Sulfide copper production

The most efficient processes in Table I are for steel and alumintim, mainly because these metals are produced in large amounts, and much technological development has been lavished on them. Magnesium and titanium require chloride intermediates, decreasing their efficiencies of production lead, copper, and nickel require extra processing to remove unwanted impurities. Sulfide ores produce sulfur dioxide (SO2), a pollutant, which must be removed from smokestack gases. For example, in copper production the removal of SO, and its conversion to sulfuric acid adds up to 8(10) JA g of additional process energy consumption. In aluminum production disposal of waste ciyolite must be controlled because of possible fiuoride contamination. 

Write a balanced net ionic equation for the reaction of nitric acid with insoluble copper(II) sulfide the products include Cu2+, S(s), and N02(g). 

In the copper production stage, copper sulfide is oxidized to molten copper metal, known as blister copper and so named because when liquid copper cools, the evolution of the residual sulfur and oxygen from the metal as sulfur dioxide gas causes blisters to form on the surface of the metal. The conversion reaction may be shown as ... 

The environmental problem of sulfur dioxide emission, as has been pointed out, is very much associated with sulfidic sources of metals, among which a peer example is copper production. In this context, it would be beneficial to describe the past and present approaches to copper smelting. In the past, copper metallurgy was dominated by reverberatory furnaces for smelting sulfidic copper concentrate to matte, followed by the use of Pierce-Smith converters to convert the matte into blister copper. The sulfur dioxide stream from the reverberatory furnaces is continuous but not rich in sulfur dioxide (about 1%) because it contains carbon dioxide and water vapor (products of fuel combustion), nitrogen from the air (used in the combustion of that fuel), and excess air. The gas is quite dilute and unworthy of economical conversion of its sulfur content into sulfuric acid. In the past, the course chosen was to construct stacks to disperse the gas into the atmosphere in order to minimize its adverse effects on the immediate surroundings. However, this is not an en-... 

The same procedure was applied to the synthesis of cadmium selenide and zinc sulfide in LLC surfactant phases using C EO surfactants. A relationship between the covalent nature of bonds in the final product and the success of the templating procedure was established on the basis of silver sulfide, copper sulfide, mercury sulfide and lead sulfide not producing the same results. The interaction of the surfactant headgroups with the precipitated mineral and with its precursor ions are necessary for direct templating. This is also confirmed by the fact that salts that bind precursor ions prevent the formation of an ordered inorganic nanostructure within the LLC phase [51]. 

This produces a residue consisting of sulfides and arsenides of Co, Ni, and Cu. Heating of the residues in the presence of NaCl causes the metals to be converted into water-soluble chlorides from which the metals are obtained by electrolysis. Current annual world production of cobalt is in the order of 15 000 tonnes, corresponding to about 1% of the annual copper production. About 20% of the cobalt comes from recycling (Saager 1984). 

Jones and colleagues have prepared 1,4-dicarbonyl compounds by conjugate additions of enolate and related anions to a,P-unsaturated sulfoxides [80,81]. For example, the lithium enolate of acetone dimethylhydrazone (83), in the presence of dimethyl sulfide-copper(I) bromide complex, underwent conjugate addition to 2-phenylsulfinyloct-l-ene (82). Quenching the reaction mixture with dimethyl disulfide gave the doubly protected 1,4-diketone derivative (84), which, on sequential hydrolysis with copper(II) acetate and trifluoroacetic acid gave the dodecane-2,5-dione (85) as the product in 54% yield from (82) (Scheme 5.27). Other examples of the addition of enolate-type species to a,p-unsaturated sulfoxides have also been reported [82.83]. 

Table 9.2-1 presents the copper production by major copper producers in the western United StiUes for the year 1978. The tonnage pi uc by dump leaching and the leaching of oxide ores was 18% of mial year tonnage. An estimated two-thirds of this, or approximately 12% of the total, may be attributed to dump leaching of low-grade predominantly sulfide-waste materials. 

C.2.2 4.9 g sodium cyanide (NaCN) Reagent water to make 1000 mL 1 to 3 min 20 to 25°C Removes copper sulfide corrosion products that may not be removed by hydrochloric acid treatment (C.2.1). 

After crushing and grinding the ore is subjected to flotation and a combined Cu-Mo sulfide concentrate is obtained. In a second flotation process the two sulfides are separated and the copper concentrate goes to copper production. 

Sulfate Reducing Bacteria SRBs have been implicated in the corrosion of cast iron and steel, ferritic stainless steels, 300 series stainless steels and other highly alloyed stainless steels, copper nickel alloys, and high nickel molybdenum alloys. They are almost always present at corrosion sites because they are in soils, surface water streams and waterside deposits in general. The key s5unptom that usually indicates their involvement in the corrosion process of ferrous alloys is localized corrosion filled with black sulfide corrosion products. 

BRUSH ALLOY 25, a heat-treatable beryllium copper product contains 1.80 to 2.00% beryllium. BRUSH ALLOY 25 is resistant to hydrogen embrittlement, and not susceptible to either sulfide stress cracking or chloride stress cracking. Moreover, in marine and certain industrial environments this alloy outperforms stainless steel, titanium, and most copper based alloys. Beryllium copper is available in a wide range of forms, including strip, tube, rod, bar, extrusions, casting and master alloy, and forging billet. 

About half of all copper production comes from chalcopyrite (CuFeSj). Other sulfide-type copper ores are chalcocite (CUjS) and covellite (CuS). The most common oxidized copper minerals are as follows ... 

LOOPING SULFIDE OXIDATION PROCESS FOR ANODE COPPER PRODUCTION... 

Figure 2. Generalized Looping Sulfide Oxidation" flow sheet for copper production...

Looping Sulfide Oxidation Process for Anode Copper Production.37... 

The reversible potential of reaction (5), under the conditions of Fig. 4 and taking Cu2 jcS to be CU1.93S (the first metastable nonstoichiometric copper sulfide oxidation product of chalcocite ), is -0.15 V. The two anodic peaks in Fig. 4, and the corresponding cathodic peaks, occur at potentials below that at which reaction (5) is possible and have been assigned to the chemisorption and desorption of xanthate. It can be seen that the chemisorption process is quite reversible. 

Rhodium occurs native with other platinum metals in river sands of the Urals and in North and South America. It is also found with other platinum metals in the copper-nickel sulfide area of the Sudbury, Ontario region. Although the quantity occurring here is very small, the large tonnages of nickel processed make the recovery commercially feasible. The annual world production of rhodium is only 7 or 8 tons. 

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