ISO 2369:1972

Aluminium fluoride for industrial use — Determination of silica content — Spectrophotometric method using the reduced silicomolybdic complex ISO 2369:1972

Publication date:   Dec 1, 1972

95.99 Withdrawal of Standard   May 27, 2002

General information

95.99 Withdrawal of Standard   May 27, 2002

ISO

ISO/TC 47 Chemistry

International Standard

71.060.50   Salts

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Scope

The method can be applied provided the phosphorus pentoxide content does not exceed 0,02 % (m/m). The principle is based on alkaline fusion of a test portion by means of a mixture of sodium carbonate and boric acid. Solution of the fused mass in excess nitric acid so that the pH of the final solution is between 0,3 and 0,5 after being diluted. Formation, in a suitable aliquot portion, of the (yellow) oxidized silicomolybdic complex under clearly defined conditions of acidity, concentration of reagents, temperature and time. Selective reduction in a high acidity sulphuric acid medium and in the presence of tartaric acid. Spectrophotometric measurement at a wavelength of about 815 nm.

Life cycle

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WITHDRAWN
ISO 2369:1972
95.99 Withdrawal of Standard
May 27, 2002