Copper tungstates

Copper tungstate Cupric sulphate 5.0 g l-1, sodium tungstate 2.5 g l-1... 

Nonsulfide Ore Flotation. Nonsulfide minerals recovered by flotation include native elements such as graphite, diamonds, copper, gold, and numerous oxides as well as salts such as carbonates, phosphates, tungstates, and the like. Examples of value-bearing nonsulfide, noncoal minerals include... 

H. 8-Hydroxyquinaldine (XI). The reactions of 8-hydroxyquinaldine are, in general, similar to 8-hydroxyquinoline described under (C) above, but unlike the latter it does not produce an insoluble complex with aluminium. In acetic acid-acetate solution precipitates are formed with bismuth, cadmium, copper, iron(II) and iron(III), chromium, manganese, nickel, silver, zinc, titanium (Ti02 + ), molybdate, tungstate, and vanadate. The same ions are precipitated in ammoniacal solution with the exception of molybdate, tungstate, and vanadate, but with the addition of lead, calcium, strontium, and magnesium aluminium is not precipitated, but tartrate must be added to prevent the separation of aluminium hydroxide. 

Discussion. The procedure is based on the formation of yellow tetraiodo-antimonate(III) acid (HSbI4) when antimony(III) in sulphuric acid solution is treated with excess of potassium iodide solution. Spectrophotometric measurements may be made at 425 nm in the visible region or, more precisely, at 330 nm in the ultraviolet region. Appreciable amounts of bismuth, copper, lead, nickel, tin, tungstate, and molybdate interfere. 

Many heavy metals react with dithiol to give coloured precipitates, e.g. bismuth, iron(III), copper, nickel, cobalt, silver, mercury, lead, cadmium, arsenic, etc. molybdate and tungstate also react. Of the various interfering elements, only arsenic distils over with the tin when a mixture is distilled from a medium of concentrated sulphuric acid and concentrated hydrobromic acid in a current of carbon dioxide. If arsenic is present in quantities larger than that of the tin it should be removed. 

C6Hi4Cl2N202Pt, Platinum(ll), cw-dichlorobis-(propanoneoxime)-, 34 82 C6Hi4Cl2N202Pt, Platinumfll), trani-dichloro-bis(propanoneoxime)-, 34 83 C6H18N4, tren, Tris(2-aminoethyl)amine, complex with copper(II), 34 138 CfiNNaOsW, Tungstate(O), pentacarbonylcyano-, sodium, 34 162... 

NgCgK4Mo-2H20, Molybdate(IV), octacyano-, potassium, dihydrate, 34 157 NgCgK4W-2H20, Tungstate(IV), octacyano-, potassium, dihydrate, 34 157 NgCu2Fe202C24H22, Copper, bis carbonyl-... 

The extremely low solubility of lead phosphate in water (about 6 x 10 15m) again suggests potentiometric analysis. Selig57,59 determined micro amounts of phosphate by precipitation with lead perchlorate in aqueous medium. The sample was buffered at pH 8.25-8.75 and a lead-selective electrode was used to establish the end-point. The detection limit is about 10 pg of phosphorus. Anions which form insoluble lead salts, such as molybdate, tungstate or chromate, interfere with the procedure. Similar direct potentiometric titrations of phosphate by precipitation as insoluble salts of lanthanum(III), copper(II) or cadmium(II) are suggested, the corresponding ion-selective electrodes being used to detect the end-point. 

Na,4Cu5H40 i4P4W30,xH2O, Tungstate(16-), (diaquatetracuprate)dohexaconta-g-oxotetra-pj-oxotriacontaoxotetrakis -[phosphatolS-J-OiOiO O O O" 0" 0" ]]triaconta-, copper(2+) sodium (1 1 14), hydrate, [125801-15-2],... 

Although flotation was developed as a separation process for mineral processing and applies lo the sulfides of copper, lead, zinc, iron-molybdenum, cobalt, nickel, and arsenic and to nonsullides, such as phosphates, sodium chloride, potassium chloride, iron oxides, limestone, feldspar, fluorite, chromite, tungstates, silica, coal, and rhodochrosilc, flotation also applies to nonmineral separations. Flotation is used in the water disposal field, particularly in connection with petroleum waste water cleanup. 

In the Biuret reaction, a purple colour develops when the protein is treated with alkaline copper sulphate. This reaction is dependent on peptide bonds and not on the side chains of individual amino-acids present. In the Folin-Ciocalteu reaction, the protein is treated with tungstate and molybdate under alkaline conditions and the formation of a complex such phenylalanine and tyrosine gives rise to a blue colour. Lowry developed one of the most widely used protein assays in which a combination of the above reactions is involved07, l8). 

Other crystals grown by this technique include lead molybdate,31 barium and strontium tungstate,32 silver acetate,33 potassium perchlorate,34 and copper(I) iodide.35... 

Tkachenko et al reported that compacts in iron, copper, nickel or cobalt matrices had operating temperature limits between 200 and 600 C, but compacts in molybdenum gave satisfactory friction and wear to 900 C in vacuum. A satisfactory composite for high-temperature aircraft brakes was described as containing 25% molybdenum disulphide, alumina and lead tungstate in a nickel matrix . The composites were pressed at 880 to 1080 MPa and sintered at 1010 C for two hours in vacuum. 

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