The feldspars are by far the most abundant group of minerals and are found in igneous, metamorphic and many sedimentary rocks. Felsdpars are framework silicates where each silica tetrahedra share all corners with its four neighbouring tetrahedra.
There are two types of feldspar:Soda peldspar(7 percent or higher Na2O) and Potash feldspar(8 percent or K2O).Feldspar- silica mixtures can occur naturally, such as in sand deposits, or can be obtaied from flotation of mined and crushed rock.
Feldspar is a common raw material int he production of ceramics.It is used for thermoluminescence and optical dating in earth sciences and archaeology.It is an ingredient in Bon Ami brand cleaner.It is used as a glazing material.
In the flooring sector, feldspar is the main constituent in the body composition. It is used as a flux, lowering the vitrifying temperature of a ceramic body during firing and forming a glassy phase. Surface tension pull the remaining solid particles together, giving a densification of the ceramic body.
In tableware, feldspar gives a good fusibility for a product without defects.In sanitaryware, the use of feldspar within vitreous ceramic bodies is used to facilitate the optimization process.
Basically, the two properties which make feldspars useful for downstream industries are their alkali and alumina content. Feldspars play an important role as fluxing agents in ceramics and glass applications, and are also used as functional fillers in the paint, plastic, rubber and adhesive industries.
The initial production of feldspar was from pegmatite bodies. Pegmatites are bodies of rock commonly of granitic composition that consist mainly of unusually large crystals or masses of quartz, feldspar, and mica. Pegmatites crystallize during the last stages of injection of granitic magma.
Feldspar is currently produced as a by-product of mining mica from pegmatites and other rocks associated with the Cherryville quartz monzonite rock (a type of granitic rock) in Cleveland County. Until recently, feldspar was also recovered from the Kings Mountain district in Cleveland and Gaston counties as a by-product of mining spodumene (source of lithium) from pegmatites.
Feldspar is ground to about 20 mesh for glassmaking and to 200 mesh or finer for most ceramic and filler applications
Glass, including beverage containers and insulation for housing and building construction, continued to be the leading end use of feldspar
Feldspar consumption has been gradually shifting from ceramics toward glass markets. Another growing segment in the glass industry was solar glass, used in the production of solar cells.
Feldspar also can be replaced in some of its end uses by clays, electric furnace slag, feldspar-silica mixtures, pyrophyllite, spodumene, or talc
