Materials Science Forum Vols. 610-613

Abstract: The atmospheric corrosion has been shown to be an electrochemical process, the atmospheric corrosion behavior of Q235 stell evaluated with ACM (Atmospheric corrosion monitor) electrochemical technique was investigated in the study. The experimental results showed that there existed a close relation between electrochemical data and climatic parameters was confirmed. Taking into consideration accuracy and sensitivity of electrochemical technique, the ISO-standardized time of wetness (TOW) seems to be too conservative. SO2 seems to be more aggressive than chloride on metal corrosion in the early stage of atmospheric corrosion but the complexion reverses in the final stage of atmospheric corrosion. The ratio of corrosion rate from integration of ACM current to corrosion rate from weight loss of test specimens, that is, cell factor is fairly constant at the same test site but varied greatly between test sites. Based on constant cell factors and close relation between electrochemical data and climatic parameters in all test sites, ACM electrochemical technique can evaluate and classify the short-term atmospheric corrosivity as a substitute for gravimetric method, and the verification shows that atmospheric corrosivity classifications according to integration of ACM current and especially to cell factor coincide with the specifications of ISO Standard.

Abstract: A raw adsorbent of konjac glucomannan was activated at strong alkaline condition. A comprehensive adsorption study of Cu2+ removal from aqueous solution by adsorption was conducted regarding the effects of initial pH, adsorbent dosage, time, temperature and Cu2+ initial concentration. The adsorption data were applied to Langmuir and Freundlich models and their contents were calculated. Thermodynamic parameter enthalpy change (△Ho) showed that physisorption played an important role in Cu2+-loaded alkaline-activated konjac glucomannan system. Experimental data were also analysed in terms of kinetic characteristics and it was found that adsorption followed well pseudo-second-order kinetics. The results obtained showed that the new adsorbent had good efficiency for the removal of Cu2+.

Abstract: Mesoporous titania nanoribbons are synthesized via an optimized soft hydrothermal process and the derived titania ion-sieves with lithium selective adsorption property are accordingly prepared via a simple solid-phase reaction between Li2CO3 and TiO2 nanomaterials followed by the acid treatment process to extract lithium from the Li2TiO3 ternary oxide precursors. The physical chemistry structure are characterized by XRD, TEM/HRTEM, SAED and N2 adsorption-desorption analysis; and the lithium selective adsorption properties are tested by the adsorption isotherm measurement and demonstrated with the distribution coefficient of a series of alkaline and alkaline-earth metal ions. Though the high temperature calcinations and lithium insertion-extraction process resulted in the agglomeration of nanostructure to large bulky particles, it implied that that the low-dimensional titania nanoribbons might be functionalized to lithium ion-sieves with remarkable adsorption capacity and selectivity, promising in the utilization of lithium extraction from aqueous resources including brine or seawater.

Abstract: The major environmental loads of mineral separation process in China iron production (with missing data) are analyzed. And the inner relationship between these loads data is qualified and the missing data are imputed using a statistic method called multiple imputation (MI), aimed to improve the quality of LCA datasets and allow industry to easily conduct a highly reliable LCA. By using computer simulation, MI replaces each missing value with a set of plausible values which represent the uncertainty of the missing data. The multiply imputed datasets are then analyzed by the standard procedures for completing data and combining the results from these analyses. The result proves that MI Method is an effective and reasonable method to solve the problem of missing data and therefore can ensure the validity and reliability of LCA.

Abstract: In order to reach the standard of the RoHS that the content of Cr6+ lower than 200ppm in ferrite, this reserch focused on the factors that influence on the content of Cr6+ during the preparation of Strontium Ferrite. The results show that the content of Cr6+ in Strontium Ferrit can be controlled among 91~117 ppm, and the optimum condition is as follows: the quality ratio of raw materials/graphite=10:1.25, the rate of the N2 flow 0.1~0.15 L/min, sintered temperature 950~1020°C, residence time 25~35min at the corresponding temperature point, granularity of the mixed system lower than 0.1~0.3mm.

Abstract: It’s a gas-liquid-solid three-phase reaction system in the reactor for flue gas desulfurization using pyrolusite pulp. Based on the two-film mass transfer theory and shrine core model, the macro-kinetics of flue gas desulfurization using pyrolusite pulp in a double magnetic stirred reactor were investigated. The effects of diffusion in solid film, surface chemical reaction, diffusion in liquid phase and gas phase of the process, have been carried out to distinguish the control step of the process. It was observed that SO2 absorption efficiency increased with the decreasing of pyrolusite particle size and varied gently when the pyrolusite particle diameter decreased to 0.18mm. SO2 absorption efficiency increased not significantly along with the increase of temperature and the liquid phase stirring speed but increased significantly along with the increase of the gas phase stirring speed. Experiment results showed that under simulated industrial conditions, gas phase diffusion was the control step compared to other related factors, given that pyrolusite particle diameter was kept below 0.1mm.

Abstract: The electrowinning method for treating high copper cyanide solution was investigated by thermodynamics analysis and experiment. The influences of copper concentration, solution temperature, electrolysis time, current density and flow rate on copper recovery and current efficiency was studied in detail and the suitable operation parameters were chosen. Copper electrowinning from the industrial barren solution with copper concentration of 12.40g/L was performed under the condition of current density of 75 mA/cm2, flow rate of 30mL/min and 50°C for 8 hours. An alloy with copper concentration of 99.87% was obtained at the cathode with total energy consumption 2938KWh/t. The used electrolysis solution added with some fresh cyanide sodium solution can be recycled to leaching process.

Abstract: Alginate calcium fibers were prepared through wet spinning with good tensile strength which can be used for cloth materials. The morphology, mechanical property and combustion property of alginate calcium fibers were investigated. Blending yarns and textile of alginate calcium fibers and combed cotton was fabricated with good hand feeling and strength. Alginate salt fiber was prepared with wet spinning machine designed according to viscose fiber spinning machine. The diameter of alginate calcium fibers was about 10-15µm in diameter with smooth surface. The tensile strength of alginate salt fiber was larger than 4.8 cN in the dry state. The value of Limited Oxygen Index (LOI) of alginate calcium fibers was 34%. The average heat release rates (HRR) of the alginate fiber is about 21 kW/m2 which was much lower than that of most synthetic and natural fibers analysized with Cone. Alginate calcium fibers is an inherent flame-retardant fiber.