At present, nanomaterials, whether produced or applied, have attracted the attention of all countries. Constant progress of nanotechnology in our country, in nanoscale SiO2, TiO2, Al2O3, ZnO2, Fe2O3 and other powder materials, has been successful in industrial production and trial production, but the existing production technology, production cost is the fatal weakness, will affect the nanometer materials applied, so to continue to improve.
Because of the rare earth elements of special electronic structure and the larger atomic radius, its chemical properties and other elements are quite different, therefore, the preparation method of nanometer rare earth oxides and post-processing technology, and other elements is also different. The main research methods are:
1. Precipitation method: including oxalic acid precipitation, carbonate precipitation, hydroxide precipitation, homogeneous precipitation, complex precipitation, etc. The method is characterized by fast nucleation, easy control, simple equipment and high purity. But difficult to filter, easy to reunite.
2. Hydrothermal method: in the condition of high temperature and high pressure, the hydrolysis reaction of ions is accelerated, and the dispersed nanocrystalline nucleus is formed. The method can obtain nanometer powder with uniform distribution and narrow particle size distribution, but it requires high temperature and high pressure equipment, expensive equipment and unsafe operation.
3. Gel method: it is an important method to prepare inorganic materials and occupies a considerable position in inorganic synthesis. Under low temperature, organic metal compounds or organic complex, through polymerization and hydrolysis reaction, the formation of sol, certain conditions to form gel, further heat treatment, can get larger surface area and good superfine nanometer powder dispersion. The method can be carried out under mild conditions, and the powder is larger and dispersive than the surface, but the reaction time is long and it will take several days to complete, and it is difficult to meet the requirements of industrialization.
4. Solid phase method: high temperature decomposition should be carried out by solid compound or intermediate solid. For example, rare earth and oxalic acid, solid phase mixed ball mill, form rare earth oxalate intermediate, then high temperature decomposition, get super fine powder. The method has high efficiency, simple equipment and easy operation, but it has irregular shape and poor uniformity.
These methods are not unique and do not necessarily apply fully to industrialization. There are also many preparation methods, such as organic microemulsion method, alcohol salt solution and so on.
Next: No Information
Related Industry Knowledge
- Introduction to rare earth elements and nanomat...
- Preparation of nanomaterials
- Origin And Development Of Rare Earth Polishing ...
- The spatial and temporal distribution and metal...
- The types of rare earth deposits in China
- What is heavy rare earth?
- Material metallurgy progress
- Basic knowledge of radioactivity in rare earth ...
- Overview of precious metal high speed electroch...
- Application of rare earth in coating industry