碱熔-电感耦合等离子体原子发射光谱法测定废弃SCR脱硝催化剂中钨

SCR废催化剂中钨的测定一般采用碱溶-硫氰酸盐分光光度法,但由于此类催化剂中含有钒,而钒(Ⅲ)能与SCN-形成绿色络合物,从而导致测定受到干扰.实验采用过氧化钠熔解试样,直接用水浸取后定容,稀释试液后加入1 g/L酒石酸溶液并控制盐酸酸度为5％,选择W 207.912 nm为分析谱线,采用电感耦合等离子体原子发射光谱法...

Determination of tungsten in waste SCR denitration catalyst by alkali fusion-inductively coupled plasma atomic emission spectrometry

The determination of tungsten in waste SCR catalyst usually adopts alkali soluble-thiocyanate spectrophotometry. However, since the catalyst contains vanadium, and vanadium (Ⅲ) could form green complex with SCN^-, leading to interference. The sample was fused with sodium peroxide in experiments followed by direct leaching and dilution with water. 1 g/L tartaric acid was added and the acidity of hydrochloric acid was controlled at 5%. W 207.912 nm was selected as the analytical line to determine tungsten in SCR denitrification catalyst by inductively coupled plasma atomic emission spectrometry (ICP-AES). It was found that the matrix interference could be eliminated only when the addition amount of sodium peroxide and tartaric acid was completely consistent with that in the prepared standard solution. The mass concentration of tungsten in the range of 2.00-20.00 μg/mL had good linear relationship with the emission intensity, and the correlation coefficient was 0.999 99. The limit of detection (mass fraction) and limit of quantification were 0.043% and 0.14%, respectively. The contents of tungsten in five waste SCR denitration catalyst samples were determined according to the experimental method, and no abnormal values were found in 11 times of testing by Grubbs test method. The spiked recoveries were between 99% and 101%. The proposed method effectively solved the difficulty for determination of tungsten in SCR denitration catalyst. It was applicable for the determination of tungsten (mass fraction of 0.50%-7.00%) in waste SCR denitration catalyst samples. It provided a new idea for the determination of tungsten in other products.