The full name of slag is "granulated blast furnace slag". It is the waste residue generated during the smelting of pig iron in steel mills. In the process of blast furnace ironmaking, in addition to iron ore and fuel (coke), an appropriate amount of limestone and dolomite are also added as fluxes to reduce the smelting temperature. The calcium oxide, magnesium oxide, waste ore in iron ore, and ash in coke obtained from their decomposition in the blast furnace melt, forming a molten material mainly composed of silicates and aluminosilicates. It floats on the surface of the molten iron and is regularly discharged from the slag discharge port. After rapid cooling with air or water, it forms granular particles, which are called granulated blast furnace slag, abbreviated as slag. For every ton of pig iron produced, 0.3-1 ton of slag needs to be discharged.

As a new type of admixture for high-performance concrete, slag micro powder has the advantages of improving various properties such as compressive strength, tensile strength, shear strength, and bending resistance of concrete. At present, replacing the amount of cement in concrete and cement products with slag powder in equal quantities has become the mainstream trend in the building materials industry. LM slag vertical mill is a specialized equipment for grinding industrial waste into powder. It integrates crushing, conveying, grinding, and drying, making it an ideal equipment for producing slag micro powder.