Abstract / scope
The method serves for the determination of siliceous impurities, together with the silica endogenous to the plant. It cancels and replaces ISO Recommendation R 763-1971, of which it constitutes a technical revision. It consists in incinerating of a test portion at 525 °C, and separating of the mineral matter insoluble in dilute hydrochloric acid solution. The method for the determination of mineral impurities, generally originating from the soil, is described in ISO 762.