The method consists in reducing of nitrate to ammonia by chromium powder in acid medium, converting of organic and urea nitrogen into ammonium sulfate by digestion with concentrated sulfuric acid in the presence of a catalyst, distilling of the ammonia from an alkaline solution and absorbing in an excess of standard volumetric sodium hydroxide solution. The method is not recommended for materials containing more than 7 % of organic matter.
Status: PublishedPublication date: 1984-05
Edition: 1Number of pages: 5
Technical Committee: ISO/TC 134 Fertilizers, soil conditioners and beneficial substances
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