Glass Glass is an inorganic amorphous solid Main Ingredients –Glass former Silicon dioxide Quartz Boric Oxide Borax –Glass Modifiers to lower melting point Soda Ash Trona –Glass Stabilizers Formers and modifiers are water soluble Having Glass Dissolve would defeat its purpose Lime is most common - Limestone or Dolomite –Other Alumina is a glass former, viscosity control, and prevent devitrification – in ceramics it acts as a flux to lower melting point Feldspars, Kaolin, and Nephaline Syenite provide Fluxing agents to and surface tension control (prevents foaming) –Flourspar Variety of minerals can provide color
Quartz SiO 2 S.G. 2.6 - 2.65, Average = 2.62 Hardness 7 Color Brown, Colorless, Violet, Gray, Yellow. Fluorescence Triboluminescent Magnetic No
Feldspar Composition Feldspars with lots Of Alakali metals (Sodium and Potassium are The Alkali Feldspars Range from Albite To Orthoclase And Microcline Those more rich in Calcium Like Anorthite form The Plagioclase series Between Albite and Anorthite
Albite NaAlSi 3 O 8 S.G. 2.61 - 2.63, Average = 2.62 Hardness 7 Color White, Gray, Greenish gray, Bluish green, Gray. Fluorescence None Magnetic No Al 2 O 3 (Alumina) 20.35 %
Anorthite CaAl 2 Si 2 O 8 S.G. 2.72 - 2.75, Average = 2.73 Hardness 6 Color Colorless, Gray, White, Red, Reddish gray. Fluorescence None Magnetic No Al 2 O 3 (Alumina) 35.84 %
Microcline KAlSi 3 O 8 S.G. 2.56 Hardness 6 Color Bluish green, Green, Gray, Grayish yellow, Yellowish. Fluorescence None Magnetic No Alumina 18.32 %
Orthoclase KAlSi 3 O 8 S.G. 2.56 Hardness 6 Color Colorless, Greenish, Grayish yellow, White, Pink. Fluorescence None Magnetic No Alumina 18.32 %
Nepheline Syenite A rock with about 22% Nepheline (a feldspathoid) and 66% Feldspar Without quartz.
Cement Objective is to produce dry ingredients that react with water and form an artificial rock –The artificial rock forms a paste that holds loose aggregate together to form concrete Dry stuff that sets with water is made of –Ca 3 SiO 5 Tricalcium Silicate 45% –Ca 2 SiO 4 Dicalcium Silicate 27% –Ca 3 Al 2 O 6 Tricalcium Aluminate 11% –Ca 4 Al 2 Fe 2 O 10 Tetracalcium Aluminoferrite 8% No big natural sources of such chemicals exist so we make them by throwing other minerals in a rotary kiln and baking them to cement clinker
The Raw Materials Need an alumina and silicate source –Classic source is a natural glass such as volcanic ash –We like to use power plant fly ash It has the alumina, silica, and iron –Can get silica from Sand, clay, and shale –Can get alumina from Bauxite, shale, clay Calcium attacks the glass to form water reactive compounds –Calcium sources Limestone, Marble, Oyster Shells
Moderating the Reaction The cement clinker from the kiln is ground to powder –Its very water reactive Too much heat to fast will destroy the strength of the artificial rock –We add gypsum as a retarder to slow down the reaction –Gypsum is added during the grinding step
Volcanic Ash Consists mostly of shards of high temperature Christobalite Quartz with some Feldspars.
Power Plant Fly Ash SiO 2 Al 2 O 3 Fe 2 O 3 CaO MgO SO 3 Na 2 O K2OK2O SiO 2 Al 2 O 3 Fe 2 O 3 CaO MgO SO 3 Na 2 O K2OK2O F Type Fly Ash oxide % 15-45 10-25 4-15 15-40 3-10 0-10 0-6 0-4 C Type Fly Ash Oxide % F type fly ash is high In iron and low in Calcium and Alkalis C type is high in Calcium And alkalis
Crystobalite SiO2 High temperature form of quartz Very brittle and reactive Is the primary form of silica that Produces occupational and exposure Related disease.