Xanthates mineral processing

Buckley, A. N., Hamilton, I. C., Woods, R., 1985. Investigation of the surface oxidation of sulphide minerals by linear potential sweep and X-ray photoelectron. In K. S. E. Forssberg(ed.), Flotation of Sulphide Minerals, Elsevier. Amsterdam, 6 41 - 60 Buckley, A. N. and Woods, R., 1990. X-ray photoelectron spectroscopic and electrochemical studies of the interaction of xanthate with galena in relation to the mechanism. Int. J. Miner. Process, 28 301 - 311... 

Buckley, A. N., 1994. A survey of the application of X-ray photoelectron spectroscopy to flotation research. Colloids Surf, 93 159 - 172 Buckley, A. N. and Woods, R., 1995. Identifying chemisorption in the interaction of thiol collectors with sulphide minerals by XPS adsorption of xanthate on silver and silver sulphide. Colloids and Surfaces A Physicochemical and Engineering Aspects, 104,2 - 3 Buckley, A. N. and Woods, R., 1996. Relaxation of the lead-deficient sulphide surface layer on oxidized galena. Journal of Applied Electrochemistry, 26(9) 899 - 907 Buckley, A. N. and Woods, R., 1997. Chemisorption—the thermodynamically favored process in the interaction of thiol collectors with sulphide minerals. Inert. J. Miner. Process, 51 15-26... 

Finkelstein, N. P., 1999. Addendum to The activation of sulphide minerals for flotation a review. Inter. J. Miner. Process, 55(4) 283 - 286 Fomasiero, D., Montalti, M., Ralston, J., 1995. Kinetics of adsorption of ethyl xanthate on pyrrhotite in situ UV and infiared spectroscopic studies. Langmuir, 11 467 - 478 Forssberg, K. S. E., Antti, B. M., Palsson, B., 1984. Computer-assisted calculations of thermodynamic equilibria in the chalcopyrite-ethyl xanthate system. In M. J. Jones and R. Oblatt (eds.). Reagents in the Minerals Industry. IMM, Rome, Italy, 251 - 264 Fuerstenau, M. C., Kuhn, M. C., Elgillani, D. A., 1968. The role of dixanthogen in xaomthate flotation ofpyrite. Trans. AIME, 241 437 Fuerstenau, M. C. and Sabacky, B. J., 1981. Inter. J. Miner. Process, 8 79 - 84 Fuerstenau, M. C., Misra, M., Palmer, B. R., Xanthate adsorption on selected sulphides in the presence of oxygen. Inter. J. Miner. Process... 

Miner. Process Extra. Metall. Rev., 2 203 - 234 Hayes, R. A. and Ralston, J., 1988. The collectorless flotation and separation of sulphide minerals by control. Inter. J. Miner. Process, 23 55 - 84 Hepel, T. and Pomianowski, A., 1977. Diagrams of electrochemical equilibria of the system copper-potassium ethyl xanthate-water at 25°C. Int. J. Miner. Process, 4 345 - 361 Heyes, G. W. and Trahar, W. J., 1977. The natural floatability of chalcopyrite. Int. J. Miner. Process, 4 317-344... 

Leppinen, J. 0., Basilio, C. I, Yoon, R. H., 1989. In-situ FTIR study of ethyl xanthate adsorption on sulphide minerals under conditions of controlled potential. Int. J. Miner. Process, 26 259 - 274... 

Natarajan, K. A., Riemer, S. C., Iwasaki, I., 1984. Influence of pyrrhotite on the corrosive wear of grinding balls in magnetite ore grinding. Inter. J. Miner. Process, 13(1) 73-81 Nesbitt, H. W., Bancroft, G. M., Pratt, A. R., Scaini, M. J., 1998. Sulfur and iron surface states on fractured pyrite surfaces. American Mineralogist, 83 1067 - 1076 Neeraj, K. M., 2000. Kinetic studies of sulphide mineral oxidition and xanthate adsorption. Doctor thesis of Virginia Polytechnic Institute and State University. A Bell Howell Company UMI dissertation Services... 

O Dell, C. S., Walker, G. W., Richardson, P. E., 1986. Electrochemistry of the chalcocite-xandiate system. J. Appl. Electrochem., 16 544-554 Opahle, I., Koepemik, K., Eschrig, H., 2000. Full potential band stracture calculation of iron pyrite. Computational Materials Science, 17(2 - 4) 206 - 210 Page, P. W. and Hazell, L. B., 1989. X-ray photoelectron spectroscopy (XPS) studies of potassium amyl xanthate (KAX) adsorption on precipitated PbS related to galena flotation. Inter. J. Miner. Process, 25 87 - 100... 

Persson, I., Persson, P., Valli, M., Fozo, S., Malmensten, B., 1991. Reaction on sulphide mineral surfaces in connection with xanthate flotation studied by diffuse reflectance FTIR spectroscopy, atomic absorption spectrophotometry and calorimetry. In K. S. E. Forssberg (ed.). Flotation of Sulphide Mineral. Inter. J. Miner. Process, 33 67 - 81 Peters, E., 1977. The electrochemistry of sulphide minerals. In J. O M. Bockris, D. A. J. Rand, B. J. Weich (eds.). Trends in Electrochemistry. New York Plenum Press, 267 - 290 Peters, E., 1986. Leaching of sulphides. In P. Sortunasundaran (ed.). Advances in Mineral Processing. Proc. Sym. Honoring N. Arbiter on His 75th Birthday, SME, Inc. Colorado, 445-462... 

Pritzker, M. D. and Yoon, R. H., 1984a. Thermodynamic calculations on sulphide flotation systems I. galena-ethyl xanthate system in the absence of metastable species. Inter. J. Miner. Process, 12 95 - 125... 

Trahar, W. J., Senior, G. D., Heyes, G. W., Creed, M. D., 1997. The activation of sphalerite by lead—a flotation perspective. Inter. J. Miner. Process, 49 121 - 148 Usui, A. H. and Tolun, R., 1974. Electrochemical study of the pyrite-oxygen-xanthate system. Inter. J. Miner. Process, 1 135 - 140... 

Woods, R., 1996. Chemisorption of thiols on metal and metal sulphide. In J. O M Bockris, B. E. Conway, R. E. White (eds.). Modem Aspects of Electrochemistry. 29 401 - 453 Woods, R., Young, C. A., Yoon, R. H., 1990. Ethyl xanthate chemisorption isotherms andEh-pH diagrams for the copper/water/xanthate and chalcocite/water/xanthate systems. Inter. J. Miner. Process, 30 17 - 33... 

Grano, S. R., Prestidge, C. A., and Ralston, J. (1997) Solution interaction of ethyl xanthate and sulfite and its effect on galena flotation and xanthate adsorption, Int. J. Miner. Process., 52(2-3), 161-186. 

Naklicki, M.L. et al.. Flotation and surface analysis of the nickel(II) oxide/amyl xanthate system, Int. J. Miner. Process., 65, 73, 2002. 

Figure 7.27. ATR spectra of pyrite particles after conditioning at two different concentrations of potassium ethyl xanthate (KEX). Reprinted, by permission, from J. O. Leppinen, Int. J. Miner. Process. 30,245 (1990), p. 251, Fig. 4. Copyright 1990 Elsevier Publishers B.V.

The examples in the preceding section, of the flotation of lead and copper ores by xanthates, was one in which chemical forces predominated in the adsorption of the collector. Flotation processes have been applied to a number of other minerals that are either ionic in type, such as potassium chloride, or are insoluble oxides such as quartz and iron oxide, or ink pigments [needed to be removed in waste paper processing [92]]. In the case of quartz, surfactants such as alkyl amines are used, and the situation is complicated by micelle formation (see next section), which can also occur in the adsorbed layer [93, 94]. 

Xanthate esters are prepared by reaction of isopropyl alcohol and carbon disulfide [75-15-0]. Isopropyl xanthates have wide use ia mineral flotation (qv) processes, and sodium isopropyl xanthate [140-93-2], C4HyOS2Na, is a useful herbicide for bean and pea fields (see Herbicides) (30). 

The pH of the pulp to the flotation cells is carefliUy controlled by the addition of lime, which optimizes the action of all reagents and is used to depress pyrite. A frother, such as pine oil or a long-chain alcohol, is added to produce the froth, an important part of the flotation process. The ore minerals, coated with an oily collected layer, are hydrophobic and collect on the air bubbles the desired minerals float while the gangue sinks. Typical collectors are xanthates, dithiophosphates, or xanthate derivatives, whereas typical depressants are calcium or sodium cyanide [143-33-9] NaCN, andlime. 

Flotation of the lead oxide minerals is a difficult problem not least because there are no known direct acting collectors. Normally, during oxide lead flotation, a sulphidization method is used with xanthate as a collector. In the majority of cases, the ore is pretreated using a desliming process, especially if the ore contains clay and Fe-hydroxides. Another method includes the preconcentration using heavy liquid. 

Silver oxide lead ores have much different flotation processing characteristics. Although this ore responds to sulphidization-xanthate system, silver recovery in the lead concentrate was usually poor and amounted to about 30 40%. Floatability of lead minerals also was not satisfactory. 

In the 2nd period ranging from the 1930s to the 1950s, basic research on flotation was conducted widely in order to understand the principles of the flotation process. Taggart and co-workers (1930, 1945) proposed a chemical reaction hypothesis, based on which the flotation of sulphide minerals was explained by the solubility product of the metal-collector salts involved. It was plausible at that time that the floatability of copper, lead, and zinc sulphide minerals using xanthate as a collector decreased in the order of increase of the solubility product of their metal xanthate (Karkovsky, 1957). Sutherland and Wark (1955) paid attention to the fact that this model was not always consistent with the established values of the solubility products of the species involved. They believed that the interaction of thio-collectors with sulphides should be considered as adsorption and proposed a mechanism of competitive adsorption between xanthate and hydroxide ions, which explained the Barsky empirical relationship between the upper pH limit of flotation and collector concentration. Gaudin (1957) concurred with Wark s explanation of this phenomenon. Du Rietz... 

The mixed-potential model demonstrated the importance of electrode potential in flotation systems. The mixed potential or rest potential of an electrode provides information to determine the identity of the reactions that take place at the mineral surface and the rates of these processes. One approach is to compare the measured rest potential with equilibrium potential for various processes derived from thermodynamic data. Allison et al. (1971,1972) considered that a necessary condition for the electrochemical formation of dithiolate at the mineral surface is that the measmed mixed potential arising from the reduction of oxygen and the oxidation of this collector at the surface must be anodic to the equilibrium potential for the thio ion/dithiolate couple. They correlated the rest potential of a range of sulphide minerals in different thio-collector solutions with the products extracted from the surface as shown in Table 1.2 and 1.3. It can be seen from these Tables that only those minerals exhibiting rest potential in excess of the thio ion/disulphide couple formed dithiolate as a major reaction product. Those minerals which had a rest potential below this value formed the metal collector compoimds, except covellite on which dixanthogen was formed even though the measured rest potential was below the reversible potential. Allison et al. (1972) attributed the behavior to the decomposition of cupric xanthate. 

Influence of Mechanical Force on the Electrode Process between Xanthate and Sulphide Minerals... 

Pozzo, R. L., Malicsi, A. S., Iwasaki, L, 1988. Pyrite-pryyhotite-grinding media contact and its effect on flotation. Minerals Metallurgical Processing, 5(1) 16-21 Pozzo, R. L., Malicsi, A. S., Iwasaki, I., 1990. Pyrite-pyrrhotite-grinding media contact and its effect on flotation. Minerals Metallurgical Processing, 7(1) 16 - 21 Prestidge, C. A., Thiel, A. G., Ralston, J., Smart, R. S. C., 1994. The interaction of ethyl xanthate with copper (II)—activated zinc sulphide kinetic effects. Colloids Surfece, A. Physicochem. Eng. Aspects, 85 51 - 68... 

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