Potassium Feldspar
Tecnodieci potassium feldspar is used as an alkali source to ensure melting in the ceramic industry. The difference of Potassium feldspar compared to sodium feldspar is that its melting degree is higher and it is also more stable.
However, due to its high expansion, attention should be paid to its ratio in glaze and body recipes.
Potassium feldspar is almost non-existent in our country compared to sodium feldspar, so it is found primarily in India, Egypt and some European countries. is imported.
What is important in potassium feldspar is the K2O ratio. The K2O value of a good potassium oxide should be minimum 11% and above. The higher the K2O ratio, the greater the risk of melting and flashing. and the more the spreading behavior will be. Of course, the ratio of TiO and FeO is also extremely important for color.
Potassium oxide is widely used in glass, ceramics, enamel, electrode, frit and plastic industries.
Feldspar or Feldspar is a group of minerals that make up 60-65% of the earth's crust. Alumina silicates containing sodium, potassium, calcium, lithium and sometimes barium and cesium
The main areas of use of feldspar are summarized below:
1. Glass Industry: The glass industry still maintains its status as the largest consumer of feldspar and nepheline syenite. Feldspathic minerals are mainly included in the glass recipe as alumina source. In addition, its flux properties are also useful. The alkalis in feldspar act as a flux to lower the melting temperature: alumina provides sensitivity and provides resistance to impact, bending and thermal shocks. To make a broad generalization, alumina content, which prevents the glass from losing its transparency and increases its viscosity during manufacturing, in addition to the above benefits, is present in containers (glass, bottles) and flat glass products at a rate of 1.5-2%. In glass fiber, it may be present at a rate of up to 15%, depending on the intended use. Nepheline syenite is an important source of silica (59-60%), alumina (23-24% Al2O3) and alkali (9.8-10.2% K2O). In glassmaking, nepheline syenite is used as flux in the melting of glass frit and constitutes 5 to 15% of the paste in container glass. Nepheline syenite is mostly used in the production of food, beverage, chemical substances, pharmaceutical bottles and jars, as well as in the production of preserved glass such as jars. A large proportion is consumed in the production of flat glass, pressed and blown glass products.
2. Ceramic Industry: Feldspathic minerals have played an important role in recipe formulations in the ceramic industry for centuries. There is no doubt that it will continue to be one of the most important markets as an end use area for feldspar and nepheline syenite in the near future. Fluxes are added to the ceramic recipe to reduce the temperature that will enable the formation of liquid when the body is fired. The flux controls the degree of vitrification of the ceramic body during firing and the product comes out of the furnace at the desired degree of vitrification. Since different ceramic bodies require different degrees of vitrification, the amount of flux to be used in certain bodies also varies. In soft porcelains (fired at low temperatures), feldspar constitutes 25-40% of the recipe composition: in tableware, 18-30%, in electroporcelain, 20-28% and in chemical-technical porcelain, 17-30%. Many technical criteria affect the amount of fluxes such as sodium and potassium feldspar or nepheline syenite to be used, and these criteria also include the properties to be gained by adding a certain flux. Examples of these are the degree of whiteness required in the final product, tensile strength, glaze retention or rejection, metalworking effect on glaze decorations and the traditional habit of the manufacturer. Potassium feldspar is more common in the ceramic industry. The advantage of potassium feldspar is that it creates a melt with high viscosity and as a result of this melt, it provides resistance against deformations of the ceramic during firing. Although feldspar is mainly used in ceramic pots and rows, nepheline syenite has begun to be preferred as flux in the manufacture of sanitary ware and tiles.
3. Production of Welding Electrodes: Welding electrodes are the traditional end-use for feldspars, as their melting properties make them an ideal component in making electrode coating material. The feldspar added to the mixture has two important functions: it acts as an arc stabilizer and protects the weld pit. Materials used as arc stabilizers include metallic additives such as potassium and sodium silicate, clay, talc, nickel and iron powders, as well as feldspar. These stabilize the arc by creating elements with low ionization potentials. In the case of filling the weld pit, slag formers from the molten solid barrier, such as feldspar, protect the weld pit and the newly welded metal.
4. Paint Industry: Paints generally contain a pigment (colorant), a medium (binder).