Research And Application Of High Alumina Bauxite Based-spinel Castable For Ladles

In order to achieve the goal of refining liquid steel and smelting clean steel, using of no-carbon refractory for ladles is very important in iron and steel smelting processes. A large number of references and date were collected and analysed, combining with function requirements of ladles refining technique and its development trend of ladles refractory's techinque. The experiments were done by using basic technique idea of high alumina bauxite based-spinel castable as ladles refractory.The thesis systematically investigated the properties of high alumina bauxite based-spinel castable for ladles with binder of pure calcium aluminate cement and MgO-SiO₂-H₂O system respectively. and this materials were tentatively used in 30t continuous casting ladle.Using high grade bauxite, middle grade sintered magnesia and sintered spinel as main raw materials, the relationship between different binders as well addtion of middle grade sintered magnesia, sintered spinel and microsilicon powder and compressive strength, volume density and liner change rate of high alumina bauxite based-spinel castable after different temperature treatment were studied. Slag resistance experiment was carried out adopting static crucible method, and change regulation of slag resistance performance of high alumina bauxite based-spinel castable was also studied. After that the effects of the binder on properties of castables and the relation between ratio of middle grade sintered magnesia, microsilicon powder and sintered spinel under different binder system were studied. The results show that: (1) Low and middle temperature compressive strength can be improved by adding pure calcium aluminate cement, but at 1600℃the linear ratio increasing was happened because CA₆ mineral phases greatly occurred resulting in slag resistence and permeability performance worsend. (2) Adding middle grade sintered magnesia powder can enlarge the line ratio and porosity after high temperature treatment. Magnesia powder can improve slag resistence permeability and corrodibility, and the addition of magnesia powder has a optimun scale. (3) Adding microsilicon powder, castable stength and volume density were increased,and porosity decreased, which released volume effect caused by high temperature reaction between MA and CA₆, castables volume steability was increased. microsilicon powder promoted Al₂O₃ soluded in spinel, which improved castables slag resistence permeability and corrodibility. But excess microsilicon powder can cause liquid phase increasing and...