Xanthated crosslinked chitosan(XCCS) resin prepared under microwave irradiation were used for adsorbing Au(Ⅲ) ions in hydrochloric acid medium.The influence of pH and temperature on the adsorption capacity of XCCS was investigated.The original XCCS and the loaded XCCS were characterized by scanning electron microscope(SEM) and X-ray diffraction(XRD),respectively.The results indicate that the XCCS has ability to adsorb Au(Ⅲ) ions and the maximum adsorption capacity of Au(Ⅲ) ions on XCCS is observed at pH 1 and 20℃.The data of batch adsorption tests are fitted to kinetic models and isotherm models,respectively.The kinetics of adsorption process is found to follow pseudo-second-order kinetic rate model,and equilibrium data agree very well with the Langmuir model.Thermodynamic calculation of the Au(Ⅲ) ions adsorption process indicates that the adsorption process is spontaneous and endothermic.
In gas injection refining processes, a great amount of gas is injected into molten metal in short time, so that very large bubbles are inevitably formed. Wide dispersion of small bubbles in the bath is indispensable for high refining efficiency. Eccentric mechanical stirring with unidirectional impeller rotation was tested using a water model for pursuing better bubble disintegration and dispersion. Absorption rate are used to research on the influence law of the bubble dispersion and disintegration and gas-liquid absorption by the influence of, rotation mode, rotation speed and gas flow rate. Compared to the experimental results of absorption rate under eccentric stirring and centric stirring ,provide the scientific experimental and theoretical guidance for high-temperature experiment of hot metal desulfurization .According to experimental and theoretical analysis, this paper has studied various factors effecting on gas absorption process and volumetric mass transfer coefficient using the system of CO2-NaOH-H2O.The results show that:the volumetric mass transfer coefficient and absorption efficiency of CO2 can be increased under eccentric stirring mode, Because bubble disperse quickly with eccentric mechanical stirring, which results in promoting complete reaction between CO2 and NaOH, and improving the mass transfer coefficient and absorption. Volumetric mass transfer coefficient and efficiency of CO2 increase with the increasing rotation speed under the condition of eccentric stirring .But volumetric mass transfer coefficient and efficiency of CO2 decrease with the increasing rotation speed under the condition of centric stirring.
The new method of in-situ desulfurization with mechanical stirring of new type impellers was introduced,in which the bubble′s dispersion and disintegration of magnesium vapor were the key to boosting the desulfurization efficiency and increasing the utilization rate of magnesium.Effects of different new type of impellers on bubble dispersion and disintegration were studied through bubble image analysis,gas-liquid mass transfer,and power consumption levels of different impeller structures.The results showed that the sloped swept-back blade impeller-2produces optimal bubble′s dispersion and disintegration,as well as higher volumetric mass transfer coefficient and CO2gas utilization while consuming the least power.Numerical simulation result with Fluent software also showed that the sloped swept-back blade impeller-2has higher turbulent kinetic energy and better velocity distribution than the other two impellers.
LIU YanZHANG Zi-muLIU Jian-nanZHANG Jun-huaMasamichi SanoZHANG Jun
