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Hydrolytic precipitation of magnesium polyvanadates in vanadium (IV, V) solutions
The phase and chemical composition of precipitates formed in Mg(VO 3 ) 2 -VOSO4-H 2 O system at initial pH from 1 to 7 and temperature from 80 to 90°C was studied. Polyvanadates of variable composition Mg x V y 4+ V 12- y 5+1 O 31–δ · n H 2 O (0.7 ≤ x ≤ 1.3, 1.2 ≤ y ≤ 2.4, 0.7 ≤ δ = 1.4) were formed...
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| Published in: | Russian journal of inorganic chemistry 2010-02, Vol.55 (2), p.305-311 |
|---|---|
| Main Authors: | , |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
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| Summary: | The phase and chemical composition of precipitates formed in Mg(VO
3
)
2
-VOSO4-H
2
O system at initial pH from 1 to 7 and temperature from 80 to 90°C was studied. Polyvanadates of variable composition Mg
x
V
y
4+
V
12-
y
5+1
O
31–δ
·
n
H
2
O (0.7 ≤ x ≤ 1.3, 1.2 ≤ y ≤ 2.4, 0.7 ≤ δ = 1.4) were formed at pH from 1 to 4 and V
4+
/V
5+
ratio from 0.43 to 9. Compounds with the general formula Mg
x
V
y
4+
V
6-
y
5+
O
16-δ
·
n
H
2
O (0.7 ≤
x
≤ 0.65,
y
= 1.0, 0.8 ≤ δ ≤ 0.85) were formed at pH from 6.0 to 7.0 and V
4+
/V
5+
ratios from 0.11 to 0.25. The maximum V
4+
concentration (
y
= 2.4) in the precipitates was achieved at the VV
4+
/V
5+
solution ratio of 1.0 and pH = 3. The precipitates in solutions with pH 3 were formed only upon addition of VO
2+
ions with the maximum rate at a V
4+
/V
5+
ratio of 0.33. These processes were limited by second-order reactions on the surface of polyvanadates. |
|---|---|
| ISSN: | 0036-0236 1531-8613 |
| DOI: | 10.1134/S0036023610020270 |