Effect of Potassium Element Content and Crystal Form of Ammonium Tetramolybdate and Reduction Conditions on Properties of Molybdenum Powder

Abstract

As the raw material for producing molybdenum products, the quality of molybdenum powder such as purity, microstructure, particle size and distribution, has great influence on the microstructure of molybdenum products, which will affect its performance. In this study, the effect of potassium element content and crystal form of ammonium tetramolybdate and reduction conditions on the properties of molybdenum powder was studied. The results show that under the same reduction conditions, the particle size of molybdenum powder obtained by the reduction of high potassium ammonium tetramebolybdate is larger than that obtained by the reduction of low potassium ammonium tetramebolybdate. The particle size distribution of molybdenum powder obtained by the reduction of ammonium tetramebolybdate with mixed crystal form (α-type and β-type) is wider, while that obtained by the reduction of ammonium tetramebolybdate with single crystal form (β-type) is narrower and the particle size is more uniform. The higher the reduction temperature is and the lower the hydrogen flow rate is, the larger the particle size of molybdenum powder will be. The agglomeration degree of molybdenum prepared by β-type ammonium tetramolybdate is lighter than that prepared by ammonium tetramolybdate with mixed crystal form (α-type and β-type), and its sieving rate is higher.