Synthesis Of Novel Ether Thiocarbamates And Their Flotation Performance

Thiocarbamates are important collectors for sulfide copper ores. A series of novel ether thiocarbamates were synthesized using N-ethoxycarbonyl isothiocyanate and ether alcohols as raw materials. The flotation performance of the novel collectors and the interaction mechanism between collectors and ores were investigated.The ethoxycarbonyl isothiocyanate was produced from sodium thiocyanate and ethyl chloroformate with N, N-dimethylaniline (DMA) as phase-transfer catalyst. Novel ether thiocarbamates were prepared with the reaction of ethoxycarbonyl isothiocyanate and ether alcohols. They were O-methoxy isopropyl-N-ethoxycarbonyl thionocarbamate (MOIPECTC-1),O-(2-methoxy-1-methylethoxy) isopropyl-N-ethoxycarbonyl thionocarbamate (MOIPECTC-2), O-[2-(2-methoxy-1-methylethoxy)-1-methylethoxy] isopropyl-N-ethoxycarbonyl thionocarbamate (MOIPECTC-3),O-butoxy isopropyl-N-ethoxycarbonyl thionocarbamate(BOIPECTC-1),O-(2-butoxy-1-methylethoxy)isopropyl-N-ethoxycarbonyl thionocarbamate (BOIPECTC-2). The influences of raw material amount, temperature and reaction time on yields were investigated. The yields of ether thiocarbamates were around80%and their purities were all above76%under the optimum conditions. UV spectrum, IR spectrum, mass spectrum,1H NMR and13C NMR were adopted to characterize their structures.Foaming tendency and flotation properties of the ether thiocarbamates for chalcopyrite were investigated systematically. Both the foam height and foam half-life increased with the increase of the ether thiocarbamates concentration, and the foam stability of BOIPECTC-2was the best, which was better than generally used MIBC. The ether thiocarbamates exhibited excellent collecting ability for chalcopyrite. The order of their collecting ability for chalcopyrite was as follows: BOIPECTC-2>BOIPECTC-1> MOIPECTC-3>Z-200> MOIPECTC-2> MOIPECTC-1. For porphyry Cu-Mo ore from Jiangxi Province, the copper recovery was improved with the increase of the thiocarbamate chain length through flotation.The results of UV spectrum and IR spectrum analysis could be concluded that ether thiocarbamates could obviously react with Cu2+except Fe2+, Ni2+, Zn2+or Pb2+ions. The results of adsorption measurement confirmed that adsorption occurred obviously between ether thiocarbamates collectors and chalcopyrite. The results of surface tension determination showed that BOIPECTC-2had the strongest ability to reduce the surface tension, which was consistent with foaming tendency results.