Near-Field Optical Examination of Potassium n-Butyl Xanthate/Chalcopyrite Flotation Products

Abstract

Abstract:The present study introduces scattering-type scanning near-field infrared optical nanospectroscopy (s-SNIM) as a valuable and well-suited tool for spectrally fingerprinting n-butyl xanthate (KBX) molecules adsorbed to chalcopyrite (CCP) sample surfaces. The collector KBX is well known to float CCP and is used in beneficiation. We thus identified KBX reaction products both by IR optical far-and near-field techniques, applying attenuated total internal reflection Fourier-transform infrared spectroscopy (ATR FT-IR) in comparison to s-SNIM, respectively. The major KBX band around 880 cm −1 was probed in s-SNIM using both the tunable free-electron laser FELBE at the Helmholtz-Zentrum Dresden-Rossendorf facility, Germany, and table-top CO 2 laser illumination. We then were able to monitor the KBX agglomeration in patches <500 nm in diameter at the CCP surface, as well as nanospectroscopically identify the presence of KBX reaction products down to the 10 −4 M concentration.

Colloidal and Immobilized Nanoparticles of Lead Xanthates

“…Fourier transform infrared (FTIR) spectra (Figure ) of the Pb­(BX) 2 particles immobilized from the hydrosols with pH 5 and the BX/Pb ratio varying from 1:1 to 3:1 were essentially similar and distinct from KBX; detailed interpretation of the spectra can be found in refs. ,,,,, The main change of the spectrum from the sample prepared at BX/Pb = 1 in the alkaline solution of stationary pH = 9.5 is a shift of the peak at 1201 cm –1 , which is due to antisymmetric stretch vibration ν as (COC), to 1182 cm –1 , while the frequency of ν as (SCS) remains almost the same (∼1030 cm –1 ).…”

“…Heavy metal salts of xantic acid (the O-ester of carbonodithionic acid) M­(SSCOR) n , where M is a metal cation, R is an alkyl group, and n = 1, 2, or 3, are utilized in the production of cellulose, rubber, pesticides, lubricants, and so forth, for example. − Xanthates of lead and transition metals are prospective precursors to nanoparticles and films of metal sulfides, allowing a low-temperature, between 100 and 200 °C, in situ preparation of nanoparticulate sulfides within the polymer matrix for photovoltaics, sensors, and so forth. − Xanthates have been proposed as capping ligands in the synthesis of metal nanoparticles and self-assembled monolayers alternative to thiols. − Xanthates of alkali metals are widely used for the precipitation and separation of heavy metals in mineral processing, hydrometallurgy, water treatment, analytical practice, ,, and, first of all, as collectors in froth flotation of metal sulfide ores . Water-insoluble xanthates of lead, copper, and some other metals likely emerge as colloidal or surface species in the reaction between the xanthate collector and aqueous cations in the flotation slurries, and their interaction with mineral surfaces is important for understanding the flotation mechanisms and performance. − The ultrafine xanthate entities are also possible carriers of lead and heavy metals in wastewaters and natural surface waters, along with metal sulfide colloids − or as their precursors. It was demonstrated , that the yield of sulfide mineral ultrafines in the mineral processing is not negligible, and their total amounts can be very significant because of large volumes of the ores; moreover, the concentrations of Pb-bearing colloids in environmental waters can be higher than that of aqueous lead ions. − …”

X-ray Photoelectron Spectroscopy in Mineral Processing Studies

“…In general, one can conclude that the quantities of dixanthogens were underestimated whereas those of metal xanthates overestimated previously. This may be explained in part by the fact that metal xanthates tend to form nanoparticles with lower visible surface [104,105], whereas dixanthogen continuously (but not completely) covers the mineral surface [106].…”