China Nonferrous Metallurgy

In order to meet the major demand of high-quality molybdenum raw materials in advanced Mo-materials, the production process and key factors of the preparation of multi-sequence non-agglomerated ammonium dimolybdate were proposed in this paper. Through experiments and structure characterization, the influence and control trend of various parameters in the crystallization process were discussed in details. As results, the regulation of the initial Mo concentration of the solution and the addition of the dispersant are beneficial to the stability of the supersaturation of the solution in the metastable zone of non-spontaneous nucleation, avoiding agglomeration and producing non-agglomerated ammonium dimolybdate with large particle size and narrow particle size distribution. The length of the crystal growth period determines the particle size and size distribution of the crystal, and the larger stirring speed promotes the growth of crystal. A series of non-agglomerated ammonium dimolybdate products with uniform morphology and narrow particle size distribution have been successfully developed in the industry. The particle sizeD50 are 80~130μm, 100~140μm, 140~180μm, 220~280μm, 280~380μm, respectively. It can effectively meet the strategic demand for ammonium dimolybdate products of different specifications at home and abroad. This technical achievement fills the domestic gap and leads the sales volume, that is laying a good foundation for the production and development of high-end molybdenum materials in China.