The presence of Sulphur (S16) in limestone is a persistent problem where metallurgical lime is desired. The limestone should be dense, massive, preferably fine-grained, compact and non-fretting on burning. For this purpose good fluxing limestone should be lower than 0.1% in Sulphur content that constituents acid.
By our advance calcination process, we reduced the Sulphur content in limestone to 0.05%.