火焰原子吸收光谱法测定烧结机头电除尘灰中银

摘要

The trade of electrostatic precipitator dust of sintering machine head is increasingly active and the content of silver is an important index for its pricing.Therefore, the investigation on determination method for silver in electrostatic precipitator dust of sintering machine head is of great significance.After the sample was pretreated by ashing in muffle furnace at 700 ℃, it was dissloved with 15 mL of aqua regia-8 mL of hydrofluoric acid-5 mL of perchloric acid via heating on electric hot plate, or digested with 6 mL of aqua regia-3 mL of hydrofluoric acid-2 mL of perchloric acid via microwave digestion.Then, the sample solution was determined by flame atomic absorption spectrometry (FAAS) with 20%-25%(volume fraction) aqua regia as medium.Consequently, the determination method of silver in electrostatic precipitator dust of sintering machine head was established by electric hot plate heating digestion-FAAS and microwave digestion-FAAS, respectively.The interference tests of coexisting elements showed that the elements in sample did not interfere with the determination except for iron and calcium.The interference of iron and calcium could be eliminated by adding 5 500 μg/mL of iron and 571.76 μg/mL of calcium (equivalent to 800 μg/mL of calcium oxide) into standard solution series of silver which was used for plotting calibration curve.The content of silver in electrostatic precipitator dust actual samples of sintering machine head was determined respectively according the two above methods.The results were consistent with those obtained by inductively coupled plasma atomic emission spectrometry(ICP-AES).The relative standard deviation (RSD, n=11) was 1.4%-2.2% and 2.0%-2.6%, respectively.The recoveries were between 95% and 104%.%烧结机头电除尘灰的交易日益活跃,而贵金属银含量为其定价的主要指标,故研究对其中银的测定方法具有重要意义.于700 ℃马弗炉中对试样进行灰化预处理后,再以电热板加热的方式用15 mL王水-8 mL氢氟酸-5 mL高氯酸对其消解,或以微波的方式用6 mL王水-3 mL氢氟酸-2 mL高氯酸对其进行消解,继而以20%~25%(体积分数)王水作为介质,用火焰原子吸收光谱法对消解液进行测定,据此,分别建立了电热板加热消解-火焰原子吸收光谱(FAAS)法与微波消解-火焰原子吸收光谱法两种测定烧结机头电除尘灰中银的方法.共存元素干扰试验表明:样品中除铁和钙外其他元素不干扰测定,通过向校准曲线用银标准溶液系列中加入5 500 μg/mL 铁、571.76 μg/mL钙(相当于800 μg/mL氧化钙)的方法可消除铁和钙对测定的干扰.分别采用实验建立的两种方法,对烧结机头电除尘灰实际样品中银进行测定,结果表明,两种方法的测定结果均与电感耦合等离子体原子发射光谱(ICP-AES)法相符,相对标准偏差(RSD,n=11)分别为1.4%~2.2%和2.0%~2.6%,回收率均在95%~104%范围内.