The tertiary amine can be used to extract Fe(Ⅲ) very effectively in the pH range resulting in partial hydrolysis of Fe^(3+) ions.The iron extracted into the organic phase can be stripped rather easily with dilute H_2...The tertiary amine can be used to extract Fe(Ⅲ) very effectively in the pH range resulting in partial hydrolysis of Fe^(3+) ions.The iron extracted into the organic phase can be stripped rather easily with dilute H_2SO_4 or even with H_2O.Fe(Ⅲ) is extracted into the tertiary amine sulfate solution in the form of[(R_3NH)_2Fe(OH)(SO_4)_2]_2 complex by adduct formation.Equa- tion was derived to represent the chemical reactions involved during extraction.From the infrared spectrum studies on the extraction species in waxy solid form separated from the so- lution,sulfate group is a bidentate ligand to the iron atom.The extraction species has been considered to contain (FeOH)_2 unit based on the ultra violet spectra.The possible structure of the extraction species has been proposed.展开更多
The present study deals with the nickel extraction and iron dissolution from nickeliferous laterite by a process of sulfation-roasting-leaching.To optimize the roasting process,response surface methodology(RSM)was uti...The present study deals with the nickel extraction and iron dissolution from nickeliferous laterite by a process of sulfation-roasting-leaching.To optimize the roasting process,response surface methodology(RSM)was utilized which employed two-level and two-factor full factorial central composite design(CCD).The factors of roasting temperature and time were studied. Experiments were carried out for fitting two non-linear regression models of nickel extraction and iron dissolution.Predicted values obtained were close to experimental values,indicating the suitability of the models.Three-dimensional surface plots and contour plot were helpful to predicting the results by performing only limited set of experiments.An area of nickel extraction from 75%to 78% and iron dissolution from 5%to 10%is obtained by an overlaid contour plot.The samples roasted at different temperatures and for different durations were characterized by XRD,which show a good agreement to iron dissolution analysis.展开更多
文摘The tertiary amine can be used to extract Fe(Ⅲ) very effectively in the pH range resulting in partial hydrolysis of Fe^(3+) ions.The iron extracted into the organic phase can be stripped rather easily with dilute H_2SO_4 or even with H_2O.Fe(Ⅲ) is extracted into the tertiary amine sulfate solution in the form of[(R_3NH)_2Fe(OH)(SO_4)_2]_2 complex by adduct formation.Equa- tion was derived to represent the chemical reactions involved during extraction.From the infrared spectrum studies on the extraction species in waxy solid form separated from the so- lution,sulfate group is a bidentate ligand to the iron atom.The extraction species has been considered to contain (FeOH)_2 unit based on the ultra violet spectra.The possible structure of the extraction species has been proposed.
文摘The present study deals with the nickel extraction and iron dissolution from nickeliferous laterite by a process of sulfation-roasting-leaching.To optimize the roasting process,response surface methodology(RSM)was utilized which employed two-level and two-factor full factorial central composite design(CCD).The factors of roasting temperature and time were studied. Experiments were carried out for fitting two non-linear regression models of nickel extraction and iron dissolution.Predicted values obtained were close to experimental values,indicating the suitability of the models.Three-dimensional surface plots and contour plot were helpful to predicting the results by performing only limited set of experiments.An area of nickel extraction from 75%to 78% and iron dissolution from 5%to 10%is obtained by an overlaid contour plot.The samples roasted at different temperatures and for different durations were characterized by XRD,which show a good agreement to iron dissolution analysis.
