Yuan Lei's Little Knowledge | How to Choose Good Kaolin
Kaolin is a non-metallic mineral, which is a kind of clay and clay rock mainly composed of kaolinite clay minerals. The performance indicators of kaolin affect its application in different industries. Let's take a look at the evaluation criteria of kaolin.
1. Whiteness brightness
The whiteness of kaolin is divided into natural whiteness and whiteness after calcination. For ceramic raw materials, the higher the calcination whiteness, the better the quality. The presence of impurities such as Fe2O3 and MnO2 in kaolin will reduce its natural whiteness.
The clay formed by the combination of kaolin and water can be deformed under the action of external force. After the external force is removed, it can still maintain the nature of this deformation, that is, plasticity. Plasticity is the basis of the forming process of kaolin in ceramic bodies, and it is also the main technical index of the process.
The particle size distribution characteristics of kaolin is of great significance to the ore's washability and process application, and its particle size has a great influence on its plasticity, mud viscosity, ion exchange capacity, molding performance, drying performance and sintering performance.
Refers to the combination of kaolin and non-plastic raw materials to form plastic mud and has a certain dry strength performance. Usually, the binding ability of kaolin with strong plasticity is also strong.
Viscosity refers to a feature of the fluid interior due to internal friction that hinders its relative flow. In the production process, viscosity is of great significance. It is not only an important parameter in the ceramic industry, but also has a great influence on the paper industry. General montmorillonite content, fine particles, exchange of cations to sodium-based, its viscosity and thickening coefficient is high.
Sinterability refers to the properties of the solid powder kaolin body heated to close to its melting point (generally more than 1000 ℃), the material spontaneously filling the intergranular space and densification. The sample should have low sintering temperature and wide sintering range (100-150 ℃).
7. Fire resistance
Fire resistance refers to the ability of kaolin to resist high temperatures without melting. The refractoriness of pure kaolin is generally about 1700 ℃. When the content of hydromica and feldspar is high, and the content of potassium, sodium and iron is high, the refractoriness decreases, and the refractoriness of kaolin is not less than 1500 ℃.
Selection, kaolin, plasticity, properties, sintering, viscosity, content, general, process, refractoriness
Kaolin is a non-metallic mineral, which is a kind of clay and clay rock mainly composed of kaolinite clay minerals. Because it is white and delicate, also known as white earth. It is named after Gaoling Village, Jingdezhen, Jiangxi Province.
Barium sulfate is based on barite as the main raw material, through beneficiation, ore washing, crushing and other processes. Barium sulfate has a hardness of 3~3.5 (Mohs) and a specific gravity of 4.3~4.7. It has the characteristics of high specific gravity, low hardness and brittleness. Barite is almost insoluble in water, ethanol and acid, soluble in hot concentrated sulfuric acid. With the development of some high-performance barium sulfate products, the application field of barium sulfate is constantly expanding.