Sulphide copper

Adsorbed molecules are more strongly held at the sites where the weakest metal-metal bonding is to be found, and these conespond to the active sites of Langmuir. A demonstration of this effect was found in smdies of the adsorption of H2S from a H2S/H2 mixture on a single crystal of copper of which die separate crystal faces had been polished and exposed to die gas. The formation of copper sulphide first occuiTed on die [100] and [110] planes at a lower H2S partial pressure dran on die more densely packed [111] face. Thus die metal atoms which are less strongly bonded to odrer metal atoms can bond more strongly to die adsorbed species from die gas phase. 

The objective in die roasting of sulphides, such as copper sulphides and zinc sulphides, is to convert these into their coiTesponding oxides by reaction with... 

Aguilar, J. O. Gomez-Daza, O. Brito, L. A. Nair, M. T. S. Nair, P. K. 2005. Optical and mechanical characteristics of clear and solar control laminated glass using zinc sulphide and copper sulphide thin films. Surface Coatings Technol. 200 2557-2565. 

Pathan, H. M. Desai, J. D. Lokhande, C. D. 2002. Modified chemical deposition and physico-chemical properties of copper sulphide (Cu2S) thin films. Appl. Surf. Sci. 202 47-56. 

Mixed copper sulphide oxide ores. These contain varieties of both sulphide and oxide minerals, and are the most complex copper-bearing ores from a beneficiation point of view. The major copper minerals present in this ore type include bomite, chalcocite, covellite, malachite, cuprite and chrysocolla. In some cases, significant amounts of cobalt minerals are also present in this ore. 

This method is the most commonly used in beneficiation if oxide copper-bearing ore. The reagent schemes used to treat oxide copper ores, mixed copper sulphide oxide ores and oxide copper cobalt ores varies from one ore type to the next, mainly by type of collector and sulphidizer used. 

The plant metallurgical results achieved in these concentrators are presented in Table 19.12. In most cases, the results obtained on mixed copper sulphide oxide ores are better than those obtained on oxide ores. The floatability of oxide copper from mixed ore is usually better than the floatability of copper from oxide ores. 

Plant results from mixed copper sulphide oxide ores... 

Takada and Ishimatari [20] extracted alkylbenzenes with normal C10-C14 and branched Cn-C13 alkyl chains from marine and coastal sediment and suspended matter in benzene methanol. The extract in benzene was then applied to a Florisil column for removal of copper sulphide and polar materials, and then subjected to silica gel column chromatography. Alkyl benzenes were quantified and identified using gas chromatography with flame ionization detection. The recoveries of alkyl benzenes were 81-94%. 

Abstract In the beginning, the mixed potential model, which is generally used to explain the adsorption of collectors on the sulphide minerals, is illustrated. And the collector flotation of several kinds of minerals such as copper sulphide minerals, lead sulphide minerals, zinc sulphide minerals and iron sulphide minerals is discussed in the aspect of pulp potential and the nature of hydrophobic entity is concluded from the dependence of flotation on pulp potential. In the following section, the electrochemical phase diagrams for butyl xanthate/water system and chalcocite/oxygen/xanthate system are all demonstrated from which some useful information about the hydrophobic species are obtained. And some instrumental methods including UV analysis, FTIR analysis and XPS analysis can also be used to investigated sulphide mineral-thio-collector sytem. And some examples about that are listed in the last part of this chapter. 

Abstract Two systems are discussed in this chapter, which are copper activating zinc-iron system with and without depressants. Firstly, the system in the absence of depressants is discussed. And it is obtained that at a specific pH the activation for each mineral occurs in a certain range. Through the electrochemical methods and surface analysis the entity contributing to the activation can be identified which are usually copper sulphides and vary for different minerals. Secondly, the system with depressants is researched. And also the effects of pulp potential on the activation are discussed. The same conclusion can be obtained as the one from the former system. Furthermore, zeta potential are involved in the discussion of activation and die mechanism can be explained firom the changes of zeta potential. Similarly, the activation mechanism of this system is also studied through solution chemistry, bonding of activator with mineral surfaces and surface analysis. 

In the actual flotation system, the activators on the sphalerite surface are some copper sulphide compounds containing different amounts of copper, namely some non-chemometric cupric sulphide. Based on the electrochemical theory of chalcocite in geologically minerogenic process, they may be chalcocite (CU2S), diulerite(Cui.96S), Cui,7i i.g2S, anilite(Cui.75S), geerite(Cui.6oS), spionkopite (CU1.40S), Cul.l2S and covellite (CuS). 

It is further substantiated by the pilot test results for a copper sulphide ore (see Table 10.6). To maintain the pulp potential in the range of 142- 189 mV, the flotation separation of copper-sulphur ore can obtain good results in collectorless or xanthate flotation system. The grade of feed ore is about 3.5% Cu, the grade of the obtained concentrate can reach to 27% - 28% Cu and recovery is above 95%. 

Table 10.6 Pilot plant test results of potential controlled-flotation of copper sulphide ore...

Kowal, A. and Domianowski, A., 1973. Cyclic voltammetry of ethyl xanthate on a natural copper sulphide electrode. Electrocnal Chem. Interf. Electrochem., 46 411 - 420 Laajalehto, K., Nowak P., Pomianowski, A., Suonien, E., 1991. Xanthate adsorption at the PbS/aqueous interface comparison of XPS, infiared and electrochemical results. Colloids Surf., 57 319-333... 

Young, C. A., Woods, R., Yoon, R. H., 1998. A voltammetric study of chalcocite oxidization to metalstable copper sulphides. In P. E. Richardson, R. Woods (ed.), Int. Symp. Electrochemistry in Mineral and Metal Processing II. Pennington Electrochem. Soc., 3-17... 

This work forms part of an effort to understand and to explore for the copper mineralisation discovered on the limits of the Dos Parecis Basin, Brasil. The mineralisation is associated with a unique dolomitic layer and corresponds to the presence of copper sulphides, mainly chalcocite. The study zone is located in the State of Rondonia, Brasil, 180 km to the south-east of the city of Ji-Parana. 

Basement rocks contain locally high copper concentrations (1,529 ppm maximum). This unit locally has copper sulphides and oxides. Mafic dykes and basement rocks do not show anomalous concentrations of Au, Ag, Cu, Pb, Zn or Mo. 

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