Mechanochemical sulfidization of a mixed sulfide/oxide copper ore by co-grinding with sulfur and additives including Mg(NO3)2 and Fe(NO3)3 salts and iron,aluminum and magnesium powders was investigated for the first t...Mechanochemical sulfidization of a mixed sulfide/oxide copper ore by co-grinding with sulfur and additives including Mg(NO3)2 and Fe(NO3)3 salts and iron,aluminum and magnesium powders was investigated for the first time.Also,the influence of sulfidization during the wet-milling process was examined on the separation efficiency and recovery of copper in detail.The results demonstrated that co-grinding with sulfur solely had the best flotation performance at the value of 0.5 wt.%and it was attributed to the possible existence of S\\O bonding on copper oxides surfaces.In addition,adding magnesium nitrate salt,magnesium powder,iron nitrate salt and aluminum powder as additive associated with 0.5 wt%sulfur into ball milling caused the flotation improvement at the amounts of 0.2 wt%,0.2 wt%,0.5 wt%and 0.5 wt%,respectively.Also,the effect of grinding time and sulfidization pH with 0.5 wt%sulfur solely was determined and pH s of 7.5 to 8.5 gave the best results.The highest recovery(75.76%)and separation efficiency(63.44%)were achieved at pH of 7.5 and 8.5,respectively.展开更多
Bacterial community dynamics and copper leaching with applied forced aeration were investigated during low-grade copper sulphide bioleaching to obtain better bioleaching efficiency.Results illustrated that appropriate...Bacterial community dynamics and copper leaching with applied forced aeration were investigated during low-grade copper sulphide bioleaching to obtain better bioleaching efficiency.Results illustrated that appropriate aeration improved bacterial concentrations and leaching efficiencies.The highest bacterial concentration and Cu^(2+)concentration after 14-d leaching were 7.61×10^(7) cells·mL^(−1) and 704.9 mg·L^(−1),respectively,at aeration duration of 4 h·d^(−1).The attached bacteria played a significant role during bioleaching from 1 to 7 d.However,free bacteria dominated the bioleaching processes from 8 to 14 d.This phenomenon was mainly caused by the formation of passivation layer through Fe3+hydrolysis along with bioleaching,which inhibited the contact between the attached bacteria and ore.Meanwhile,16S rDNA analysis verified the effect of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans on the bioleaching process.The results demonstrate the importance of free and attached bacteria in bioleaching.展开更多
The bioleaching of copper sulphide minerals was investigated by using A. ferrooxidans ATF6. The result shows the preferential order of the minerals bioleaching as djurleite〉bomite〉pyritic chalcopyrite〉covellite〉po...The bioleaching of copper sulphide minerals was investigated by using A. ferrooxidans ATF6. The result shows the preferential order of the minerals bioleaching as djurleite〉bomite〉pyritic chalcopyrite〉covellite〉porphyry chalcopyfite. The residues were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. It is indicated that jarosite may not be responsible for hindered disso- lution. The elemental sulfur layer on the surface of pyritic chalcopyrite residues is cracked. The compact surface layer of porphyry chalcopy- rite may strongly hinder copper extraction. X-ray photoelectron spectroscopy （XPS） further confirms that the passivation layers of covellite, pyritic chalcopyrite, and porphyry chalcopyrite are copper-depleted sulphide Cu4S11, S8, and copper-rich iron-deficient polysulphide CtuFe2S9, resoectivelv. The ability of these oassivation layers was found as Cu4Fe2S9〉Cu4S11〉S8〉iarosite.展开更多
基金the AbbasAbad copper mineShahrood University of Technology for their financial support during this research。
文摘Mechanochemical sulfidization of a mixed sulfide/oxide copper ore by co-grinding with sulfur and additives including Mg(NO3)2 and Fe(NO3)3 salts and iron,aluminum and magnesium powders was investigated for the first time.Also,the influence of sulfidization during the wet-milling process was examined on the separation efficiency and recovery of copper in detail.The results demonstrated that co-grinding with sulfur solely had the best flotation performance at the value of 0.5 wt.%and it was attributed to the possible existence of S\\O bonding on copper oxides surfaces.In addition,adding magnesium nitrate salt,magnesium powder,iron nitrate salt and aluminum powder as additive associated with 0.5 wt%sulfur into ball milling caused the flotation improvement at the amounts of 0.2 wt%,0.2 wt%,0.5 wt%and 0.5 wt%,respectively.Also,the effect of grinding time and sulfidization pH with 0.5 wt%sulfur solely was determined and pH s of 7.5 to 8.5 gave the best results.The highest recovery(75.76%)and separation efficiency(63.44%)were achieved at pH of 7.5 and 8.5,respectively.
基金This work was supported by National Science Foundation for Excellent Young Scholars,China(No.51722401)Key Project of National Natural Science Foundation,China(No.51734001)Fundamental Research Funds for the Central Universities(No.FRF-TP-18-003C1).
文摘Bacterial community dynamics and copper leaching with applied forced aeration were investigated during low-grade copper sulphide bioleaching to obtain better bioleaching efficiency.Results illustrated that appropriate aeration improved bacterial concentrations and leaching efficiencies.The highest bacterial concentration and Cu^(2+)concentration after 14-d leaching were 7.61×10^(7) cells·mL^(−1) and 704.9 mg·L^(−1),respectively,at aeration duration of 4 h·d^(−1).The attached bacteria played a significant role during bioleaching from 1 to 7 d.However,free bacteria dominated the bioleaching processes from 8 to 14 d.This phenomenon was mainly caused by the formation of passivation layer through Fe3+hydrolysis along with bioleaching,which inhibited the contact between the attached bacteria and ore.Meanwhile,16S rDNA analysis verified the effect of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans on the bioleaching process.The results demonstrate the importance of free and attached bacteria in bioleaching.
文摘The bioleaching of copper sulphide minerals was investigated by using A. ferrooxidans ATF6. The result shows the preferential order of the minerals bioleaching as djurleite〉bomite〉pyritic chalcopyrite〉covellite〉porphyry chalcopyfite. The residues were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. It is indicated that jarosite may not be responsible for hindered disso- lution. The elemental sulfur layer on the surface of pyritic chalcopyrite residues is cracked. The compact surface layer of porphyry chalcopy- rite may strongly hinder copper extraction. X-ray photoelectron spectroscopy （XPS） further confirms that the passivation layers of covellite, pyritic chalcopyrite, and porphyry chalcopyrite are copper-depleted sulphide Cu4S11, S8, and copper-rich iron-deficient polysulphide CtuFe2S9, resoectivelv. The ability of these oassivation layers was found as Cu4Fe2S9〉Cu4S11〉S8〉iarosite.
