Sodium metasilicate (Na2SiO3) is a versatile ingredient in areas such as detergents, fireproofing and adhesives. This inorganic chemical is available in different grades depending on the manufacturer’s needs.
For example, sodium metasilicate 9 MOL is common as a component of wet and dry mixes in shotcrete applications. Shotcrete involves shooting a dry mix of cement through one hose, while another adds water to create a wet mixture. This technique is used for construction on structures such as buildings, tunnels and swimming pools. One key benefit of shotcrete is the strength of the resulting structure, exhibiting ten percent more resistance than standard concrete structures.
At 176℉, sodium metasilicate 9 MOL begins releasing a significant amount of water, which is needed for proper installation. It also has low dust content that leads to a more controlled worksite. Other grades of sodium metasilicate (e.g. anhydrous, pentahydrate) have been proven to improve material strength even under low temperature conditions. Alternatively, it can also be used to repair and reinforce furnace linings for high temperature uses. This method is even able to work on irregular surfaces and overhead areas due to the high rate at which material is shot. In wet-mix shotcrete, the compound’s silicon dioxide (SiO2) reacts quickly, resulting in a shorter setting and hardening time.
In addition to shotcrete, sodium metasilicates are also used in sealants. Their properties provide durability and strength to structures such as walls, bridges and slabs. Although sodium metasilicate dissolves easily in mixes, once it hardens it helps protect against aqueous solutions. In slurries, sodium metasilicate reduces the mobility of water.
While shotcrete is a popular application for sodium metasilicate, it has many other industrial and construction applications. It is used in oil well cements to prevent separation of solids from the high water-containing cement matrix. In some cases, sodium metasilicate can act as an extender, allowing a higher ratio of water to cement and thus reducing material costs. It is also ideal for fire-resistant settings such as refractories.