Abstract
The method is applicable to products having silica contents exceeding 10 mg/kg. The principle is based on the formation of yellow oxidized silico-molybdic complex in a strongly acid medium, in the presence of boric acid to suppress interference by fluorides. Selective reduction of this complex with a mixture of aminonaphtholsulphonic acid (4-amino-3-hydroxynaphthalene-1-sulphonic acid), sodium metabisulphite and sodium sulphite, in the presence of oxalic acid and in a strongly acid medium so as to suppress interference by phosphates. Photometric measurement of the blue-coloured complex at a wavelength of about 795 nm.
-
Status: WithdrawnPublication date: 1974-12
-
Edition: 1Number of pages: 3
-
- ICS :
- 71.060.40 Bases
Life cycle
Got a question?
Check out our FAQs
Opening hours:
Monday to Friday - 09:00-12:00, 14:00-17:00 (UTC+1)
Keep up to date with ISO
Sign up to our newsletter for the latest news, views and product information.