After clays fledspar is one of the main raw materials which used in earthen wares. Feldspars divided to three groups: calcite, sodic and potassic. Feldspar as flux is used in many ceramic products and does not have plastic property. Sodic feldspar is weaker flux than potassic feldspar. Feldspar affects on all properties of fired products such as transparency, expansion and casting properties of slurry. From view point of flexural strength, bodies containing sodic feldspar are weaker than bodies containing potassic feldspar, but thermal expansion coefficient of bodies containing sodic feldspar is higher amount. Sodic and potassic feldspars are used in the glaze, but potassic feldspar seems more appropriate for reaction with silica and formation more stable glaze. Feldspar during melting has high surface tension, so presence of too much feldspar in glaze can cause island defect in glaze. Potassic feldspar consumption amount is higher than other feldspars. About 65% of the feldspars in glass industry, 30% in ceramic industries and 5% as fillers and other items are consumed. In glass industry, feldspar is a source for required sodium and aluminum. Impurities with feldspar are often quartz, mica, iron and iron compounds and titanium oxide.
Generally, the main consumptions of feldspar are:
Flux in ceramic body and glaze
Ceramic manufacturing industry such as porcelain, tiles
Production of color
India is one of the largest and the most-known geographic areas in supplying and producing of feldspar clay. India is very rich in feldspar mines and their products have many customers in all over the world. Since APA Group has an exclusive representative and partnership in India, is able to purchase and import of feldspar with constant quality and according to international standards. In addition to providing quality products, regular depots exist in store of APA Company; also presence of experienced experts of laboratory for provide some services such as consultation for the formulation is the benefits of working with the APA Ceram Group.