How can limestone be used to make glass

Iron and Steel. Non-Ferrous metallurgical processing. Oil, Gas and Biofuels. Pulp and Paper. Civil Engineering. Wastewater and Sludge. Animal Nutrition. Animal Sanitation. Citrus Pulp Pellets. Building Materials. Environment Environment. Flue Gas Treatment. Agriculture Agriculture. Float glass. Container glass. Continuous glass fiber filaments. Glass fibers for insulation. Limestone also helps to improve the handling and formability of the molten glass. In a pure silica melt, viscosity is high and this alongside with high temperature makes the glass difficult to shape, especially when it needs to hold a form, for example, in the production of glass containers.

Limestone reduces the viscosity, making the liquid glass easier to handle and form into the required shape. A final benefit of limestone in glassmaking is that it helps to avoid devitrification, a process of crystallization around small impurities in the mix that causes clouding and other defects.

Limestone is therefore an essential part of the batch. However, limestone comes in two basic types: high calcium and dolomitic. The difference between the two relates to the relative magnesium Mg content. The balance of calcium and magnesium content effects the glassmaking process in a number of ways. For example, it affects the viscosity at different temperatures by adjusting the steepness of the viscosity curve. How do you determine which of these two types of limestone is going to work best in your process?

Flat glass manufacturers tend to use more dolomitic limestone, since the higher magnesium content helps to counteract crystallization in the tin bath during cooling, which is slower than in container glassmaking. Too much calcium in the batch creates a calcium-rich surface at the end of the bath that attracts water vapor and carbon dioxide, creating a white film on the surface of the glass.

Although acid can be used to remove this film, from a health, safety and environmental perspective—as well as a cost and process optimization basis—it is better to avoid its formation in the first place. If you are a container glass manufacturer, high-calcium limestone may be more appropriate, as the glass is cooled more rapidly than in flat glass production, so that it keeps its form during the blowing process.

Faster cooling presents less of a risk of devitrification and is less sensitive to hazing. Fiberglass manufacturers tend to use more dolomitic limestone. However, the choice of limestone is highly dependent on the desired properties of the fibers, which vary widely depending on the type of fiberglass being produced.

Carmeuse application specialists can provide more information on the best use of limestone in fiberglass production, tailored to your process. Economic stability and profitable growth. Quality of all activities.

Nordkalk LS. Nordkalk Filtra A. Limestone Powder. Nordkalk Parfill. Nordkalk Limus. Nordkalk AtriGran. Nordkalk Fostop Structure.

Nordkalk Aito. Slaked lime. Nordkalk SL. Nordkalk QL. Nordkalk Terra. Fine calcite. Nordkalk C-Series. Calcite for GCC. Ultrafine PCC. Nordkalk Enrich C for coatings. However, adding soda to the mixture reduces its chemical durability, making it prone to dissolve when in contact with liquids. Once the mixture of silica, soda, and limestone is heated, it can be cooled and molded for a variety of applications.

At Corning, we know glass. We know how to strengthen it through chemical processes like ion exchange, and we know how to bend it to make optical fiber that can stretch over vast distances. Our knowledge of glass goes back more than a century, allowing us to remain on the cutting edge of research and development. From simple soda-lime to complex glass structures that enable augmented reality, glass is an adaptable, wide-ranging material.