Available online at www.sciencedirect.com

m%' ScienceDirect

JOURNAL OF IRON AND STEEL RESEARCH, INTERNATIONAL. 2012, 19(11). 33-38

Reaction of F e O V 2 0 5 System at High Temperature

Z H A N G Sheng-q in 1 ' 2 , XIE B i n g 1 , W A N G Y u 1 , G U A N T i n g 1 , C A O Hai - l i an 1 , ZENG Xiao-Ian 1

(1 . College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China; 2. School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331, China)

Abstract: FeO and V 2 0 5 are two main components of the obtained vanadium steel slag, and the reaction of FeO-V 2 0 5

system determines the physical property of the slag. Through thermodynamic calculation and experimental study, it can be found that within the ranges of steel-making temperature, V 2 0 5 is reduced to V 0 2 . As FeO exists in FeO-V 2 0 5 system, V 0 2 will be reduced to V 2 0 3 further while FeO is oxidized to Fe 2 03 . In this multi-system, as the con­tent of FeO and temperature increase, the system will have products in turn such as V 3 Os , V 3 0 4 , F e V 0 4 , Fe 2 VO 4

and F e 3 0 4 . The products are mainly V3O5 and Fe 2 0 3 when the content of FeO is 0. 58 mol and the temperature is 1100 K, and as the temperature increases, F e 2 0 3 starts to react with V 2 0 5 and then generates F e V 0 4 ; F e V 0 4 disap­pears while the content of FeO and the temperature increase at the same time, and then Fe 2 V 0 4 is generated by the reaction of FeO, F e 2 0 3 and V 2 0 3 . Iron oxides are also generated such as F e 3 0 4 and so on. Keywords: FeO; V 2 O s ; reaction; thermodynamic calculation; experiment

V-bearing titanomagnetite is one of the main raw materials in vanadium extraction. T h e magnet i te re­served in Panzhihua-Xichang area of China has ex­ceeded 10 billion t o n s , which takes up 62. 2 % of va­nadium reserve of China 1- 1 ] . Vanadium is widely used in the fields such as s tee l , chemical indus t ry , aero­space and so on1-2-1. T h e vanadium content in hot metal of some manufacturers such as Chuanwei Steel, Xichang Xingangye Industry and Pan Steel (Chengdu) has reached from 0 . 1 8 % to 0 . 3 0 % . If the hot metal containing vanadium is smelted wi thout converter vanadium extraction process , there would be a large quantity of vanadium being oxidized into slag and producing steel slag containing vanadium which con­tains V 2 0 5 from 2 % to 5 % . T h e production of steel slag in China reaches millions tons per y e a r [ 3 ] , and this is not only the loss of vanadium resources but also pollution to the environment.

F e O - V 2 0 5 - C a O is the representat ive composi­tion in vanadium-containing steel s lag , and it could be seen as the basic slag of this slag system. Some related works of reactions between the above compo­nents have been done before. T h e possible reactions

between V2O3-V2O5 from 298 to 1473 Κ were s tud­ied by Koji Kosuge1-4-1. T h e transformation mecha­nism from V 2 0 5 to V 2 0 3 at 873 Κ was researched by D S Su and R Schlogl by heating the sample in vacu-u m [ s ) . V 2 0 3 being oxidized to V 2 0 4 th rough the re­action V 2 0 3 ( s ) + F e 2 0 3 = 2 F e O + . V 2 0 4 ( s ) in vana­dium slag was investigated by C H E N G Dong-hu i [ 6 ] . The distr ibution of vanadium between hot metal and slag in BOF at 1 873 Κ was studied by Y A N G Su-bo by thermodynamics experiment 1- 7-'. At p resen t , this kind of slag system has not been systematically ana­lyzed by researchers.

T h r o u g h thermodynamic calculation and experi­m e n t s , the reactions that possibly happen in the main composition F e O - V 2 0 5 have been analyzed and tested in order to provide scientific basis and techno­logical and theoretical support for reusing solid waste vanadium-containing steel slag.

1 Thermodynamic Analysis on FeO-V 20 5 System

Fe is t ransi t ion e lement , and the valence of Fe is 2 + and 3 + ; the valence state of vanadium is vari­ab le , and vanadium can generate multiple oxides

Foundation Item ·. I t e m S p o n s o r e d by Nat iona l Bas ic R e s e a r c h P r o g r a m of China ( 2 0 0 7 C B 6 1 3 5 0 3 ) ; Natura l Sc ience F o u n d a t i o n of C h o n g q i n g Ci ty of

China ( C S T C ) ( 2 0 1 0 B B 4 2 9 1 )

Biography:ZHANG S h e n g - q i n ( 1 9 7 4 — ) , F e m a l e , M a s t e r ; E-mail: s h e n g q i n z h a n g @ 1 6 3 . c o m ; Received Date: Ju ly 1 8 , 2 0 1 1

3 4 Journal of Iron and Steel Research, International Vol. 19

with oxygen in different valences such as 2 + , 3 + , 4 + and 5 + [ 8 ] . T h e stabili ty of the two substances contained in F e O - V 2 0 5 binary system changes wi th external factors , and the oxidation reaction and de­composition reaction happen under certain condition™.

V 2 0 5 ( l ) = V 2 0 4 ( s ) + y 0 2 ( g )

AG? = 3 4 8 0 0 - 1 0 . 96T kj · π ι ο Γ 1 (1)

V 2 0 4 ( s ) = V 2 0 3 ( s ) + - | - 0 2 ( g )

AGl = 2 0 9 7 0 0 - 7 3 . 0 9 T kj · m o l - 1 (2)

V 2 0 3 ( s ) = 2 V O ( s ) + y 0 2 (g )

AGl = 3 5 3 5 0 0 - 7 7 . 4 5 T kj • m o l " 1 (3)

2 F e O ( s ) + y 0 2 (g ) = F e 2 0 3 ( s )

AGl = —287 023 + 121. 94T kj · π ι ο Γ 1 (4 ) w h e r e , AG" is the s tandard Gibbs free energy change of the chemical reaction; and Τ is temperature .

Calculated by thermodynamic data from the four equations above, it can be learned that in pure oxygen a tmosphere , tempera ture range in Eqn. ( 1 ) is from 943 to 2 273 K. And in that range of temper­a tu r e , A G ? > 0 , so the reaction will not proceed spontaneously , tha t i s , V 2 0 5 will not decompose.

But in a tmosphere condit ion, judging reaction proceeding or function AG should not be used as shown in Eqn. ( 5 ) C l o : 1 .

ρ A G = AG 8 + i ? T l n -~f (5 )

w h e r e , Po 2 is the partial pressure of oxygen; P 9 is the s tandard p ressure ; and R is molar gas constant . T h e value of P 0 z is equal to 0. 2 1 P 8 in a tmosphere condition. Calculating from Eqn. ( 5 ) , it can be learned that V 2 0 5 will decompose while the temper­ature is below 1446 K. Under inert a tmosphere , supposing Po 2 = 0. 1 X 0. 2 1 Ρ β , the decomposing tempera ture of V 2 O s will fall to 808 K. So it can be learned that as P 0 z decreases , AG} will also de­crease , and as a r e su l t , under inert a tmosphere , the decomposing tempera ture of V 2 0 5 will decrease as the decomposing t rend of V 2 0 5 increases.

Within the temperature range from 298 to 1 633 Κ in Eqn. (2) and that from 298 to 2 073 Κ in Eqn. ( 3 ) , AG\ > 0 , AGl > 0 , namely in pure oxygen a tmos­phe re , V 2 0 4 and V 2 0 3 will not decompose. Under the inert a tmosphere when Po 2 = 0. 1 X 0. 2 1 P 9 , wha t still can be obtained is AG 2 > 0 and AG 3 > 0 , namely V 2 0 4 and V 2 0 3 will not decompose.

F rom Eqn. ( 4 ) , it can be known that under the s tandard condition, FeO can generate oxidizing reac­

tion when the tempera ture is below 2 353 K. Combined with the heat system in practical fer­

rous meta l lurgy, only V 2 O s which could stand alone among the vanadium oxide can decompose while V 0 2 and V 2 0 3 cannot decompose directly. But if there is 0 2 , FeO which exists alone will be oxidized. Considering the system that vanadium oxide and FeO coexist , for example , in F e O - V 2 0 5 sys tem, as FeO takes in 0 2 released by vanadium oxide, and then they will couple to make reaction proceed posi­t ively, the result of which shows the reduction of vanadium oxide and the oxidation of FeO shown from Eqn. (6) to Eqn. ( 8 ) C l l ] .

2 F e O ( s ) - f - V 2 0 5 ( l ) = F e 2 0 3 ( s ) + V 2 0 4 ( s ) AG?, = - 2 5 2 223 + 1 1 0 . 1 8 T kj · m o l - 1 (6)

2 F e O + V 2 0 4 ( s ) = F e 2 0 3 + V 2 0 3 ( s ) AGl = —77 323 + 48. 8 5 T kj · m o l " 1 (7 )

2 F e O + V 2 0 3 ( s ) = F e 2 0 3 + 2 V O ( s ) AG? = 6 6 4 7 7 + 44. 4 9 T kj · m o l - 1 (8)

T h e operating tempera ture range of Eqn. (6 ) is from 943 to 1633 K. It can be analyzed from Eqn. (6) that in s tandard condition and within the operating tempera ture range from 943 to 1633 K, AGe,-<0, thus V 2 0 4 can be generated. In F e O - V 2 0 5 sys tem, V 2 0 5 will be decomposed into V 2 0 4 ( V 0 2 ) and 0 2 , and at the same t ime , FeO in this system will take in 0 2 released by V 2 0 5 to generate Fe 2 0 3 . As FeO has taken in oxygen and reduced the oxygen potential of this sys t em, which is equivalent to gradually reduc­ing the decomposition products of V 2 0 5 , thus it makes decomposition of V 2 0 5 easily continue. So the above two reactions accelerate mutua l ly , which makes the reaction tha t is difficult to go on when the reaction is sole become quick within a quite wide tempera ture range. T h e same as in Eqn. ( 7 ) , V 2 0 3

can be generated within the tempera ture range , namely below 1 583 K. As A G i > 0 , Eqn. ( 8 ) that generates V O cannot be carried out.

In F e O - V 2 0 5 binary sys tem, the decomposition of vanadium dioxide and the oxidation of FeO make this binary system extend to a system which contains many oxides such as FeO, Fe 2 0 3 , V 2 0 5 , V 2 0 4 ( V 0 2 ) , V 2 0 3

and so on , namely the binary system becomes poly-nary system. And in this polynary sys t em, mult iple substances can generate different dioxides by reac­tions from Eqn. (9) to Eqn. ( 1 4 ) [ 1 2 ] .

F e O ( s ) + F e 2 0 3 ( s ) = F e 3 0 4 ( s ) AGl = —24 097 — 8. 3 3 T k j · ι η ο Γ 1 (9)

F e O ( s ) + V 2 0 3 ( s ) = F e V 2 0 4 ( s ) AG?, = - 2 4 7 0 0 - 2 . 2 5 T k j · π ι ο Γ 1 (10)

F e 2 0 3 ( s ) + V 2 0 5 ( s ) = 2 F e V 0 4 ( s ) (11)

Issue 11 Reaction of FeO-V2 O5 System at High Temperature 35

FeO(s) + y V 2 0 3 ( s ) + ~ F e 2 0 3 (s) = Fe 2 V 0 4 (s)

(12)

y V 2 0 4 ( s ) + V 2 0 3 ( s ) = V 3 0 5 ( s ) (13)

3 V 2 0 3 ( s ) + 2 F e O = F e 2 0 3 + 2 V 3 0 4 ( s ) (14) As AGI<0 and A G 1 0 < 0 , based on the Gibbs

principle of minimum free energy , it can be known that Eqn. ( 9 ) and Eqn. ( 1 0 ) can proceed positively at any tempera ture . F rom Eqn. (11) to Eqn. ( 1 4 ) , the direction of the chemical reaction could not be judged th rough calculation because of lacking related thermodynamic da ta , but whether these reactions can happen should be judged by experiments .

2 Experimental Verification on Reaction Mechanism of FeO-V2Os System

2.1 Experimental material and equipment The experimental materials in this experiment are

pure ferrous oxalate F e C 2 0 4 · 2 H 2 0 , which can de­compose to obtain F e O , and analytical pure vanadi­um pentoxide V 2 0 5 . In order to ensure the weighing accuracy of sample and avoid the oxidation of ferrous oxala te , the experimental materials have to been de­hydrated at 383 Κ for 3 h in the airt ight oven before conducting an experiment and then it also needs to be stored in an airtight container to reserve.

Based on the composit ions of the vanadium-containing s lag , the composit ion design is shown in Tab le 1.

Sample N 3 , N 6 , N 9 , N10 and N i l are selected to be analyzed. Magnesia crucibles are chosen as the experimental crucibles. 5K-10-16 MoSi 2 high tem­perature electric stove is chosen as the experimental high tempera ture furnace. And the samples are ana­lyzed by Rigaku D/MAX-IUCX X-ray diffraction in­s t rument . T h e MoSi 2 furnace and the temperature controller devices are shown in Fig. 1.

Table 1 Experimental points of FeO-V 2 0 5 system (molar percent)

N l N 2 N 3 N 4 N 5 N 6 N 7 N 8 N 9 N 1 0 N i l N 1 2

* F e o 0 · 5 °- 5 2 °- 5 8 ° · 6 3 ° · 6 8 0· 72 0 . 7 5 0. 79 0 . 8 2 0 . 8 5 0 . 8 8 0 . 9

*v2o5 0 . 5 0 . 4 8 0 . 4 2 0 . 3 7 0 . 3 2 0 . 2 8 0 . 2 5 0 . 2 1 0 . 1 8 0 . 1 5 0 . 1 2 0 . 1

Furnace shell — Molten iron and slag — MTLQ-2 temperature

controller 1

•

Ι Ο Ι

Furnace cover

Heating unit Furnace tube MgO crucible

|~~ Graphite crucible Corundum support Thermocouple

Foamed ' alumina plug Furnace tube tray

Fig. 1 Experimental equipment

2.2 Experimental process The samples were required to be weighed strictly

and prepared according to the expectant composition, and after being fully ground and mixed in the agate mortar, they were put in the magnesia crucibles. Afterwards, the magnesia crucibles were put in the high-temperature pipe furnace immediately, and then it was sealed up by put t ing argon into it and heated up. The rate of argon flow was controlled at 2 L/min at the beginning. After all the gas in the furnace was ex­pelled, the flow rate was decreased to 1 L / m i n and kept until the end of the experiments . In the next step, the samples were heated up to exceed 20 Κ to target tempera ture for 10 min and then cooled slowly

until the experimental requirement was met. Keep the tempera ture under such circumstances for 45 min , then take out the sample and cool it to the room tempera ture quickly. At the end of the experi­men t , differential scanning calorimeter ( D S C ) ex­periment and X-ray diffraction experiment were con­ducted to analyze the equilibrium composition1-1 3-1.

2. 3 Experimental result and analysis T h e DSC tempera ture decreasing curves of sam­

ple N 3 , N 6 , N 9 , N10 and N i l are shown in Fig. 2. T h e peaks in Fig. 2 are exothermic peaks , and the temperatures of all kinds of exothermic peaks in the tempera ture decreasing process of DSC curves are shown in Table 2.

As shown in Fig. 2 , there is an exothermic peak turning up at 885. 9 K , the tempera ture of which is a little lower than the melt ing point of V 2 0 5 (943 Κ ) , and this can be seen as the phase change heat genera­ted when the mixed phase s tar ted to melt.

T h e X-ray diffraction ( X R D ) atlases of chosen samples at corresponding tempera ture for 45 min are shown from Fig. 3 to Fig. 9. Because three s trongest peaks are not detected at the same t ime , some spec­tral lines are not marked.

It can be learned from Fig. 3 (a) that firstly sample

36 Journal of Iron and Steel Research, International Vol. 19

6 0 0 1 0 0 0 1 4 0 0 1 8 0 0 77K

Fig. 2 Cooling curve of different components in DSC experiment

Table 2 Temperature of cooling curve

N u m b e r T e m p e r a t u r e / K

N 3 8 8 5 . 9 1 1 0 9 . 8

N 6 1 0 5 3 . 8 1 2 4 3 . 2 1 5 3 8 . 2

N 9 1 2 4 0 . 7 1 5 4 1 . 6 1 6 8 7 . 6

N 1 0 1 2 3 9 . 2 1 5 4 0 . 5 1 6 4 9 . 9

N i l 1 5 3 1 . 1 1 7 6 3 . 7

N3 reacts to form the products Fe 2 0 3 , V 0 2 and V 2 0 3 according to Eqn. ( 4 ) , Eqn. ( 6 ) and Eqn. ( 7 ) at 1100 K. V 0 2 will react wi th V 2 0 3 as Eqn. (13) to generate V 3 0 5 , and the final products are F e 2 0 3 and V 3 0 5 . Fig. 3 ( b ) is an X-ray diffraction pat tern of N3 sample after it has reacted at 1 210 Κ for 45 min. Compared with Fig. 3 (a) , the detected products are different al though the tempera ture was rising up. Besides, Fe 2 0 3 , F e V 0 4 and V 0 2 have also been de­tected in Fig. 3 ( b ) , but there was no V 3 0 5 detec­ted. This shows that the reactions of samples in Fig. 3 (a ) and (b ) are different under corresponding conditions. T h e N3 sample in Fig. 3 ( b ) firstly re­acts according to Eqn. ( 4 ) and Eqn. ( 5 ) , and then reacts according to Eqn. ( 1 0 ) after rising tempera­t u r e , namely , V 2 0 5 was consumed to react wi th F e 2 0 3 and F e V 0 4 was generated. T h e few remaining V 2 0 5 was coupled to FeO and generated V 0 2 . As the quanti ty of V 0 2 was l i t t le , it was not reduced to V 2 0 3 fur ther , as a resu l t , there was no V 3 0 5 gener­ated. T h a t i s , Eqn. (6) and Eqn. (12) do not occur in

2 0 0

150

100

5 0

(a) l - F e 2 O a

2 - V 3 0 5

10 30 50

l - F e a Q ,

2 - F e V 0 4

3-VO2

UiiLU 70 10 2 0

2Θ/Π 4 0 6 0 8 0

( a ) 1 1 0 0 K» ( b ) 1 2 1 0 K.

Fig. 3 XRD pattern of N3 sample

Fig. 3 ( b ) . The analysis results of Fig. 3 (a ) and ( b ) show that wi th the tempera ture rising F e 2 0 3 reacts wi th V 2 0 5 to generate F e V 0 4 easily, tha t is to say , high tempera ture is helpful to generate F e V 0 4 .

Fig. 4 (a) shows the XRD result of sample N6 after being kept at 1210 Κ for 45 min. Compared with Fig. 3 ( b ) , the experiment tempera ture is the same and the only difference is that the composition of N6 is dif­ferent from that of N 3 . These two kinds of samples generate F e V 0 4 , F e 2 0 3 and V 0 2 at the tempera ture of 1210 K, which shows that F e V 0 4 is generated more easily as tempera ture increases. Besides those

three kinds of substances as mentioned above, V 2 0 5

was also detected which has not reacted completely, and the reason could be that the stove a tmosphere is not controlled effectively and there is little oxygen in stove. Fig. 4 ( b ) shows the result after sample Ν 6 was kept at 1 540 Κ for 45 min. Compared wi th the diffraction result of N6 at 1210 Κ [ F i g . 4 ( a ) ] , V 2 0 3 , F e 2 V 0 4 , F e 3 0 4 and V 3 0 4 appeared at 1 540 Κ while detected substance F e V 0 4 , Fe 2 0 3 and V 0 2

disappeared at 1 210 K. T h e calculating resul ts of Eqn. (5 ) and Eqn. (6 ) show that the more FeO and higher temperature make Eqn. (6 ) proceed to right.

Issue 11 Reaction of FeO~V 2 0 5 System at High Temperature 37

3 0 0 0

2 0 0 0 h

1 0 0 0

80 10 2 0 / ( ° )

( a ) 1 2 1 0 K ; ( b ) 1 540 K.

Fig. 4 XRD pattern of N6 sample

Furthermore, when the same temperature was increased, there was a less increment for AG 9 in Eqn. ( 6 ) than in Eqn. ( 5 ) . On the basis of the Second Law of Thermodynamics, the reaction in Eqn. ( 6 ) is easier to proceed than tha t in Eqn. ( 5 ) under that condi­tion. Namely at high t empera tu re , Eqn. (6) will re­place Eqn. ( 5 ) . At the same t ime , the generation of V 2 0 3 causes Eqn. (11) and Eqn. (13) to proceed and there are new material F e 2 V 0 4 and V 3 0 4 presented in products. T h e appearance of F e 2 V 0 4 and the dis­appearance of F e V 0 4 have proven that F e 2 V 0 4 is easier to be generated than F e V 0 4 when FeO is more

and tempera ture is high. When FeO content in the sample has reached a

certain degree ( χ^οΞ^Ο. 8 1 ) , the products of reac­tion almost stay the same with the increasing tem­perature . It can be learned from Fig. 5 and Fig. 6 that vanadium oxide disappears , and only the oxide of Fe and F e 2 V 0 4 are left.

T h e above experimental resul ts show that there is no F e 2 V 0 4 generated in F e O - V 2 0 5 sys tem, and the reason for this phenomenon is tha t FeO is easily to be oxidized to generate Fe 2 0 3 , and Fe 2 0 3 would replace V 2 0 3 in F e V 2 0 4 to form F e 2 V 0 4 .

4 0 0 0

3 0 0 0

I 2 0 0 0

1 0 0 0

(a)

1 2

10

l - F e - A

2 - F e 2 V 0 4

" ί"·· -ι

3 0 5 0 70 9 0

2 0 0 0

1 0 0 0

0

2 θ / ( ° )

(b) 1 - F e 3 0 4

2 - F e 2 V 0 4 1

3 - F e 2 0 3

1 1

2 2

10 3 0 50 70 9 0

( a ) 1 5 4 0 K ; ( b ) 1 7 2 3 K.

Fig. 5 XRD pattern of N i l sample

3 Conclusions

1) Thermodynamic calculation shows that V 2 0 5

can be decomposed at the temperature below 1800 Κ, but the products V 0 2 and V 2 0 5 cannot be decom­

posed fur ther ; however , in the F e O - V 2 0 5 sys tem, because of the existence of F e O , it will couple with V 0 2 to generate V 2 0 3 but not couple with V 2 0 3 to generate V O .

2) Tempera ture and the content of FeO influence

38 Journal of Iron and Steel Research, International Vol. 19

i

6 0 0 0

4 0 0 0

2 0 0 0

1 0 0 0

0

1 - F e a 0 4

2-Fe 2V0 4

3 - F e 2 0 a

iy J A.. 10 3 0 5 0

26V(°) 70 90

Fig. 6 XRD pattern of N9 sample at 1723 Κ

the composition of products in the F e O ~ V 2 0 5 sys­tem. In tha t sys tem, when the content of FeO and the tempera ture are a little low, the main products are F e 2 0 3 , V 0 2 and V 2 0 3 . A s the content of FeO and tempera ture increase, vanadium oxides disap­pear gradual ly , and the ferrovanadium compounds and iron compounds s tar t to generate. T h e natural order of ferrovanadium compounds firstly is F e V 0 4 , and then is F e 2 V 0 4 .

3) F e V 0 4 can be seen as the product of F e 2 0 3

(generated by F e O ) and V 2 0 5 , and the generated condition is that the content of V 2 0 5 is a little high­er and some of them have not been decomposed. F e 2 V 0 4 can be seen as the product of V 2 0 3 ( g e -neated by FeO and V 2 0 5 ) and a few quanti ty of F e 2 0 3 , and the generation condition of it is that a little V 2 0 5 decompose completely and the content of FeO is h igh , jus t a few of it has been oxidated.

4) In FeO-V 2 05 binary system, it is inevitable for

F e 2 0 3 to appear. As a resu l t , there are partial V 3 +

in FeV 2 0 4 replaced by F e 3 + to generate Fe 2 V 0 4 .

References;

[ I ] T A N G Ming-quan . Secondary C o m p r e h e n s i v e Ut i l i zat ion of

Panzhihua M i n e ' s R e s o u r c e s of V a n a d i u m T i t a n i u m arid Iron

[ J ] . Min ing and Metal lurgical E n g i n e e r i n g , 2 0 0 6 ( 3 ) : 32 ( i n

C h i n e s e ) .

[ 2 ] H U A N G H a n - s h e n g . Compel l ing V a n a d i u m C h e m i s t r y [ J ] .

Global Chemica l In format ion , 2 0 0 2 , 6 : 10 ( i n C h i n e s e ) .

[ 3 ] L I U H u a - a n , LI L i a o - s h a , Y U Liang. T h e Compar i sons for

V a n a d i u m Extrac t ion T e c h n i q u e s F r o m V-Bear ing Sol id

W a s t e s [ J ] . Journal of A n h u i U n i v e r s i t y of T e c h n o l o g y : N a t ­

ural S c i e n c e , 2 0 0 3 , 2 0 ( 4 ) : 126 ( i n C h i n e s e ) .

[ 4 ] Koji K o s u g e . T h e P h a s e Diagram and P h a s e Trans i t ion of the

ν 2 0 3 - ν 2 0 5 S y s t e m [ J ] . J P h y s C h e m S o l i d s , 1 9 6 7 , 2 8 : 1 6 1 3 .

[ 5 ] Su D S , Sch log l R. T h e r m a l D e c o m p o s i t i o n of Divanadium

P e n t o x i d e V 2 O 5 : T o w a r d s Nanocrys ta l l ine V2O3 P h a s e [ J ] .

Csta lys i s i L e t t e r s , 2 0 0 2 , 8 3 ( 3 / 4 ) : 115 .

[ 6 ] C H E N G Dong-hui. Theoretical Research of Vanadium Slag Chemi­

cal Formation [ J ] . Fanadium and T i t a n i u m , 1993 ( 4 ) · 31 ( i n

C h i n e s e ) .

[ 7 ] Y A N G S u - b o , L U O Z e - z h o n g , C A I Kai -ke . T h e r m o d y n a m i c

S t u d y on Dis tr ibut ion of V a n a d i u m B e t w e e n Mel t and S lag in

B O F [ J ] . Iron and S t e e l , 2 0 0 6 , 4 1 ( 3 ) . 36 ( i n C h i n e s e ) .

[ 8 ] L I A O S h i - m i n g , B O T a n - l u n . Fore ign V a n a d i u m M e t a l l u r g y

[ M ] , Be i j ing: Metallurgical Industry Press , 1985 ( in Chinese) .

[ 9 ] L I A N G Y i n g - j i a o , C H E Yin-chang . Inorganic T h e r m o d y n a m i c

Data H a n d b o o k [ M ] . S h e n y a n g : N o r t h e a s t e r n U n i v e r s i t y

P r e s s , 1994 ( i n C h i n e s e ) .

[ 1 0 ] W A N G Shu-Ian, L I A N G Ying-jiao. Physical Chemistry [ M ] .

Beij ing: Metal lurgical Industry P r e s s , 2 0 0 7 ( i n C h i n e s e ) .

[ I I ] Z H A N G S h e n g - q i n , X I E B i n g , C A O Hai- l ian. T h e r m o d y ­

namic Equi l ibr ium of Binary S y s t e m F e O - V i O s at 9 8 0 'C [ J ] .

China N o n f e r r o u s M e t a l l u r g y , 2 0 1 0 ( 2 ) : 70 ( i n C h i n e s e ) .

[ 1 2 ] Z H A N G Z h e n - h e , Yamaura Jun- ich i , Y u t a k a U e d a . F l u x

G r o w t h and M a g n e t i c Proper t i e s of F e V 0 4 S ing le Crys ta l s

[ J ] . Journal of Sol id S t a t e C h e m i s t r y , 2 0 0 8 ( 1 8 1 ) : 2 3 4 6 .

[ 1 3 ] T u r u Y a m a s h i g t a t , Pe ter H a y e s . A n a l y s i s of X P S Spectra of

F e 2 + and F e 3 + Ions in O x i d e Mater ia l s [ J ] . Appl i ed Surface

S c i e n c e , 2 0 0 8 ( 2 5 4 ) : 2 4 4 1 .