (25 million cubic feet) of a mixture of red mud and water with a pH of 12. The mixture was released into the valley of Torna river and flooded parts of the city of
Devecser and the
406:, a sort of reservoir created by a dam. The impoundments are typically lined with clay or synthetic liners. The US does not approve of the use of the waste due to the danger it poses to the environment. The EPA identified high levels of arsenic and chromium in some red mud samples.
666:
energy required by the Bayer
Process is very much dependent on the quality of the raw material . average specific energy consumption is around 14.5 GJ per tonne of alumina, including electrical energy of around 150 kWh/t
398:
One use of red mud is in ceramic production. Red mud dries into a fine powder that contains iron, aluminium, calcium and sodium. It becomes a health risk when some plants use the waste to produce aluminium oxides.
490:
process caused it to replace the Le
Chatelier process which was used to produce alumina from bauxite. The Deville process was abandoned in favor of the Bayer process, which marks the birth of the modern field of
110:, meaning that they are both acidic and basic. The solubility of Al(III) in water is very low but increases substantially at either high or low pH. In the Bayer process, bauxite ore is heated in a
375:
7 to 21 gigajoules per tonne (0.88 to 2.65 kWh/lb) (depending on process), of which most is thermal energy. Over 90% (95-96%) of the aluminium oxide produced is used in the
850:
513:
and flash tanks were used and larger reactors decreased the amount of heat lost. Efficiency was increased by connecting the autoclaves to make operation more efficient.
299:) or sodium aluminate; a significant amount is also used as a filler in rubber and plastics as a fire retardant. Some 90% of the gibbsite produced is converted into
90:
Bauxite ore is a mixture of hydrated aluminium oxides and compounds of other elements such as iron. The aluminium compounds in the bauxite may be present as
130:
with fine-grained aluminium hydroxide crystals from previous extractions. The precipitation may take several days without addition of seed crystals.
106:(α-AlO(OH)); the different forms of the aluminium component and the impurities dictate the extraction conditions. Aluminium oxides and hydroxides are
647:
425:
villages of Kolontár and Somlóvásárhely. The incident resulted in 10 deaths, more than a hundred injuries, and contamination in lakes and rivers.
900:
614:
Alessio Angelo
Scarsella, Sonia Noack, Edgar Gasafi, Cornelis Klett, Andreas Koschnick (2015). "Energy in Alumina Refining: Setting New Limits".
126:(primarily ) in an extraction process. After separation of the residue by filtering, gibbsite is precipitated when the liquid is cooled and then
352:
The left-over, 'spent' sodium aluminate solution is then recycled. Apart from improving the economy of the process, recycling accumulates
587:
Hind, Andrew R.; Bhargava, Suresh K.; Grocott, Stephen C. (January 1999). "The surface chemistry of Bayer process solids: a review".
1370:
821:
458:, at 1,200 °C (2,190 °F), leaching the sodium aluminate formed with water, then precipitating aluminium hydroxide by
434:
705:
Hind, Andrew R.; Bhargava, Suresh K.; Grocott, Stephen C. (1999). "The
Surface Chemistry of Bayer Process Solids: A Review".
631:
568:
485:. Working in Saint Petersburg, Russia to develop a method for supplying alumina to the textile industry (it was used as a
197:. The solution is clarified by filtering off the solid impurities, commonly with a rotary sand trap and with the aid of a
893:
395:. Due to the low extraction yield much of the gallium ends up in the aluminium oxide as an impurity and in the red mud.
613:
921:
760:"The Red Mud Accident in Ajka (Hungary): Plant Toxicity and Trace Metal Bioavailability in Red Mud Contaminated Soil"
367:
For bauxites having more than 10% silica, the Bayer process becomes uneconomic because of the formation of insoluble
758:
Ruyters, Stefan; Mertens, Jelle; Vassilieva, Elvira; Dehandschutter, Boris; Poffijin, Andre; Smolders, Erik (2011).
1534:
516:
Today, the process produces nearly all the world's alumina supply as an intermediate step in aluminium production.
118:
solution (caustic soda) at a temperature of 150 to 200 °C (302 to 392 °F). At these temperatures, the
1000:
995:
886:
759:
1274:
1160:
732:
229:
solution was cooled and treated by bubbling carbon dioxide through it, a method by which aluminium hydroxide
267:
But later, this gave way to seeding the supersaturated solution with high-purity aluminium hydroxide (Al(OH)
1529:
1524:
1284:
525:
421:
415:
291:
Some of the aluminium hydroxide produced is used in the manufacture of water treatment chemicals such as
1443:
535:
471:
376:
391:
has led scientists and refiners to seek uses for it. It has received attention as a possible source of
368:
230:
497:
The engineering aspects of the process were improved upon to decrease the cost starting in 1967 in
205:, to remove the fine particles. The undissolved waste after the aluminium compounds are extracted,
1047:
661:
296:
271:) crystal, which eliminated the need for cooling the liquid and was more economically feasible:
1169:
1337:
1305:
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83:
1069:
1052:
8:
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324:
863:
778:
437:
in France developed a method for making alumina by heating bauxite in sodium carbonate,
63:. The aluminium oxide must be further purified before it can be refined into aluminium.
1220:
1117:
929:
641:
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292:
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32:
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40:
558:
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502:
459:
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137:) converts the aluminium oxide in the ore to soluble sodium aluminate, NaAlO
1430:
1150:
1145:
1102:
794:
127:
1300:
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312:
210:
878:
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to a temperature of about 1,470 K (1,200 °C; 2,190 °F).
198:
107:
56:
786:
757:
1345:
1310:
1180:
1064:
1007:
403:
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impurities in the liquors, so that they can be extracted profitably.
189:
The other components of
Bauxite, however, do not dissolve. Sometimes
165:
This treatment also dissolves silica, forming sodium silicate :
119:
36:
1473:
1240:
1212:
1037:
392:
357:
316:
103:
99:
91:
78:
466:, which was then filtered and dried. This process is known as the
1097:
1074:
1042:
968:
822:"Bayer's Process for Alumina Production: A Historical Production"
498:
486:
387:
353:
331:
67:
28:
24:
707:
Colloids and
Surfaces A: Physicochemical and Engineering Aspects
589:
Colloids and
Surfaces A: Physicochemical and Engineering Aspects
505:. This was done by increasing the heat recovery and using large
1478:
985:
226:
218:
214:
202:
52:
225:
and some unreacted alumina. The original process was that the
1012:
559:
Harris, Chris; McLachlan, R. (Rosalie); Clark, Colin (1998).
420:
On
October 4, 2010, the Ajka alumina plant in Hungary had an
342:
1483:
739:. United States Environmental Protection Agency. 2015-04-22
848:
Habashi, F. (2005). "A short history of hydrometallurgy".
371:, which reduces yield, so another process must be chosen.
958:
509:
and precipitation tanks. To more effectively use energy,
16:
Industrial means of refining bauxite to produce alumina
561:
Micro reform – impacts on firms: aluminium case study
402:
In the United States, the waste is disposed in large
193:
is added at this stage to precipitate the silica as
704:
586:
1516:
733:"TENORM: Bauxite and Alumina Production Wastes"
409:
70:as a byproduct despite low extraction yields.
23:is the principal industrial means of refining
894:
66:The Bayer process is also the main source of
646:: CS1 maint: multiple names: authors list (
1429:
847:
582:
580:
472:Hall–Héroult electrolytic aluminium process
901:
887:
481:The Bayer process was invented in 1888 by
908:
577:
77:
31:(aluminium oxide) and was developed by
1517:
767:Environmental Science & Technology
882:
35:. Bauxite, the most important ore of
816:
814:
812:
810:
808:
806:
804:
435:Henri Étienne Sainte-Claire Deville
13:
563:. Melbourne: Industry Commission.
14:
1546:
922:Non-ferrous extractive metallurgy
831:. Fathi Habashi, Laval University
801:
680:"The Aluminum Smelting Process"
51:), the rest being a mixture of
872:10.1016/j.hydromet.2004.01.008
751:
725:
698:
672:
654:
607:
552:
1:
1275:Bottom-blown oxygen converter
719:10.1016/S0927-7757(98)00798-5
601:10.1016/S0927-7757(98)00798-5
546:
624:10.1007/978-3-319-48248-4_24
7:
526:Ajka alumina plant accident
519:
416:Ajka alumina plant accident
410:Ajka alumina plant accident
10:
1551:
428:
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73:
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1323:
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1198:
1131:
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1023:
941:
928:
916:
369:sodium aluminium silicate
1001:Underground in soft rock
996:Underground in hard rock
686:. aluminumproduction.com
382:
133:The extraction process (
1535:Metallurgical processes
478:was invented in 1887.
39:, contains only 30–60%
474:was invented, and the
379:to produce aluminium.
297:Polyaluminium chloride
87:
1329:(by aqueous solution)
1161:Gravity Concentration
910:Extractive metallurgy
81:
1444:Hall–Héroult process
1123:Mechanical screening
618:. pp. 131–136.
541:History of aluminium
536:Hall–Héroult process
377:Hall–Héroult process
84:process flow diagram
1166:Magnetic separation
1113:Cyclonic separation
934:(by physical means)
919:Metallurgical assay
864:2005HydMe..79...15H
779:2011EnST...45.1616R
684:Aluminum Production
662:"Energy efficiency"
476:cyanidation process
153:+ NaOH → NaAlO
141:, according to the
1530:Aluminium industry
1525:Chemical processes
1247:Refractory linings
1118:Gyratory equipment
930:Mineral processing
88:
1512:
1511:
1462:
1461:
1423:
1418:Electrometallurgy
1412:
1411:
1371:Gold chlorination
1330:
1319:
1318:
1205:
1194:
1193:
1156:Jig concentrators
954:Natural resources
949:Geological survey
935:
787:10.1021/es104000m
633:978-3-319-48610-9
616:Light Metals 2015
570:978-0-646-33550-6
293:aluminium sulfate
143:chemical equation
1542:
1427:
1426:
1422:(by electricity)
1421:
1404:Pan amalgamation
1376:Gold cyanidation
1366:In situ leaching
1334:
1333:
1328:
1209:
1208:
1203:
964:Economic geology
939:
938:
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829:scs.illinois.edu
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799:
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773:(4): 1616–1622.
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713:(1–3): 359–374.
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595:(1–3): 359–374.
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483:Carl Josef Bayer
457:
456:
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311:, by heating in
207:bauxite tailings
195:calcium silicate
124:sodium aluminate
122:is dissolved as
116:sodium hydroxide
61:titanium dioxide
33:Carl Josef Bayer
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1449:Castner process
1420:
1408:
1385:
1327:
1325:Hydrometallurgy
1315:
1289:
1285:IsaKidd process
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1202:
1190:
1141:Froth flotation
1127:
1081:
1019:
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511:heat exchangers
492:hydrometallurgy
470:. In 1886, the
468:Deville process
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445:
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112:pressure vessel
102:(Îł-AlO(OH)) or
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50:
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41:aluminium oxide
17:
12:
11:
5:
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1270:Parkes process
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1236:Flash smelting
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1200:Pyrometallurgy
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858:(1–2): 15–22.
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1381:Bayer process
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1361:Tank leaching
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1351:Heap leaching
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114:along with a
113:
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85:
80:
71:
69:
64:
62:
58:
54:
42:
38:
34:
30:
26:
22:
21:Bayer process
1431:Electrolysis
1391:Amalgamation
1380:
1146:Jameson cell
1103:Hydrocyclone
855:
849:
833:. Retrieved
828:
770:
766:
753:
741:. Retrieved
736:
727:
710:
706:
700:
688:. Retrieved
683:
674:
665:
656:
615:
609:
592:
588:
560:
554:
515:
496:
480:
432:
419:
404:impoundments
401:
397:
386:
373:
366:
362:
351:
313:rotary kilns
290:
266:
231:precipitates
188:
169:2 NaOH + SiO
164:
134:
132:
89:
65:
27:to produce
20:
18:
1467:Co-products
1301:Calcination
1265:Cupellation
1181:Dry washing
1170:Magnetation
1093:Ore sorting
1058:Pebble mill
1025:Comminution
737:www.epa.gov
211:iron oxides
209:, contains
57:iron oxides
1519:Categories
1504:Stamp sand
1454:Downs cell
1186:Buddle pit
1176:Rocker box
1033:Stamp mill
974:Base metal
942:Extraction
547:References
507:autoclaves
249:→ 2 Al(OH)
199:flocculant
108:amphoteric
82:The Bayer
55:, various
1346:Lixiviant
1311:Liquation
1204:(by heat)
1065:Ball mill
1008:Recycling
642:cite book
433:In 1859,
317:calciners
279:O + NaAlO
135:digestion
120:aluminium
37:aluminium
1474:Tailings
1338:Leaching
1306:Roasting
1257:Refining
1241:ISASMELT
1213:Smelting
1070:Rod mill
1053:SAG mill
1038:Arrastra
795:21204523
743:12 April
690:12 April
520:See also
422:incident
393:vanadium
358:vanadium
283:→ Al(OH)
227:alkaline
201:such as
104:diaspore
92:gibbsite
1499:Red mud
1489:Clinker
1243:furnace
1151:Panning
1108:Trommel
1098:Vanning
1075:IsaMill
1048:AG mill
1043:Crusher
991:Surface
969:Mineral
860:Bibcode
835:6 April
775:Bibcode
499:Germany
487:mordant
429:History
388:Red mud
364:fluid.
354:gallium
295:, PAC (
237:2 NaAlO
223:titania
100:böhmite
94:(Al(OH)
74:Process
68:gallium
29:alumina
25:bauxite
1479:Gangue
1280:Poling
1086:Sizing
986:Mining
793:
630:
567:
325:Al(OH)
287:+ NaOH
245:O + CO
219:calcia
215:silica
203:starch
173:→ Na
157:+ 2 H
149:Al(OH)
128:seeded
59:, and
53:silica
1294:Other
1013:Scrap
825:(PDF)
763:(PDF)
667:Al2O3
383:Waste
241:+ 3 H
1494:Chat
1484:Slag
837:2018
791:PMID
745:2018
692:2018
648:link
628:ISBN
565:ISBN
501:and
462:, CO
356:and
341:+ 3
303:, Al
191:lime
19:The
959:Ore
868:doi
783:doi
715:doi
711:146
620:doi
597:doi
593:146
275:2 H
181:+ H
177:SiO
98:),
43:(Al
1521::
866:.
856:79
854:.
827:.
803:^
789:.
781:.
771:45
769:.
765:.
735:.
709:.
682:.
664:.
644:}}
640:{{
626:.
591:.
579:^
494:.
448:CO
439:Na
332:Al
330:→
323:2
259:CO
255:Na
253:+
233::
221:,
217:,
213:,
145::
1172:)
1168:(
902:e
895:t
888:v
874:.
870::
862::
839:.
797:.
785::
777::
747:.
721:.
717::
694:.
650:)
636:.
622::
603:.
599::
573:.
464:2
453:3
444:2
347:O
345:2
343:H
338:3
336:O
334:2
327:3
309:3
307:O
305:2
285:3
281:2
277:2
269:3
261:3
257:2
251:3
247:2
243:2
239:2
185:O
183:2
179:3
175:2
171:2
161:O
159:2
155:2
151:3
139:2
96:3
86:.
49:3
47:O
45:2
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