1961 Volume 47 Issue 4 Pages 612-616
No satisfactory and reliable method for the determination of metallic iron in basic slag has been available. Although HgCl2 method has found wide. usage in the determination of metallic iron, no application to the determination of metallic iron in basic slag has been re-ported. As part of a program to develop chemical methods of analysis for basic slag, an investigation of the determination of metallic iron by EDTA titration technique was undertaken in the laboratory of Toto Steel Mfg-Co., Ltd.
In the recommended method, 0.5g of sample in 50ml of ethyl alcohol solution, containing HgCl2 of about 10 times of metallic iron, kept at 60°C for 20mn, to dissolve only metallic iron and leaving the iron oxides, CaO, etc. unattacked regardless of their ratios. Then the solution was filtered and washed with ethyl alcohol, and 10ml of (NH4) 2S2O8 (20%) solution, 2ml of 1 to 1 HCl, and 100ml of water were added to the filtrate. pH of the solution was adjusted to 2.0-2.5, with 50% of ammonium acetate solution and iron (III) was titrated at 40°C with a standard EDTA solution using tiron as an indicator. In this titration, Hg2+ did not interfere.