Sulphide Ores, Concentration

High concentrations of lead were detected in the wine-coloured and black shales of the Volcanic Sedimentary Complex with 96 mg kg 1 and 52 mg kg"1, respectively. The highest concentrations were reported for the Cu-Pb-Zn massive sulphide ore samples from the abandoned mines of Cabezas del Pasto, Romanera and Serrencillas where concentrations of Pb exceeded 5000 mg kg"1. 

Tests have been done further on the separation of a Cu-Pb mixed concentration of ethyl xanthate flotation of copper-lead-iron sulphide ore by E- control modifying with H2O2. Test results are presented in Table 10.3. It indicates the possibility of selective flotation separations of copper-lead flotation concentration by control. The feed of copper-lead mixed concentrated assayed Cu 6.53% and Pb 62.38%. Using hydrogen peroxide as a potential modifier, a copper concentration with 24.19% Cu and recovery with 89% can be obtained after separation. 

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%. 

Matte-slag-gas reactions in Cu-Fe-Ni sulphide ores. Sulphide ores are a major source of Cu, Ni and precious metals. A basic principle of the extraction processes is to blow air into the molten sulphide in order to oxidise (1) S, which forms a gas and (2) Fe, which forms predominantly FeO and then partitions to a slag phase which covers the matte. A key element in the recovery of the metals is the solidification of the matte which separates into a sulphur-rich matte and metal-rich liquid. This process may occur under non-equilibrium conditions with precious metals concentrating in the last metallic liquid. 

It should not be assumed that anomalous concentrations necessarily indicate contamination. Bolviken and Lag (1977) have described areas in Norway where the absence of vegetation is due to the toxic effects of high concentrations of metals in soils as a result of weathering of sulphide ores close to the surface. This is a natural process having nothing to do with contamination. 

The Elmore vacuum method was an outcome of the above. This is an oil flotation process, as distinct from an oil separation process. The pulp of ore and water, mixed with a very small quantity of oil and enough sulphuric acid to make tho mixture slightly acid, is exposed to a partial vacuum the air dissolved in the water rises up through it in the form of bubbles, floating the oiled sulphides to the top, whence they are drawn off. From a 2 to 3 per cent, copper ore, concentrates of up to 20 per cent, can be produced. 

These concentration processes aro of comparatively recent invention, and are increasingly applied to the treatment of low grade sulphide ores and the tailings from table concentrations. 

If one considers the possible use of a similar route for treating sulphide ore or bulk concentrates at or near the mine to maximize recoveries, there are some fundamental difficulties that must be overcome. 

P.M.J. Gray, Metallurgical Characterisation of the Zinc-Lead-Copper-Silver-Gold-Pyritic Ores Complex Sulphides. Processing of Ores. Concentrates and By-products. A.D. Zunkel et al., Eds., TMS-AME, Warrendale, PA, U.S.A.. 1985, 759-772. 

C.J. Perron, New Atmospheric Leach Process for Copper Sulphide Ores and Concentrates , Cooper 99 Cobre 99. Volume IV. The Minerals, Metals and Materials Society, Warrendale, PA, U.S.A., 1999,151-165. 

J.M. Heame, R. Haegele and R.D. Beck, Hydrometallurgy Recovery of Zinc from Sulphide Ores and Concentrates , Zinc and Lead Processing. J.E. Dutrizac, J.A. Gonzalez, G.L. Bolton and P. Hancock, Eds., Canadian Institute of Mining, Metallurgy and Petroleum, Montreal, Canada, 1998, 765-780. 

Upstream of the roaster, the run-of-mine sulphide ore is milled and then concentrated in froth flotation cells. The 75 wt% solids roaster feed slurry contains approximately 40% copper and 4% cobalt (dry basis). 

Silver has many intensive lines in breakdown spectrum, the strongest ones at 328 and 338 nm in the UV part of the spectrum and at 520 and 546 nm in the visible (Fig. 8.42a, b), which it may be potentially used in radiometric sorting. Silver is relatively uniformly distributed in massive sulphide ores (average values for the deposits 10-50 ppm), but local enrichments occur (up to 150-300 ppm of Ag). Silver usually has higher concentration comparing to gold and in certain cases may be analyzed by online LIBS. For example, we have positive laboratory scale experience with 10 samples of copper bearing rocks from Peru. It is very rare... 

Lead ores are initially crushed and concentrated by flotation, when lighter impurities such as zinc sulphide are removed. At this stage ore concentrates in general contain about... 

Recovery rates for concentrates range from 93-97 per cent lead for coarse, high grade sulphide ores down to 70 per cent, or less, for finer grade, low grade material. AME (1992) pp 27-28. 

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