Pyrite deposits are primarily endogenous; in addition, ferrous sulfide, formed by coal-sulfur deposition, is also worthy of study. Sulfur in magma exists in large quantities deep in the Earth, even before solidification. When magma enters the crust, the reduced pressure causes the sulfur to be separated. Iron sulfide is also known as pyrite, pyrrhotite, and marcasite. The most common pyrite crystals are hexagonal, octahedral, and pentagonal. Hexagonal crystals have fine striations on their faces.
Iron sulfide, also known as ferrous sulfide, sulfur enhancer, or pyrite, is a naturally mined ore. It contains 45-50% sulfur and 45-50% iron, making it highly effective in increasing sulfur. It is commonly used to increase sulfur in castings and is also effective in many areas for environmental pollution and sewage treatment. However, when used for environmental pollution or sewage treatment, it is usually crushed into a powder of around 325 or 200 mesh, which is more effective, but is not suitable for sewage treatment. Therefore, different particle sizes are required for different purposes.
Ferrous sulfide, produced by smelting pyrite in an electric furnace, generally has a sulfur content of 23-35%, along with other trace elements. The color of this ferrous sulfide is also different from that of iron sulfide. While ferrous sulfide is generally yellow, ferrous sulfide is generally gray-silver, with particle sizes typically ranging from 10-50 mm. Furthermore, ferrous sulfide is generally used only in castings. Because ferrous sulfide is smelted in an electric furnace, it has a higher purity. Therefore, when distinguishing between iron sulfide and ferrous sulfide, one can use color, content, and price to determine the difference.