Acid mine drainage activation mechanism on lime-depressed pyrite flotation from copper sulfide ore

The lime-depressed pyrite from Cu differential flotation tailings with acid mine drainage(AMD)as a natural activator was recovered.The effect of AMD on lime-depressed pyrite flotation was investigated by a series of laboratory flotation tests and surface analytical techniques.Flotation test results indicated that AMD could effectively activate the pyrite flotation with a sodium butyl xanthate(SBX)collector,and a high-quality sulfur concentrate was obtained.Pulp ion concentration analysis results indicated that AMD facilitated desorption of Ca^(2+)and adsorption of Cu^(2+)on the depressed-pyrite surface.Adsorption measurements and contact angle analysis results confirmed that adding AMD improved the adsorption amount of SBX collector on the pyrite surface and increased the contact angle by 31°.Results of Raman spectroscopy and X-ray photoelectron spectroscopy analysis indicated that AMD treatment promoted the formation of hydrophobic species(S^(0) hydrophobic entity and copper sulfides)and the removal of hydrophilic calcium and iron species on the pyrite surface,which reinforced the adsorption of collector.The findings of the present research provide important theoretical basis and technical support for a cleaner production of copper sulfide ores.

Enhanced sulfidization flotation of cuprite by surface modification with hydrogen peroxide

Hydrogen peroxide was used as an oxidant to modify the cuprite surface and enhance its sulfidization.Surface-adsorption and infrared spectroscopy measurements indicated that the modification of the cuprite surface with hydrogen peroxide before sulfidization increased the adsorption capacity of xanthate.Zeta potential,scanning electron microscopy-energy dispersive X-ray spectroscopy,X-ray photoelectron spectroscopy,and time-of-flight secondary ion mass spectrometry results showed that the modification with hydrogen peroxide increased the contents of S^(2−)and Sn^(2−)species on the cuprite surface.Microflotation tests showed that the recovery of cuprite increased from 61.74%to 83.30%after the modification of the surface with hydrogen peroxide.These results confirm that the modification of the cuprite surface with hydrogen peroxide enhances the sulfidization of cuprite,which in turn improves its flotation.

Determination of Fe and Zn contents and distributions in natural sphalerite/marmatite by various analysis methods

The contents of Fe and Zn in natural sphalerite samples were determined by chemical titration and spectroscopic techniques(portable X-ray fluorescence(P-XRF) spectrometry, electron probe microanalysis with energy dispersive spectroscopy(EPMA-EDS), electron probe microanalysis with wavelength dispersive spectroscopy(EPMA-WDS), and time-of-flight secondary ion mass spectrometry(To F-SIMS)). Besides, the distribution of Fe and Zn in sphalerite samples was analyzed by imaging EPMA-WDS and imaging To F-SIMS. The results show that Fe and Zn contents determined by each spectroscopic technique have good linearity with those determined by chemical titration(R^2>0.77), and the R^2 values of Fe are generally greater than those of Zn. The imaging analysis results revealed that Fe and Zn are not uniformly distributed in the sphalerite.

Effects of BaCl_2 on K-feldspar flotation using dodecyl amine chloride under natural pH

The effects of BaCl2 on the flotation of K-feldspar using dodecyl amine chloride as the collector under natural pH wereinvestigated by flotation tests, absorption measurements, Fourier transform infrared spectroscopy （FTIR） and X-ray photoelectronspectroscopy （XPS）. The results indicated that lower BaCl2 concentration can increase the floatability of K-feldspar, whereas higherBaCl2 concentration can significantly inhibit the flotation of K-feldspar. Peaks at 3548.18, 3475.56 and 3414.35 cm？1in the FTIRspectra of K-feldspar adsorbed by dodecyl amine chloride revealed three forms of -OH. XPS analyses of K-feldspar adsorbed byBa2＋ showed that the concentration of K atom was reduced by nearly twice as those of Si, Al, and O. The activation of BaCl2 at a lowconcentration was mainly caused by Ba2＋ in the form of the ion exchange between K＋ and Ba2＋. The inhibitory action of BaCl2 at ahigh concentration is mainly attributed to the physical absorption of Ba2＋ on the surface of K-feldspar and the fact that a highconcentration of Cl？ causes the chemical equilibrium of dodecyl amine chloride to be changed, and the dodecyl amine chloride in theform of RNH2H＋ is reduced.

Surface characteristics,collector adsorption,and flotation response of covellite in oxidizing environment

The surface characteristics,collector adsorption,and flotation response of covellite in the presence of NaClO and FeCl_(3) were investigated using micro-flotation tests,X-ray photoelectron spectroscopy(XPS),time-of-flight secondary ion mass spectrometry(TOF-SIMS),and contact angle measurements.The micro-flotation test results indicated that covellite was effectively inhibited by the presence of NaClO and FeCl_(3).However,the dosages of these depressants were large,and the conditioning time was long.The results of the XPS and TOF-SIMS analyses indicated that NaClO could oxidize the covellite surface and reduce the active sites of Cu.Oxidation products,including CuO and Cu(OH)_(2),were generated on the covellite surface.After the addition of FeCl_(3),the precipitation of iron hydroxide on the covellite surface increased the content of hydrophilic species on the mineral surface.Thus,the adsorption of ammonium dibutyl dithiophosphate on covellite surface was prevented,which reduced the floatability of the covellite.

Interaction mechanism of ferrate(Ⅵ) with arsenopyrite surface and its effect on flotation separation of chalcopyrite from arsenopyrite

Potassium ferrate(K_(2)FeO_(4)) was used as a novel environmental-friendly depressant,and its inhibition effect on flotation performance of arsenopyrite and chalcopyrite using potassium ethyl xanthate(PEX)as a collector was investigated by flotation experiments,contact angle measurements,adsorption measurements,localized electrochemical impedance spectroscopy(LEIS)measurements,and X-ray photoelectron spectroscopy(XPS)analyses.The results showed that K_(2)FeO_(4)strongly depressed arsenopyrite in a pH range of 4−11,and the flotation separation of chalcopyrite from arsenopyrite could be realized in the presence of 5×10^(−4)mol/L K_(2)FeO_(4)and 5×10^(−5)mol/L PEX at pH 8 or 10.In the presence of K_(2)FeO_(4) and PEX,the contact angle and the xanthate adsorption capacity of arsenopyrite decreased significantly.LEIS measurements showed that the addition of ferrate could significantly increase the impedance of the arsenopyrite surface.XPS analyses further confirmed that ferrate accelerated the oxidation of arsenopyrite surface.

Exploring the Wenchuan earthquake fault through the accurate location of WFSD-4#Well using seismic reflection

Deep drilling data on seismogenic faults that are obtained directly can help in understanding earthquake mechanisms and the resulting changes in deep structure and material composition.However,geophysical data are necessary to ensure that the planned borehole accurately drills through the target faults.In this study,the deep crustal structure of the Longmenshan fault is explored to obtain seismogenic fault characteristics of the Wenchuan earthquake.A scientific drilling project,Wenchuan Earthquake Fault Scientific Drilling No.4 Borehole(WFSD-4)is proposed with a borehole designed to drill through the north section of the fault zone while penetrating as many geological bodies and target layers related to seismogenic fault slip as possible.High-precision seismic exploration is then carried out to study the deep structure of the fault zone and achieve the scientific objective of the borehole.Two high-precision deep seismic reflection lines were arranged perpendicularly to the fault zone,and data were obtained through special acquisition schemes and processing methods.Finally,the surface position and drilling depth route of WFSD-4 are determined based on the interpretation results of seismic profiles.The seismic reflection method for site selection of the Wenchuan earthquake fault scientific drilling is proven feasible by comparing the interpretation with the actual drilling results,laying the foundation for further study on the deep structures of fault zones.