Iron ore
In cast iron sulfur promotes the formation of white iron. As little as 0.5% can counteract the effects of slow cooling and a high silicon content . White cast iron is more brittle, but also harder. It is generally avoided, because it is difficult to work, except in China where high sulfur cast iron, some as high as 0.57%, made with coal and coke, was used to make bells and chimes . According to , good foundry iron should have less than 0.15% sulfur. In the rest of the world a high sulfur cast iron can be used for making castings, but will make poor wrought iron.
Cookware and bakeware
Cast iron is a porous material that rusts easily. As a result, it typically requires seasoning before use. Seasoning creates a thin layer of oxidized fat over the iron that coats and protects the surface, and prevents sticking.