Oxide copper ores properties

The above processes involve separation based either on bulk properties (for example, size, density, shape, etc.) directly or by subtle control of the chemistry of the narrow interfacial region between the mineral particle and the aqueous solution in which it is suspended. In the processing of certain ores, such as those of uranium, gold or oxidized copper, chemical alteration of the minerals may be required to recover the valuable metals. These techniques are not discussed here, except to include those aspects which are directly related to surfaces and interfaces. 

Sulfide collectors ia geaeral show Htfle affinity for nonsulfide minerals, thus separation of one sulfide from another becomes the main issue. The nonsulfide collectors are in general less selective and this is accentuated by the large similarities in surface properties between the various nonsulfide minerals (42). Some examples of sulfide flotation are copper sulfides flotation from siUceous gangue sequential flotation of sulfides of copper, lead, and zinc from complex and massive sulfide ores and flotation recovery of extremely small (a few ppm) amounts of precious metals. Examples of nonsulfide flotation include separation of sylvite, KCl, from haUte, NaCl, which are two soluble minerals having similar properties selective flocculation—flotation separation of iron oxides from siUca separation of feldspar from siUca, siUcates, and oxides phosphate rock separation from siUca and carbonates and coal flotation. 

Silver sulfate decomposes above 1085°C into silver, sulfur dioxide, and oxygen. This property is utilized ia the separation of silver from sulfide ores by direct oxidation. Silver sulfate is reduced to silver metal by hydrogen, carbon, carbon monoxide, zinc, and copper. 

Cobalt is the thirtieth most abundant element on earth and comprises approximately 0.0025% of the earth s cmst (3). It occurs in mineral form as arsenides, sulfides, and oxides trace amounts are also found in other minerals of nickel and iron as substitute ions (4). Cobalt minerals are commonly associated with ores of nickel, iron, silver, bismuth, copper, manganese, antimony, and 2iac. Table 1 Hsts the principal cobalt minerals and some corresponding properties. A complete listing of cobalt minerals is given ia Reference 4. 

A.4 Identify all the chemical properties and changes in the following statement Copper is a red-brown element obtained from copper sulfide ores by heating them in air, which forms copper oxide. Heating the copper oxide with carbon produces impure copper, which is purified by electrolysis. ... 

Tenorite (CuO Cu = 80%, SG = 6.5) is usually present in mixed copper oxide and sulphide ore. The flotation properties of tenorite are similar to that of cuprite. 

Although the study of materials chemistry is a relatively new entry in both undergraduate and graduate curricula, it has always been an important part of chemistry. An interesting timeline of materials developments from Prehistoric times to the present may be found in Appendix A. By most accounts. Neolithic man (10,000-300 B.C.) was the first to realize that certain materials such as limestone, wood, shells, and clay were most easily shaped into materials used as utensils, tools, and weaponry. Applications for metallic materials date back to the Chalcolithic Age (4,000-1,500 B.C.), where copper was used for a variety of ornamental, functional, and protective applications. This civilization was the first to realize fundamental properties of metals, such as malleability and thermal conductivity. More importantly, Chalcolithic man was the first to practice top-down materials synthesis (see later), as they developed techniques to extract copper from oxide ores such as malachite, for subsequent use in various applications. 

Flotation has been used for more than 100 years to separate sulphides, oxides and other salts from ores, as well as to obtain phosphates, barite, chromite and other materials. Up to 90% of copper, lead, nickel, zinc are extracted using flotation in the USA [152 - 153]. In Russia, flotation is widely used to additionally obtain apatite, barite and phosphates. Flotation of iron oxides is not used in practise yet, but the number of experiments carried out in this direction is rather large. The main physicochemical principles of flotation have been discussed above [59 -74]. Here, only some practical problems will be discussed. In [153], requirements are pointed out which apply to three-phase flotation foams, and the main components of the process are defined, i.e. surfactant - collector surfactant - frother activator, depressants, colligend, gangue. The peculiarities of flotation and foam separation in batch and continuous modes are outlined as well as the structure and properties of the main types of flotation agents described. As surfaces of the majority of mineral particles are hydrophilic in nature, hydrophobisation of particles is necessary for a selective separation. 

Such bacteria multiply in very aidic solutions (pH < 4.5). Their greatest amoxmt (on average 10 -10 cell-g" ) are discovered in water of copper sulphide and sulphide-polymetallic ore. The source of energy for them are oxidizing processes of not only protoxide metals in water solutions but also almost all reduced forms of sulphur. Bacteria Leptospira ferrooxidans are also capable of oxidizing protoxide iron with getting energy. These bacteria are close in a number of properties to Thiobacillus ferrooxidans, but as opposed to them do not oxidize sulphur. 

Humans have at all times made use of the components of the earth s crust. As a consequence of the discovery that even rare materials may have technically interesting properties, there has been a drive to widen the exploitation of natural resources. New separation methods have made the extraction of desirable elements possible. Such rare elements are often obtained as by-products of the mining of common ores. Gold and platinum, for instance, are present in the anode sludge from electrolytic copper refining. The mineral molybdenite, a sulfide, is roasted at 800°C to the oxide from which molybdenum metal and its alloys are produced. During the roasting process the oxide of a rare element, rhenium, volatilizes and its compounds can be extracted from the gas phase as a by-product. Several examples of this type are treated in the different element chapters of this book. 

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