EDTA络合滴定法测定不锈钢除尘灰中锌含量OA

To accurately determine the zinc content in stainless steel dust,and to address the interference of chromium(Cr3+/Cr6+)and nickel(Ni2+)in EDTA complexometric titration,an analytical method of"precipitation separation,reduction,precipitation separation,masking,and titration"was established.After the sample was acid-dissolved using a"hydrochloric acid,nitric acid and perchloric acid"system,Cr6+was reduced to Cr3+using ascorbic acid,followed by precipitation separation of Cr3+with ammonia,masking of Ni2+with thiourea,and titration with standard EDTA solution using xylenol orange as the indicator in an acetate-acetate buffer system at pH 5.5.The results showed that this method effectively eliminates the interference from chromium and nickel,with spiked recoveries ranging from 96.3%to 104.1%and a relative standard deviation(RSD)of 0.14%to 0.44%(n=6).The method is simple to operate,highly accurate,and precise,making it suitable for routine determination of zinc content in stainless steel dust.