الفهرس 
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Abstract
The present thesis includes four parts. The most important results
and conclusions of the various parts are given below.
In the first part, a literature survery concerning the kinetics of
reactions in the solid state, thermal decomposition of oxalates, and
carbonates, with a specieal emphasize on the kinetics and thermal
formation of chromates, zincates and titanates.
The second part consists of preparation of pure zinc oxalate
dihydrate and preparation the mixture of ZnC204. 2H20- Cr203 by the
impregenation method. The structure of the various prepared samples
were characterized and studied by differential thermal analysis -
thermogravimetry (DTA-TG) and X-ray diffraction techniques.
The kinetic of the solid - solid reaction was studied at a temperature
range of 115-200(; for the thermal dehydration step of ZnC204. 2H20
mixture.whereas at a temperature range 340-440’t for thermal
.decomposition of anhydrous ZnC204, using isothermal and dynamic
thermogravimetric techniques. The kinetic of the solid - solid reaction
for ZnC204.2H20-Cr203 mixture was also studied at higher
temperature range 290-490t using dynamic thrmogravimetric
technique. Kinetic analysis of the reactions were discussed in view of
state of reaction models based on diffusion of reactants through
•continuous product layer, phase boundary reactions, reaction orders
Prout - Tompkins equation, Exponential law equation and random
nucleation models.
Kinetic analysis of isothermal data of thermal dehydration step and
thermal decomposition step of ZnC204. 2H20 was carried out for
weight loss fraction (ce) values in the range 0.02 < u < 0.99.
Kinetic analysis of dynamic TG curves were discussed and a critical
composition was made of three integral methods; one of Coats and
Redfern, second of Ozawa and the third of Diefallah’s composite
method. The results showed that the dynamic results are in a good
agreement with those obtained under isothermal thermogravimetric
conditions. The dynamic results showed that there is a systematic
decrease in activation parameters with increasing heating rates
according to Coats-Redfern method.
Kinetic analysis of data by a computer program analysis according
to various theoretical models showed that the thermal dehydration
reaction and the thermal formation of ZnCr204 is best described by
.(F 1) whereas the thermal decomposition reaction is best described by
(R2) where those models give the highest correlation coefficients and
less standard deviations than the other models.
In the thrid part of thesis, the preparation of BaC03 - ZnO and
BaCZ04·HzO- ZnCZ04• 2HzO mixtures were carried out by the
impregenation method. The structure of the various prepared mixtures
were characterized and studied by differential thermal analysis and
thermogravimetry (DTA and TG) and by X-ray diffraction techniques.
The kinetic of the solid - solid reaction was followed in the
temperature range 850 - 1070°C for the formation of barium zincate
dihydrate from BaC03-ZnO mixture using isothermal and dynamic
thermogravimetric techniques. While the kinetic of the solid - solid
reaction was followed in the temperature range 840 - 1130 t for the
formation of barium zincate dihydrate from BaCZ04• HzO- ZnCZ04.
2HzO mixture using dynamic thermogravimatric technique. Kintic
analysis of the reactions were discussed in view of different stolid state
reaction models.
Kinetic analysis of data by a computer program analysis according
to various theroretical models showed that the thermal formation of
barium zincate dihydrate from BaCOrZnO and BaCZ04. HzOZnCZ04
· 2HzO mixtures is best described by (R3) which gives the
highest correlation coefficient and less standard deviation than the other
models.
Kinetic analysis ofisothnnal data of thermal formation of barium
zincate dihydrate from BaC03-ZnO mixture was carried out for weight
fraction (a.) values in the range 0.04 < a. < 0.99.
It was found that the barium zincate dihydrate formation was
increased with increasing the temperature. Kinetic analysis of dynamic
.TG curves were discussed and a critical composition was made of three
integral methods; one of Coats and Redfern, second of Ozawa and the
third of Diefallah’s composite method. The results showed that the
dynamic results are in a good agreement with those obtained under
isothermal thermogravimetric conditions but within exprimental errors
for the thermal formation of BaZn02.2H20 from BaC03 - ZnO mixture
whereas, in case of the thermal formation of barium zincate dihydrate
from BaCZ04• H20- ZnCZ04. 2H20, the dynamic results showed that
there is an agreement between the composite method and Coats -
Redfern methods, but Ozawa method, gives much less satisfactory
results. There is an agreement between the dynamic results obtained for
thermal formation of barium zincate dihydrate from BaC03 - ZnO
mixture and those are obtained for the thermal formation of barium
zincate dihydrate from BaCZ04. H20- ZnC204. 2HzO mixture
according to composite and Coats - Redfern methods. But there is e,
disagreement according to Ozawa method.
The fourth part, consists of preparation of mixture of
ZnCz04.2HzO- TiOz (Anatase) mixture by the impregenation method.
This mixture was calcined at 110 ’C for 6 hours. The structure of the
prepared mixture was characterized using by differential thermal
analysis,thermal gravimetry (DTA - TG) and X-ray diffraction
techniques.
The kinetic of the solid - solid reaction was followed in the
temperature range 90- 200 °c for the thermal dehydration step and in
the temperature range 270- 430 ’t for the thermal formation step of
ZnTiO) for ZnC204• 2H20 - Ti02 (Anatase) mixture using isothermal
and dynamic thermograviametric techniques. Kinetic analysis of the
reactions were discussed in view of different solid state reaction
models.
Kinetic analysis of data by a computer program analysis according
to various theoretical models showed that the thermal dehydration
reaction is best described by (D)) whereas the thermal formation
reaction of ZnTiO) is best described by (R2) which they give the
highest correlation coefficients and less standard deviations than the
other models.
Kinetic analysis of isothermal data of thermal dehydration step and
thermal formation step of ZnTiO) in ZnC204. 2H20 - Ti02 (Anatase)
mixture was carried out for weight fraction (a) values in the range
0.02< a < 0.99.
Kinetic analysis of dynamic TG curves were discussed and a critical
composition was made of three integral methods ; one of Coats -
Redfern, second of Ozawa and the third of Diefallah’s composite
method. The results showed that there is an agreement among the
composite, Coats - Redfern and Ozawa methods, but the isothermal
method gives much less satisfactory results for dehydration step.
whereas there is an agreement among composite, Coats - Redfern and
of isothermal methods, but Ozawa method gives much less satisfactory
results for zinc titanate formation step. Morever, the values of
activation energy calculated according to Coats - Redfern method
increase with increasing heating rate, while for log A values, the results
showed non systematic trend.