Preparation And Characterization Of Rare Earth Yttrium Sols And Yttrium Oxide

Yttrium sol is an inorganic coating used as a molten film casting coating with the advantages of improving material hardness,strengthening strength and corrosion resistance;yttrium oxide powder has unique properties in magnetism,electricity and light,and has broad application prospects in metallurgy,chemical and material fields.As high value-added materials of yttrium,yttrium sol and yttrium oxide powder have high research value.There is no stable and inexpensive preparation process for yttrium sol in China,and yttrium sol cannot be prepared in large quantities.And most of the preparation processes of nano-yttrium oxide powder materials have problems of poor product quality,environmental pollution and high equipment requirements,which make it difficult to realize mass production.Therefore,it is important to carry out research on yttrium sol and yttrium oxide powder material preparation to develop China’s abundant rare earth yttrium resources and improve their utilization value.Based on this,in this thesis,stable yttrium sols were prepared by the complex stabilization method,and yttrium oxide nanoparticles were prepared by the sol-gel and microemulsion methods,with the following main findings:（1）Stable yttrium sols were prepared by the citric acid coordination method,and the results showed that:yttrium nitrate solution was added with n_{yttrium nitrate}:n_{citric acid}=1:1.5 as the coordination agent,and m_{yttrium nitrate}:m_urea=200:1 as the stabilizer,and the reaction was carried out at 80℃for 45 minutes after adjusting the p H,and yttrium sols with a zeta potential of 46.35 m V,a viscosity of 19.45 c P,a yttrium content of 22.59%and a particle size of 20-35 nm could be obtained.19.45 c P,22.59%yttrium content,and 20-35 nm particle size.The effect of yttrium sol as a coating material was also verified,and the results showed that the uniform distribution and high purity fully met the market requirements for yttrium sol viscosity of 10 c P,yttrium oxide content of 14%and stability.（2）The process conditions for the preparation of yttrium oxide by sol-gel method at low temperature were investigated,and the results showed that lactic acid and polyethylene glycol were added at the ratio of m _A:m_{yttrium nitrate}=1:500 under the condition of ice bath at 0℃,and lactic acid could prevent the growth of sol particles and polyethylene glycol could protect the sol particles from agglomeration,and the p H was adjusted and aged for 4 h.After calcination at 750℃for 4 h,yttrium oxide with D₅₀=12.63μm could be obtained.12.63μm yttrium oxide,with primary particle size of 20-30 nm.（3）A system that can form stable microemulsions using only one aqueous phase and one oil phase was studied,and nanoscale yttrium oxide was prepared using this microemulsion system.The results showed that tralatone X-114:yttrium nitrate solution=5:1 tralatone X-114 was added to yttrium nitrate solution by volume ratio,0.5 mol/L oxalic acid solution was added as a precipitant,and the reaction was immediately filtered and dried at the end of the reaction.Calcined at 750℃for 4 h,nanoscale yttrium oxide with D50=0.22μm can be obtained with small particles of primary particle size in the range of 10-20 nm.This paper aims at the difficult and unstable preparation of yttrium sols,and uses the method of citric acid coordination to obtain stable yttrium sols with simple preparation method;the sol-gel method is used to obtain yttrium oxide with uniform morphology and particle size dispersion at low temperature;a system that can form stable microemulsions using only a single aqueous and oil phase is studied,and nanoscale yttrium oxide is prepared by this microemulsion system.The related research work is important for improving the performance and added value of rare-earth functional materials and upgrading the rare-earth yttrium materials industry.