Jianhua Chen

A Quantum Mechanics Study on the Electronic Structure of Impurity-Bearing Sphalerite (ZnS)

A quantum mechanics study on the electronic properties and copper activation of Fe- and Cd-bearing sphalerite (ZnS) has been done using density-functional theory (DFT). Calculated results indicate that Fe impurity introduces the impurity state near the Fermi level and Fe-S bond shows stronger covalent character. Moreover, Fe impurity could not be replaced by Cu atom due to the more stable electronic structure, which results in the reduced copper adsorption amount. For the Cd-bearing ZnS, the Cd-Zn substitution introduces large lattice distortion and the Cd-S bond shows stronger ionic bonding character than Zn-S bond. For Cd-bearing sphalerite, Cd atom is easily replaced by Cu atom, which could increase the Cu2+ adsorption. The experiments of copper adsorption on the synthesized Fe-doped and Cd-doped ZnS samples confirm the simulation prediction.

Advanced Treatment Process of Metal Ions in Wastewater from a Mine

This paper mainly studied the removal of metal ions in wastewater from a mine. On the research basis of using traditional coagulation-sedimentation process to remove metal ions, this study took Zn and Cd ions as major research targets, and conducted the research of advanced treatment of mining wastewater. Enhanced coagulation and enhanced ion exchange process was adopted, and water quality indexes after treatment reach the national third class standard of surface water quality.

Flotation Behavior of Smelting Abandoned Copper Slags

The flotation of smelting copper slags in Yunnan has been studied in this paper. The influences of grinding fineness, different kinds of collectors and the dosage of sodium sulfide, GZT, which influence the flotation results, are tested. The experimental results show that in the first stage of roughing, a good flotation result is obtained, the concentrate copper grade reaches 24.12% and the flotation recovery rate reaches 82.98%, when the grade of copper slags is about 2.1%, under the circumstances that the grinding fineness is 85.6%, the amount of Y-89 is 400g/t, the amount of sodium sulfide is 2500g/t, and the amount of GZT is 80g/t.

Study on Flotation Techniques of Tailings in Dachang Mining

For the characteristics of complex paragenetic relationship, the high oxidation rate of lead antimony zinc minerals and serious sliming, GZ was used as activator and depressor, and GC was used as collector. In this study, we recover lead, antimony and zinc from tailings in Dachang mining efficiently without using copper sulfite as activator.

Effects of Metal Ion Dopants on Absorption Spectra and Photoreactivity of TiO2 Nanoparticles

This paper has systematically investigated the effects of 13 metal ion dopants on the photoreactivity and UV adsorption of TiO2 nanoparticle. The pure and ion-doped TiO2 nanoparticles were prepared using so-gel method. The absorption spectra of the TiO2 nanoparticles were obtained using UV-Visible spectrometer. The wavelength of the absorption edge of TiO2 was calculated using the tangent method. In general, different doping ion types were observed to exhibit different effects on the absorption spectra and photoreactivity of TiO2 nanoparticles. Ion concentrations were also shown to play a important role in the photoreactivity of the catalyst except Ag+, La3+, Zn2+ ions. Results reveal that red shift occurred to all ion-doped TiO2 nanoparticles with absorption edge ranging from 426 nm to 437 nm under optimal ion concentrations. Photocatalysis was shown to be inversely proportional to the amount of red shift of the absorption edge of implanted TiO2. Among the ions investigated, Ni-doped TiO2 nanoparticles have shown highest photoreactivity at the ion concentration 6.04×1017cm-3. The research results may provide references about enhancing the photoreactivity of TiO2 nanoparticles by applying metal ion doping.