Ferro Silicon Magnesium is most commonly used as an additive in steelmaking and iron casting. It also has the feature of helping as an inoculant for products such as Gray Cast Iron, Nodular Cast Iron and Vermicular Cast Iron. Nodulizers are added to the liquid cast iron to promote the formation of spheroid graphite. Nodulizers are Ferro Silicon alloys and contain Magnesium, but there are also rare-earth elements containing rare-earth elements when needed.