Feldspar: Feldspar can be either potash feldspar or soda feldspar. Feldspar is used in the body as a flux - it brings alumina and silica along with the alkalis. Feldspar helps the body to vitrify at lower temperature. During firing, the alumina, silica from ball clays, china clays, silica and feldspar, combines in the presence of soda or potash along with other fluxes like calcium, magnesium etc.
Feldspar can be used either as dry ground powder or wet ground liquid. Selection of good quality feldspar source places a very major role in attaining a very good body formulation which ultimately gives a better finished product having very high fired strength, white colour body and good thermal co-efficient match between body and glaze.
In some factories, some times both potash feldspar and soda feldspar are mixed in the ratio of 1:1 or 1:2 to get better vitrification at very low temperature.
