ISO 2369:1972
Withdrawn
A Withdrawn Standard is one, which is removed from sale, and its unique number can no longer be used. The Standard can be withdrawn and not replaced, or it can be withdrawn and replaced by a Standard with a different number.
Aluminium fluoride for industrial use Determination of silica content Spectrophotometric method using the reduced silicomolybdic complex
Hardcopy , PDF , PDF 3 Users , PDF 5 Users , PDF 9 Users
29-05-2019
English, French
01-12-1972
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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.
| DocumentType |
Standard
|
| Pages |
4
|
| PublisherName |
International Organization for Standardization
|
| Status |
Withdrawn
|
| Standards | Relationship |
| BS 4993-3:1974 | Similar to |
| NBN T 03 439 : 1983 | Identical |
| NFT 20 161 : 84 FD | Identical |
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