Zinc bismuthate

To a suspension of sodium bismuthate (20 g, 34.54 mmol) in water (30 ml), a 15% aqueous solution (300 ml) of zinc chloride hexahydrate was added and the resulting mixture was refluxed for 1.5 h. After cooling, the mixture was filtered off and the brown solid was washed successively with hot water (100 ml) and acetone (100 ml), and dried over calcium chloride to afford zinc bismuthate yield 20.5 g (99%) [92BCJ1131]. 

Bismuth oxide and mixed bismuth/metal oxide systems as oxidant or oxidation catalyst 

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Zinc bismuthate, PhCH3 or CH3CN, reflux, 0.5-2 h, 56-85% yield. ... 

Heating with the following solids, their fusions, or vapours (a) oxides, peroxides, hydroxides, nitrates, nitrites, sulphides, cyanides, hexacyano-ferrate(III), and hexacyanoferrate(II) of the alkali and alkaline-earth metals (except oxides and hydroxides of calcium and strontium) (b) molten lead, silver, copper, zinc, bismuth, tin, or gold, or mixtures which form these metals upon reduction (c) phosphorus, arsenic, antimony, or silicon, or mixtures which form these elements upon reduction, particularly phosphates, arsenates,... 

In the fifth edition of his Cours de Chymie, Nicolas Lemery confused bismuth with zinc. Bismuth, said he, is a Sulphureous Marcassite that is found in the Tinn Mines many do think it is an imperfect Tinn which partakes of good store of Arsenick its pores are disposed in another manner than those of Tinn, which is evident enough because the Menstruum which dissolves Bismuth cannot intirely dissolve Tinn. There is another sort of Marcassite, called Zinch, that much resembles Bismuth.. . Marcassite is nothing else but the excrement of a Metal, or an Earth impregnated with Metallick parts. The Pewterers do mix Bismuth and Zinch in their Tinn to make it found the better (52). 

BETTERTON-KROLL PROCESS. A process for obtaining bismuth and purifying desilverized lead that contains bismuth. Metallic calcium or magnesium is added to the molten lead to cause formation of high-melting intennetaHic compounds with bismuth. These separate as a surface scum and are skimmed off. The excess calcium and magnesium are removed from the lead by use of chlorine gas as mixed molten chlorides of lead or zinc. Bismuth of 99.995% purity is produced in this way. 

Nevertheless, when Friedeberg carried out an extraction of silver using dithizone in carbon tetrachloride at pH 2, he found that copper was left in solution. Evidently, this separation is based on a slow rate of attainment of equilibrium of the reaction with copper in the presence of EDTA, for he noted that at higher concentrations the copper is extracted slowly. Friedeberg also found that EDTA prevents the extraction by dithizone of lead, zinc, bismuth, cadmium, nickel, cobalt, and thallium at any pH value. 

Zinc bismuthate Zn(Bi03)2, readily obtained as a light brown solid from sodium bismuthate and zinc chloride, has been successfully employed for the oxidation of alcohols, thiols, thioethers and oximes (Scheme 5.8) [92BCJ1131, 94SC489]. The yields are comparable with or better than those of the barium permanganate and pyridinium chlorochromate oxidations. 

Scheme 5.8. Zinc bismuthate oxidation of alcohols, thiols, sulfides and oximes [92BCJ1131, 94SC489].

In this case the freezing-point curve is of the simple type (Fig. 33). Such curves have been obtained in the case of a number of pairs of metals, e.g, zinc—cadmium, zinc—aluminium, copper—silver (Heycock and Neville), tin— zinc, bismuth—lead (Gautier), and in other cases. From molten mixtures represented by one branch of the freezing-point curve one of the metals will be deposited while from mixtures represented by the other branch, the other metal will separate out. At the eutectic point the molten mass will solidify to a heterogeneous mixture of the two metals, forming what is known as the eutectic alloy, Such an alloy, therefore, will melt at a definite temperature lower than the melting-point of either of the pure metals. 

For dords rich in gold that cannot be extracted by acid leaching, the dord is melted and chlorine is injected. A silver chloride slag will be formed leaving pure gold. The silver chloride slag includes traces of other metals, but some metal chlorides such as zinc, bismuth and arsenic will be volatilised. 

The formation of rare earth silicates can be accelerated by the addition of flux material to the reaction mixture. The accelerators may be halides, carbonates, sulfates or oxides of alkali metals, earth alkaline metals, lead, zinc, bismuth, etc. (Leskela and Niskavaara, 1981). The amount of the accelerator represents only a few percent of the total weight of the reaction mixture. For example, using alkah fluorides it is possible to reach a complete conversion to silicate in the temperature range 1000-1300°C (Watanabe and Nishimura, 1978 Leskela and Niskavaara, 1981). 

Zirconium resists some types of molten metals, but the corrosion resistance is affected by trace impurities, such as oxygen, hydrogen, or nitrogen. Zirconium has a corrosion rate of less than 1 mpy in liquid lead to bOO C, lithium to 800°C mercury to 100°C, and sodium to 600°C. The molten metals known to attack zirconium are aluminum, zinc, bismuth, and magnesium. 

Several nineteenth century authors refer to whites of antimony (as well as of various other elements such as zinc, bismuth, mercury or quicksilver and tin in the same context, usually when discussing alternatives to lead white (q.v.)). For example Osborn (1845) writes that From antimony and from zinc, whites have been made which have been said to possess, with sufficient body, and great beauty, assured permanence. Heaton (1928) also lists antimony white, giving the composition as antimony oxide . The British firm Cookson Lead and Antimony Co. developed and introduced an antimony oxide-based white pigment around 1920 under the trade name Timonox. 

The behavior, in which two liquid phases exist in equilibrium, although hitherto not described for the hydro-carbon-oxygen systems, is not peculiar to them. The ozone-oxygen system, shown in Figure 10, has been found to exhibit such a phenomenon , and also such diverse systems as benzoic acid-water, shown in Figure 11, phenol-water, succinic nitrile-water9, zinc-bismuth, and resorcinol-water. ... 

Bang-Jun Chen et al.. Lead Zinc Bismuth Roll. In non-ferrous metal smelting manual. ( Bei Jing The metallurgical industry, 1996 ), 160-171. 

Harris, P. Interfacial reactions of tin-zinc-bismuth alloys. Surf. Mount. Technol. 1999, 11 (3), 46-52 (UK). 

Several product groups have worked with the tin-zinc-bismuth (Sn-Zn-Bi) alloys for reflow, but with difficulty as discussed later in this chapter. With a wide range of alloys to choose from, the task of selecting the best alloy was difficult. 

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