Refractory clay is the main raw material for the production of aluminum silicate refractory materials, and its refractoriness requirements are higher than 1580℃ of all kinds of hard clay, soft (semi-soft) clay and clay shale, collectively known as refractory clay.
Natural refractory clay, usually clay mainly kaolinite (Al2O3 2SiO2 2H2O) as its main component, that is, water-bearing silicate as the main body, and mixed with free quartz, topaz, rutile and organic compounds and other mixtures.
Most of the non – single minerals are dispersed by particles less than 1.2μm in diameter.
According to the formation of clay is different, can be divided into: primary clay and secondary clay.
Primary clay is when the parent rock (such as feldspar) has weathered to form clay and remains in place.
Secondary clay is also known as drift clay, it is the original clay transferred to other places under natural dynamic conditions and then deposited clay, its fine particle size, large dispersion, high plasticity.
Refractory clay applied in refractory industry mainly has the following two categories.
(1) Hard clay is characterized by dense organization, large hardness, extremely fine particles, water is not easy to disperse, plasticity is very low.
This kind of clay is often light gray, gray or gray in appearance.
Conch – like fracture, some surface has a sense of greasy, easy to weathering broken into pieces.
(2) Soft (semi-soft) clay is often massive, soft tissue, good plasticity.
The color of this clay varies greatly due to the type and amount of impurities.
Gray, dark gray, black;
Others are purple, pale red or white.