Oxide-based melt industrial slag generated in the pyrometallurgical process; it is one of the important products of the smelting and refining of iron and steel, ferroalloys and non-ferrous metals. The main components are CaO, FeO, MgO, MnO (alkaline oxide), etc., SiO2, P2O5, Fe2O3 (acidic oxide), etc. and Al2O3 (amphoteric oxide); in addition, industrial furnaces often contain sulfides, such as steel smelting slag It contains a small amount of CaS, and the slag of non-ferrous heavy metal smelting sometimes contains more FeS, Cu2S or Ni3S2; a small amount of metal is also entrained in the slag; some strongly reducing slag contains CaC2. In the metallurgical process, various physical and chemical reactions occur between molten slag and molten metal, molten iron alloy, molten matte, furnace gas and other products to achieve the expected metallurgical purpose of the process. Due to the low solubility between industrial slag and metal or molten matte and the difference in the specific gravity of the two, they are separated from each other. Depending on the composition, the slag condenses into a rock-like or glass-like substance.

Classification and composition of industrial slag

According to different metallurgical processes, industrial slag can be divided into smelting slag and refined slag. Using ore (including man-made rich ore or concentrate, etc.) as raw materials for reduction smelting, industrial slag or oxidation smelting, the slag formed while obtaining coarse metals or matte is called smelting slag. The slag produced by refining crude metal (smelting steel with pig iron, refining copper from blister copper, etc.) is called refined slag. The main function of these two types of slag is to remove the useless or harmful substances in the raw materials from the metal products. There is another type of slag whose main function is to enrich certain useful substances contained in the raw materials in order to facilitate the recycling of them in the next process. It is called enriched slag, such as high titanium slag obtained by reduction smelting of titanium concentrate and converting Vanadium slag and niobium slag obtained from pig iron containing vanadium and niobium are used as raw materials for extracting titanium, vanadium, and niobium, respectively. There is also a type of so-called "synthetic slag", which is industrial slag material prepared in advance with various raw materials according to the metallurgical role of the slag, such as slag for electroslag remelting, protective industrial slag for ingot casting or continuous steel casting, and steel The residue of the liquid is washed with residue, etc.