Amorphous alloy(MGs)is a solid alloy with disordered atomic accumulation obtained by ultra-rapid solidification of alloy melt.The atom deviates from the equilibrium position and is in metastable state.Up to now,a larg...Amorphous alloy(MGs)is a solid alloy with disordered atomic accumulation obtained by ultra-rapid solidification of alloy melt.The atom deviates from the equilibrium position and is in metastable state.Up to now,a large number of MGs have been applied to the treatment of dye and heavy metal contaminated wastewater and ideal experimental results have been obtained.However,there is no literature to systematically summarize the chemical reaction and degradation mechanism in the process of degradation.On the basis of reviewing the classification,application,and synthesis of MGs,this paper introduces in detail the chemical reactions such as decolorization,mineralization,and ion leaching of Fe-based amorphous alloy(Fe-MGs)in the degradation of organic and inorganic salt wastewater through direct reduction or advanced oxidation mechanism.Compared with crystalline materials,the higher reaction rate of Fe-MGs can be attributed to lower activation energy,negative redox potential,loose product layer,and band structure with downward shift of valence band top.Finally,some suggestions and prospects are put forward for the limitations and research prospects of MGs in the environmental field,which provides a new idea for the synthesis of new environmental functional materials.展开更多
Aimed at high content of valuable metals, complicated composition, difficult to separation of precious metals six component alloy wastes, the present paper proposed a new technology of high efficient separation and pu...Aimed at high content of valuable metals, complicated composition, difficult to separation of precious metals six component alloy wastes, the present paper proposed a new technology of high efficient separation and purification. Using fragmentation technology realizes fast dissolution of palladium, silver, copper and zinc in the wastes, and high efficient and complete separation of them from gold and platinum; using evaporation thermal decomposition technology of mixed solution produced by nitric acid dissolving palladium, silver, copper and zinc, complete and high efficient separation of silver from palladium was realized; by control of solution acidity, using hydrazine reduction method, high efficient and complete separation of gold from platinum was realized. Using this new technology, the recovery rates of palladium and silver are above 99%, and gold and platinum above 98%, the grade of pure metals are above 99.95%.展开更多
Wet dust removal systems used to control dust in the polishing or grinding process of Mg alloy products are frequently associated with potential hydrogen explosion caused by magnesium-water reaction.For purpose of avo...Wet dust removal systems used to control dust in the polishing or grinding process of Mg alloy products are frequently associated with potential hydrogen explosion caused by magnesium-water reaction.For purpose of avoiding hydrogen explosion risks,we try to use a combination of chitosan(CS)and sodium phosphate(SP)to inhibit the hydrogen evolution reaction between magnesium alloy waste dust and water.The hydrogen evolution curves and chemical kinetics modeling for ten different mixing ratios demonstrate that 0.4wt%CS+0.1wt%SP yields the best inhibition efficiency with hydrogen generation rate of almost zero.SEM and EDS analyses indicate that this composite inhibitor can create a uniform,smooth,tight protective film over the surface of the alloy dust particles.FTIR and XRD analysis of the chemical composition of the surface film show that this protective film contains CS and SP chemically adsorbed on the surface of ZK60 but no detectable Mg(OH)_(2),suggesting that magnesium-water reaction was totally blocked.Our new method offers a thorough solution to hydrogen explosion by inhibiting the hydrogen generation of magnesium alloy waste dust in a wet dust removal system.展开更多
The aluminothermic reduction of zinc oxide（ZnO） from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content ...The aluminothermic reduction of zinc oxide（ZnO） from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the surface tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the aluminothermic reduction rate of ZnO was analyzed at the following values： 0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO particles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450？500 mesh. The results show an increase in Zn concentration in the prepared alloys up to 5.43wt% for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.展开更多
基金This research was funded by the National Natural Science Foundation of China(NSFC)[Grant Nos.51661015 and 52061024]the Natural Science Foundation of Zhejiang Province[Grant No.LQ20E010002].
文摘Amorphous alloy(MGs)is a solid alloy with disordered atomic accumulation obtained by ultra-rapid solidification of alloy melt.The atom deviates from the equilibrium position and is in metastable state.Up to now,a large number of MGs have been applied to the treatment of dye and heavy metal contaminated wastewater and ideal experimental results have been obtained.However,there is no literature to systematically summarize the chemical reaction and degradation mechanism in the process of degradation.On the basis of reviewing the classification,application,and synthesis of MGs,this paper introduces in detail the chemical reactions such as decolorization,mineralization,and ion leaching of Fe-based amorphous alloy(Fe-MGs)in the degradation of organic and inorganic salt wastewater through direct reduction or advanced oxidation mechanism.Compared with crystalline materials,the higher reaction rate of Fe-MGs can be attributed to lower activation energy,negative redox potential,loose product layer,and band structure with downward shift of valence band top.Finally,some suggestions and prospects are put forward for the limitations and research prospects of MGs in the environmental field,which provides a new idea for the synthesis of new environmental functional materials.
文摘Aimed at high content of valuable metals, complicated composition, difficult to separation of precious metals six component alloy wastes, the present paper proposed a new technology of high efficient separation and purification. Using fragmentation technology realizes fast dissolution of palladium, silver, copper and zinc in the wastes, and high efficient and complete separation of them from gold and platinum; using evaporation thermal decomposition technology of mixed solution produced by nitric acid dissolving palladium, silver, copper and zinc, complete and high efficient separation of silver from palladium was realized; by control of solution acidity, using hydrazine reduction method, high efficient and complete separation of gold from platinum was realized. Using this new technology, the recovery rates of palladium and silver are above 99%, and gold and platinum above 98%, the grade of pure metals are above 99.95%.
基金This work was supported by the National Natural Science Foundation of China(52074066).
文摘Wet dust removal systems used to control dust in the polishing or grinding process of Mg alloy products are frequently associated with potential hydrogen explosion caused by magnesium-water reaction.For purpose of avoiding hydrogen explosion risks,we try to use a combination of chitosan(CS)and sodium phosphate(SP)to inhibit the hydrogen evolution reaction between magnesium alloy waste dust and water.The hydrogen evolution curves and chemical kinetics modeling for ten different mixing ratios demonstrate that 0.4wt%CS+0.1wt%SP yields the best inhibition efficiency with hydrogen generation rate of almost zero.SEM and EDS analyses indicate that this composite inhibitor can create a uniform,smooth,tight protective film over the surface of the alloy dust particles.FTIR and XRD analysis of the chemical composition of the surface film show that this protective film contains CS and SP chemically adsorbed on the surface of ZK60 but no detectable Mg(OH)_(2),suggesting that magnesium-water reaction was totally blocked.Our new method offers a thorough solution to hydrogen explosion by inhibiting the hydrogen generation of magnesium alloy waste dust in a wet dust removal system.
基金the support provided for the development of this research from Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico NacionalConsejo Nacional de Ciencia y Tecnologia (Project CB 81251)
文摘The aluminothermic reduction of zinc oxide（ZnO） from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the surface tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the aluminothermic reduction rate of ZnO was analyzed at the following values： 0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO particles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450？500 mesh. The results show an increase in Zn concentration in the prepared alloys up to 5.43wt% for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.
