| The cerussite can be collected by the collectors which usually used for collect sulfide minerals, and the ethyl xanthogenate also can collect cerussite at certain conditions. Meanwhile, the influence of the slime on zinc oxysalt minerals' flotation separation process can be reduced obviously by using combined collector which is composed of amine and neutral surfactants.The flotation behaviors of cerussite, smithsontie and hemimorphite, which are three kinds of typical lead-zinc oxysalt minerals have been investigated systematically on the conditions of using ethyl xanthate, ethyl sodium aerofloat, xylenol phosphorodithioic acid, ammonium dibutyl dithiophosphate, dodecylamine(DDA), octadecylamine(ODA), N-laurel ethanediamine, C5-9 hydroximic acid and TW-706 as collectors, and using sodium sulfide, sodium hydroxide, muriatic acid, n-butanol, iso-butanol, ter-butanol, n-hexanol, n-octanol, iso-octanol, ferric chloride, calcium chloride, aluminium chloride, lead nitrate as regulators, and the floating separation test of two kinds of artificial mixed minerals composed by cerussite mixed with smithsonite and hemimorphite individually have been conducted based on the results of monomineral flotation tests. The mechanism of the interaction between agents and minerals have been analysed based on the calculation results of solution chemistry, calculation results of collector's structural performance, HLB value of combined collector, calculation results of covalent bond's degree, calculation results of frontier orbital's energy of minerals, zeta potential measurement results of the minerals, FTIR measurement results of minerals and agents, XPS measurement results of minerals and surface tension measurement results of solution.The results show that the cerussite that haven't been activated by Na2S can be floated in the flotation system at the suitable conditions, which ethyl xanthate, ethyl sodium aerofloat, xylenol phosphorodithioic acid and ammonium dibutyl dithiophosphate used as collectors. Cerussite can't be floated by ethyl xanthate while the dosage of ethyl xanthate used for float sulfide minerals, but cerussite can be floated well if the dosage of ethyl xanthate is expanded the 20 times. The using dosage's relationship of four mentationed collectors is ethyl xanthate>ethyl sodium aerofloat> xylenol phosphorodithioic acid> ammonium dibutyl dithiophosphate while cerussite has well floatability. Cerussite can be intensely activated by Na2S, and the dosage of ethyl xanthate, ethyl sodium aerofloat, xylenol phosphorodithioic acid, ammonium dibutyl dithiophosphate which are used as collectors can be obviously decreased while the opportune dosage of Na2S is used. Whether Na2S be used as regulator or not, the cerussite can be collected well by DDA.Whether Na2S be used as regulator or not, both of smithsonite and hemimorphite can't be collected by ethyl xanthate, ethyl sodium aerofloat, xylenol phosphorodithioic acid, ammonium dibutyl dithiophosphate. Smithsonite and hemimorphite can be collected well while DDA and ODA is used as collector, and the using dosage of ODA is lesser than DDA's, and the using dosage of DDA and ODA is lesser while they are used for collect hemimorphite than used for collect smithsonite. There is obviously influence of monohydric alcohol on the floating behavior of zinc oxysalt minerals while DDA or ODA is used as collector, the dosage of DDA or ODA can be reduced while monohydric alcohol exist, and the laws of this influence is the normal monohydric alcohol is more evident than isomerism monohydric alcohol, meanwhile the effect is more evident with the increasing of the number of carbon atom of normal monohydric alcohol's molecule. There is no obvious influence of adding mode of n-octanol on the floating behavior of zinc oxysalt minerals while DDA or ODA used as collector. The same flotation effect was achieved when using the combination collector which 25.0% amount of substance proportion DDA or ODA was replaced by n-octanlo, compare with using DDA or ODA alone did. Smithsonite and hemimorphite can be activated by opportune dosage of Na2S, and the dosage of DDA or ODA can be reduced. Both of smithsonite and hemimorphinte can be inhibited by Fe3+?Al3+?Pb2+?Ca2+, and it is more effective on smithsonite than hemimorphite, while using DDA as collector. Both of smithsonite and hemimorphite can be collected by N-laurel ethanediamine, C5-9 hydroximic acid and TW-706.The cerussite-smithsonite and cerussite- hemimorphite artificial mixed mineral floating separation tests' result show that the cerussite unactivated by Na2S can be separated well from the artificial mixed minerals at the conditions of using ammonium dibutyl dithiophosphate as collector, using terpenic oil as frother. For cerussite-smithsonite artificial mixed mineral, the maximum value of selectivity index is 12.8 which is achieved at the conditions of pH of pulp is 7.0, the dosage of ammonium dibutyl dithiophosphate is 100.0mg/L, the dosage of terpenic oil is 29.4mg/L, meanwhile the Pb and Zn grade of the concentrate is 72.97% and 3.34%, and the recovery of Pb and Zn is 91.9% and 6.5%. For cerussite-hemimorphite artificial mixed mineral, the maximum value of selectivity index is 15.7 which achieved at the same conditions which listed above, meanwhile the Pb and Zn grade of the concentrate is 75.3% and 2.19%, and the recovery of Pb and Zn is 90.9% and 3.9%.The results of solution chemistry calculation, surface tension measurement of solution, potential measurement of the minerals, FTIR measurement of minerals and agents, XPS measurement of minerals, and quantum-mechanical calculation of mineral' s crystal by computer indicate that the interaction of ethyl xanthate, ethyl sodium aerofloat, xylenol phosphorodithioic acid, ammonium dibutyl dithiophosphate with cerussite is chemical adsorption, which mechanism is due to the PbS which is generated by the S atom of collector's polar group bonding with the the Pb atom of cerussite. The differentiation of collecting ability of four collectors on cerussite is determined by their structure, and there is obvious effect of hydrophobicity of collector's nonpolar group on collecting ability, the increasing hydrophobicity of ethyl xanthogenate, which is caused by the hydrophobic association of nonpolar group of ethyl xanthogenate is the mechanism of cerussite can be collected by ethyl xanthogenate at high using dosage. The interaction of DDA and ODA with smithsonite and hemimorphite is physical absorption, which mechanism is due to the the electrostatic adsorption between amine's cationic and mineral's surface which has negative charge. The interaction of N-laurel ethanediamine with smithsonite and hemimorphite is physical absorption, and the collecting ability of C5-9 hydroximic acid and TW-706 on smithsonite and hemimorphite is due to the complex which is generated by the polar group of collectors bonding with the metal atom of minerals. The activation of Na2S to cerussite is due to the PbS located at the cerussite's surface, which is the product of the reaction between Na2S and cerussite, and the activation of Na2S to the smithsonite and hemimorphite is due to the HS" ion adsorbed on the smithsonite and hemimorphite's surface and lead to the zeta potential drop. The influence of monohydric alcohol on using amine to float smithsonite and hemimorphite is due to the decrease of amine's CMC and the decrease of surface tension of solution which are made by monohydric alcohol. The inhibition of metal cation to the smithsonite and hemimorphite is due to the metal cation and metal hydroxide adsorbed on the smithsonite and hemimorphite's surface and lead to the zeta potential up. The covalence ability of M-O bond (M is metal atom) of cerussite, smithsonite and hemimorphite's crystal is one of the factors which affect the bonding ability between mineral's surface metal atom and polar group of collector, and the frontier orbital energy of cerussite, smithsonite and hemimorphite's crystal is one of the factors which determine the difficulty of their flotation separation. |
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