The new method named as LEACHEX process which combines leaching of minearl and extraction of metalfrom leaching liquor is used to proccss scheelite concentrate.Elimination of solid film consisting of tungstic acidand ...The new method named as LEACHEX process which combines leaching of minearl and extraction of metalfrom leaching liquor is used to proccss scheelite concentrate.Elimination of solid film consisting of tungstic acidand the controlling step of chemical reaction are illustrated and an empirical kinetic equation is proposed basedon unreacted-shrinking-core model.90 percent decomposition of scheelite can be attained in 1800 seconds.展开更多
The global reaction rates for industrial high-temperature shift reaction catalyst WB-2, cylindrically shaped and measuring φ9×7mm, have been investigated in an internal-recycle gradientless reactor at pressures ...The global reaction rates for industrial high-temperature shift reaction catalyst WB-2, cylindrically shaped and measuring φ9×7mm, have been investigated in an internal-recycle gradientless reactor at pressures of 7×10~5 and 13×10~5 Pa (gauge). The pore-size distribution and the tortuosity factor have also been measured.in this part of the paper, by using the intrinsic kinetic equation obtained at atmospheric pressure for conditions under pressure, the numerical solutions of the effectiveness factors for 17 groups of experimental data of the global rates have been computed according to the simplified multieomponent diffusion model presented in the second part of the paper, and the results compared satisfactorily with experimentally observed values. It is therefore proposed that experiments for globdl rates under pressure would not be necessary for investigating the kinetic behavior under pressure for reactions for which the operating pressures are not too high such as the case for high-temperature shift rcaction.展开更多
Under atmosphe（）e press（）ne, rates of deseption of CO（） from unmod（）ed carbonated potash solutior （27 wt%）and modified carbonated potash solution（27 wt%） containing DETA as a catalyst, have been measured i...Under atmosphe（）e press（）ne, rates of deseption of CO（） from unmod（）ed carbonated potash solutior （27 wt%）and modified carbonated potash solution（27 wt%） containing DETA as a catalyst, have been measured in a laboratory stirred reactor. Experiments were carried out with concentrations of DETA from 0—40g/L and temperatures from 90—104℃The results, show that the desorption of CO<sub>2</sub> from hot carbonated solutions with and without the addition of DETA, may be considered a pseudo-first order reversible reaction, and that the desorption of CO<sub>2</sub> from carbonated potash solution calalysed by DEIA is in agreement with the mechanism of simultancous reactions of CO<sub>2</sub> with amine molecules and with hydroxyl ions in solution. Mathematical models for desorptions rate cocflicient have been cstablished, and optimum concentration of DETA is proposed.展开更多
Hydrodynamics in vertical tubular leaching reactor was studied in this work. Based on the observation of particle saltation in curved and square return bends, the inclined return bend was developed and examined. For t...Hydrodynamics in vertical tubular leaching reactor was studied in this work. Based on the observation of particle saltation in curved and square return bends, the inclined return bend was developed and examined. For the narrow and wide size distribution particle system, the method for calculating the particle holdup in upflow and downflow tubes was derived on the basis of generalized fluidization equation. The model of unit pressure drop was given and examined by experiments.展开更多
The open turbine rotating disc contactor (OTRDC) has been installed simply by adding three narrow strips to the lower surface of each rotating disc in the rotating disc contactor (RDC), so it can be used for the syste...The open turbine rotating disc contactor (OTRDC) has been installed simply by adding three narrow strips to the lower surface of each rotating disc in the rotating disc contactor (RDC), so it can be used for the system with high solid particle content. Hydrodynamics and axial mixing have been investigated in a 0.152m diameter OTRDC of different compartment height for the system of tap water and quartz particles. A model has been developed to describe the flow of liquid and solid phases. The solid phase holdup can be calculated satisfactorily according to the model equations. Axial mixing data have been treated by the backflow model and the correlations for predicting backflow ratios of liquid and solid phases in OTRDC have been presented.展开更多
In this paper we report the ferroelectric glass-ceramics possessing both piezoelectric and pyroelectric properties.The properties can be comparable to those of corresponding ceramics or single crystals.
Isothermal P-x data for homogeneous, and P-x’-x" data for partially miscible mixtures for the ternary system methanol-methyl methacrylate-water have been determined at 25, 35, 45, 55 and 60℃. By using a modifie...Isothermal P-x data for homogeneous, and P-x’-x" data for partially miscible mixtures for the ternary system methanol-methyl methacrylate-water have been determined at 25, 35, 45, 55 and 60℃. By using a modified UNIQUAC model and binary parameters only, the predicted ternary phase equilibrium data were found to be in good agreement with the experimental results, indicating the adequacy of using binary model parameters in computing vapor-liquid and liquid-liquid-vapor equilibria covering pressures ranging from reduced to atmospheric.展开更多
Isothermal P-x data tor the binary systems methanol-methyl methacrylate and methanol-water, and isothermal P-x’-x" data for the binary system methyl methacrylate-water have been determined at 25, 35, 45, 55 and...Isothermal P-x data tor the binary systems methanol-methyl methacrylate and methanol-water, and isothermal P-x’-x" data for the binary system methyl methacrylate-water have been determined at 25, 35, 45, 55 and 60℃. Based on the maximum likelihood principle, the modified UNIQUAC model pa rameters for these binary systems were obtained by fitting the experimental data. Vapor compositions were then calculated, and the results were compared with literature data.展开更多
It is found that the reactor has four types of flow regimes:a,b,c,and d,of which b is desirable inoperation.Therefore it is essential to find the criteria for flow regime transitions.On the basis of momen-tum,energy a...It is found that the reactor has four types of flow regimes:a,b,c,and d,of which b is desirable inoperation.Therefore it is essential to find the criteria for flow regime transitions.On the basis of momen-tum,energy and mass balance principles,theoretical criteria are obtained and agree well with the experi-mental results,which can be expressed展开更多
Mass transfer in a flat plate membrane oxygenator was studied and a convective mass transfer modelfor instantaeous reversible oxygenation of Cassonian fluid was presented. Numerical solution of the model canbe obtaine...Mass transfer in a flat plate membrane oxygenator was studied and a convective mass transfer modelfor instantaeous reversible oxygenation of Cassonian fluid was presented. Numerical solution of the model canbe obtained with finite difference method. When展开更多
The treatment of a multicomponent reversible reaction network is extremely complicated because largenumber of rate constants must be precisely determined and because the calculation based on these rateconstants is ted...The treatment of a multicomponent reversible reaction network is extremely complicated because largenumber of rate constants must be precisely determined and because the calculation based on these rateconstants is tedious.In order to reduce the degrees of freedom of the process,the authors propose a methodin which the reactor and the separator are regarded as a whole.Based on this approach,an N-componentreversible reaction system can be dealt with as a two—component system.Consequently,a simple and ac-cessible way of the apparent rate determination is suggested.For fiist-order reactions,an explicit,simplifiedexpression has been derived for both lumped and distributed parameter reaction systems.展开更多
A new series of 1222-type thallium-indium layered cuprate compounds(Tl,In)Sr_(2)(Nd,Ce)_(2)Cu_(2)O_(z)have been successfully synthesized in the pure or nearly pure form and identified by powder x-ray diffraction analy...A new series of 1222-type thallium-indium layered cuprate compounds(Tl,In)Sr_(2)(Nd,Ce)_(2)Cu_(2)O_(z)have been successfully synthesized in the pure or nearly pure form and identified by powder x-ray diffraction analyses.The structure of the compounds is directly related to that of Nb-1222 NbSr_(2)(Nd,Ce)_(2)Cu_(2)O_(z),with a tetragonal body-center lattice.The lattice parameters are a=3.85Å,c=29.56Åfor(Tl_(0.7)ln_(0.3))Srz(Nd_(0.5)Ce_(0.5))_(2)Cu_(2)O_(z),and a=3.85Å,c=29.28Åfor lnSr_(2)(Nd_(0.75)Ce_(0.25))_(2)Cu_(2)O_(z).Resistance measurements showed that(T1_(1-x)In_(x))Sr_(2)(Nd_(0.75)Ce_(0.25))_(2)Cu_(2)O_(z)(x≤0.8)are superconducting with Tc(onset)=30-40K.展开更多
Although the dielectric constant (ε) and the permanent dipole moment (μ) of solvents have for a long time been used to describe the polarity of solvents, but they can only describe the nonspecific clectrostatic inte...Although the dielectric constant (ε) and the permanent dipole moment (μ) of solvents have for a long time been used to describe the polarity of solvents, but they can only describe the nonspecific clectrostatic interactions. In addition, between solute and solvent molecules there are also some specific interactions such as electron pair donor and accepter (EPD/EPA), hydrogen bond donor and accepter (HBD/HBA), etc. In recent years, by means of spectroscopic measurements and other methods, many empirical solvents parameters have been established, such as the Lewis acidity parameter Er(30), donor展开更多
In a previous paper, insertion of dichlorocarbene into the Sn—Cl bond was reported. In this paper, it is shown that, similar to the Si—H and Ge—H bonds,the Sn—H bond can also undergo insertion reaction with dichlo...In a previous paper, insertion of dichlorocarbene into the Sn—Cl bond was reported. In this paper, it is shown that, similar to the Si—H and Ge—H bonds,the Sn—H bond can also undergo insertion reaction with dichlorocarbene: R3SnH+:CCl2→R3SnCl2H （R=C2H5, n-C4H9） Besides, tri-n-butylallyltin undergoes展开更多
文摘The new method named as LEACHEX process which combines leaching of minearl and extraction of metalfrom leaching liquor is used to proccss scheelite concentrate.Elimination of solid film consisting of tungstic acidand the controlling step of chemical reaction are illustrated and an empirical kinetic equation is proposed basedon unreacted-shrinking-core model.90 percent decomposition of scheelite can be attained in 1800 seconds.
基金Project supported by the Science Fund of the Ministy of Chemical Industey of China
文摘The global reaction rates for industrial high-temperature shift reaction catalyst WB-2, cylindrically shaped and measuring φ9×7mm, have been investigated in an internal-recycle gradientless reactor at pressures of 7×10~5 and 13×10~5 Pa (gauge). The pore-size distribution and the tortuosity factor have also been measured.in this part of the paper, by using the intrinsic kinetic equation obtained at atmospheric pressure for conditions under pressure, the numerical solutions of the effectiveness factors for 17 groups of experimental data of the global rates have been computed according to the simplified multieomponent diffusion model presented in the second part of the paper, and the results compared satisfactorily with experimentally observed values. It is therefore proposed that experiments for globdl rates under pressure would not be necessary for investigating the kinetic behavior under pressure for reactions for which the operating pressures are not too high such as the case for high-temperature shift rcaction.
文摘Under atmosphe（）e press（）ne, rates of deseption of CO（） from unmod（）ed carbonated potash solutior （27 wt%）and modified carbonated potash solution（27 wt%） containing DETA as a catalyst, have been measured in a laboratory stirred reactor. Experiments were carried out with concentrations of DETA from 0—40g/L and temperatures from 90—104℃The results, show that the desorption of CO<sub>2</sub> from hot carbonated solutions with and without the addition of DETA, may be considered a pseudo-first order reversible reaction, and that the desorption of CO<sub>2</sub> from carbonated potash solution calalysed by DEIA is in agreement with the mechanism of simultancous reactions of CO<sub>2</sub> with amine molecules and with hydroxyl ions in solution. Mathematical models for desorptions rate cocflicient have been cstablished, and optimum concentration of DETA is proposed.
文摘Hydrodynamics in vertical tubular leaching reactor was studied in this work. Based on the observation of particle saltation in curved and square return bends, the inclined return bend was developed and examined. For the narrow and wide size distribution particle system, the method for calculating the particle holdup in upflow and downflow tubes was derived on the basis of generalized fluidization equation. The model of unit pressure drop was given and examined by experiments.
文摘The open turbine rotating disc contactor (OTRDC) has been installed simply by adding three narrow strips to the lower surface of each rotating disc in the rotating disc contactor (RDC), so it can be used for the system with high solid particle content. Hydrodynamics and axial mixing have been investigated in a 0.152m diameter OTRDC of different compartment height for the system of tap water and quartz particles. A model has been developed to describe the flow of liquid and solid phases. The solid phase holdup can be calculated satisfactorily according to the model equations. Axial mixing data have been treated by the backflow model and the correlations for predicting backflow ratios of liquid and solid phases in OTRDC have been presented.
文摘In this paper we report the ferroelectric glass-ceramics possessing both piezoelectric and pyroelectric properties.The properties can be comparable to those of corresponding ceramics or single crystals.
文摘Isothermal P-x data for homogeneous, and P-x’-x" data for partially miscible mixtures for the ternary system methanol-methyl methacrylate-water have been determined at 25, 35, 45, 55 and 60℃. By using a modified UNIQUAC model and binary parameters only, the predicted ternary phase equilibrium data were found to be in good agreement with the experimental results, indicating the adequacy of using binary model parameters in computing vapor-liquid and liquid-liquid-vapor equilibria covering pressures ranging from reduced to atmospheric.
文摘Isothermal P-x data tor the binary systems methanol-methyl methacrylate and methanol-water, and isothermal P-x’-x" data for the binary system methyl methacrylate-water have been determined at 25, 35, 45, 55 and 60℃. Based on the maximum likelihood principle, the modified UNIQUAC model pa rameters for these binary systems were obtained by fitting the experimental data. Vapor compositions were then calculated, and the results were compared with literature data.
文摘It is found that the reactor has four types of flow regimes:a,b,c,and d,of which b is desirable inoperation.Therefore it is essential to find the criteria for flow regime transitions.On the basis of momen-tum,energy and mass balance principles,theoretical criteria are obtained and agree well with the experi-mental results,which can be expressed
基金The paper was presented in the lst National Rheology Conference of China and was supported by NatiOnal Natural Science Foundation of China.
文摘Mass transfer in a flat plate membrane oxygenator was studied and a convective mass transfer modelfor instantaeous reversible oxygenation of Cassonian fluid was presented. Numerical solution of the model canbe obtained with finite difference method. When
文摘The treatment of a multicomponent reversible reaction network is extremely complicated because largenumber of rate constants must be precisely determined and because the calculation based on these rateconstants is tedious.In order to reduce the degrees of freedom of the process,the authors propose a methodin which the reactor and the separator are regarded as a whole.Based on this approach,an N-componentreversible reaction system can be dealt with as a two—component system.Consequently,a simple and ac-cessible way of the apparent rate determination is suggested.For fiist-order reactions,an explicit,simplifiedexpression has been derived for both lumped and distributed parameter reaction systems.
基金Supported by a grant of the Arkansas Energy Office.
文摘A new series of 1222-type thallium-indium layered cuprate compounds(Tl,In)Sr_(2)(Nd,Ce)_(2)Cu_(2)O_(z)have been successfully synthesized in the pure or nearly pure form and identified by powder x-ray diffraction analyses.The structure of the compounds is directly related to that of Nb-1222 NbSr_(2)(Nd,Ce)_(2)Cu_(2)O_(z),with a tetragonal body-center lattice.The lattice parameters are a=3.85Å,c=29.56Åfor(Tl_(0.7)ln_(0.3))Srz(Nd_(0.5)Ce_(0.5))_(2)Cu_(2)O_(z),and a=3.85Å,c=29.28Åfor lnSr_(2)(Nd_(0.75)Ce_(0.25))_(2)Cu_(2)O_(z).Resistance measurements showed that(T1_(1-x)In_(x))Sr_(2)(Nd_(0.75)Ce_(0.25))_(2)Cu_(2)O_(z)(x≤0.8)are superconducting with Tc(onset)=30-40K.
文摘Although the dielectric constant (ε) and the permanent dipole moment (μ) of solvents have for a long time been used to describe the polarity of solvents, but they can only describe the nonspecific clectrostatic interactions. In addition, between solute and solvent molecules there are also some specific interactions such as electron pair donor and accepter (EPD/EPA), hydrogen bond donor and accepter (HBD/HBA), etc. In recent years, by means of spectroscopic measurements and other methods, many empirical solvents parameters have been established, such as the Lewis acidity parameter Er(30), donor
文摘In a previous paper, insertion of dichlorocarbene into the Sn—Cl bond was reported. In this paper, it is shown that, similar to the Si—H and Ge—H bonds,the Sn—H bond can also undergo insertion reaction with dichlorocarbene: R3SnH+:CCl2→R3SnCl2H （R=C2H5, n-C4H9） Besides, tri-n-butylallyltin undergoes
