36:
267:
642:
In chemically reduced rocks, magnetite may be absent due to the propensity of iron to enter olivine, and wüstite may only be present if there is an excess of iron above what can be used by silica. Thus, wüstite may only be found in silica-undersaturated compositions which are also heavily chemically
699:
in the process. The resulting catalyst particles consist of a core of magnetite, encased in a shell of wüstite, which in turn is surrounded by an outer shell of iron metal. The catalyst maintains most of its bulk volume during the reduction, resulting in a highly porous high-surface-area material,
626:
The ratio of Fe to Fe within a rock determines, in part, the silicate mineral assemblage of the rock. Within a rock of a given chemical composition, iron enters minerals based on the bulk chemical composition and the mineral phases which are stable at that temperature and pressure. Iron may only
525:
728:
pit in which the steel or iron was placed provided a highly reducing, virtually oxygen-free environment, producing a thin wüstite layer on the metal. At the welding temperature, the iron becomes highly reactive with oxygen, and will spark and form thick layers of
654:, carbonate-bearing melilitic rocks, and other rare alkaline rocks may satisfy these criteria. However, wüstite is not reported in most of these rocks in nature, potentially because the redox state necessary to drive magnetite to wüstite is so rare.
907:
Schenck, Rudolf; Dingmann, Thomas (1927). "Gleichgewichtsuntersuchungen über die
Reduktions-, Oxydations- und Kohlungsvorgänge beim Eisen III" [Stoichiometric studies on the reduction, oxidation and carbonation processes in iron III].
733:
when exposed to the air, which makes welding the iron or steel nearly impossible. To solve this problem, ancient blacksmiths would toss small amounts of sand onto the white-hot metal. The silica in the sand reacts with the wüstite to form
592:
Once the Fe is consumed, then oxygen must be stripped from the system to further reduce it and wüstite is converted to native iron. The oxide mineral equilibrium assemblage of the rock becomes wüstite–magnetite–iron.
414:
742:
that shielded the metal from oxygen and helped extract oxides and impurities, leaving a pure surface that can weld readily. Although the ancients had no knowledge of how this worked, the ability to
695:). The pulverized iron metal is burnt (oxidized) to give magnetite or wüstite of a defined particle size. The magnetite (or wüstite) particles are then partially reduced, removing some of the
408:
As the redox state of a rock is further reduced, magnetite is converted to wüstite. This occurs by conversion of the Fe ions in magnetite to Fe ions. An example reaction is presented below:
683:) production, which relies on wüstite-derived catalysts. The industrial catalyst is derived from finely ground iron powder, which is usually obtained by reduction of high-purity
596:
In nature, the only natural systems which are chemically reduced enough to even attain a wüstite–magnetite composition are rare, including carbonate-rich
964:
324:
520:{\displaystyle {\ce {{\underset {magnetite}{FeO.Fe2O3}}+{\underset {graphite/diamond}{C}}->{3FeO}+{\underset {carbon\ monoxide}{CO}}}}}
336:
935:
Jozwiak, W. K.; Kaczmarek, E.; et al. (2007). "Reduction behavior of iron oxides in hydrogen and carbon monoxide atmospheres".
1059:
1054:
1069:
981:
604:
and lightning-affected rock, and perhaps the mantle where reduced carbon is present, exemplified by the presence of
87:
663:
188:
317:
1049:
405:
of oxidation within rocks at which point the rock is so reduced that Fe, and thus hematite, is absent.
643:
reduced, satisfying both the need to remove all Fe and to maintain iron outside of silicate minerals.
1064:
1044:
639:
olivine and thus for every two Fe ions, one Fe is used and one molecule of magnetite is created.
570:
remains wüstite-magnetite. Furthermore, the redox state of the rock remains at the same level of
343:
77:
566:
because, until all Fe present in the system is converted to Fe, the oxide mineral assemblage of
178:
871:
838:
782:
621:
401:
386:
374:
305:
102:
8:
875:
889:
803:
168:
977:
893:
739:
247:
708:
According to Vagn
Fabritius Buchwald, wüstite was an important component during the
1016:
969:
944:
917:
879:
367:
313:
221:
201:
58:
973:
948:
578:
555:
289:
120:
97:
1038:
921:
738:, which melts just below the welding temperature. This produced an effective
717:
713:
669:
309:
158:
109:
51:
1010:
391:
Iron minerals on the Earth's surface are typically richly oxidized, forming
1028:
814:
779:
347:
328:
647:
297:
231:
132:
884:
859:
766:
O), and iron substitutes for magnesium. Periclase, when hydrated, forms
1022:
747:
651:
363:
241:
799:
Zinc, aluminium, and other metals may substitute for iron in wüstite.
35:
826:
818:
763:
759:
684:
601:
396:
355:
293:
258:
668:
Approximately 2–3% of the world's energy budget is allocated to the
822:
810:
793:
789:
771:
735:
725:
709:
636:
628:
609:
574:
559:
399:, with a mixture of Fe and Fe. Wüstite, in geochemistry, defines a
392:
20:
585:) in the Fe–O redox system, this can be compared to buffering the
308:
crystal system in opaque to translucent metallic grains. It has a
767:
743:
673:
632:
605:
359:
266:
211:
696:
571:
351:
281:
70:
530:
The formula for magnetite is more accurately written as FeO·Fe
806:
721:
597:
395:, with Fe state, or in somewhat less oxidizing environments,
301:
16:
Iron(II) oxide (FeO) mineral formed under reducing conditions
730:
567:
278:
153:
Greyish white to yellow or brown; colorless in thin section
67:
1001:. Det Kongelige Danske Videnskabernes Selskab. p. 65.
451:
438:
300:. It has a grey colour with a greenish tint in reflected
664:
Haber process § Production of iron-based catalysts
635:
if it is present as Fe; Fe cannot enter the lattice of
586:
23:, a zinc and iron sulfide mineral of formula (Zn,Fe)S.
417:
910:Zeitschrift für anorganische und allgemeine Chemie
519:
615:
1036:
934:
700:which enhances its effectiveness as a catalyst.
906:
965:Ullmann's Encyclopedia of Industrial Chemistry
746:iron contributed to the movement out of the
657:
546:. Magnetite is one part FeO and one part Fe
337:Max Planck Institute for Iron Research GmbH
316:of 5.88. Wüstite is a typical example of a
333:Kaiser-Wilhelm-Institut für Eisenforschung
883:
788:Oxidation and hydration of wüstite forms
490:
366:pipes. It also is reported from deep sea
996:
646:In nature, carbonate rocks, potentially
265:
589:in the H/OH acid–base system of water.
380:
1037:
928:
346:in Germany, it has been reported from
961:
860:"IMA–CNMNC approved mineral symbols"
857:
758:Wüstite forms a solid solution with
955:
753:
13:
14:
1081:
997:Buchwald, Vagn Fabritius (2005).
703:
373:Its presence indicates a highly
226:1.735–2.32 in synthetic crystals
34:
999:Iron and Steel in Ancient Times
720:was performed using a charcoal
288:O) is a mineral form of mostly
990:
900:
851:
616:Effects upon silicate minerals
483:
358:, India; and as inclusions in
304:. Wüstite crystallizes in the
284:, sometimes also written as Fe
1:
974:10.1002/14356007.a02_143.pub2
962:Appl, Max (2006). "Ammonia".
844:
712:to facilitate the process of
331:and founding director of the
1060:Non-stoichiometric compounds
949:10.1016/j.apcata.2007.03.021
937:Applied Catalysis A: General
577:. Considering buffering the
270:Crystal structure of Wüstite
7:
1055:Minerals in space group 225
832:
318:non-stoichiometric compound
10:
1086:
1070:Minerals described in 1927
1011:Mineral Data Pub. PDF file
661:
619:
384:
257:Forms solid solution with
18:
716:. In ancient times, when
658:Role in nitrogen fixation
253:
240:
230:
220:
210:
200:
187:
177:
167:
157:
149:
144:
131:
108:
96:
86:
76:
57:
47:
42:
33:
28:
922:10.1002/zaac.19271660111
562:. Magnetite is termed a
323:Wüstite was named after
19:Not to be confused with
968:. Weinheim: Wiley-VCH.
778:), a common product of
627:enter minerals such as
306:isometric-hexoctahedral
864:Mineralogical Magazine
813:(iron(II) carbonate),
521:
327:(1860–1938), a German
271:
183:Subconchoidal to rough
1023:Wüstite on Mindat.org
783:metamorphic reactions
750:and into the modern.
522:
269:
254:Other characteristics
88:Strunz classification
839:Normative mineralogy
622:Normative mineralogy
415:
387:Mineral redox buffer
381:Wüstite redox buffer
375:reducing environment
163:Pyramidic, prismatic
885:10.1180/mgm.2021.43
876:2021MinM...85..291W
858:Warr, L.N. (2021).
453:
440:
342:In addition to its
809:may be related to
517:
514:
481:
458:
441:
428:
312:of 5 to 5.5 and a
272:
246:Soluble in dilute
1050:Iron(II) minerals
1031:Accessed 3/5/2006
1025:Accessed 3/5/2006
1019:Accessed 3/5/2006
1013:Accessed 3/5/2006
512:
509:
506:
502:
499:
493:
479:
471:
467:
464:
457:
444:
431:
424:
420:
368:manganese nodules
350:, Greenland; the
264:
263:
1077:
1003:
1002:
994:
988:
987:
959:
953:
952:
932:
926:
925:
904:
898:
897:
887:
855:
754:Related minerals
682:
554:, rather than a
526:
524:
523:
518:
516:
515:
513:
510:
507:
504:
500:
494:
491:
482:
480:
477:
476:
469:
465:
459:
455:
454:
452:
449:
442:
439:
436:
429:
422:
314:specific gravity
222:Refractive index
202:Specific gravity
193:
126:
117:
114:Hexoctahedral (m
64:
63:(repeating unit)
38:
26:
25:
1085:
1084:
1080:
1079:
1078:
1076:
1075:
1074:
1035:
1034:
1029:Webmineral data
1007:
1006:
995:
991:
984:
960:
956:
933:
929:
905:
901:
856:
852:
847:
835:
777:
756:
706:
694:
690:
681:
677:
666:
660:
624:
618:
584:
579:redox potential
558:of wüstite and
553:
549:
545:
541:
537:
533:
503:
498:
486:
472:
468:
463:
450:
445:
437:
432:
421:
419:
418:
416:
413:
412:
389:
383:
362:in a number of
287:
191:
124:
119:
115:
62:
61:
24:
17:
12:
11:
5:
1083:
1073:
1072:
1067:
1065:Oxide minerals
1062:
1057:
1052:
1047:
1045:Cubic minerals
1033:
1032:
1026:
1020:
1014:
1005:
1004:
989:
983:978-3527306732
982:
954:
927:
899:
870:(3): 291–320.
849:
848:
846:
843:
842:
841:
834:
831:
775:
755:
752:
705:
704:Historical use
702:
692:
688:
679:
662:Main article:
659:
656:
620:Main article:
617:
614:
600:, meteorites,
582:
556:solid solution
551:
547:
543:
539:
535:
531:
528:
527:
497:
489:
485:
475:
462:
448:
435:
427:
385:Main article:
382:
379:
290:iron(II) oxide
285:
262:
261:
255:
251:
250:
244:
238:
237:
234:
228:
227:
224:
218:
217:
214:
208:
207:
204:
198:
197:
194:
185:
184:
181:
175:
174:
171:
165:
164:
161:
155:
154:
151:
147:
146:
145:Identification
142:
141:
135:
129:
128:
112:
106:
105:
100:
98:Crystal system
94:
93:
90:
84:
83:
80:
74:
73:
65:
55:
54:
49:
45:
44:
40:
39:
31:
30:
15:
9:
6:
4:
3:
2:
1082:
1071:
1068:
1066:
1063:
1061:
1058:
1056:
1053:
1051:
1048:
1046:
1043:
1042:
1040:
1030:
1027:
1024:
1021:
1018:
1015:
1012:
1009:
1008:
1000:
993:
985:
979:
975:
971:
967:
966:
958:
950:
946:
942:
938:
931:
923:
919:
915:
911:
903:
895:
891:
886:
881:
877:
873:
869:
865:
861:
854:
850:
840:
837:
836:
830:
828:
824:
820:
816:
812:
808:
805:
800:
797:
795:
791:
786:
784:
781:
773:
769:
765:
761:
751:
749:
745:
741:
737:
732:
727:
723:
719:
718:blacksmithing
715:
714:forge welding
711:
701:
698:
686:
675:
671:
670:Haber process
665:
655:
653:
649:
644:
640:
638:
634:
630:
623:
613:
611:
607:
603:
599:
594:
590:
588:
580:
576:
573:
569:
565:
561:
557:
495:
487:
473:
460:
446:
433:
425:
411:
410:
409:
406:
404:
403:
398:
394:
388:
378:
376:
371:
369:
365:
361:
357:
353:
349:
345:
344:type locality
340:
338:
334:
330:
326:
321:
319:
315:
311:
310:Mohs hardness
307:
303:
299:
295:
291:
283:
280:
276:
268:
260:
256:
252:
249:
245:
243:
239:
235:
233:
229:
225:
223:
219:
215:
213:
209:
205:
203:
199:
195:
190:
186:
182:
180:
176:
173:{001} perfect
172:
170:
166:
162:
160:
159:Crystal habit
156:
152:
148:
143:
139:
136:
134:
130:
122:
113:
111:
110:Crystal class
107:
104:
101:
99:
95:
91:
89:
85:
81:
79:
75:
72:
69:
66:
60:
56:
53:
52:Oxide mineral
50:
46:
41:
37:
32:
27:
22:
998:
992:
963:
957:
940:
936:
930:
913:
909:
902:
867:
863:
853:
815:wollastonite
801:
798:
787:
780:serpentinite
757:
707:
667:
645:
641:
625:
595:
591:
564:redox buffer
563:
529:
407:
402:redox buffer
400:
390:
372:
348:Disko Island
341:
332:
329:metallurgist
322:
274:
273:
137:
916:: 113–154.
802:Wüstite in
724:, the deep
652:kimberlites
648:carbonatite
354:coalfield,
335:(presently
298:native iron
292:found with
232:Pleochroism
133:Space group
1039:Categories
845:References
748:Bronze Age
602:fulgurites
538:than as Fe
364:kimberlite
325:Fritz Wüst
294:meteorites
242:Solubility
189:Mohs scale
121:H–M symbol
78:IMA symbol
943:: 17–27.
894:235729616
827:magnesite
819:enstatite
760:periclase
685:magnetite
484:⟶
456:magnetite
426:⋅
397:magnetite
356:Jharkhand
259:periclase
140:(no. 225)
833:See also
823:diopside
811:siderite
804:dolomite
794:limonite
790:goethite
736:fayalite
726:charcoal
710:Iron Age
637:fayalite
629:pyroxene
610:graphite
575:fugacity
560:hematite
511:monoxide
470:graphite
393:hematite
360:diamonds
216:5.7 g/cm
192:hardness
179:Fracture
169:Cleavage
48:Category
21:Wurtzite
1017:Euromin
872:Bibcode
768:brucite
674:ammonia
633:olivine
606:diamond
478:diamond
275:Wüstite
212:Density
123:: (4/m
92:4.AB.25
59:Formula
43:General
29:Wüstite
980:
892:
825:, and
807:skarns
697:oxygen
598:skarns
572:oxygen
508:
505:carbon
352:Jharia
890:S2CID
770:(Mg(O
722:forge
302:light
196:5–5.5
150:Color
103:Cubic
978:ISBN
792:and
744:weld
740:flux
731:slag
672:for
631:and
568:iron
296:and
286:0.95
236:None
206:5.88
138:Fm3m
127:2/m)
970:doi
945:doi
941:326
918:doi
914:166
880:doi
687:(Fe
608:or
492:FeO
423:FeO
339:).
248:HCl
118:m)
82:Wüs
1041::
976:.
939:.
912:.
888:.
878:.
868:85
866:.
862:.
829:.
821:,
817:,
796:.
785:.
764:Mg
678:NH
650:,
612:.
587:pH
581:(E
501:CO
430:Fe
377:.
370:.
320:.
279:Fe
68:Fe
986:.
972::
951:.
947::
924:.
920::
896:.
882::
874::
776:2
774:)
772:H
762:(
693:4
691:O
689:3
680:3
676:(
583:h
552:3
550:O
548:2
544:4
542:O
540:3
536:3
534:O
532:2
496:+
488:3
474:/
466:C
461:+
447:3
443:O
434:2
282:O
277:(
125:3
116:3
71:O
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