What are the main components, additive components, and impurity components of refractory materials?

What are the main components of refractory materials?

The main component of refractory materials is the basis of the properties of refractory materials and is the main component that constitutes refractory raw materials. Its content and properties determine the properties of refractory materials. The main component can be a high melting point oxide, such as magnesium oxide, zirconium oxide, alumina and silica. It can also be a composite oxide, typically magnesia-aluminum spinel (MgO·Al2O3), dolomite (MgO·CaO), etc.; it can also be some elemental and non-oxides. According to the content of the main components, refractory materials can be divided into two types:

(1) Acid refractory materials.

Acidic refractory materials include siliceous refractory materials, clay refractory materials, and semi-siliceous refractory materials.

(2) Refractory materials that tend to be neutral.

From a chemical point of view, neutral refractory materials are strictly speaking only carbonaceous refractory materials, which have no application in the steelmaking process. Refractory materials that tend to be neutral mainly include: 1) high-aluminum refractory materials. Al2O3>45% in this type of products is a weakly acidic refractory material that tends to be neutral. 2) Chromium refractory materials are alkaline but tend to be neutral.

(3) Alkaline refractory materials.

Refractory materials in which MgO and CaO account for the absolute majority in products are called alkaline refractory materials, which mainly include magnesia carbon bricks, dolomite bricks, magnesia calcium sand, magnesia chrome bricks, forsterite and spinel refractory materials. Among them, strongly alkaline refractory materials are mainly magnesia and dolomite refractory materials.

What are the additive components of refractory materials?

In the production process of refractory materials, a small amount of other ingredients is added in order to promote some performance changes of a certain type of refractory material and simplify the production process. For example, to reduce the sintering temperature and sintering range, optimize the cost structure and improve the performance of refractory materials, some small amounts of ingredients added are called additive ingredients. Adding ingredients can significantly improve the performance of refractory materials and reduce production costs.

What are the impurity components of refractory materials?

Impurity components refer to the fact that during the production and processing of refractory materials, due to the limited purity of raw materials, some small amounts of components that have a negative impact on the performance of the refractory materials enter the refractory materials. These small amounts of components are called impurity components. Generally, iron oxide or ferrous oxide, potassium oxide (K20), and sodium oxide (Na20) are harmful impurity components in refractory materials. Impurity components have a strong fluxing effect at high temperatures. They interact with each other or with the main components, causing the temperature of the eutectic liquid phase to decrease or the amount of liquid phase to increase, thereby reducing the performance of f refractory materials. For example, when the Fe2O3 content in magnesia-chromium bricks is high, when the molten steel refining atmosphere changes from oxidation to reduction, magnesium ferrite (MgO·Fe2O3) and magnesia-floustite transform, causing the magnesia-chromium bricks to crack.

For alkaline refractories based on oxides, the acidic oxides contained, and for acidic refractories based on oxides, the alkaline oxides contained are considered impurity components.