Al2O3-SiC-C (ASC) refractory Materials have excellent characteristics such as high strength, strong thermal shock stability, resistance to acid and alkali slag erosion, and good erosion resistance. Therefore, it is widely used as a refractory lining material for blast furnace iron ditch (main iron ditch, nozzle, tap ditch, slag ditch, etc.); the inner lining material of the mixer, torpedo tank, and hot metal ladle; gunning materials for mixers and torpedo tanks; blast furnace taphole clay, ladle wall, and bottom brick. Key parts of steel smelting such as continuous casting system. Then, when preparing Al2O3-SiC-C (ASC) refractory materials, how to choose the bonding agent? According to experienced refractory material manufacturers and sales companies, they gave the following Al2O3-SiC-C (ASC) refractory materials bonding agent selection direction.
Selection of Al2O3-SiC-C (ASC) Refractory Materials Bonding Agent
Due to the quality of the binder, it determines the compactness of the refractory materials after forming, and even the performance of the refractory. The use technology of the bonding agent has become one of the most important factors determining the performance of monolithic refractories. The following introduces two inorganic binders, aluminate cement, and β-Al2O3.
(a) Aluminate cement
The properties of aluminate cement mainly depend on its mineral composition.
Monocalcium aluminate (abbreviated as CA) is the main mineral in various high alumina cement. It has high hydraulic activity, and it hardens quickly although the setting is not fast. It is the main source of the strength (especially the early strength) of high alumina cement.
Calcium dialuminate (abbreviated as CA2), contains more in high alumina cement with lower calcium oxide content. For example, the ratio of CA2 to CA content in aluminum cement containing about 70% Al2O3 is about 1. Its hydration hardening is slower, the early strength is lower, and the later strength is higher.
Dodecacalcium heptaaluminate (abbreviated as C13A7) is often present in a small amount in high alumina cement with a small Al2O3/CaO ratio and low SiO2 content. It has the characteristics of fast hydration and rapid condensation, but the strength is not high. If the content of such minerals in cement is high, it may reduce the strength of the later stage. When it exceeds 10%, it will often cause rapid setting.
Calceolate (C2AS) exists in high alumina cement with high SiO2 content. Pure anorthite does not undergo hydration reaction and has no positive effect on the hydration and hardening of the cement.
In the 1970s, the Japanese first used β-Al2O3 as a binder for refractory castables. After the 1980s, China also gradually carried out research on β-Al2O3 combined with castables, and now it has been mass-produced. The use of β-Al2O3 bonded corundum castables in some high-temperature furnaces in the metallurgical and chemical sectors has been found to have superior high-temperature performance than pure calcium aluminate cement-bonded castables. The biggest feature of β-Al2O3 as a castable binder is that it does not contain CaO. Because β-Al2O3 transforms into α-Al2O3 at high temperature, the temperature of β-Al2O3 combined castable is higher, exceeding 1700℃.
After β-Al2O3 is hydrated, AI(OH)3 and AlOOH are formed, which can play the role of cementing and hardening. This is the application principle of β-Al2O3 as a castable binder. With the advancement of production technology, the performance of β-Al2O3 micro powder has gradually been recognized by people, and the application of it as a binder in castables for iron troughs has become increasingly widespread. Among the many crystal forms of β-Al2O3, β-Al2O3 is the only form that has the ability to spontaneously hydrate at high temperatures. The hydration reaction equation is β-Al2O3+2H2O→Al(OH)+AlOOH.
Rongsheng Refractory Materials Manufacturer
To buy high-quality refractory products, you must choose a supplier with a manufacturer. Rongsheng is a strong refractory manufacturer. Rongsheng’s refractory brick production workshop is equipped with advanced equipment, and the newly constructed fully automatic unshaped refractory production line has an annual output of tons. Rongsheng refractory manufacturer is a good choice to purchase high-quality refractory lining materials for thermal furnace equipment. To purchase Al2O3-SiC-C (ASC) refractory materials, customized unshaped refractory castables, customized special-shaped refractory bricks, please contact us. We will provide you with high-quality refractory products according to your specific project needs.