There are two types of sulfur additive for your choice, one is called pyrite which contain 45% sulfur, and the other is contain 30% sulfur, the pyrite generally supplied in the size 3-8mm or 5-40mm can also accept customed in the size 10-50mm, the 30% sulfur type is always in the 10-50mm, it is through purity smelted, so contain less impurities, but the content of sulfur is also less, welcome for contact Anyang Huatuo Metallurgy for more details. The gray cast iron contains 0.06%-0.1% sulfur will be beneficial to improve its cutting performance, improve the inoculation effect in the production process, improve the graphite shape, and improve the mechanics of the casting.In order to obtain high quality gray mouth castings, should keep the reasonable balance of sulfur in the molten iron, if the sulfur is not unevern, it is necessray to do sulfur increasing treatment in time.