1. Overview
Silicon steel grade magnesium oxide is a high quality material used in the manufacture of silicon steel with high purity, low impurities and excellent particle distribution. Magnesium hydroxide is the main raw material for the preparation of silicon steel grade magnesium oxide. In this paper, we will discuss the process study of preparing silicon steel grade magnesium oxide by magnesium hydroxide.
2. Raw material selection
The raw material of magnesium hydroxide used should have the following characteristics:
High purity (Mg(OH)2 content >99.0%)
Low impurity content (CaO, SiO2, Fe2O3, etc.)
Fine particle size and narrow particle size distribution
3. Preliminary treatment
Dewatering: Dehydrate the raw material of magnesium hydroxide at 150-200℃ to remove water.
Grinding: Dehydrated magnesium hydroxide is ground to reduce particle size and even particle distribution.
4. Calcination
Low Temperature Calcination: The ground magnesium hydroxide is calcined at 600-700°C for a few hours to convert to magnesium oxide.
High-temperature calcination: The magnesium oxide after low-temperature calcination is calcined at a high temperature of 1600-1800°C to further remove impurities and improve grain density.
5. Quality control
Strict quality control of intermediate and final products is carried out at each processing stage, including:
Purity analysis: Determination of Mg(OH)2, MgO and other impurities using X-ray diffraction (XRD) or atomic absorption spectroscopy (AAS).
Particle size analysis: Determination of particle size distribution using a laser particle size analyzer.
Crystal structure analysis: Use scanning electron microscope (SEM) or transmission electron microscope (TEM) to observe the crystal structure, surface morphology and densification.
6. Product Performance
High purity: The MgO content of silicon steel grade magnesium oxide should be 99.5% or more, with very low impurity content.
Dense structure: The magnesium oxide grains after high temperature calcination are dense, with good electrical insulation and thermal conductivity.
Fine particles: The average particle size should be less than 1μm with uniform distribution.
7 Conclusion
The process study of preparing silicon steel grade magnesium oxide by magnesium hydroxide shows that through careful raw material selection, strict quality control and optimization of process parameters, magnesium oxide with high purity, fine grains and dense structure can be prepared to meet the requirements of silicon steel industry. Mastering this process is crucial for improving the quality and performance of silicon steel.