Properties of Column Separation of Iron,Lead,Arsenic,Nickel and Cobalt on the Extraction Resin-CL-TBP,Determination and Application of the Distribution Coefficients

Distribution coefficients (Kd) of Fe(Ⅲ),Pb(Ⅱ),As(Ⅲ,Ⅴ),Ni(Ⅱ) and Co(Ⅱ) on the extraction resin (CL-TBP) in hydrochloric and nitric acid medium of different acidities were determined.As shown by experimental data,① value of Kd of Fe(Ⅲ) was found to be larger than 104 in 5-9 mol·L-1 HCl medium,while values of Kd of Pb(Ⅱ),As(Ⅲ,Ⅴ),Ni(Ⅱ) and Co(Ⅱ) were equal to or smaller than 12,indicating that under this condition,Fe(Ⅲ) was strongly adsorbed on the resin and Pb(Ⅱ),As(Ⅲ,Ⅴ),Ni(Ⅱ) and Co(Ⅱ) were not adsorbed;and ② value of Kd of Fe(Ⅲ) were found to be less than 12 in HNO3 medium with its acidity less than 2 mol·L-1;based on this fact,0.5 mol·L-1 HNO3 was selected as an eluent to elute Fe(Ⅲ) from the resin.Absorption capacity of the CL-TBP resin was also determined.On the base of these phenomena,a method for the ICP-AES determination of trace amounts of Pb(Ⅱ),As(Ⅴ),Ni(Ⅱ) and Co(Ⅱ) in high-purity iron oxide after column-chromatographic separation on CL-TBP resin was proposed.