Abstract：Ferromolybdenum is mainly used as molybdenum additive in steelmaking process. The content of iron in ferromolybdenum will affect the composition of final steel. Through the composition analysis of the commercially available ferromolybdenum certified reference materials and ferromolybdenum samples, it was found that the main element of molybdenum and a small amount of nickel and copper in the samples would interfere with the determination of iron by potassium dichromate titration. The samples were treated by acid dissolution-sodium hydroxide precipitation separation or sodium peroxide alkali fusion to separate the main interfering element of molybdenum during sample decomposition. If the content of nickel or copper in ferromolybdenum sample solution was not less than 1 mg, their interference with the determination could be ignored, and the content of iron in sample solution could be directly determined by potassium dichromate titration. If the content of nickel or copper was more than 1 mg, their interference could not be ignored, and they should be removed by ammonia precipitation before determination of iron by potassium dichromate titration. Consequently, the determination of iron in ferromolybdenum by potassium dichromate titration was realized by converting the results. After the actual samples and certified reference materials of ferromolybdenum were treated by acid dissolution-sodium hydroxide precipitation separation and sodium peroxide alkali fusion respectively, iron were determined by potassium dichromate titration. For the actual samples, the relative standard deviation (RSD, n=11) of determination results was 0.25% and 0.24%,respectively. For the certified reference materials, the determination results of the two methods were consistent with standards values, and the relative errors of two methods were 0.043%-0.16% and 0.025%-0.19%, respectively.
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