Forecasting of Perspective Flotation Reagents on the Base of Structure Based Virtual Screening
The molecular models of complexes of poorly studied mineral clusters and reagents in developing the principles of evaluation of forecasting in flotation reagent activity have been created and optimized by using Chem Bio 3D and ChemOffice2005 by Cambridge Soft with optimization by MM2. It is proposed to use structure based virtual screening (SBVS) and reduce enormous amount of chemical compounds to a more manageable number for synthesis and screening which could lead to potential flotation candidates. The metal tellurides and arsenic sulfides as poorly explored types of minerals have been investigated. HOMO, SOMO, LUMO and total energies, atomic charges and s, p, d-population were determined for the various compounds. The strategy of prognosis of collector activity evaluation (PCAE) has been proposed as a consistent approach to estimate the interaction between a collector and a mineral cluster to search the analogue of butyl xanthate. The relationship between PCAE and flotability has been established. Our results indicate that the lower PCAE the stronger the interaction between the collector and the mineral cluster. The binary complexes of various reagents on the mineral surface have been studied. It was shown that the lowest magnitude of PCAE was obtained for arsenopyrite with binary mixture of dibutyl dithiophosphoric acid and diethylaminoethyl xanthic acid that indicated the high chemical activity of the combination of reagents. Forecasting of perspective flotation reagents by screening of chemical compounds and theoretical results obtained from research can provide a basis for innovative technology in mineral processing.
Adsorption of dithiophosphate and dithiophosphinate on chalcopyrite
Abstract Electrochemical behavior of chalcopyrite was investigated in the absence and presence of dithiophosphate (DTP) and dithiophosphinate (DTPI), selective thiols against Fe-sulfides in the flotation of sulfide ores, in potentiostatically controlled electrochemical condition. Diffuse reflectance Fourier transformation (DRIFT) spectroscopy was applied to determine the type of adsorbed collector species, and Hallimond tube flotation tests were performed to clarify the role of polarization potential and thiol collectors on the floatability of chalcopyrite. DRIFT spectroscopy study proposed that dithiolate of DTP, (DTP) 2 , was the major surface compound formed under oxidizing potentials in slightly acidic and neutral conditions. However, DTP species formed on mineral surface in alkaline condition could not be determined possibly due to heavy surface coating of metal oxyhydroxides. DTPI species formed on chalcopyrite was found to be in the form of CuDTPI + (DTPI) 2 . Additionally, presence of adsorbed DTPI, DTPI 0 , was also detected. Self-induced floatability was significantly high particularly in slightly acidic condition and decreased by increasing pH due to surface coating of metal oxyhydroxides. Addition of both collectors improved the flotation performance at all pH values. However, the positive effect of DTP at high alkaline pH values was lower than that of DTPI. This was attributed to weak collecting property and lower hydrocarbon chain length of DTP compared to DTPI. Effect of pulp potential could not be observed in slightly acidic condition, but it became apparent at higher pHs. Although better flotation responses were obtained in mildly oxidizing potentials, both collectors enlarged the floatability potential range of chalcopyrite.
Optical properties, phonons and electronic structure of iron pyrite (FeS2)
The reflectivity spectrum has been measured for photon energies between 0.03 eV and 12 eV and the optical transmission between 0.03 eV and the absorption edge at 0.95 eV. The real and imaginary part of the dielectric function have been calculated using a Kramers-Kronig analysis and an energy level scheme has been derived. All phonon modes expected by group theoretical analysis have been observed.