Raw materials for blast furnace ironmaking

　　The raw materials for blast furnace smelting are mainly composed of iron ore, fuel (coke) and flux (limestone).

　　Generally, smelting 1 ton of pig iron requires 1.5-2.0 tons of iron ore, 0.4-0.6 tons of coke, 0.2-0.4 tons of flux, and a total of 2-3 tons of raw materials. In order to ensure the continuity of blast furnace production, sufficient raw materials are required.

　　Therefore, it is particularly important for both pig iron manufacturers and steel mills to purchase raw materials.

　　Although the smelting principle of pig iron is the same, the process flow is also different due to different methods and smelting equipment. The following is a brief introduction.

　　Blast furnace production is continuous. The first generation blast furnace (from start-up to overhaul and shutdown) can be continuously produced for several to more than ten years. During production, iron ore, coke and flux are continuously loaded from the furnace top (generally, the furnace top is composed of materials and hoppers, and modern blast furnaces are bell valve furnace top and bell less furnace top), hot air (1000 ~ 1300 ℃) is blown from the tuyere at the lower part of the blast furnace, and fuel such as oil, coal or natural gas is injected. The iron ore loaded into the blast furnace is mainly a compound of iron and oxygen. Under high temperature, the carbon in the coke and the injected material and the carbon monoxide generated by the combustion of carbon will capture the oxygen from the iron ore to obtain iron. This process is called reduction. Pig iron is made from iron ore through reduction reaction, and molten iron is discharged from the tap hole. Gangue in iron ore, coke and ash in the injected material combine with limestone and other fluxes added into the furnace to form slag, which is discharged from the tap hole and slag hole respectively. The gas is derived from the furnace top and used as industrial gas after dedusting. The modern blast furnace can also use the high pressure on the top of the furnace to generate electricity with some of the derived gas.

　　Pig iron is the product of blast furnace (refers to smelting pig iron in blast furnace), and the product of blast furnace is not only pig iron, but also ferromanganese, belonging to ferroalloy products. Ferromanganese blast furnace does not participate in the calculation of various indexes of ironmaking blast furnace. In the process of blast furnace ironmaking, by-products such as water slag, slag wool and blast furnace gas are also produced. Features of blast furnace ironmaking: large scale. Whether in other countries or China, the volume of blast furnace is expanding. For example, Baosteel's blast furnace in China is 4063 cubic meters, with a daily pig iron output of more than 10000 tons, more than 4000 tons of slag and more than 4000 tons of coke consumption.

　　At present, the blast furnace volume of domestic single pig iron manufacturers has reached about 500 cubic meters, but most of them are still between 100-300 cubic meters, and even there are small blast furnaces with high energy consumption and high pollution below 100 cubic meters. Their product quality is uneven, they are published in a scattered manner, and they do not have a long-term scale, nor can they be compared with international steel mills.