What makes ceramics
Raw materials for the manufacture of ceramic products are divided into materials for crock, glazes and materials for decoration.
“ Materials for the shard are plastic clay substances (clay, kaolin), emaciated (quartz) materials and fluxes."
Clay
is a finely dispersed rock, which is a mixture of various minerals - aqueous aluminosilicates (kaolinite, etc.). Clay is divided by fire resistance, ability to sintering, painting. In the production of porcelain and earthenware, refractory, white-burning clays are used (no more than 0.8–1% of iron oxides), while pottery manufactures low-melting, red-burning clay.
Kaolin
is the most valuable clay material, characterized by high refractoriness, but weak plasticity; due to the lower content of coloring impurities, it has an almost pure white color.
The ceramic production is based on the characteristic properties of clay materials - the ability to form plastic dough with water and to easily form, to maintain cohesion in the dry state and to acquire strength and hardness after roasting. Clay materials, especially kaolin, increase the whiteness, strength, chemical and thermal stability of fired products.
Detergents
non-plastic materials (quartz, quartz sand), which regulate plasticity, reduce shrinkage of products during drying and roasting, form a shard structure during roasting.
Smelters
are fusible materials (feldspar, pegmatite, perlite, bone ash, etc.), which reduce the firing temperature and promote sintering of the crock. When melted during firing, they form a transparent, viscous glass that binds the mass of the particles, fills the pores, partially dissolves the clay substances and releases mullite crystals from the melt. The fluxes cause translucency and other properties of the crock.