Fundamental Research Of Flotation On Typical Sulphides/Carbonates/Oxides Of Cu, Pb, Zn And Fe

In this paper typical flotation of sulphides (chalcopyrite, galena, sphalerite and pyrite),carbonates of Cu/Pb/Zn (malachite, cerussite and smithsonite) and iron oxides (magnetite, hematite and limonite) are studied with xanthates (ethylxanthate, butylxanthate, octylxanthate and dodecylxanthate), sodium diethyldithiocarbamate(DDTC), amonium dibutyldithiophosphte(DDTP), lauric amine(LA), octodecylamine(ODA), sodium dodecylsulfate(DSF), sodium dodecylsulphonate(DSP), oleic acid and isopropyl thionocarbamate(PTNC). These minerals, unactivated, interacted with 12 kinds of collectors are detected by FTIR. After reviewing the references, author point out that molecular mechanics could be used in simulating and calculating interaction of Collector-Minerals.The interaction energy of Collector-Minerals are simulated and computed by use of molecular mechanics.According to results of flotation and FTIR, interaction energy of Collector-Minerals can be used in interpreting the mechanism of flotation behavior.After series of flotation tests, there are not strictly traditional sulphide collectors and oxide collectors. Oleic acid is a strong collector of all kinds of tested minerals included sulphides, malachite, smithsonite and iron oxides. The xanthates with long hydrocarbon chain are high efficient cllectors of sulphides, malachite, cerussite and smithsonite. The amine cllectors are also good collectors of sulphides, malachite, cerussite, smithsonite and magnetite. The well known collectors of oxide minerals (sodium dodecylsulfate, sodium dodecylsulphonate) are also collectors of sulphide minerals and carbonate minerals of Cu/Pb/Zn.The test results of xanthates with different hydrocarbon chain illustrate that xanthatewith the longer of the hydrocarbon chain will show the bigger of reagent logP (the stronger of reagent hydrophobic ability), the more negative of interaction energy in Collector-Minerals system slightly, and the stronger of ability to recover typical sulphides and carbonates of Cu/Pb/Zn. The relationship between results of FTIR and flotation results without limit of collector dosage show positive correlative phenomena generally although there are some negative correlative phenomena.1) In sulphide system the collector, which finger mark peak on mineral surface is detected by FTIR, can be used to float sulphides. The collectors, which finger mark peak on mineral surface is not detected by FTIR, can also be used to float sulphides.2) In unactivated carbonates of Cu/Pb/Zn, the collectors with long hydrocarbon chain, which finger mark peak on mineral surface is detected by FTIR, can be used to float carbonates. The collectors with long hydrocarbon chain, which finger mark peak on mineral surface is not detected by FTIR, can also be used to float carbonates. Some of collectors, which finger mark peak on mineral surface is detected by FTIR, can't be used to float carbonates because of their short hydrocarbon chain.3) In three kinds of iron oxides system, the collectors, which finger mark peak on mineral surface is detected by FTIR, can be used to float these iron minerals, otherwise can not be used to float iron oxide minerals.The results of simulation and computation on interaction energy in Collector-Mineral system can explained the interaction phenomena correctly when it links with flotation results and FTIR results.In this paper it is point out that collector interacts on metal atom on minerals in erect model (only polar group interacted on minerals) generally, while amine collector interacts on nonmetal atom on minerals in erect model. Its possibility is bigger than that collector interacts on mineral in parallel model (polar group and hydrocarbon chain interacted on mineral).According to the interaction energy of H2O and OH- on nine kinds of test minerals, it is concluded that H2O and OH- can interact on minerals and form hydrating layer on minerals. Its interaction energy, and so called energy bulwark, must be overcome by collector when collector interacts on minerals.When xanthates, dithiophosphate and dithiocarbamate interact on chalcopyrite, the two S atoms in dithio-group interact on Cu atom and neighbor Fe atom. For example, xanthate, dithiophosphate and dithiocarbamate interact on chalcopyrite in model of the illustrated figure (see right) When xanthates, dithiophosphate and dithiocarbamate interact on malachite and cerussite, only one of two S atoms in dithio-group interacts on metal atom.Simulation and computation results of molecular mechanics linked with logP data of reagents could be used to explain the mechanism in flotation of carbonates of Cu/Pb/Zn. For example, it is concluded that collectors can or can't overcome energy bulwark of hydrating layer on minerals according to interaction energy in Collector-Minerals. The collectors, which have big logP, can be used to float carbonate minerals.Comparing with sulphides and oxide minerals (carbonates and oxides), interaction energy in Collector-Minerals (Carbonates or Oxides) system is higher than that in Collector-Sulphides system generally. Therefor it shows that ability of interaction in Collector-Minerals (Carbonates or Oxides) system is lower than that in Collector-Sulphides system. When unactivated carbonates are flotated totally, collector needs much more dosage or much longer hydrocarbon chain.Simulation and computation results of molecular mechanism also show that the possibility of collectors interacting on minerals is small with long carbon chain when collectors interact on mimerals in parallel model (polar group and hydrocarbon chain interacting on minerals). Only ethylxanthate and isopropyl thionocarbamate in test reagents interact on minerals more possibly after overcoming water molecule interaction energy on minerals. All kinds of test collectors are even not able to interact on chalcopyrite in parallel model.This paper shows that molecular mechanics is in favor of opening out foundamental flotation principle in atom scale.