【摘要】 由于脱硝粉煤灰拌制混凝土时产生刺鼻性气味,需要为脱硝粉煤灰氨含量检测提供方法依据。为此,参照水质氨氮测定方法标准、外加剂氨含量测定方法和氨气敏电极法检测10个电厂的粉煤灰样品,研究现行标准方法检测粉煤灰氨含量的适用性。试验结果表明,粉煤灰氨含量在13～393mg/kg之间,不同方法检测结果最大相差78 mg/kg,相对误差在8%～87%之间,检测方法的关键在于样品制备时如何将粉煤灰中的铵(氨)彻底转移至待测溶液中。研究表明,将5 g粉煤灰与200 mL蒸馏水混合,加入强碱NaOH调整混合液的pH值大于12后蒸馏,能够将粉煤灰中铵(氨)较彻底地转移至待测溶液中,残留量小于15 mg/kg,然后利用滴定法可以精确测定氨含量。蒸馏-滴定法可以作为实验室粉煤灰氨含量检测方法。另外,氨气敏电极法通过溶解、搅拌、过滤等步骤将粉煤灰中的铵(氨)转移至待测溶液中,检测结果与蒸馏-滴定法测定值相差-7～23 mg/kg,可用于快速测定粉煤灰氨含量。更多还原

【Abstract】 Due to the pungent smell occurred during mixing concrete with the denitrified fly ash,it is necessary to provide a basis for the method of detecting the ammonia content of the denitrified fly ash.Therefore,with the reference of the standard for determination of ammonia-nitrogen content for water quality,the detection method for ammonia content of concrete admixtures and the ammonia-gas sensitive electrode method,the fly ash samples from 10 power plants are detected for investigating the applicability of the method for detecting ammonia content of fly ash from the current relevant standard.The detection results show that the ammonia contents of fly ash are between 13～393 mg/kg,while the maximum error among the different methods is 78 mg/kg and the relative error is between 8%～87%.The key point of the detection method is how to transfer the ammonium(ammonia)in fly ash to the solution to be detected thoroughly.The investigation result shows that mixing 5 g fly ash with 200 mL distilled water and adjusting the pH value of the mixed solution to be greater than 12 by means of adding NaOH,and then distilling it,the ammonium(ammonia)in fly ash can be thoroughly transferred into the solution to be detected with the residual amount of less than15 mg/kg,after that,the ammonia content can be accurately detected by the method of titration.The distillation-titration method can be taken as the lab-detection method for detecting the ammonia content of fly ash.Additionally,the ammonia-gas sensitive electrode method can transfer ammonium(ammonia)in fly ash into the solution to be detected through the steps of dissoluting,mixing,filtering,etc.,of which the detection result has a difference of-7～23 mg/kg with that obtained from the distillationtitration method,thus can be used for quick detection of ammonia in fly ash.更多还原