Limestone, an important component in glassmaking, is used to stabilize the glass. This improves its mechanical properties and physical appearance.
Specifications for Limestone in Glassmaking
A solution is formed when lime is heated with silica, (SiO 2), and sodium carbonate(Na 2CO 3). It does not crystallize once it cools. It becomes amorphous, clear, and almost colorless when it cools and then hardens to glass.
Because glass is a mixture of different compounds, it doesn’t have a particular melting point. It softens gradually as it is heated. Glass can be molded into useful shapes by being blown. Our material has been used in the manufacture of container glass made from lime.
High limestone is required by the glass industry (CaCO3 at 94.5%). The combined CaCO3/MgCO3 should reach 97.5%. It is considered objectionable to use iron or other coloring materials like carbon. Fe2O3 should never exceed 0.2% (maximum). For colorless glasses, limestone should not exceed 0.04 percent; while for bottle glass, Fe2O3 can be as high as 0.05%.
McGrath’s Limestone is perfect for the glass industry because it is very pure and has very few contaminants or undesirables that could be harmful to the glassmaking process. It has a low Iron level, usually 0.03% Fe2O3, with a high Calcium content (98.5% CACO3) and the additional benefit of a consistent Magnesium concentration of 1% MgCO3. Limestone production can provide both economic as well as environmental benefits for glass producers.
We currently produce high-quality limestone to make container glassware.
Commercial Glass Making
Soda Lime Glass makes up the majority of commercial glasses, bottles, and containers. A majority of the raw materials used for the manufacture of glass include silica sand and soda ash as well as calcium limestone or Dolomitic limestone.
Soda lime glass is made by melting the raw materials, such as Silica Sand or Silicon Dioxide, SiO2), with Soda Ash (Sodium Carbonate, Na2CO3), Limestone (Calcium Carbonate), CaCO3) and Limestone (Calcium Carbonate), plus a small portion of other materials to enhance specific properties, such as coloring. The soda-lime glass composition is 60-75% silica with 12-15% soda and 5-12% lime.
Once the glass batch is produced, it’s fed into the furnaces. Temperatures can reach over 1500°C. Iron oxide is used in the production of green and brown bottles. Clear bottles are made from materials that are free from coloring agents.
Normally, sand melts at temperatures above 2000°C and softens below that. However, adding soda will act as a flux and lower the melting point to 1000°C. The soda makes the glass water-soluble and soft, but not very durable. Limestone is added to the glass to increase the hardness and chemical endurance.
Soda-lime is a relatively affordable, chemically strong, fairly hard, and very workable glass. Because it can be re-softened, remelted many times, it’s ideal for recycling. These characteristics make it suitable to manufacture a wide range of glass products, including bottles. All glass bottles and containers are made now automatically by either ‘Press and Blow or Blow and Blow using compressed air.