Feldspar

Feldspar is an amalgamation of a group of minerals containing potassium, sodium, calcium and aluminium silicates. They are the most common rock-forming minerals.
general feldspar formulae:
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the common feldspar is potassium feldspar, namely, orthoclase (k2o, al2o3, 6sio2).
Sodium feldspar is albite (na2o, al2o3, 6sio2)
calcium feldspar is anorthite (cao, al2o3, 2sio2).
applications of feldspar:
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feldspar is used as bonding agent along with magnesium oxide, magnesium chloride and other synthetic glue in the manufacture of abrasives, wheels, discs and other shapes.
The three major areas of usages are:
1.in making the body composition of several types of procelain, china and earthenware and also in the preparation of glazes and enamel.
2.as an important ingredient in the glass sand batch.
3.as a bonding agent in the manufacture of bonded abrasives like wheels and discs of garnet, corundum, emery etc.
the glass and ceramic industries are the major users of feldspar and account for 95% of their total consumption.
the main vitrifying (fluxing) agent in ceramic bodies is feldspar. The majority of white ware bodies contain good proportions of feldspar which acts as a flux. In the ceramic industry, the flux is defined as that portion of the body which develops glass phase. This is provided mostly by feldspar. In order to develop the desired amount of vitrification, the amount of flux in a ceramic body should be in a correct , and if excess of flux is added, the fired body becomes very glassy and consequently, brittle. Feldspar is used in varying proportions in porcelain, china and earthenware.
potash feldspar is used in varying proportions in the glass industry also. It may contain 10 to 15% of the batch. In the glass industry, feldspar is valued for two purposes, since it acts as a flux and secondly, for alumina content. Alumina provides the resistance in glass to impact, bendings, and thermal shock.
feldspar is also used as bonding agent along with magnesium oxide, magnesium chloride and other synthetic glue in the manufacture of abrasives, wheels, discs and other shapes.