Silver xanthate

A wide range of structural motifs are found for the copper-triad xanthates, ranging from monomeric species to layer structures. This variety of structures can be ascribed to the flexible coordination modes adopted by the xanthate ligands in this group, in particular for the copper and silver xanthates. However, there is a dearth of binary xanthate structures with only two available for copper and one each for silver and gold. The paucity of data can be ascribed directly to the inability to obtain suitable crystals for structure determination. Phosphine adducts are known for all three elements of this group and in the case of both copper and silver, mixed-metal species are also known. 

A solventless thermolysis method was adopted for the synthesis of size controlled Ag2S nanopartieles. In this method, silver xanthate was prepared by adding silver nitrate solution dropwise on to potassium xanthate containing each octyl, hexadecyl and carnaubyl xanthates separately in a methanolie solution. Silver xanthate precipitates that form rapidly were washed and in water/methanol mixture and methanol after centrifugation and dried. The silver xanthate was then heated to... 

Voltammograms for silver in the presence of ethyl xanthate display a prewave " as shown in Fig. 8. The reversible potential of the silver/sil-ver ethyl xanthate couple at a xanthate concentration of 10" mol dm" is 0 V, and the major anodic and cathodic peaks arise from the formation and reduction of silver xanthate, respectively. Reversible chemisorption of xanthate is responsible for the currents observed at more negative potentials. Xanthate has also been found " to chemisorb on silver sites on silver-gold alloys. 

The potential dependence of ethyl xanthate coverage has also been determined for silver-gold alloys. In this system, xanthate chemisorbs onto silver sites in the alloy surface, and, as with silver itself, adsorption occurs at potentials below that at which silver xanthate is formed. Figure 11 presents the coverages determined for this system. The solid lines represent the Frumkin isotherm previously derived for silver. The isotherms for the alloys were obtained by introducing a silver activity term, taking values of activity derived from the thermodynamic data collated by... 

A number of compounds of the types RBiY2 or R2BiY, where Y is an anionic group other than halogen, have been prepared by the reaction of a dihalo- or halobismuthine with a lithium, sodium, potassium, ammonium, silver, or lead alkoxide (120,121), amide (122,123), a2ide (124,125), carboxylate (121,126), cyanide (125,127), dithiocarbamate (128,129), mercaptide (130,131), nitrate (108), phenoxide (120), selenocyanate (125), silanolate (132), thiocyanate (125,127), or xanthate (133). Dialkyl- and diaryUialobismuthines can also be readily converted to secondary bismuthides by treatment with an alkali metal (50,105,134) ... 

Pyridazines form complexes with iodine, iodine monochloride, bromine, nickel(II) ethyl xanthate, iron carbonyls, iron carbonyl and triphenylphosphine, boron trihalides, silver salts, mercury(I) salts, iridium and ruthenium salts, chromium carbonyl and transition metals, and pentammine complexes of osmium(II) and osmium(III) (79ACS(A)125). Pyridazine N- oxide and its methyl and phenyl substituted derivatives form copper complexes (78TL1979). 

Wulfenite and minetizit are mainly associated with oxide lead silver ores. Very little to no research data are available on these two minerals. Most recently, research work was carried out on these minerals using natural ore. It has been demonstrated that wulfenite and minetizit can be recovered using sulphidization and modified xanthate. 

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. 

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... 

Woods, R., Basilio, C. I., Kim, D. S., Yoon, R. H., 1994. Chemisorption of ethyl xanthate on silver-gold alloys. Colloids and Surfaces A Physicochemical and Engineering Aspects, 83(1) 1-7... 

Insoluble starch xanthate (ISX) releases magnesium and takes up heavy metals. There are also a number of proprietary chemicals developed by various companies (e.g. Environmental Technology of Sanford, Florida) for removal of complexed copper, silver (from photographic process wastes), arsenic, nickel, lead, mercury, zinc, cadmium, barium, and other heavy metals. 

The structure of the only binary xanthate structure of silver, that is, [Ag(S2COEt)]00, has only just recently become available (130). There is... 

Quite frequently the natural surface of a mineral requires preliminary chemical treatment before it will form the surface film required for collection One of the commonest instances of this is with sphalerite (zinc sulphide), which does not float properly when treated with xanthates. If, however, it is given a preliminary treatment with dilute copper sulphate solution, a very small amount of copper sulphide is deposited on the surface and the ore becomes floatable, the surface being now capable of reaction with xanthates. Such treatment is usually termed activation in general, an activating solution for a sulphide mineral should contain a metallic ion whose sulphide is less soluble than that contained in the mineral for zinc sulphides, silver, copper, mercury, cadmium, and lead salts are all effective activators. 

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