Matte, temperature

Soda. Process. Use of a soda smelting process for treating copper drosses in the reverberatory furnace increases the copper to lead ratios in the matte and speiss, and aUows lower operating temperatures. A flow sheet describing this process is shown in Figure 11. 

Ratings may be improved by approximately 20% if the busbars are painted black with a non-metallic matt finish paint. This is because heat dissipation through a surface depends upon temperature, type of surface and colour. A rough surface will dissipate heat more readily than a smooth surface and a black body more quickly than a normal surface. Also refer to Section 51.4.4 and Table 51.1. 

The production of copper from sulphide minerals is accomplished with a preliminary partial roast of die sulphides before reaction widr air in the liquid state, known as mattes, to form copper metal (conversion). The principal sources of copper are minerals such as chalcopyrite, CuFeSa and bornite CuaFeSa, and hence the conversion process must accomplish the preferential oxidation of non, in the form of FeO, before the copper metal appears. As mentioned before, tire FeO-SiOa liquid system is practically Raoultian, and so it is relatively easy to calculate the amount of iron oxidation which can be canned out to form this liquid slag as a function of the FeO/SiOa ratio before copper oxidation occurs. The liquid slag has a maximum mole fraction of FeO at the matte blowing temperatures of about 0.3, at solid silica saturation. 

The sulphur dissociation pressure of Fe/FeS at the matte blowing temperature of about 1573 K can be calculated from the following data... 

D. Schmicker, T. Hibma, K. A. Edwards, P. B. Howes, J. E. MacDonald, M. A. James, M. Breeman, G. T. Barkema. Low-temperature growth of thin Pb layers and the quantum size effect. J Phys Condens Matt 9 969, 1997. 

The essential constituent of the bath is sodium tetrachromate, Na2Cr40,3, which is, however, only stable at temperatures below about 25°C. This temperature should therefore not be exceeded in the operation of the bath. Current densities of 75-150 A/dm are used. The current efficiency of the bath is high (30-35%) so that the metal is deposited at the rate of about 1 tm/min. The deposits are normally matt in appearance, but are comparatively soft and readily polished. 

High strength Temperature stability Specific splicing tendency Matt surface 1 5 PETP... 

The dried chromatogram is first dipped in reagent solution 1 for 1 s, dried briefly in a stream of cold air and then dipped in reagent solution 2 for 1 s. The TLC/HPTLC plate is then held upright on tissue paper to allow excess reagent to drain away when the layer appears matt it is covered with a glass plate and kept at room temperature for 5 min. Afterwards it is dried in a stream of hot air and exposed to ammonia vapor. 

The copper remaining in lead after the above operation is removed by matte formation. Finely divided sulfur is added to molten lead at temperatures slightly above its melting point, and the melt is stirred continuously. Copper sulfide forms and floats on the surface, leaving the bullion substantially free of copper (less than 0.005%). The standard free energies of formation of cuprous sulfide and lead sulfide are about the same the observed separation must, therefore, be due to kinetic factors or to the influence of certain minor impurities that are present in the lead. 

Societe Le Nickel (SLN) employ similar chemistry at their operations to treat mattes obtained from the pyrometallurgical treatment of Ni-bearing oxidic laterite ores.104 It has demonstrated at laboratory scale that Ni-containing lateritic ores may be directly leached into HC1 acid solution without pyrometallurgical pre-concentration at atmospheric pressure and relatively low temperature (ca. 70 °C).105... 

The following hypotheses was tested in the first approximation if the vaporization of volatile oxides, sulfides, and metals of all the considered chemical elements at roasting and/or conversion temperature plays a significant role in the contamination of Karabash atmosphere, their calculated equilibrium pressure over the Cu-concentrate, slag, matte or copper melt (or their chemical composition) should strongly correlate with the detected abundance of these elements in snow samples. If such a significant correlation is detected, the corresponding process exerts primary... 

Figure 10.78 Comparison between calculated and experimental matte compositions (Ni Cu wt ratio 2 I) at different temperatures and SO2 partial pressures (from Taylor and Dinsdale 1990).

Charcoals matte") at temperatures which, fuse jila ... 

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