Hebei Messi Biology Co., Ltd. stated that magnesium oxide is a typical alkaline earth metal oxide, which is widely used in industry, medicine, food and other fields. Nano-magnesium oxide has surface effect, volume effect, etc. Its performance is superior to ordinary magnesium oxide and can be used in new fields such as electronic ceramics and catalysts.
However, nano magnesium oxide is easy to agglomerate and its morphology is difficult to control, which limits its application. Spherical nano-magnesium oxide agglomerated powder has the advantages of large specific surface area and uniform particle size distribution. Therefore, it has high reactivity, strong chemical stability, and strong bonding ability with the matrix. It can be widely used in batteries, catalysts, bactericides, and nanoceramics. Coatings and other fields.
Hebei Messi Biology Co., Ltd. stated that it uses emulsion method combined with uniform precipitation method to prepare spherical nano-magnesium oxide agglomeration powder to solve the problem of limited application of nano-magnesium oxide. The main contents are as follows:
1. Using urea as a uniform precipitant and magnesium nitrate as a salt solution, nanometer magnesium oxide powder was prepared in a high-temperature sealed environment. The effects of the concentration of magnesium nitrate, the molar ratio of urea and magnesium nitrate, reaction time, and reaction temperature on the average particle size and particle size distribution of nano-magnesium oxide powder were studied. The precursor powder and nano-magnesium oxide powder were characterized using TG-DTA, BET, XRD, laser particle size tester, and SEM. The results show that the particle size of the prepared magnesium oxide powder is approximately 30nm and the particle size distribution is uniform. Finally, the mechanism of preparing nano-magnesium oxide by uniform precipitation method was briefly discussed. The results showed that the urea hydrolysis reaction controls the entire reaction process, and choosing the appropriate reaction time and temperature will determine the performance of nano-magnesium oxide.
2. In order to achieve the purpose of controlling the morphology of agglomerated particles, the relationship between the emulsion viscosity and the water phase and emulsifier content in the emulsion as well as the relationship between the electrical conductivity and the water phase content were studied. In addition, the effects of the emulsification method and the HLB value of the composite emulsifier on the emulsion stability were also studied. The results show that the emulsion prepared using digital homogeneous emulsifier and compound emulsifier with HLB=5.5 has better stability. Finally, the ternary system phase diagram of the W/O type emulsion was drawn, and it was found that the stable emulsion had milky white areas and transparent areas, and the morphology of the emulsion was observed. It was found that the emulsion has good sphericity, uniform dispersion and micron level, and can be used as a soft template for the preparation of spherical agglomerated powders.
3. The emulsion method combined with the uniform precipitation method was used to prepare nano-magnesium oxide agglomerated powder with good sphericity and narrow particle size distribution, and the influence of various experimental factors on the powder properties was studied. The results show that when the emulsion system is stable, the morphology and particle size distribution of magnesium oxide agglomerated powder are less affected by the concentration of magnesium salt, reaction time, molar ratio of urea and magnesium salt solution, and reaction temperature; however, they are affected by the M value (emulsifier volume fraction), N value (aqueous phase volume fraction), emulsification stirring speed, and calcination heating rate have a greater impact.
4. In order to maximize the specific surface area of the agglomerated powder while maintaining sphericity, an orthogonal experiment of L9 (34) was designed, using the specific surface area value of the agglomerated powder as an indicator to obtain the optimal process conditions. Under these conditions, magnesium oxide agglomerated powder was prepared, and the powder was characterized by XRD, BET, and SEM. The results show that the obtained agglomerated powder has good sphericity and excellent dispersion properties. The particle size distribution range is: 2 μm to 50 μm, the average particle size is about 30 μm, and the BET value is 54.65 m2/g.
Finally, the mechanism of preparing spherical nano-magnesium oxide agglomerated powder by combining the uniform precipitation method and the emulsion method was briefly discussed. The results showed that the stable emulsion and emulsification stirring rotation speed, and the calcination heating rate will determine the performance of the magnesium oxide spherical agglomerated powder.
