The main raw material for making glass bottles
The various materials used to prepare the glass batch are collectively referred to as glass raw materials. The glass batch for industrial production is a mixture of generally 7 to 12 individual components. Depending on their amount and use,Can be divided into glass main materials and accessories.
The main raw material refers to a raw material in which various constituent oxides are introduced into the glass, such as quartz sand, sandstone, limestone, feldspar, soda ash, boric acid, lead compound, bismuth compound, etc., which are converted into glass after dissolution.
Auxiliary materials are materials that give the glass some essential or accelerated melting process. They are used in small amounts, but they work very important. They can be divided into clarifying agents and coloring agents depending on the role they play.
Decolorizer, opacifier, oxidant, flux.
Glass raw materials are more complicated, but they can be divided into main raw materials and auxiliary raw materials according to their functions. The main raw materials constitute the main body of the glass and determine the main physical and chemical properties of the glass. The auxiliary materials impart special properties to the glass and bring convenience to the manufacturing process.
1, the main raw materials of glass
(1) Silica sand or borax: The main component of silica sand or borax introduced into glass is silica or boron oxide, which can be separately melted into a glass body during combustion, which determines the main properties of the glass, correspondingly called silicate glass or boron. Acid salt glass.
(2) Soda or Glauber’s salt: The main component of soda and thenardite introduced into the glass is sodium oxide. In calcination, they form a fusible double salt with an acidic oxide such as silica sand, which acts as a flux and makes the glass easy to form. However, if the content is too much, the thermal expansion rate of the glass will increase and the tensile strength will decrease.
(3) Limestone, dolomite, feldspar, etc.: The main component of limestone introduced into glass is calcium oxide, which enhances the chemical stability and mechanical strength of the glass, but the excessive content makes the glass crystallized and reduces heat resistance.
As a raw material for introducing magnesium oxide, dolomite can increase the transparency of the glass, reduce thermal expansion, and improve water resistance.
Feldspar is used as a raw material for the introduction of alumina, which controls the melting temperature and also improves durability. In addition, feldspar can also provide potassium oxide components to improve the thermal expansion properties of the glass.
(4) Broken glass: Generally speaking, not all new materials are used in the manufacture of glass, but 15%-30% broken glass is blended.
2, glass auxiliary materials
(1) Decolorizing agent: impurities in the raw material, such as iron oxide, will bring color to the glass. Commonly used soda, sodium carbonate, cobalt oxide, nickel oxide, etc. are used as decolorizing agents, which present complementary colors to the original color in the glass. The glass becomes colorless. In addition, there is a color reducing agent capable of forming a light color compound with colored impurities, such as sodium carbonate which can be oxidized with iron oxide to form ferric oxide, so that the glass changes from green to yellow.
(2) Colorants: Some metal oxides can be directly dissolved in a glass solution to color the glass. If the iron oxide makes the glass yellow or green, the manganese oxide can appear purple, the cobalt oxide can appear blue, the nickel oxide can appear brown, and the copper oxide and chromium oxide can appear green.
(3) Clarifying agent: The clarifying agent can reduce the viscosity of the glass melt, so that the bubbles generated by the chemical reaction can easily escape and clarify. Commonly used clarifying agents are chalk, sodium sulfate, sodium nitrate, ammonium salts, manganese dioxide and the like.
(4) Opacifier: The opacifier can turn the glass into a milky white translucent body. Commonly used opacifiers are cryolite, sodium fluorosilicate, tin phosphide, and the like. They are capable of forming particles of 0.1 – 1.0 μm suspended in glass to make the glass opacified.