The Core Strength of Dolomite

In the colorful world of ceramics, there exists such a seemingly ordinary mineral that hides within the raw materials but silently contributes significantly to the birth and quality improvement of ceramics. This mineral is calcite, a calcium-magnesium carbonate mineral, which, due to its unique properties, holds an undeniable position in the ceramic industry.

I. The Unique Characteristics of Dolomite

The chemical composition of dolomite is CaMg(CO₃)₂. It is usually white or grayish-white, has a glassy luster, and has a hardness ranging from 3.5 to 4. Its specific gravity is approximately 2.8 - 2.9. The most significant characteristic of dolomite is that it decomposes when heated at high temperatures, releasing carbon dioxide and generating two important oxides, calcium oxide (CaO) and magnesium oxide (MgO).

Moreover, after calcination, the dolomite exhibits excellent fluxing properties, which can lower the firing temperature of ceramic bodies. At the same time, it also has certain plasticity, which is beneficial for enhancing the bonding strength of the bodies during ceramic molding and reducing cracking phenomena. Additionally, dolomite is abundant in resources, widely distributed, and relatively inexpensive, which provides favorable conditions for its extensive application in the ceramic industry.

II. The Crucial Role in the Ceramics Industry

1. The Outstanding Performance of the Raw Materials

In the production of ceramic raw materials, dolomite plays a significant role in multiple aspects. It can modify the composition of the mixing system, thereby reducing the firing temperature of the body. This not only helps to save energy costs but also reduces potential adverse effects on the body during the high-temperature firing process. Moreover, dolomite can promote the dissolution of quartz and the formation of mullite. By appropriately increasing the amount of quartz and reducing the amount of feldspar, the transparency of the body can be effectively enhanced, improving the texture and aesthetic appeal of ceramic products. Adding 0.5% to 8% of dolomite to the high-temperature ceramic raw materials yields particularly significant results.

2. The Unique Advantages of the Glaze Material

When dolomite is used in the preparation of glazes, it can simultaneously introduce CaO and MgO, resulting in the glaze presenting a transparent rather than opalescent state. Practical experience has fully demonstrated that compared to adding calcite to feldspar glazes, glazes with dolomite added are less prone to smoking and rarely experience crystallization. This is because dolomite, as a complex salt mineral, has a special chemical composition that gives the glaze such advantages. Moreover, dolomite can promote the transformation of quartz and the formation of mullite, further expanding the firing range and making the ceramic firing process more stable and controllable.

3. Facilitating the Preparation of New Types of Ceramics

The application scope of dolomite is not limited to the traditional ceramic field. It also plays an important role in the preparation of new structural ceramics and functional ceramics. For instance, the production of common porous ceramic balls, inorganic ceramic membranes, and corundum-based ceramics, etc., all cannot be done without the participation of dolomite. It provides strong support for the performance improvement and diversified development of new ceramic materials.