Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Sodium ammonium chromate preparation

Copper(ll) chromite is obtained by heating copper chromate, CuCr04 at 400°C. The Adkin catalyst, a mixture of copper oxide and copper chromite, is prepared by mixing aqueous solutions of copper nitrate, sodium dichromate and ammonium hydroxide the orange precipitate of copper ammonium chromate formed is dried and then heated below 400°C. [Pg.265]

The raw material for this preparation is the chromic anhydride from the preceding preparation, which contains at least a small amount of sodium acid sulphate. This dissolves with the chromic anhydride, and it should remain in the mother liquor (as neutral sulphate) from which the ammonium chromate is crystallized. The second and third crop of crystals of the latter, however, are likely to be contaminated with sodium sulphate. An excess of ammonium hydroxide is used to insure the formation of the neutral chromate. [Pg.326]

In the one-bath chroming method (metachrome process), complex formation must be preceded by dye diffusion. For this reason, the release of CrVI must be delayed. The dye liquor is prepared with metachrome mordant (a mixture of sodium chromate and ammonium sulfate) and sodium sulfate. After a prerun at 40-50 °C, the system is heated slowly and dyed at boiling temperature for 45-90 min. Shortly before dyeing is completed, the bath is exhausted by the addition of acetic acid. [Pg.385]

Potassium Chromate, KjCrOj, is usually prepared fi-om the dichromate vide infra) by neutralisation of the excess of CrOa above that necessary to form the normal salt, e.g. by potassium carbonate in aqueous solution by fusion of the dichromate with potassium nitrate or potassium carbonate, and extraction with water by interaction of potassium dichromate with ammonium chloride or sodium hydrogen phosphate. ... [Pg.58]


See other pages where Sodium ammonium chromate preparation is mentioned: [Pg.12]    [Pg.140]    [Pg.158]    [Pg.183]    [Pg.192]    [Pg.235]    [Pg.238]    [Pg.225]    [Pg.54]    [Pg.507]    [Pg.660]    [Pg.652]    [Pg.136]    [Pg.158]    [Pg.218]    [Pg.221]    [Pg.292]    [Pg.705]    [Pg.639]    [Pg.734]    [Pg.711]    [Pg.698]    [Pg.12]    [Pg.732]    [Pg.652]   
See also in sourсe #XX -- [ Pg.277 ]




SEARCH



Ammonium chromate

Ammonium preparation

Ammonium sodium chromate

Sodium ammonium

Sodium chromate

Sodium preparation

© 2024 chempedia.info