摘要
提出了一种高氯酸处理、硫酸亚铁铵滴定法快速测定钢铁中铬钒的方法。高氯酸溶解样品,并冒高氯酸烟至锥形瓶瓶口5~10 s,在稀硫酸-磷酸混合酸中,以苯代邻氨基苯甲酸为指示剂,硫酸亚铁铵溶液滴定铬(Ⅵ)、钒(Ⅴ)合量。不分解指示剂,在亚砷酸钠存在下,直接用高锰酸钾选择性氧化钒(Ⅳ),尿素存在下,亚硝酸钠还原过量氧化剂,硫酸亚铁铵溶液滴定钒(Ⅴ)。测钒时,指示剂无校正值。并讨论样品处理方法、亚砷酸钠对高锰酸钾用量的缓冲作用以及对亚硝酸钠用量的拉平效应。方法快速、简便、准确、实用,选择性好。
A new method for rapid determination of chromium and vanadium in iron and steel by ammonium ferrous sulfate titration after perchloric acid treatment was proposed.The sample is dissolved with perchloric acid,then perchloric acid fume is generated to the top of conical flask for 5~10 s.Ammonium ferrous sulfate is used to titrate the total contents of chromium(Ⅵ)and vanadium(Ⅴ)with phenylanthranilic acid as an indicator in a dilute mixed acid of H2SO4-H3PO4.Vanadium(Ⅳ)is selectively oxidized with KMnO4 under the presence of Na3AsO3 directly,and excess oxidants are reduced with NaNO2 in the presence of urea.Vanadium(Ⅴ)is titrated with ammonium ferrous sulfate,undecomposed phenylanthranilic acid as an indicator,without correcting value of the indicator.The treatment of iron and steel specimens was discussed.Na3AsO3 buffer action on the dosage of KMnO4,and its levelling effect on Na NO2 in the oxidation of vanadium(Ⅳ)were investigated respectively.The proposed method is satisfactory with the advantages of rapidity,simplicity,accuracy,practicality and selectivity.
作者
李传启
杨崇秀
邹佳影
LI Chuan-qi;YANG Chong-xiu;ZOU Jia-ying(Central Laboratory,China Chang Jiang Energy Corporation,Wuhan 430200,China)
出处
《广州化学》
CAS
2020年第4期19-22,共4页
Guangzhou Chemistry
关键词
铬
钒
钢铁
高氯酸处理
快速测定
硫酸亚铁铵滴定法
chromium
vanadium
iron and steel
perchloric acid treatment
rapid determination
ammonium ferrous sulfate titration
