Feldspar is by far the most abundant group of minerals in the earth's crust, forming about 60% of terrestrial rocks. Most deposits offer sodium feldspar as well as potassium feldspar and mixed feldspars. Feldspars are primarily used in industrial applications for their alumina and alkali content. Feldspar includes aluminum silicates of soda (sodium oxide), potassium (potassium oxide), or lime (calcium oxide). Feldspars are relatively hard at 6 on Mohs' hardness scale. Feldspars are generally light-colored, including white, pink, tan, green, or gray. The color varies due to impurities within the crystal structure. Feldspar is the mineral that gives granite its pink, green or gray color.
SPECIFICATION
A) PHYSICAL PROPERTIES:
1. Form : Lump / Pebbles & Grains / Powder
2. Appearance
a) Before firing : Pinkish
b)After firing at SK-9 : Glassy white sintered mass
B) CHEMICAL PROPERTIES:
1. Loss in Ignition : 1%
2. Si02 : 6% Max
3. AL203 content : 19% Max
4. Fe0203 - Ti02 : 0.5% Max
5. Alkali
a) K20 Content : 10.5% Min.
b) Na20 Content : 4.0% Max.
Glass: Feldspar is an important ingredient in the manufacture of glass. Because it acts as a fluxing agent, reducing the melting temperature of quartz and helping to control the viscosity of glass and thus reducing production costs.
Ceramics: In the manufacture of ceramics, feldspar is the second most important ingredient after clay. Feldspar does not have a strict melting point, since it melts gradually over a range of temperatures. This greatly facilitates the melting of quartz and clays and, through appropriate mixing, allows modulations of this important step of ceramic making. Feldspars are used as fluxing agents to form a glassy surface and improve the strength, toughness, and durability of the ceramic body, and cement the crystalline phase of other ingredients, softening, melting and wetting other batch constituents.
Fillers: Feldspars also are used as fillers and extenders in applications such as paints, plastics, detergents and rubber. Beneficial properties of feldspars include good dispersability, high chemical inertness, stable pH, high resistance to abrasion, low viscosity at high filler loading, interesting refractive index and resistance to frosting. The products used in such applications are generally fine-milled grades.
Enamel frits and glazes: Feldspar assists the enamel composition, assuring the absence of defects and the neatness of the end product: e.g. enamel frits, ceramic glazes, ceramic tile glazes, sanitaryware, tableware, electrical porcelain and giftware. And many other end-uses :Mild abrasives, urethane, welding electrodes (production of steel), latex foam, etc.
