Determination of Total Iron in Iron Ores by Titanium Trichloride Reduction-Organic Redox Indicator Method

Abstract

In order to prevent the poliution of the drain-age from a chemical labolatory by Hg, the authors proposed two new methods for the determination of total iron in iron ores in place of JIS method in which Fe (III) is reduced with SnCl₂ and the excess of reductant is oxidized HgCl₂. Those method are as follows:
For the purpose of verification analysis we established TiCl₃ reduction-ITS indicator method in which the most part of Fe (III) is reduced with SnCl₂, the remaining reduced with TiCl₃ and the excess of TiCl₃ is oxidized with K₂Cr₂O₇ using indigo tetrasulfonic acid as the indicator. Dissolution of sample and titration of Fe (II) are the same as JIS method.
Cu (<2mg) and V (<3mg) do not interfere. Analytical results of iron ores by this method agreed closely with those by JIS method.(d_max=0.04%Fe)
For the purpose of rapid analysis was established TiCl₃ reduction-NR indicator method in which main reagents used are H₃PB₄+H₂SO₄, metallic Al and neutral red indicator in place of HC1, SnCl₂and ITS indicator in the former method, respectively. Sn and V (>1.2mg) interfere. Analytical results of iron ores without interfering elements by the later are similar to the former.