| This research work was supported by the project of Key Technique for Comprehensive Utilization of Associated metals (In, Ag, Ca, et al.) from Refractory Zn-Sn-Cu-In Multi-metal Sulfide Ore, from the Major Industry Technology Develops Special of 2008 of the National Development and Reform Commission.There is an abundant refractory iron-bearing marmatite reserve in China. Wenshan Dulong ore of Yunnan, take is as example.possesses 2,400,000 tons of Zn,37,790,000 tons of In,260,000 tons of Sn and 78,000 tons of Cu, in which the reserves of In and Sn rank the first and the third in China, respectively; however, the iron grades in zinc minerals reaches as high as 20% Fe. The economic value of these valuable minerals, including Copper, Zinc, Indium, Tin and iron sulfide, et al., reaches as high as 110 billion RMB. These copper, zinc, tin and iron sulfide minerals embedded in such an orebody have ever been believed worthless, due to their fine and complex associations with each other. Such a dilemma results in the difficulty that the separation between Copper and Zinc is ineffective, and the zinc minerals can not be easily floated, as a result of its high iron content. With the conventional copper sulphate as activator and the high-alkali flotation process, the grade of zinc concentrate is very low with poor recovery and the recoveries of other associated minerals such as indium, silver and cadmium in zinc minerals are even much lower than that of zinc mineral, resulting in the huge waste of such a resource. Therefore, the research on effective separation of the valuable minerals from this refractory multi-metal sulfide ore has significant theoretical and practical values.There nowadays exit the following problems for the effective processing of this refractory multi-metal sulfide ore, they are:(1) copper can not be effectively separated from zinc minerals, because of their fine association with each other, leading to the high zinc content (10-18%) in copper concentrate and the loss of zinc minerals; (2) high iron-bearing sphalerite can not be effectively floated with the conventional copper sulphate as activator, and the zinc concentrate has only a 41-45% Zn grade with high impurity of iron sulfide; (3) iron sulfide minerals can not be effectively depressed under a high-alkali condition during the zinc-sulfide separation process, resulting in the low recoveries of zinc and other associated minerals. In addition, the high-alkali condition is also not favorable for the desulphurization process followed, and the separations for S-Sn and for Fe-S can not be effectively achieved, significantly deteriorating the recovery of Sn and Fe.The multi-metal sphalerite with high irons was used for the present work; its process mineralogy was analyzed, and the practical Cu-Zinc and Zinc-S separations are carried out at a pilot- and full- scales, respectively. The behaviors of sphalerites with super-high, high and low irons and of the pyrrhotite during their flotations with different reagent combinations are also investigated; the selective activation of pure sphalerite with iron and the depression of pure pyrrhotite were both tested with X-41, and its activation effect was further confirmed on a practical sphalerite. Moreover, the adsorption and potentiodynamic tests closely related with a high iron sphalerite were made; and the selective activation and depression mechanisms of X-41 were also discussed, with the main conclusions as follows:(1) The results of flotation results for pure iron sphalerite indicate that the activation ability follows the order X-41>CuSO4>PbNO3>NH4Cl, whether for high or low iron sphalerites;(2) The results of flotation results for practical iron sphalerite indicate that, while the process and reagents combination were optimum, the flotation results of the pilot-scale in laboratory obviously precedes that of the full-scale one on spot. Compared to the full-scale, the pilot-scale achieved a 7.93% Cu grade higher and 11.92% Cu recovery higher copper concentrate, with its Ag grade and recovery 118 g/t and 7.47% higher, respectively; and achieved a 4.56% Zn grade higher and 3.26% Zn recovery higher zinc concentrate, with its In grade and recovery 74.9 g/t and 4.20% higher respectively.(3) The results of industrial test indicates that the experimental performance of X-41 is significantly superior to that of copper sulphate; under a low-alkali condition, i.e., at a pH of 9, the X-41 obtained a copper concentrate assaying 2.12% Cu higher with 10.29% recovery higher, with its Ag grade and recovery 59.30 g/t and 8.32% higher respectively, in comparison with those of copper sulphate; and obtained a 1.16% Zn grade higher and 2.35% Zn recovery higher zinc concentrate, with its In grade 9.20 g/t higher and recovery 2.60% higher and its Ag grade 2.84% higher and recovery 4.69% higher and its Ca grade 50.0 g/t higher and recovery 3.25% higher, respectively. The use of X-41 produces an overall economic value reaching as high as 52.0525 million RMB per year.
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