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Tungsten gravimetric

Volumetric methods are not as reliable as the gravimetric and are mainly serviceable for comparative purposes. In one method, WO3 is dissolved in excess of standard sodium hydroxide, and the excess titrated a similar method uses ethylamine to dissolve the WO3, the excess being then titrated with oxalic acid. Silica, tantalum, and columbium do not interfere with the latter method. An attempt to reduce tungsten to the blue oxide, then titrate back with ferric alum in the presence of thiocyanate, has not been successful. Somewhat more accurate results are obtained by precipitating a neutral solution of ammonium tungstate with an excess of lead acetate and titrating the excess lead by means of ammonium molybdate-4... [Pg.292]

Gravimetric determination of tungsten with tetraphenylarsonium chloride after its extraction as thiocyanate (pH = 2 to 4)... [Pg.1506]

See other pages where Tungsten gravimetric is mentioned: [Pg.2]    [Pg.69]    [Pg.138]    [Pg.202]    [Pg.785]    [Pg.785]    [Pg.410]    [Pg.131]    [Pg.201]    [Pg.48]    [Pg.27]    [Pg.20]    [Pg.26]    [Pg.31]    [Pg.431]   
See also in sourсe #XX -- [ Pg.269 ]



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