Determining Iron Grades of Ores or Concentrates Containing Sulfide Minerals

Titration is often used to determine the iron grade in sulfide ores. In this method, HCl is used as the main solvent. If the ore contains iron sulfide minerals, such as pyrite, it cannot be completely dissolved in HCl, and the measurements error will be high. Therefore, roasting is used to determine the iron grade in such cases. But roasting requires special equipment and it is usually time consuming. On the other hand, while HNO3 can dissolve sulfide minerals, the results often contain a high measurement error due to remaining acid during titration. In this study, a new method to determine the iron grade in iron sulfide ores was proposed by using perchloric acid. The iron grade of a high pyrite-containing ore was determined by the new method, and the results were compared to those obtained by the traditional roasting or HNO3 titration. The new method was found to provide iron grade values close to the roasting method. The proposed method was tested on a number of samples with known iron grades. Results showed 0.999 determination coefficient (R-2) suggesting this method is reliable and it can be used to analyze iron grade in sulfide mineral-containing ores.