| The extraction capability of Au3+in H2SO4-NaClO3 system with imidazolium ionic liquids and pyridine ionic liquids-[C16mim][NTf2]and[Hpy][NTf2]-which acts the extraction,and n-pentanol which acts the diluent was studied in this research.The influencing factors of leaching gold with H2SO4-NaClO3 system was confirmed.The effects of pH,the concentration of the ionic liquids,the concentration of Au3+and the ratio were examined for Au???extraction.We also analysed the extraction selectivity of gold.According to the anion-exchange mechanism of Au???extraction with ionic liquids was confirmed by UV-vis,infrared spectrum,HMR and slope method.The experiment indicated that two kinds of ionic liquids have high extraction selectivity of gold comparing with the traditional extraction solvent-TBP.After the Au???extraction,then we mixed up the Ionic liquid phase with oxalic acid to make the Reduction reaction for getting the gold.The primary influencing factors were the concentration of NaClO3 and NaCl,the temperature and the leaching time.The optimun conditions of[C16mim][NTf2]and[Hpy][NTf2]were the extraction rate was mostly 100%when c?NaCl?=0.03g/mL,c?H2SO4?=0.16ml/ml,c?NaClO3?=0.08g/mL,T=75?.The result indicates that the extractant[C16mim][NTf2]has a good extraction performance and better selectivity of Al???,Cu???,Fe???and Zn???when the extractant dosage is 5g/L,c(Au3+)=0.05g/L,the phase ratio(VIL/Vaq)is 1:3,the pH value of the leaching liquor is 1.6,the extraction time is 2 min and the shaking speed is 90 rpm in the room temperature.The extraction rate could be 99.6%.The extraction coefficient for Au to Al?Cu?Fe?Zn and Ni is 466?780?1118?1404 and 541.Comparing with the traditional extraction solvent-TBP,the extraction selectivity of TBP is worse than ionic liquids'.As for the pyridine ionic liquids,the result indicates that the extractant[Hpy][NTf2]has a good extraction performance and better selectivity of Al???,Cu???,Fe???,Zn???and Sn???when the extractant dosage is 10g/L,c(Au3+)=0.06g/L,the phase ratio(VIL/Vaq)is 1:3,the pH value of the leaching liquor is 1.6,the extraction time is 2 min and the shaking speed is 90 rpm in the room temperature.The extraction rate could be 98.51%.The extraction coefficient for Au to Al?Cu?Fe?Zn and Sn is 260?161?186?296 and 247.The extraction kinetics of Au3+in H2SO4-NaClO3 with imidazolium ionic liquids,[C16mim][NTf2],and n-pentanol was studied in this research.The influence of the Stirring speed and the temperature to the extractant speed was studied in the research.r.The result indicates that extraction reaction is the diffusion control as well as the chemical control.the Extraction reaction is Mixed reaction when the Stirring speed is 90250rpm,the temperature is 298K338K.It indicates that high stirring speed and high temperature is beneficial to extraction reaction.The Ea=35.80KJ·mol. |
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