Preparatrion Of Magnesia Micro-powder In Planetary Ball Mill By Adding Organic-grinding Aid

With the high energy smash equipment development, mechanical disintegration process which is a traditional smash processes also has be widely used in the preparation and modification various tiny powder with the characteristics of low cost and high output. While it has been as other additional means of preparation micro-powder for its characters of inefficiency and higher energy cost. Therefore, improving efficiency, reducing energy consumption are significant. MgO powder as one of the bonding agents for refractory with the characteristics of high refractoriness (2800℃) and excellent resistance to fouling. The addition of magnesia powder not only reduce refractory pores, make products densification, promote sintering, has excellent high temperature and thermal shock resistance. Reunion and hydration of magnesia powder make it difficult to prepare or to save. In this paper, mechanical disintegration process are used to prepare magnesium oxide powder with adding self-made grinding aid for modifying magnesium oxide, increasing its dispersion, so as to solve their reunion, hydration, sticky ball, sticky pot issues, and improving the grinding efficiency to achieve the purpose of reducing energy consumption.Based on Rehbinder's strength weakened theory, Mardulier's particles dispersed theory and the surface electrolytic properities of magnesia powder, suitable surfactants are selected and experimental needed grinding aids are prepared. The results of experiment reveal that, in the prepare period of magnesia powder by high energy ball milling process, the adsorption of surfactants on the surface or cracks changes intergranular applied force to raising efficiency. Through the analysis of Laser granularity analyser test results, because of the different mechanism of planetary ball mill and vibration mill, parameters of the experiment is quite different. The plant-type mill which do the planets rotate in horizontal direction contrasting to the vibromill relying on the ball mill of the vibration up and down, the powder be knoted at the bottom of the pot easily and bad for the long time grinding. While the ratio of grinding media to material of vibromill could be changed largly to get lesser powder and reduce grinding time.Through the analysis of hydration testing results, the hydrophobic groups can effective adhering to the surface of MgO, and the hydration resistance of MgO powder is significantly improved. When more modifier are added, the hydration resistance will decrease for the hydrophobic nature changed. Through the analysis of potentiometric analyzer results, (NaPO3)6 as a dispersant in castable with the best results compound with modified magnesium oxide, the absolute value ofζis 30mV, and second is Na5P3O10(20mV). but FS20 should not as the dispersant together with modified magnesia.The magnesia based bonding agent which mixed by MgO and SiO2 powder (4:1) and SiO2 powder are used in the magnesia based castables to researching the usability of magnesia based bonding agent. The results indicate that under the low temperature, the mount of MgO-SiO2-H2O is reduced for less SiO2 powder had, while more MgO powder accelerate sintering under the high temperature in the samples bonded by magnesia based bonding agent. therefore, the magnesia based bonding agent bonded castable has larger low, medium and high intensity than SiO2 powder bonded.