| In the development and utilization of golden resources, the flotation research of gold-bearing pyrite, in which gold exists in the form of micro inclusions, has been obtained more and more attention. For the fine disseminated grain size, part of pyrite and gangue become slime after fine grinding gold-bearing pyrite to liberation and this affects the surface effect between floatation reagent and gold-bearing pyrite and result in the loss of part of the liberated gold-bearing pyrite in the tailings. In this paper, The gold-bearing pyrite flotation was enhanced by the application of the high efficiency collector S6, the carrier flotation of coarse and fine particles and the combined activator.According to the principle of isomerism of chemical agents, a new high efficient collector S6, (CH3)2CH(CH2)2CH(OCSS)CH3, for gold-bearing pyrite was designed and synthesized by reverse synthetic analysis method. Based on the method of group electronegativity, by UV absorption peak wavelength and Pauling ionic percent calculation, it was obtained that S6 with 73.5% xanthate group has the wavelength 381.6nm and is significantly higher than that of Ethyl xanthate, butyl xanthate, Amyl xanthate and Y89. The study shows that the bigger the absorption band wavelength results in the smaller the electronegativiyt, the lower the ionic character of a bond between the mineral and the reagent and the stronger the covalence. From these, the S6 and the mineral interaction ability are stronger, the collector performance is better; through changing S6’s carbon chain length and the electronic effect of non polarity group, the hydrophobic properties was increased while increasing the solid affinity of the reagent. The flotation tests of pure pyrite minerals showed that S6 has better collecting property than butyl xanthate, Amyl xanthate and Y89.Through controlling the proportion of coarse and fine grain of gold-bearing pyrite, the carrier effect was realized to improve the pyrite flotation effect. When the proportion of -0.025mm fine pyrite grain is small, the interaction between +0.074mm coarse grain and fine grain is small; when the proportion of fine grain is above 70%, coarse grains have carrier effect to fine grains to improve the overall recovery of pyrite. DLVO theory shows that the interaction between pyrite particles is related to the electrostatic interaction and hydrophobic interaction. When its carbon chain length increased, the collector reacted with the surface of the gold-bearing pyrite and was beneficial to promote mineral hydrophobic agglomeration. So the flotation of pyrite is enhanced.The mechanism study of enhancement of flotation of gold-bearing pyrite by using the combined activator of copper sulfate and ammonium sulfate shows that copper ammonia complex ion was formed by the reaction between ammonia ion produced by ammonium sulfate and copper ion produced by the copper sulfate. And copper ammonia complex ion has the effect on buffering and stabilization of copper ions. Furthermore charged copper ammonia complex ion is more easily adsorbed on the negatively charged mineral surface, increased the activation center, strengthen the flotation of gold-bearing pyrite.The results of the study of improving flotation for Guizhou Guilong and Zijinshan gold ore show that combined using of high efficient collector S6 and ammonium butyl aerofloat in closed-ciucuit test, contrasted to combined using of butyl xanthate and ammonium butyl aerofloat, gold recovery of Huilong gold ore increased 2.63%; compared with butyl xanthate, sulfur recovery was increased 3.35% by using the similar sulfur concentrate when the high efficient collector S6 was using for Zijinshan copper tailings in closed-ciucuit test.The research results of this thesis can provide references for the promotion and efficient recovery of similar gold ore with fine grains gold-bearing pyrite. |
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