Prepartion Of Ulta-fine Powder Of MoO₃ Thought Extacting Mo From Mud

Mo is a type of rare precious metal and it plays an irreplaceable role due to its special physical and chemical properties in the metallurgy, chemical industry, textile and national defence, thus it is one of the indispensable materials in modern scientific and technological progress. Moreover, Mo is a kind of non-renewable resource and with increasing the production and living and increasing its usage, Mo resource decreasing rapidly. Therefore, it should recycle from waste residue of Mo, relieve the tension of its usage and reduce environment pollution.The Mo content in the FeMo collect dust often above the low grade Mo mines. At present, there is no one who can make use well of the waste residue of Mo, it is not only cause the environment pollution but also waste the resources. If finding the reasonable method that extracting the Mo from the Mo residue and use it as precursor to prepare high value-added Mo production, it must promote second resource reuse, developing circular economy, and the country.In this study, adopting tertiary amine N235 as extractant is used to extract Mo solution which is used to prepare （NH₄）₆Mo₇O₂₄. And make the comparison of it and （NH₄）₆Mo₇O₂₄ purchased on the market. Furthermore, ultra-fine MoO₃ powders and MoO₃ nanoparticles hydrosol were prepared by two kinds of （NH₄）₆Mo₇O₂₄, and make the comparison of the prepared productions.At first, the key component of FeMo collect dust samples were determined, ICP-AES result showed that Mo-mud contain plenty of Fe, Al, Mn, Cu and Zn in addition to Mo. The Mo solution was prepared by extracting Mo from Mo-mud which was extracted by acid. Mo extracted by N235 was underwent the separation and purification, precipitation and obtain the purer （NH₄）₆Mo₇O₂₄ that is as precursor to synthetize ultra-fine MoO₃ powders.At first, the effects of concentration and the type of surface active agent on the size of MoO₃ were studied. Determine the concentration of prepared solution and select CTMAB as surface active agent. The effect of usage of surface active agent, pH of solution and static placing time on the grain size of MoO₃ were studied. The optimized condition is obtained from orthogonal experiment, as follows: the usage of surface active agent CTMBA is 3 ml, pH=3.5, static placing time is 24 h. Obtained the size of MoO₃ powders by the synthetic conditions is 2.840μm. And obtained the size of MoO₃ powders adopting the （NH₄）₆Mo₇O₂₄ extracting Mo from the Mo-mud is 2.962μm. Then, compare the two prepared MoO₃ through scanning electronic microscope （SEM） and photoluminescence experiment. The result showed that （NH₄）₆Mo₇O₂₄ purchased on the market is uniformity and neat and surface is smooth; the MoO₃ prepared by adopting Mo from the Mo-mud contains metal impurities which effect the lighting.The preparation of MoO₃ nanoparticles hydrosol was studied. 2 mol/L HCl solutions as reaction medium must be ensured. The influences of quantity addition of HCl, titration rate and mixing speed in the reaction on the hydrosol are studied. 2 mL of quantity addition of HCl, 1.0 mL/min of titration rate and the fast mixing are the optimum condition under which the prepared ydrosol has better transmissivity. The stability of MoO₃ nanoparticle hydrosols prepared by adopting Mo from the Mo-mud and prepared by adopting （NH₄）₆Mo₇O₂₄ purchased on the market were studied. The result showed that their stability are both well.From the grain size/quantity distribution map of the two prepared hydrosols we could see that the grain size of hydrosol prepared by adopting （NH₄）₆Mo₇O₂₄ purchased on the market is smaller than that prepared by adopting Mo from the Mo-mud, and its peaks locate at 357 nm and 559.6 nm, respectively. From the photoluminescence experiment on the two hydrosols we can learn that the colour darkens with the increase of illumination time and metal impurities effects the lighting.