Surface Analysis and Sulphur-Extract

The X-ray diffraction diagrams of pyrite before and after treatment with sodium sulphide are shown in Fig. 3.10, which appears to confirm the presence of sulphur because the diffraction band of elemental sulphur occurs after pyrite treated with Na2S. 

Sun et al. (1993a) reported the effects HS ion concentration on the adsorption of HS , the amount of extracted sulphur and sulphur-induced flotation of pyrite as shown in Fig. 3.11. The results show that dining sodium sulphide-induced collectorless flotation, it involves the adsorption of HS ion on the mineral and the HS adsorbed can be oxidized into sulphur to render pyrite and arsenopyrite surface hydrophobic due to the fact that the adsorption density of HS ion increases with the HS ion concentration and the amount of extracted sulphur and hence the flotation rate increases with the increase of adsorption density. It suggests that the mechanism of sodium sulphide-induced collectorless flotation of pyrite takes place hy reactions  

McCarron et al. (1990) used the X-ray photoelectron spectroscopy to analyze chalcopyrite and pyrite surface after being conditioned in sodium sulphide solutions. They found that multilayer quantities of elemental sulphur were produced at the surface of both minerals in 3 x 10 and 3 x 10 mol/L sulphide solutions although for a given sulphide concentration, the surface coverage of elemental sulphur for p)uite was greater than that for chalcopyrite under open circuit conditions. Eliseev et al. (1982) concluded that elemental sulphur was responsible for the hydrophobicity of pyrite and chalcopyrite treated with sodium sulphide. Luttrell and Yoon (1984a, b) observed a shoulder due to elemental sulfixr near 164 eV in the S (2p) spectra from relatively pure chalcopyrite floated after being conditioned at different pulp potential established by different hydrosulphide concentration. 

4 Comparison between Self-Induced and Sodium Sulphide-Induced Collectorless Flotation 

It may be seen from the results in Chapter 2 that the floatability descends in the order of chalcopyrite galena, pyrrhotite, bomite, arsenopyrite and pyrite in self-induced collectorless flotation but the order is just reversed in sodium sulphide-induced flotation, the phenomena of which may be explained in the light of their rest potential as shown in Table 3.1. 

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Abstract The sodium sulphide-induced collectorless flotation of several minerals are first introduced in this chapter. The results obtained are that sodium sulphide-induced collectorless flotation of sulphide minerals is strong for pyrite while galena, jamesonite and chalcopyrite have no sodium sulphide-induced collectorless flotability. And the nature of hydrophobic entity is then determined through J h-pH diagram and cyclic voltammogram, which is element sulphur. It is further proved widi the results of surface analysis and sulphur-extract. In the end, the self-induced and sodium sulphide-induced collectorless flotations are compared. And it is found that the order is just reverse in sodium sulphide-induced flotation to the one in self-induced collectorless flotation. 

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