Iranian Socity of Crystallography and Mineralogy
Iranian Journal of Crystallography and Mineralogy
1726-3689
2588-4719
6
1
1998
4
1
The Effect of Sintering Temperature on Magnetic Properties
of Barium Ferrite Produced by Corecipitation
3
10
FA
Y
Isotropic sa mples of Barium Ferrite are prepared by
coprecipit a tion method. To study the effect of sintering
temperature on magnetic propeTl ies of Barium ferrite we have
sintered the samples in diUerent temperature from 900 up to
J 100°C. Mean partieal size and porosity of the samples are
dete rmind by scanning electron miecroseop (SEM), magnetic
phase and magnetic parameters are measured by X-ray
diffractomet ry (XRD) and DC Magne tic Hysteresis Loop.
Experimental results show that the best magnetic parameters,
coe rcive force He, remanence magnetization B, and maximum
stored magenetie energy (BH)mu is found in samples with
sintering temperature about 900 to 950°C.
Sintering temperature, Barium Fernte, Microstructure
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Iranian Socity of Crystallography and Mineralogy
Iranian Journal of Crystallography and Mineralogy
1726-3689
2588-4719
6
1
1998
4
1
Characterization of Three Iranian Kaolins
for Transformation to Y Zeolite
11
22
FA
Y
N
N
The extensive use of zeolites as catalysts and catalyst
suppo rts in heteregenous cll t:tly~i ... in the che mical and
petrochemical industries is well established. Kaolin is a suitable
aluminosilicate mineral which in appropriate conditions can be
transformed to a three dimensional zeolite structure with a high
surface area. A vast and dispersed kaolin deposites in the
country are high potential sources for studing synthesis of
zeoli tes. The kaolins investigated in this study were from
Zenoo z ~ Azarba y jan , Rokh·Scf c ed ~ Khora s an and
Samirom· Esfahan. Theywere activated by ca lcination at 750°C
to convert them to meta kaolin. Synthesis gel was prepared from
metakaolin, sodium hydroxide, sodium silicate and sodium
chloride. Synthesis was performed by hydrothermal method at
101YC. The products were examined by XRD and EDX/SEM for
structural and chemical analysis. All three types kaolins were
converted to zeolite Y in specific condition. Silicon to aluminum
ratio in the prepared zeolite framework was in the range of
1.7·2.15 where the highest value belongs to the zeolite prepared
from Samirom kaolin.
,
Kaolin, Y Zeolite, Si/Al ratio
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Iranian Socity of Crystallography and Mineralogy
Iranian Journal of Crystallography and Mineralogy
1726-3689
2588-4719
6
1
1998
4
1
Application of Geochemical and Statistical Methods
for Prospecting of Ore Deposits in
North· East of Khorasan.
23
39
FA
Y
N
N
For evaluation of the mineral potential of Sirutr area
in the north east of Khorasan, 140 stream sediment samples were
analyzed for Ni , Co, Ag, Sb, Hg and Au. Results of these
analyses ind ica te an unusual assay for most of these elemen ts,
especia lly for gold a nd ant imony. Statis tical analyses and
co mparison of geologic map with the surrace anomaly maps
indicate a posit ive re lations hip between Ni a nd Co with mafic
and ultramafic rocks in the area; while the unusual distribution
of gold, antimony and to a lesser extent mercury can be related
to the hydrotbermal processes. From this study it is concluded
th a t the statistical analyses along with the geological and
geochemical studies are very useful in recognition of the
mineralized areas and understanding of tbe mineralizing
processes.
Gold, Nickel, Cobalt, Statistical analyses, prospecting.
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Iranian Socity of Crystallography and Mineralogy
Iranian Journal of Crystallography and Mineralogy
1726-3689
2588-4719
6
1
1998
4
1
Thermal Behaviour of Two Iranian Natural Zeolites
41
52
FA
Y
N
N
Thermal behaviour of zeolites is an important
property regarding their application in different fields. This
property mainly is related to the presence of water molecules in
their crystalline structures. It is known that zeolites give up water
molecules upon heat ing, a phenomena which affects remaining
water molecules and other clements in the framework. This
effect mainly depends on the cation type, amount of cations
present in the framework. heating rate, AJJ Si ratio and type of
the framework. In most zeolites dehydration causes unit cell
contract ion and in some cases st ructural collapse will happen
upon dehydrat ion. In the latter situation t he phenomena is an
irreversible process. In this project two samples of zeolite form
different deposits were investigated. The chemicnl analysis and
unit cell formula of the sample were firstly determined. Different
cataionic forms were then propared. The sample were all
subjected to thermal analysis a nd the effect of ingoi ng cations
were investingated.
Zeolite, Thennal Behaviour, Thomsonite, Mesolite
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Iranian Socity of Crystallography and Mineralogy
Iranian Journal of Crystallography and Mineralogy
1726-3689
2588-4719
6
1
1998
4
1
Mineralogical, Geochemical and industrial use of
bentonites from Ferdows, Kashmar and Ghonabad
in comparison with imported activated bentonites
53
66
FA
Y
N
Bentonites from Kashmar, Gonabad and Ferdows
were studied and compared with imported types. Bentonites
have a very wide range of industrial uses. Chemical and
mineralogica l composit ion of montmo rillo nite wit hin t he
bentonite control its kind of application. Bentonites from
Kashmar have the higbest content of Cao and A120) and K20.
High expandibiity, good adhesive property a nd having high
content of Na20 indicate that Ferdows bentonites are Na-type.
Gonabad bentonites are Na-Ca-Type. Kashmar, Ferdows and
Gonabad bentonites were treated for acti vat io n. In term of
exc hangable ca t io ns, Kashmar bent o nite is compa rable with
imported activated be ntonites from China a nd Turkey .
Detemination of Ca and Na montmorionite based on the X-Ray
pattern is not very e asy. The position of the first peak of
montmorillonite we re compared with Na20 content of
bentonites. JJ the first peak of montmorillonite is more than 7.3
degree and t he Na20 co nte nt of bentonite is more than 2
percent, therefore montmorillonite is Na-type. If the first peak is
less than 7 degree and Na20 content of bentonite is less than 1.5
percent, the montmorillonite is Ca-type.
Bentonite, Montmorillonite, Activated, Khorasa n.
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