Silica sand, also known as industrial sand, is high-purity sand that’s made up of two main elements – silica and oxygen. Its high level of silica and oxygen content gives it a unique range of properties that make it well-suited to a large number of applications.

In this article, we’ll take a look at why silica sand is such an important part of glass manufacturing and the role that it takes in this process.

High-quality silica sand makes up around three-quarters of the batch of raw materials used in the glassmaking process. The other quarter is made up of soda, limestone, and clarifying agents along with a percentage of recycled glass. The following is the process for making flat glass, which is commonly produced with silica sand.

• Batched – The main components, including the silica sand, limestone, soda, and recycled glass, are weighed and sorted into batches.
• Melted – The batched raw materials enter a furnace that reaches temperatures up to 1600°C and become molten.
• Floated – The molten glass is then ‘floated’ on a bath of molten tin and drawn through rolling machines where it becomes flattened.
• Cooled – The molten glass leaves the bath of molten tin and is cooled to a temperature of 600°C. It passes over rollers and can be cut and worked in a predictable way.

The particle size of the sand grains is a key factor in glassmaking, as grains that are too coarse may not melt efficiently in the furnace and could lead to blemishes in the final product. On the other hand, grains that are too fine could be sucked into the airflows of the furnace and lost.

Another key factor in the process is the chemistry of the sand, with different levels of iron oxide, chromes, and other metals required to produce the various colors of glass. These are all strictly controlled to ensure the sand meets the requirements of the glassmaker and the end consumer.