PRE-TREATMENT METHOD FOR MEASURING CONCENTRATION OF FIXED AMMONIA IN AMMONIUM LIQUOR

摘要

PURPOSE: Provided is the method for pre-treating the ammonium liquor to measure the concentration of fixed ammonia in the ammonium liquor by eliminating interfering substances during titration with sulfuric acid. Previous art is measurement by ion chromatography where the complex processes of eliminating impurities and diluting the sample if it is highly concentrated etc., are needed before the measurement. The measured concentration of this titration method and ion chromatography for the same pre-treated sample are found to be identical. CONSTITUTION: The pre-treatment method comprises: distilling ammonia liquor and collecting in boron; adding EDTA to ammonium water in a volume ratio of 1 : 1; adjusting pH more than 9.5 by addition of KOH to convert the fixed ammonia to free ammonia; distilling at 50-60deg.C for 2-3 minutes and titrating with sulfuric acid. The final measurement value should be the concentration where amount of KOH, used for pH control and reacted with sulfuric acid during titration, is deducted from the total amount of sulfuric acid used for titration.