Abstract

A method for the analysis of ZrO2 in zirconium-tanned leathers has been developed. A 2.000g leather sample is ashed at 700°C and the ZrO2 in the ash is fused with 3g K2S2O7 at 500°C for 20 minutes. The melt is then dissolved in a hot solution of HNO3, CHNO3 = 1 mol/l. The solution thus obtained is boiled for 3 minutes and the Zr4+ is titrated with a standard solution of EDTA against a xylenol indicator at a temperature above 90°C. Samples from two leathers with ZrO2 content of 10.50% and 3.30% were analyzed. The results obtained have good analytical characteristics. The relative standard deviation is sr <1.0%. The value of the relative error as determined by the loss of zirconium during melting / sZrO2 / < 4%.