Flotation mineral separation

Very finely divided minerals may be difficult to purify by flotation since the particles may a ere to larger, undesired minerals—or vice versa, the fines may be an impurity to be removed. The latter is the case with Ii02 (anatase) impurity in kaolin clay [87]. In carrier flotation, a coarser, separable mineral is added that will selectively pick up the fines [88,89]. The added mineral may be in the form of a floe (ferric hydroxide), and the process is called adsorbing colloid flotation [90]. The fines may be aggregated to reduce their loss, as in the addition of oil to agglomerate coal fines [91]. 

Collectors Fitting into Fattice Cavities. Lattice site fitting of collectors at sohd walls has been invoked as a means of explaining the selective behavior of amines (cationic coUectors) as reagents in the flotation-separation of soluble salt minerals such as KCl and NaCl (22). 

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. 

This book systematically summarizes the researches on electrochemistry of sulphide flotation in our group. The various electrochemical measurements, especially electrochemical corrosive method, electrochemical equilibrium calculations, surface analysis and semiconductor energy band theory, practically, molecular orbital theory, have been used in our studies and introduced in this book. The collectorless and collector-induced flotation behavior of sulphide minerals and the mechanism in various flotation systems have been discussed. The electrochemical corrosive mechanism, mechano-electrochemical behavior and the molecular orbital approach of flotation of sulphide minerals will provide much new information to the researchers in this area. The example of electrochemical flotation separation of sulphide ores listed in this book will demonstrate the good future of flotation electrochemistry of sulphide minerals in industrial applications. 

At pH = 6, the flotation recovery of marmatite, arsenopyrite and pyrrhotite as a function of depressant dosage GX2 is given in Fig. 5.22. With the increase of GX2 dosage, the flotation recovery of these three minerals decreases. However, marmatite remains with reasonably high flotation recovery of above 70%, and arsenopyrite and pyrrhotite exhibit poor flotation with recovery of below 35% when the concentration of GX2 is above 120 mg/L. It indicates the possibility for flotation separation of marmatite from arsenopyrite and pyrrhotite by using 2,3-dihydroxyl propyl dithiocarbonic sodium as a depressant and butyl xanthate as a collector. 

The influence of pulp potential on the flotation of marmatite, arsenopyrite and pyrrhotite with 10 mol/L butyl xanthate as a collector in the presence of 150 mg/L 2,3-dihydroxyl propyl dithiocarbonic sodium (GX2) has been tested. Taking the flotation recovery to be 50% as a criterion, above which the mineral is considered to be floatable and otherwise not floatable, the upper and lower potential limits of the flotation of marmatite, arsenopyrite and pyrrhotite at different pH are presented in Fig. 5.25 and Table 5.1. It is evident that marmatite is floatable in some range of potential at various pH, whereas arsenopyrite and pyrrhotite are not floatable in the corresponding conditions. It suggests that the flotation separation of marmatite from arsenopyrite and pyrrhotite may be... 

Grinding is essential for the liberation of sulphide minerals in order to achieve effective flotation. The grinding process, however, may also have a various effects on the flotation separation because of the galvanic interactions among the grinding media and the different minerals due to the high redox activity of sulphide mineral and iron media as well as thio-reagents. 

Chapter 10 Electrochemical Flotation Separation of Sulphide Minerals... 

The flotation separation of galena, sphalerite and pyrite in Fankou lead-zinc mine is very complicated because these three minerals are finely disseminated. The OPCF technology is also successfully applied to this plant to separate these three minerals. Here, pH is modified to 12 by lime and pulp potential is maintained as less than 170 mV. The mixture of xanthate and DDTC is used as a collector in flotation of galena. CUSO4 is used as a collector in the flotation of sphalerite. The principal flowsheet of OPCF for flotation separation of Fankou lead-zinc ore is given in Fig. 10.20. The comparison of results of plant production for OPCF and old flowsheet is listed in Table 10.16. It can be seen that the OPCF technique... 

Feng Qiming, 1989. Pulp electrochemistry of flotation of sulphide minerals theory and technology (Ph.D. thesis). Central South University of Technology Feng Qiming, Chen Jin, Xu Shi, 1991. Relationship between thermodynamics, property of reactive products on sulphide and collectorless flotation separation of sulphide minerals. J. CSIMM (suppl.), 22(3) 28 - 35... 

Copper-nickel matte obtained in this stage is allowed to cool slowly over a few days to separate mineral crystals of copper sulfide, nickel sulfide and nickel-copper alloy. The cool matte is pulverized to isolate sulfides of nickel and copper by froth flotation. Nickel-copper alloy is extracted by magnetic separation. Nickel metal is obtained from the nickel sulfide by electrolysis using crude nickel sulfide cast into anodes and nickel-plated stainless steel cathodes. 

FLOTATION. A method of separating minerals from waste rock nr solids of different kinds by agitating the pulverized mixture of solids with water, oil. and special chemicals that cause preferential welling of solid panicles of certain types by the oil. while other kinds are not wet. The unwelled particles arc carried to the surface by the air bubbles and thus separated from the wetted particles A frothing agent is also used to stabilize the bubbles In Ihe form of a froth that can be easily separated from the body of the liquid (froth flotation). Do not confuse with floatation. 

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