Crystallization kinetics for the system CuSO4-ZnSO4-H2O forming solid solutions

1986 ◽  
Vol 51 (11) ◽  
pp. 2473-2480 ◽  
Author(s):  
Jaroslav Nývlt ◽  
Věra Šnoblová ◽  
Miloslav Karel
Keyword(s):  
Solid Solution ◽  
Growth Rate ◽  
Crystal Growth ◽  
Fluidized Bed ◽  
Solid Solutions ◽  
Nucleation Rate ◽  
Diffusion Mechanism ◽  
Crystal Growth Rate ◽  
Component System ◽  
Metastable Zone

The three-component system CuSO4-ZnSO4-H2O forms three types of solid solution. Metastable zone widths measured for selected solution compositions at two cooling rates were used to calculate the kinetic parameters of nucleation. The rate of crystal growth was measured by the fluidized bed method. The results show that the addition of Zn2+ to a solution of CuSO4 increases both the nucleation and crystal growth rates, whereas Cu2+ added to a solution of ZnSO4 retards the nucleation rate and slightly increases the rate of crystal growth. The nucleation rate (the metastable zone width) is substantially more sensitive to the addition of a second component than is the rate of crystal growth. The crystal growth rate is controlled by a diffusion mechanism.

Comparison of copper sulphate pentahydrate growth rates determined by different methods

1990 ◽  
Vol 55 (7) ◽  
pp. 1691-1707 ◽  
Author(s):  
Miloslav Karel ◽  
Jiří Hostomský ◽  
Jaroslav Nývlt ◽  
Axel König
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Fluidized Bed ◽  
Growth Rates ◽  
Copper Sulphate ◽  
Crystal Growth Rate ◽  
Effect Of Temperature ◽  
Rotating Disc ◽  
Shape Factors ◽  
Data Treatment

Crystal growth rates of copper sulphate pentahydrate (CuSO4.5 H2O) determined by different authors and methods are compared. The methods included in this comparison are: (i) Measurement on a fixed crystal suspended in a streaming solution, (ii) measurement on a rotating disc, (iii) measurement in a fluidized bed, (iv) measurement in an agitated suspension. The comparison involves critical estimation of the supersaturation used in measurements, of shape factors used for data treatment and a correction for the effect of temperature. Conclusions are drawn for the choice of values to be specified when data of crystal growth rate measurements are published.

Studies on nucleation and crystal growth kinetics of plutonium(IV) oxalatex

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chuanbo Li ◽  
Bo Wang ◽  
Xiang Li ◽  
Taihong Yan ◽  
Weifang Zheng
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Nucleation Rate ◽  
Crystal Growth Rate ◽  
Acid Solutions ◽  
Dilution Ratio ◽  
Secondary Nucleation ◽  
Supersaturation Ratio ◽  
Crystal Growth Kinetics ◽  
Kinetics Of

Abstract A new method is developed to calculate the dilution ratio N of the two reactant solutions during nucleation rate determination. When the initial apparent supersaturation ratio S N  = f(N) in the dilution tank is controlled between 1.66 and 1.67, the counted nuclei is the most, both nuclei dissolving and secondary nucleation avoided satisfactorily. Based on this methoed, Plutonium(IV) oxalate is precipitated by mixing equal volumes of tetravalent plutonium nitrate and oxalic acid solutions. Experiments are carried out by varying the supersaturation ratio from 8.37 to 22.47 and temperature from 25 to 50 °C. The experimental results show that the nucleation rate of plutonium(IV) oxalate in the supersaturation range cited above can be expressed by the equation R N  = A N exp(−E a /RT)exp[−B/(ln S)2], where A N  = 4.8 × 1023 m−3 s−1 , and E a  = 36.2 kJ mol−1, and B = 20.2. The crystal growth rate of plutonium(IV) oxalate is determined by adding seed crystals into a batch crystallizer. The crystal growth rate can be expressed by equation G(t) = k g exp(−E’ a /RT) (c − c eq) g , where k g  = 7.3 × 10−7 (mol/L)−1.1(m/s), E’ a  = 25.7 kJ mol−1, and g = 1.1.

Roles of Additives on Crystal Growth Rate of Precipitated Calcium Carbonate

2007 ◽  
Vol 124-126 ◽  
pp. 707-710 ◽  
Author(s):  
Ji Whan Ahn ◽  
Woon Kyoung Park ◽  
Kwang Suk You ◽  
Hee Chan Cho ◽  
Sang Jin Ko ◽  
...  
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Calcium Carbonate ◽  
Flow Rate ◽  
Nucleation Rate ◽  
Gas Flow ◽  
Crystal Growth Rate ◽  
Gas Flow Rate ◽  
Precipitated Calcium Carbonate ◽  
Co2 Gas

The characteristics of nucleation and the crystal growth of aragonite-precipitated calcium carbonate in Ca(OH)2 – MgCl2 – CO2 system by a carbonation process is investigated. MgCl2, in this study, was added in order to increase the formation yield of aragonite precipitated calcium carbonate. Optimum conditions of the concentration of the reactants, the temperature and the amount of additives were studied. The formation yield of calcite gradually decreased, and the formation yield of aragonite increased with the addition of MgCl2. A higher formation yield of above 98% for aragonite is obtained by the adding of the Mg2+ ion in a 0.2M Ca(OH)2 – 0.6M MgCl2 – CO2 system at 80. The nucleation rate increased as the temperature decreased and as the CO2 gas flow rate increased. The particle size and aspect ratio increased at a high temperature, a low flow rate of gas, and a high concentration of Ca(OH)2 slurry. Small-sized aragonite was obtained at a low temperature. The increase in crystal size with the decrease in the CO2 gas flow rate can be explained by the decrease in the nucleation rate, in addition to the increase in the crystal growth rate resulting from the decrease in the dissolution rate to CO3 2- ion.

TEMPERATURE DEPENDENCE OF THE CRYSTAL GROWTH RATE IN POLAR GLACIERS

1987 ◽  
Vol 48 (C1) ◽  
pp. C1-661-C1-662 ◽  
Author(s):  
J. R. PETIT ◽  
P. DUVAL ◽  
C. LORIUS
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Temperature Dependence ◽  
Crystal Growth Rate

Optical resolution of N-formylphenylalanine succeeds by crystal growth rate differences of diastereomeric salts

2007 ◽  
Vol 18 (2) ◽  
pp. 260-264 ◽  
Author(s):  
Laura Bereczki ◽  
Emese Pálovics ◽  
Petra Bombicz ◽  
György Pokol ◽  
Elemér Fogassy ◽  
...  
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Optical Resolution ◽  
Crystal Growth Rate ◽  
Diastereomeric Salts
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