Application of Ball Clay in Refractory Raw Materials
August 13, 2018
Application of ball clay in refractory raw materials
Ball clay is widely used in the ceramic industry, and the refractory industry is also widely used, especially for ramming, castables and plastics. Because these amorphous refractories are constructed, they should be kept strong before use because of the ball clay. A combination of high plasticity and dry strength is often used to improve the working properties and drying strength of amorphous refractories.
Ball clay has good adhesion, 10%-15% ball clay, which can combine 85%-90% non-plastic materials. It is often used in some advanced refractory materials with high clinker content or most of the raw materials being calcined, such as dense clay bricks, high-quality high-alumina bricks, mullite products, corundum products, chrome corundum skateboard bricks and silicon carbide products, and refractory kiln furniture. The amount of clay used in refractory materials is generally 5%-25%.
Chemical composition: The chemical composition of spherical clay fluctuates greatly, alumina is 17%-35%, silica is 45%-74%, but its content of iron oxide and titanium oxide is usually higher than that of kaolin, and iron oxide is 1%-1.6%,titanium oxide 1% -1.4%. China's Guangxi Weiluo and other earth clays have low iron oxide content, half of which is less than 0.7%, and are high-quality spherical clay.
Mineral composition: The main mineral of ball clay is kaolinite, the minor minerals are montmorillonite, halloysite (polyhydrate kaolinite) and illite, mica, quartz and organic matter such as lignite are also frequently found. In commercially available ball clays, the main mineral content is: kaolinite 20%-95%, illite 5%-45%, quartz 1%-70%.
Particle size composition: Ball or clay is always finer than refractory clay and kaolin, both in theory and in practice. Fine grain size is a prerequisite for good plasticity and low sintering temperature of spherical clay. Generally, particles below 2 microns account for more than 75%. In the same mining area, the more particles, the higher the alumina content. Plasticity is the most important physical property of ball clay. The plasticity order of the refractory clay is that the spherical clay is larger than the refractory clay and larger than the kaolin. The plasticity index of the ball clay is generally close to or greater than 20%, while the refractory clay and kaolin are typically less than 20%. The ball clay has a low sintering temperature and generally starts from 1200 degrees, but the sintering range is wide, usually 150-200 degrees, which is another important feature of the ball clay, and is particularly important for the use of refractory materials in combination with clay.
The ball clay may have a refractoriness of greater than 1580 degrees or less, but is typically 1610-1770 degrees.
The method of mining ball clay: underground mining with open pit, which mining method depends on the depth, thickness, grade quality of the seam, the depth of the cover and the inclination of the seam, most of which are open-pit mining, low cost and good quality. The use of underground mining.