The most comprehensive introduction to refractory clay: type, distribution, perf

Posted by adela li on December 15th, 2016

Clay is not a single mineral, but a mixture of a variety of hydrous aluminum silicate minerals with diameters less than 0.001 mm. It is characterized by plasticity in a wet and fine powder Refractory company state (crushed and mixed with water), dried and hardened and heated to a high temperature for vitrification.

Clay according to their growth can be divided into:
Primary clay. Refers to the weathering of feldspar after the formation of kaolinite and other water-bearing silicate minerals, quartz and so on. Incomplete weathered fragments refractory brick for sale remain in place, while soluble salts are dissolved.
Secondary clay. Is a clay that is re-deposited from native clays under natural dynamic conditions to other locations.
3. The chemical composition, impurity and companion of primary clay are restricted by mother rock composition.
According to the plasticity of clay can be divided into:
Soft clay (or strong plastic clay). Most of these clays are secondary clays. Due to fine particles, dispersion degree, it is plasticity.
Hard clay (or weakly plastic clay). Such clay plasticity is poor, mostly native clays.
According to the rock type is divided into kaolin, refractory brick kaolinite clay (also called soft clay), kaolinite rock.
Main Distribution of Refractory Clay in China

The Significance of A12O3 / SiO2 for Refractory Clay
Clay is a soil-like mixture consisting mainly of aqueous aluminum silicate. The main chemical composition is A12O3 and SiO2. When the A12O3 content and the A12O3 / SiO2 ratio closer to the theoretical value of kaolinite (Al2O3 39.5%, A12O3 / SiO2 = 0.85), indicating that the higher the purity of such clay.refractories  The more kaolinite content in clay, the better the quality. The higher the value of A12O3 / SiO2, the higher the refractoriness of the clay and the wider the range of sintering and melting of the clay, and vice versa.
Impurities in hard clays
Impurities in the hard clay is mainly composed of CaO, MgO, Na2O, K2O, etc., in the use of heating process, easy to form eutectic or flux from the role, the total should not exceed 5%.
Characteristics of soft clay in China
Soft clay because of different origin, performance is also quite different. In general, soft clay in Northeast generally higher iron content, which is better performance for the Jilin Ash and Clay Bay Clay; North China soft clay most of the excellent combination of clay, of which the ancient rule of production The best performance. However, Scorpion Ling Zimei clay contains a lot of organic matter, should be used when the attention.
The main characteristics of the ball clay
Ball clay is a relatively pure and has a high plasticity of refractory sedimentary clay, is also a B-axis disorder kaolinite variants, the crystallization of poor development, crystal morphology is spherical, Nan ball or book-like. Particles are very fine, viscous than ordinary clay. Dry state of the ball clay hygroscopicity than ordinary clay significantly, the color was dark, usually containing organic matter. The high dry strength, melting range, after burning was light. The main mineral composition of kaolinite in ball clay accounts for more than 70%. The chemical composition of the ball clay and kaolinite is similar to the thermal expansion curve and similar. The best ball clay refractoriness is 1710 ° C. The impurities in the ball clay to free SiO2 and a variety of silicate-based, in which the most typical mica material is the main source of alkaline impurities.