Rare earth nanomaterials' production technology

At present, both production and application of nanomaterials have attracted the attention of all countries. China's nanotechnology has made continuous progress, in nano-level SiO2, TiO2, Al2O3, ZnO2, Fe2O3 and other powder materials, has been successful industrial production or trial production, but the existing production process, high production cost is its fatal weakness, will affect the promotion and application of nanomaterials, so we should continue to improve.

Due to the special electronic structure and large atomic radius of rare earth elements, their chemical properties are very different from those of other elements, so the preparation method and post-treatment technology of rare earth nanooxides are also different from those of other elements. 

The main research methods of rare earth elements include:

1. Precipitation method

 Including oxalic acid precipitation, carbonic acid precipitation, hydroxide precipitation, homogeneous precipitation, complex precipitation and so on. The main characteristics of this method are: solution nucleation is fast, easy to control, simple equipment, high purity products can be prepared. But harder to filter and easier to unite.  

2. Hydrothermal method

Accelerate and strengthen the hydrolysis reaction of ions under high temperature and high pressure, and form dispersed nanocrystalline nuclei. This method can produce nano powder with uniform dispersion and narrow particle size distribution, but it requires high temperature and high pressure equipment, which is expensive and unsafe to operate.  

3. Gel method

It is an important method to prepare inorganic materials and occupies a considerable position in inorganic synthesis. At low temperature, organometallic compound or organic complex, through polymerization or hydrolysis reaction, forming sol, forming gel under certain conditions, further heat treatment, can be larger than the surface, better dispersion of ultrafine nano powder. The method can be carried out under mild conditions, and the powder obtained has large specific surface and good dispersion, but the reaction time is long, and it takes several days to complete, which is difficult to meet the requirements of industrialization.  

4. Solid phase method

Through solid compounds or intermediate solid phase, high temperature decomposition. Such as rare earth nitrate and oxalic acid, solid phase mixing ball grinding, the formation of rare earth oxalate intermediate, and then high temperature decomposition, get ultrafine powder. This method has high reaction efficiency, simple equipment and easy operation, but the shape of the powder is irregular and the uniformity is poor.  

These methods are not unique and may not be fully applicable to industrialization. There are also many preparation methods, such as organic microemulsion method, alcohol brine solution and so on.