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Minerals flotation basis

Metals are obtained by the treatment of oxides and sulfide ores found in the earth. However, there is an initial difficulty—the desirable ores are often mixed up with those of little commercial value, and the problem is to obtain the desired ore free from those of lesser worth. For many years now, largely due to the initiative of Australian workers, it has been possible to find organic substances which, when added to a suspension of mixed ores, pick out the desired one, and (when air is bubbled into the system) float it to the surface, from which it can be raked off, i.e., separated and made available for chemical or electrochemical extraction of the metal. It turns out that the basis of this mineral flotation technology involves the Wagner and Traud mixed-potential concept and is thus indirectly related to corrosion theory. [Pg.270]

Selective flotation of apatite from dolomite was predicted by single mineral tests In the pH range of 7 to 10, and of dolomite from apatite at pH of about 5, with 4 X 10 kmol/m of sodium oleate collector. Once again, mixed mineral (50 50) tests did not yield the selectivity predicted on the basis of the single mineral flotation studies. [Pg.192]

Mixed Mineral Flotation Tests. Flotation of 88 12 apatite-dolomite mixtures was conducted to verify the selectivity predicted on the basis of single mineral experiments. Results presented in Table II demonstrate that at dodecylamine concentration of 1.6 X10" kmol/m apatite can be selectively recovered from the mixture leaving dolomite In the sink fraction. [Pg.193]

Activators enhance the adsorption of collectors, eg, Ca " in the fatty acid flotation of siUcates at high pH or Cu " in the flotation of sphalerite, ZnS, by sulfohydryl collectors. Depressants, on the other hand, have the opposite effect they hinder the flotation of certain minerals, thus improving selectivity. For example, high pH as well as high sulfide ion concentrations can hinder the flotation of sulfide minerals such as galena (PbS) in the presence of xanthates (ROCSS ). Hence, for a given fixed collector concentration there is a fixed critical pH that defines the transition between flotation and no flotation. This is the basis of the Barsky relationship which can be expressed as [X ]j[OH ] = constant, where [A ] is the xanthate ion concentration in the pulp and [Oi/ ] is the hydroxyl ion concentration indicated by the pH. Similar relationships can be written for sulfide ion, cyanide, or thiocyanate, which act as typical depressants in sulfide flotation systems. [Pg.49]

The basic flow sheet for the flotation-concentration of nonsulfide minerals is essentially the same as that for treating sulfides but the family of reagents used is different. The reagents utilized for nonsulfide mineral concentrations by flotation are usually fatty acids or their salts (RCOOH, RCOOM), sulfonates (RSO M), sulfates (RSO M), where M is usually Na or K, and R represents a linear, branched, or cycHc hydrocarbon chain and amines [R2N(R)3]A where R and R are hydrocarbon chains and A is an anion such as Cl or Br . Collectors for most nonsulfides can be selected on the basis of their isoelectric points. Thus at pH > pH p cationic surfactants are suitable collectors whereas at lower pH values anion-type collectors are selected as illustrated in Figure 10 (28). Figure 13 shows an iron ore flotation flow sheet as a representative of high volume oxide flotation practice. [Pg.50]

On the basis of the function it performs, the flotation process can be divided into two categories (i) bulk and (ii) selective. The process is called bulk or collective flotation when it accomplishes the separation of several valuable components from the gangue minerals. In selective flotation, one valuable component is separated from several others. This selectivity could be accomplished by either using collectors selective with respect to a particular mineral or by differential flotation wherein two or more mineral concentrates are recovered consecutively from the same feed by using modifiers. [Pg.186]

The inherent hydrophobicity once thought to be typical of sulphides (Ravitz and Porter, 1933) is now thought to be restricted to sulphides such as molybdenite (Chander et al., 1975) and other minerals or compound with special structural feature (Gaudin et al, 1957b). Common commercial sulphide minerals, which are needed to recover in flotation, are normally composed of anion (S ) and heavy metal ions such as Cu, Cu, Pb, Zn, Hg, Sb, Bi transitive metal ion such as Fe, Co, Ni and noble and rare metal ions such as Ag, Au, Mo. On the basis of structural pattern or mode of linkage of the atoms or polyhedral imits in space, Povarennyk (1972) introduced a crystallochemical classification of sulphide minerals, which have six major patterns as shown in Table 1.1. [Pg.3]

To fully understand the physical-chemical basis of flotation in these systems so that new flotation procedures might be developed to make other appropriate mineral separations, extensive research in applied surface chemistry is required. [Pg.290]

Shergold, H.L. Flotation in Mineral Processing in The Scientific Basis of Flotation, Ives,... [Pg.419]

Barbery, G. Engineering Aspects of Flotation in the Minerals Industry in The Scientific Basis of Flotation, Ives, K.J. (Ed.), Martinus NijhofF The Hague, 1984, pp. 289-348. [Pg.419]

This type of adsorption is the basis for a number of important industrial processes, notably the separation of mineral ores by froth flotations (Somasun-daran, 1979), the de-inking of waste paper (Turai, 1982), the ultrapurification of fine powders for the chemical and ceramic industries (Mougdil, 1991), and the production of foamed concrete. In the last case, for the concrete to entrain air, it is not even necessary for the liquid phase to show any foaming. In most of the processes used above, surfactants, such as salts of long-chain carboxylic acids or long-chain amines, that adsorb with their polar or ionic heads oriented toward the solid and their hydrophobic groups oriented away from it, are used to make the surface of the solid hydrophobic. [Pg.299]

The multilayer adsorption of fatty acids on minerals has been shown to occur by the direct adsorption of precipitated metallic salts of the collectors. In fact, it has been shown, on the basis of solubility product data for a number of cationic soaps of fatty acid collectors, that the precipitation of such salts is indeed required for the incipient flotation. [Pg.249]

Barbery G. (1984) Engineering aspects of flotation in minerals industry flotation machines, circuits and their simulation, in the scientific basis of flotation. In Ives KJ, editor. NATO-ASl series, Martinus Nijhoff Publishers, The Hague, p 289-348. [Pg.446]

Shergold, H. L. 1984. Flotation in mineral processing. In The Scientific Basis of Flotation, Ed, K. J. Ives. [Pg.105]


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See also in sourсe #XX -- [ Pg.216 ]




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Mineral flotation

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