The modelling and optimization for the alkaline sulphide leaching of a complex copper concentrate containing 1.69% Sb and 0.14% Sn were studied.Response surface methodology,in combination with central composite face-c...The modelling and optimization for the alkaline sulphide leaching of a complex copper concentrate containing 1.69% Sb and 0.14% Sn were studied.Response surface methodology,in combination with central composite face-centred design（RSM-CCF）,was used to optimise the operating parameters.The leaching temperature,sulphide ion concentration and solid concentration were chosen as the variables,and the response parameters were antimony and tin recovery,and the time required to achieve 90% Sb dissolution.It was confirmed that the leaching process was strongly dependent on the reaction temperature as well as the sulphide ion concentration without any significant dependence on the solid concentration.Furthermore,a mathematical model was constructed to characterise the leaching behaviour.The results from the model allow identification of the most favourable leaching conditions.The model was validated experimentally,and the results show that the model is reliable and accurate in predicting the leaching process.展开更多
Designing high entropy alloys(HEAs) with high strength and excellent ductility has attracted extensive scientific interest. In the present work, the CALPHAD(calculation of phase diagrams) method was applied to guide t...Designing high entropy alloys(HEAs) with high strength and excellent ductility has attracted extensive scientific interest. In the present work, the CALPHAD(calculation of phase diagrams) method was applied to guide the design of an(FeCoNi)92Al2.5Ti5.5 HEA strengthened by precipitation hardening. The grain size as well as the size and volume fraction of the precipitates was tailored via a thermomechanical process to optimize the mechanical properties.The uniformly dispersed nano-precipitates are Ni3(Al,Ti)-type precipitates with an L12 ordered structure presenting a fully coherent interface with the face-centered cubic(FCC) matrix.The yield strength of the alloy increases from 338.3 to1355.9 MPa and the ultimate tensile strength increases from 759.3 to 1488.1 MPa, while the elongation maintains a reasonable value of 8.1%. The striking enhancement of strength is mainly caused by the precipitate’s hardening mechanism,which is evaluated quantitatively by various analytical models.The deformation-induced microbands and the coherent precipitates sheared by dislocations are the deformation and strengthening mechanisms contributing to the superior combination of ductility and strength in the present HEA.This investigation demonstrates that the CALPHAD method is beneficial to the design and optimization of HEAs.展开更多
文摘The modelling and optimization for the alkaline sulphide leaching of a complex copper concentrate containing 1.69% Sb and 0.14% Sn were studied.Response surface methodology,in combination with central composite face-centred design（RSM-CCF）,was used to optimise the operating parameters.The leaching temperature,sulphide ion concentration and solid concentration were chosen as the variables,and the response parameters were antimony and tin recovery,and the time required to achieve 90% Sb dissolution.It was confirmed that the leaching process was strongly dependent on the reaction temperature as well as the sulphide ion concentration without any significant dependence on the solid concentration.Furthermore,a mathematical model was constructed to characterise the leaching behaviour.The results from the model allow identification of the most favourable leaching conditions.The model was validated experimentally,and the results show that the model is reliable and accurate in predicting the leaching process.
基金supported by the Fundamental Research Funds for the Central Universities of Central South University (2019zzts052)the National Natural Science Foundation of China (51828102)
文摘Designing high entropy alloys(HEAs) with high strength and excellent ductility has attracted extensive scientific interest. In the present work, the CALPHAD(calculation of phase diagrams) method was applied to guide the design of an(FeCoNi)92Al2.5Ti5.5 HEA strengthened by precipitation hardening. The grain size as well as the size and volume fraction of the precipitates was tailored via a thermomechanical process to optimize the mechanical properties.The uniformly dispersed nano-precipitates are Ni3(Al,Ti)-type precipitates with an L12 ordered structure presenting a fully coherent interface with the face-centered cubic(FCC) matrix.The yield strength of the alloy increases from 338.3 to1355.9 MPa and the ultimate tensile strength increases from 759.3 to 1488.1 MPa, while the elongation maintains a reasonable value of 8.1%. The striking enhancement of strength is mainly caused by the precipitate’s hardening mechanism,which is evaluated quantitatively by various analytical models.The deformation-induced microbands and the coherent precipitates sheared by dislocations are the deformation and strengthening mechanisms contributing to the superior combination of ductility and strength in the present HEA.This investigation demonstrates that the CALPHAD method is beneficial to the design and optimization of HEAs.
