Zinc-xanthate salt

Table 8 summarizes domestic consumption by use for amyl alcohols. About 55% of the total 1-pentanol and 2-methyl-1-butanol production is used for zinc diamyldithiophosphate lubrication oil additives (150) as important corrosion inhibitors and antiwear additives. Amyl xanthate salts are useful as frothers in the flotation of metal ores because of their low water solubiUty and miscibility with phenoHcs and natural oils. Potassium amyl xanthate, a collector in flotation of copper, lead, and zinc ores, is no longer produced in the United States, but imports from Germany and Yugoslavia were 910 —1100 t in 1989 (150). 

Figure 4.41 presents the FTIR reflection spectra of ethyl xanthate adsorption on marmatite at different pH. The characteristic absorption peaks 1210, 1108, 1025 cm occurred. It has been reported that the characteristic absorption bands of dixanthogen are 1260, 1240, 1020 and 1105 cm and those bands of zinc xanthate are 1030, 1125 and 1212 cm (Mielezarski, 1986 Leppinen, 1990). It is derived from Fig.4.41 that there may exist the mixture of dixanthogen and zinc xanthate because both distinct peaks of dixanthogen and xanthate salt appeares in Fig. 4.41, which further confirms the results from the UV analysis in Fig. 4.36 and Fig. 4.37. It can also be seen from Fig. 4.41 that the intensity of the IR peaks is strong indicating the stronger adsorption of xanthate on marmatite accounting for its good floatability in weak pH media. When pH increased above 7, only a very weak peak appeared in the spectra indicating very weak or no adsorption of xanthate on marmatite accounting for its very poor floatability in alkaline pH media.

The salts of alkyl xanthates, A/,A/ -di-substituted dithio-carbamates and dialkyidithiophosphates [26] are effective peroxide decomposers. Since no active hydrogen is present in these compounds, an electron-transfer mechanism was suggested. The peroxide radical is capable of abstracting an electron from the electron-rich sulfur atom and is converted into a peroxy anion as illustrated below for zinc dialkyl dithiocarbamate [27] ... 

A few diazonium salts are unstable in solution, and many are in the solid state. Of these, the azides, chromates, nitrates, perchlorates (outstandingly), picrates, sulfides, triiodides and xanthates are noted as being explosive, and sensitive to friction, shock, heat and radiation. In view of their technical importance, diazonium salts are often isolated as their zinc chloride (or other) double salts, and although these are considerably more stable, some incidents involving explosive decomposition have been recorded. 

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... 

From the flotation results in Fig. 4.21 and the voltammogram in Fig. 4.22, it is derived that the hydrophobic entity of collector on marmatite is mainly of disulphide of xanthate and dithiocarbamate, which is further confirmed by the above UV analysis. However, the UV analysis also suggested the coexistence of collector salts. We propose that the initial oxidation products of xanthate and dithiocarbamate on marmatite should be mainly of disulphide. At higher potential, the adsorbed disulphide may be decomposed and react with surface zinc species to form some parts of collector salts as in the following reactions ... 

Xanthates. These compounds (12) are relatively fast accelerators which are used at low temperature because most examples decompose without cross-linking at higher temperature. Xanthates (qv) are produced by reaction of equimolar amounts of alcohol and carbon disulfide in the presence of caustic. The sodium salt is then converted to the zinc compound or oxidized to the disulfide. 

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. 

Polyoxyalkylene derivatives are typical of the oxygen-containing viscose modifiers. In this type of modifier, association involving the ether oxygen of the polyoxyalkylene chain is believed to be part of the mechanism by which acid diffusion and cellulose regeneration are retarded. Two possibilities exist, (I) protonation of the ether oxygen [200] retards hydrogen ions from penetration into the filament and facilitates formation of zinc cellulose xanthate and (II) formation of chelate compounds with zinc and zinc salts that increase the stability of the semipermeable membrane [201]. 

Isobutyl valerinate. See Isobutyl valerate Isobutyl vinyl ether. See Vinyl isobutyl ether Isobutyl xanthic acid, potassium salt. See Potassium isobutyl xanthate Isobutyl xanthic acid, sodium salt. See Sodium isobutyl xanthate Isobutyl Zimate . See Zinc diisobutyldithiocarbamate 2-lsobutyoxyethanol. See Ethylene glycol isobutyl ether... 

Zinc salts are added to the spin bath to slow down the regeneration reaction by forming a less easily decomposed zinc cellulose xanthate intermediate. This allows greater stretch levels to be applied and results in fibers with thicker skins. There is still imcertainty as to whether the zinc cellulose xanthate gel acts by hindering acid ingress or water loss. High levels of zinc in the spin bath allow the production of tough fibers for tire reinforcement and industrial use. 

Fig. 4. Staple fiber washing sequence 1, a hot acid wash (2% H2SO4 at 90°C) decomposes and washes out most of the insoluble zinc salts. This wash completes the regeneration of xanthate and removes as much sulfur as possible in the form of recoverable CS2 and H2S 2, an alkaline sodium sulfide desulfurization bath solubilizes sulfurous by-products and converts them into easily removed sulfides 3, a sulfide wash to remove the sulfides created in bath 2 4, a bleach bath (optional) uses very dilute hypochlorite or peroxide to improve fiber whiteness 5, a dilute acid or sour bath removes any remaining traces of metal ions and guarantees that any residual bleaching chemicals are destroyed 6, a controlled-pH freshwater final wash removes the last traces of acid and salt prior to drsdng and 7, a finish bath gives the fiber a soft handle for easy drying and subsequent processing.

Optimal conditions for the precipitation of starch xanthate from sodium starch xanthate as the zinc salt have been determined as a xanthate degree of substitution greater than 0.02 and a zinc ion concentration in solution between 0.005 and 0.015 M. Other properties of the starch xanthates were also reported. Aqueous solutions of starch xanthate, butane-2,3-diol dixanthate and alkali-gelatinized starch have been treated with butane-2,3-diol diglycidyl ether and other diepoxides to produce viscous gels. Epoxy resins also reacted with xanthate to form viscous gels. Solids were precipitated from the gels and their compositions deduced from their elemental contents and infrared spectra. 

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