, Jiangxi Wollastonite
Siliceous raw materials are divided into crystalline silica and cemented silica. The main chemical composition is SiO2, which is a typical acid refractory raw material. The melting point of pure silicon material is 1713 ° C. Siliceous materials include silicate compounds, which are the main components of the earth's crust. The appearance of crystalline silica is generally milky white, off-white, light yellow, and reddish-brown. It has a bright luster, and its cross section is smooth and continuous, with sharp edges, hardness, The intensity is greater. The appearance of cemented silica is white, off-white, yellow-gray, black, red, etc. The cross section is dense and shell-shaped, without obvious granular structure, the sharp edges of the cross section are not obvious, and there is almost no gloss.
Classification of silica There are many classifications of silica, which can be classified according to the brick-making process, structural density, crystal form conversion speed, degree of thermal expansion, and use.
(1) According to the brick making process, it can be divided into two types: cemented silica and crystalline silica. (2) According to the crystal form conversion speed, it can be further divided into fast-converted silica, medium-converted silica, slow-converted silica, and extremely slow-converted silica. (3) According to the structural density, it is classified as extremely dense (porosity less than 1.2%), dense (porosity 1.2% to 1.4%), relatively porous (porosity 4.0% to 10.0%), and porous (porosity greater than 10.0%) Of silica. (4) According to the degree of thermal expansion, it is divided into silica with low heat (less than 1150 ° C), medium heat (1150-1225 ° C), and high heat (greater than 1225 ° C). (5) Divided into silica for refractories and silica for ferroalloys according to application. Siliceous materials are mainly used in ceramics, glass, cement, refractory and other industrial fields. Because of their extensive use in the inorganic non-metallic materials industry, Career Kilns are collectively referred to as silicate industry.
The siliceous raw materials used in the refractory industry are mainly quartzite, silica sand, diatomaceous earth, fused silica, and amorphous silica fume.