Application of nanotechnology in magnesia refractories

Magnesia refractories have many advantages, such as high melting point, excellent high temperature volume stability, good mechanical properties, etc. They have been widely used in high temperature industrial fields such as steel, metallurgy, building materials, ceramics, etc.

Different high-temperature industrial fields have different requirements for the selection of magnesia refractories. Generally speaking, magnesia refractories are divided into magnesia carbon refractories, magnesia calcium refractories, magnesia aluminum refractories and other refractories with different properties and uses according to chemical composition. At the same time, the performance of different kinds of magnesia refractories is the decisive factor to judge whether the high-temperature industrial kiln can maintain long-term normal and stable production.

In order to adapt to the rapid development of high temperature industry, the requirements of high temperature industry on furnace lining materials are becoming higher and higher. The traditional magnesia refractories can no longer meet the use standards of high-performance refractories. It is of great value to use nanotechnology to prepare high-performance multiphase materials to improve the properties of materials. At present, due to its surface effect, small size effect, quantum size effect and macro quantum tunnel effect, nanotechnology has been widely used in the field of refractories, and successfully prepared lightweight and multi-functional multiphase refractories.

The preparation of multiphase magnesia refractories by using nanotechnology can not only alleviate the demand for high-performance magnesia materials in high-temperature industry, but also realize the lightness and multifunction of magnesia refractories, so as to improve the added value of products. Undoubtedly, the emergence of nanotechnology has provided favorable conditions for the preparation and modification of high-end magnesia refractories.

The application of nanotechnology in magnesia refractories has brought revolutionary changes to the preparation of magnesia refractories. Nanotechnology has made further improvement and extension in improving slag resistance and thermal shock resistance of low-carbon magnesia carbon refractories, hydration resistance of magnesia calcium refractories, sintering performance and mechanical properties of magnesia aluminum refractories, etc., making the development of magnesia refractories enter a new period. However, it is still in an immature stage and faces many key problems that need to be solved. The quality of these key problems will directly affect the development space and speed of nanotechnology in magnesia refractories, mainly in the following aspects:

1. Dispersion of nanomaterials. In the process of ball milling and mixing, when the particle size reaches the nanometer scale, the positive and negative charges on the surface of the nano particles gather, and their specific surface area and surface energy increase and are in an energy unstable state. Under the combined action of van der Waals force and Coulomb force, which are ubiquitous among particles, the nano particles are easy to agglomerate and agglomerate to form secondary large particles. If the mixture is mixed directly without dispersion, the existence of agglomerated secondary particles will lead to abnormal grain growth, resulting in performance degradation. At the same time, microporous structure will be formed between agglomerated nano powder particles, reducing the sintering density.
2. Compatibility of nano materials with magnesia refractory matrix. The key problem to be considered in preparing high performance magnesia refractories is the interface interaction between nano materials and magnesia refractory matrix, that is, the compatibility of dispersed phase and matrix phase, and the matching of thermal properties. The structure and function of magnesia refractories were optimized by controlling the compatibility and thermal performance of the two materials, so as to achieve a kind of magnesia multiphase refractories with excellent structure function integration.
3. Economic applicability of nano materials to magnesia refractories. The preparation process of nanomaterials is complex, and the price is relatively expensive, and the requirements for the purity of nanomaterials are high, which leads to the increase of the production cost of magnesia refractories. For large-scale refractory manufacturers, cost effect is also one of the main requirements of enterprises. The application of nanotechnology in magnesia refractories must be carefully analyzed in advance.

In a word, with the rapid development of high temperature industries such as steel, cement, petroleum and chemical industry, nanotechnology has a huge development space in the application of magnesia refractories. The market urgently needs more clean and high-performance magnesia refractories to ensure the development of high temperature industries, which requires magnesia refractories to have good corrosion resistance in addition to high melting point, high density and low porosity Heat resistance and certain mechanical strength shall be taken into account, and economic applicability shall also be considered. Therefore, the application of nanotechnology in magnesia refractories is an important way to develop long-life magnesia refractories with structure function integration.