Geoscience Reference
In-Depth Information
BaZr
1
2
x
M
x
O
3
2
x
ð
M
Al
;
Ga
;
In
x
5
0
:
20
Þ
5
;
SrZrO
3
2
α
ð
M
Al
;
Ga
;
In
x
0
:
20
Þ
5
;
5
Ce
1
2
x
Pr
x
O
2
:
δ
Ce
1
2
x
Bi
x
O
2
2
δ
and so on
[149
152]
.
The preparation of these solid solutions is carried out usually at temperatures
of 150
250
C under autogeneous pressure. Morey-type autoclaves, or other commer-
cially available autoclaves like Parr or Berghoff autoclaves provided with Teflon
liners, are used for the synthesis of these oxides. The pH is maintained usually at high-
er levels (
10). The commonly used solvents are KOH or NH
4
OH.
Figure 9.33
shows the SEM photographs of BaZr
1
2
x
M
x
O
3
2
α
ð
.
Þ:
There are several other varieties of mixed oxides synthesized under hydrother-
mal conditions. Hydrothermal technique is especially suitable for obtaining such
unique structures, which are impossible to obtain by other conventional methods.
M
Al
;
Ga
;
In
x
0
:
20
5
;
5
References
[1] J.H. Crocket, Noble metals in sea-floor hydrothermal mineralization from the Juan de
Fuca and mid-Atlantic ridges: a fractional on of gold from platinum metals in hydro-
thermal fluids, Can. Miner. 28 (1990) 639
648.
[2] M.D. Hannington, J.M. Peter, S.D. Scott, Gold in sea-floor polymetallic sulfide depos-
its, Econ. Geol. 81 (1986) 1867
1883.
[3] H. Rau, A. Rabenau, Hydrothermal growth of some elements, J. Cryst. Growth 3/4
(1968) 417
421.
[4] A. Rabenau, H. Rau, Hydrothermal synthesis of gold, Naturwissenschaften 55 (1968)
336
339.
[5] D.I. Bujor, Synthetische Versuche uber die Bildung der Golder Zlagerstatten zu brad in
rumanien, Ark. Kemi Miner. Och. Geol., 26A, 1948.
[6] H. Honma, N. Shikazono, M. Nakata, Hydrothermal synthesis of gold, electrum and
argentite, Can. Miner. 29 (1991) 217
221.
[7] S.P. Ogryzlo, Hydrothermally experiments with gold, Econ. Geol. 30 (1935) 400
424.
[8] R.W. Henley, Soluble of gold in hydrothermal chloride solutions, Chem. Geol. 11
(1973) 73
87.
[9] D.S. Glyuk, A.A. Khlebnikova, Gold solubility in water, HCl, HF and sodium and
potassium chloride, fluoride, carbonate and bicarbonate solutions at a pressure of
1000 kg/cm
2
, Dokl. Acad. Sci. USSR Earth Sci. Sect. 254 (1980) 190
194.
[10] N. Shikazono, Selenium content of acanthite and the chemical environments of
Japanese vein-type deposits, Econ. Geol. 73 (1978) 524
533.
[11] P. Pan, S.A. Wood, The solubility of Pt and Pd sulfides and Au metal in bisulfide solu-
tions II. Results at 200
350
C and at saturated vapor pressure, Mineral. Deposita 29
(1994) 373
390.
