Iron sulphide has good high temperature stability. Because of the above chemical reaction, it becomes an important filler for high-end grinding wheel. But the key to all this chemistry is purity. Another key factor is the composition of the impurities. A large number of impurities may be harmful to grinding and increase the wear of the grinding wheel, reducing the working life of sulfur, sulfur dioxide, and sulfur trioxide react with the surface of the workpiece to form FexSy: (I) form a protective layer; (II) acting as a lubricant, absorbing oxygen between 400 and 475 degrees to reduce the oxidation of the resin and the oxidation burn of the workpiece, thus prolonging the high temperature working life of the grinding wheel, (I)4fes2 + 1102→2FE203 + 8S02(II)4fes + 702→4FE203 + 4SO21,400-475 degrees is a limit easily reached by grinding wheel. The above reaction creates an oxygen-free and anoxic environment for grinding wheel, therefore, the high temperature performance of the grinding wheel is improved. 2,650 degree absorbed heat and decomposed reaction occurred, which reduced the working temperature of grinding wheel. FES2→ FES + s 3 enters the melting state at about 1100 degrees, which becomes a good lubricant and protects the grinding wheel. FES (s)→ Fes (L)