有机助磨剂在机械法制备和改性MgO微粉中的应用

发布时间：2018-05-16 05:45

本文选题：氧化镁微粉 + 有机助磨剂　；参考：《武汉科技大学》2010年硕士论文

【摘要】： 机械粉碎法是一种传统的粉体加工过程,具有成本低、产量高及制备工艺简单易行等特点,广泛用于制备和改性各种微粉体。然而同时其又具有效率低,能耗大的缺点,生产中多作为其它制粉法的补充手段。因此提高粉磨效率、降低能耗,对机械粉碎法具有很重要的意义。MgO微粉作为耐火材料用微粉之一,具有耐火度高(2800℃)、抗侵蚀性优良的特点,其充当结合剂不仅能够提高材料强度,而且能够减小耐火材料气孔使其致密化,促进烧结,但因氧化镁微粉容易团聚和水化影响了其大范围的使用。本文拟采用机械粉碎法制备氧化镁微粉,在粉磨过程中通过添加自制有机助磨剂以提高球磨机粉磨效率,降低粉磨时间,以达到节能的目的；同时所添加的助磨剂通过对所得粉体表面改性起到改善其水化性能的效果,能够有效的解决氧化镁微粉制备和存放过程中的粘球、粘罐、团聚和水化的问题。基于Rehbinder的强度削弱理论、Mardulier的颗粒分散理论及氧化镁微粉表面电性能,选择合适表面活性剂并配置得到了实验所需助磨剂。为了研究带有不同官能团的表面活性剂对氧化镁粉助磨作用的大小,分别配置了含有酰胺键、羟基、羧基和醚键的四种助磨剂。通过对所得粉体激光粒度分析结果知,高能球磨法制备氧化镁微粉过程中,所添加助磨剂通过在颗粒裂纹及新生表面吸附改变颗粒间作用力,能够起到有效的助磨作用,提高了粉磨效率,但因配方中所含官能团的不同,其助磨作用的大小也略有不同；在水平方向做行星转动的行星球磨机与依靠球磨罐的上下振动粉磨的振动磨相比,行星磨所得粉体更加容易结块于球磨罐底部,不利于长时间的粉磨,而振动磨则可以通过更大范围的调节球料比来得到更细粒度的粉体,降低粉磨时间。通过对氧化镁微粉水化性能测试结果分析知,所添加助磨剂中的改性剂疏水基链段通过在球磨罐中不断的搅拌和翻转,能够有效的吸附于氧化镁微粉表面使其抗水化性能得到提高。但是当其添加量过大时,游离的疏水基链段将与已吸附在固体表面上的表面活性剂疏水基链相互作用,使得粉体表面呈现亲水性,从而使粉体抗水化性能降低。通过对氧化镁微粉Zeta电位结果进行分析发现,(NaPO3)6与改性后氧化镁在溶液中ζ绝对值为30mV,而添加Na5P3O10为20.62 mV,添加FS仅为9.64 mV。因此,使用本文所制氧化镁微粉作为耐火材料浇注料结合剂使用时,最佳分散剂为(NaPO3)6,其次为Na5P3O10,而FS20则不宜作为分散剂与改性后氧化镁共同使用。为进一步研究MgO微粉在浇注料中使用性能,将制备得到氧化镁微粉与SiO2微粉混合(质量比4：1)作为镁质结合剂用于镁质浇注料中,与SiO2微粉结合的镁质浇注料性能进行对比。由实验结果知,镁质结合剂由于含二氧化硅的量较少,在低温条件下产生较少MgO-SiO2-H2O超细粉凝聚结合,在高温条件下,由于含有更多的氧化镁微粉促进烧结,因此镁质结合剂结合镁浇注料的中温、高温强度较SiO2微粉结合镁质浇注料大。
[Abstract]:Mechanical pulverization is a traditional process of powder processing with low cost, high production and easy preparation. It is widely used in the preparation and modification of various micropowders. However, it has the disadvantages of low efficiency and high energy consumption. It is used as a supplementary means of other pulverizing methods in production. Therefore, the efficiency of grinding and energy consumption are reduced. Mechanical pulverization is of great significance to.MgO powder as one of the micro powder used in refractories. It has high refractoriness (2800 C) and excellent corrosion resistance. It can not only improve the strength of the material, but also reduce the porosity of the refractory material and promote the sintering, but it is easy to be reunited and hydrated by the Magnesium Oxide micro powder. Magnesium Oxide micro powder was prepared by mechanical pulverization. In the process of grinding, a self-made organic grinding aid was added to improve the grinding efficiency of the ball mill and reduce the grinding time to achieve the purpose of saving energy. At the same time, the added grinding agent improved its hydration performance through the surface modification of the obtained powder. The effect can effectively solve the problem of sticking, sticking, reassembling and hydration of Magnesium Oxide powder in the process of preparation and storage.
Based on the strength weakening theory of Rehbinder, the particle dispersion theory of Mardulier and the surface electrical properties of Magnesium Oxide micro powder, the suitable surfactants were selected and the required grinding agents were obtained. In order to study the effect of the surfactant with different functional groups on the grinding effect of magnesia powder, the amide bonds, hydroxyl groups and carboxyl were arranged respectively. Four kinds of grinding aids with base and ether bonds. Through the results of particle size analysis of the powders obtained, it is known that in the preparation of Magnesium Oxide micropowder by high energy ball milling, the added grinding agent can improve the grinding efficiency by changing the intergranular force on the particle crack and the new surface, and improves the grinding efficiency, but the functional group contains the functional group. The size of the grinding aid is slightly different, and the planetary ball mill in the horizontal direction is more likely to be more easily caked at the bottom of the ball mill than by the vibratory mill that depends on the upper and lower vibrational grinding of the ball mill, which is not conducive to long grinding, while the vibratory mill can be used to regulate the ball in a larger range. It is better to get finer grained powder and lower grinding time.
Through the analysis of the test results of the Hydration Performance of Magnesium Oxide micro powder, it is found that the hydrophobic group of the modifier in the added grinding agent can be effectively adsorbed on the surface of Magnesium Oxide powder to improve its hydration resistance by stirring and turning over the ball mill, but when the addition amount is too large, the free hydrophobic chain segment will be absorbed. The hydrophobicity of the surface active agent attached to the surface of the solid makes the surface of the powder present hydrophilicity, thus reducing the hydration resistance of the powder. Through the analysis of the Zeta potential results of Magnesium Oxide micropowder, the absolute value of the zeta of (NaPO3) 6 and the modified Magnesium Oxide in the solution is 30mV, and the addition of Na5P3O10 is 20.62 mV, and the addition of FS is only 9.. 64 mV., therefore, the best dispersant is (NaPO3) 6, followed by Na5P3O10 when using the Magnesium Oxide micro powder as the binder of refractory castable, while FS20 should not be used as a dispersant and the modified Magnesium Oxide.
In order to further study the performance of MgO micro powder in castable, the properties of magnesia castable which is combined with SiO2 powder in magnesia castable by mixing Magnesium Oxide micro powder and SiO2 powder (mass ratio 4:1) as magnesia binder for magnesia castable are compared. It is known from the experimental results that the magnesia binder is low at low temperature because of the amount of silica containing less. Under the conditions, less MgO-SiO2-H2O ultrafine powder condensation is produced. Under the high temperature conditions, more Magnesium Oxide micro powder is used to promote sintering. Therefore, the magnesia binder combined with magnesium castable is higher at middle temperature and higher at high temperature than that of SiO2 powder.

【学位授予单位】：武汉科技大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TB383.3

【引证文献】