1、Separation of enargite and tennantite from non-arsenic copper sulfide minerals by selective oxidation or dissolution D. Fornasiero , D. Fullston , C. Li, J. Ralston a Ian Wark Research Institute, the ARC Special Research Centre for Particle and Material Interfaces, Uniersity of South Australia, The
2、Mawson Lakes Campus, Mawson Lakes, S.A. 5095,Australia Rio Tinto Technology Development, Research Ae., Bundoora, Vic., 3083, Australia Received 10 March 2000； accepted 19 July 2000 Abstract Selective oxidation of minerals was investigated as a means to separate by flotation the copper sulfide minera
3、ls of chalcocite, covellite and chalcopyrite from the arsenic copper sulfide minerals of enargite and tennantite in mixed mineral systems. It was found that a separation of these minerals could be feasible after selective oxidation of their surfaces in slightly acidic pH conditions, or after oxidati
4、on and selective dissolution of the surface oxidation products with a complexant in basic pH conditions. q2001 Elsevier Science B.V. All rights reserved. Keywords: Selective flotation； Copper sulfide minerals； Tennantite； Enargite； Oxidation； X-ray photoelectron spectroscopy 1. Introduction Arsenic
5、is an undesirable element that causes serious toxicological and environmental problems in smelting of arsenic-containing minerals e.g., Padilla et al., 1998； Dutre and Vandecasteele, 1995 . Although hydrometallurgy or pyrometallurgy could be used to remove this element, increasing severity of enviro
6、nmental legislation has resulted in a progressive reduction of the amount of arsenic allowable in processing bi-products（ Morizot and Ollivier, 1993） . As a result, high financial penalties are imposed by smelters to treat copper ores containing higher than 0.2 wt.% arsenic （ Wilson and Chanroux, 19
7、93 . ） It would be more economically and environmentally beneficial to remove the minerals containing arsenic at an earlier stage such as during flotation. Their separation is nevertheless difficult as they generally have similar flotation behaviour to the valuable minerals with which they are assoc
8、iated. This is the case in separating arsenopyrite (FeAsS) from pyrite, or removing enargite（ Cu3 AsS4） and tennantite（ Cu12 As4 S13） from covellite（ CuS） , chalcocite（ Cu2 S） and chalcopyrite（ CuFeS2） . Apart from arsenopyrite, the amount of literature dealing with the separation of arsenic mineral
9、s is scarce. One of the potential separation methods relies on the selective oxidation of sulfide minerals due to differences in their electrochemical properties （ e.g., Tolley et al.,1996； Byrne et al., 1995； Kydros et al., 1993； Wang et al., 1992； Beattie and Poling, 1988； Guongming and Hongen, 19
10、89； Chander, 1985） .Oxidation can promote the adsorption of collectors, such as xanthate, at low to moderate levels of oxidation, or prevent their adsorption at high levels of oxidation by creating a physical barrier of oxidation products for their diffusion to the mineral surface. The oxidation beh
11、aviour of non-arsenic copper sulfide minerals(chalcocite, covellite and chalcopyrite) is well established (e.g., Richardson and Walker, 1985； Hamilton and Woods, 1984) ,whereas only a limited amount of literature is available on the oxidation of enargite and tennantite (Fullston et al., 1999a； Cordo
12、va et al., 1997； Mielczarski et al., 1996a) . A recent study on these minerals has shown that their rate of oxidation at pH 11.0 follows the order: chalcocite tennantiteenargitecovellitechalcopyrite (Fullston et al., 1999b) .This order, for the non-arsenic minerals, is in agreement with that of thei
13、r rest potential value or their flotation response in the absence or presence of collectors(Crozier, 1995； Majima, 1969) . Furthermore, it was reported that xanthate collector adsorbs more on chalcopyrite than on tennantite (Mielczarski et al., 1996b) .For a similar flotation system containing antimony copper sulfides, a satisfactory separation of chalcopyrite from tetrahedrite (Cu12Sb4S13 , the antimony analogue of tennantite). was obtained and was attributed to the faster oxidation rate of tetrahedrite than
