Reduced iron powder
Reduced iron powder, namely, production of pig iron by direct reduction method. Under the reduction refers directly below the melting temperature of iron ore into iron production process of sponge iron, its products for direct reduced iron (DRI), also known as sponge iron.
The product has not been melted, remains the ore profile due to restore loss of oxygen to form a large number of stomata, sponge-like under the microscope is named. Sponge iron is characterized by low carbon (<1%) and saved in the ore gangue. These features make it not suitable for large-scale application converter, only instead of the steel scrap as steelmaking raw materials.
And coal-based direct reduction method based law two classes. Former cracking produces H2 and CO gas is natural gas, and as a reducing agent in shaft furnaces, tank furnaces or in a fluidized bed of iron oxide reduced to sponge iron in iron ore. Mainly include the Midrex, HYL III, FIOR method. Coal-which is used as a reducing agent, rotary kiln, tunnel kiln and other equipment within the iron oxide reduction in iron ore. FASMET main method.
(1) the process short, direct reduced iron and steelmaking;
(2) no Coke, coking coal shortage does not affect;
(3) pollution, abolition of the coke oven, sinter processes;
(4) sponge iron, sulfur, phosphorus and other harmful impurities and low content of non-ferrous metals and smelting furnace stainless steel types. Disadvantages of direct reduction method:
(1) higher requirements on raw materials: air base to have natural gas; coal with high ash melting point and reactivity of coal;
(2) sponge iron prices are generally higher than those of steel scrap.
Direct reduction process has a history of hundreds of years, but not for a larger breakthrough until in the 1960 of the 20th century. Enter in the 1990 of the 20th century, the production process maturity and its further development. The main reason is:
(1) the development and utilization of natural gas, in particular efficient natural gas into law, provides for reducing gas, direct reduction obtained abundant and relatively cheap energy source.
(2) the need for rapid development of EAF steelmaking, as well as a variety of high quality steel, greatly expanded the demand for sponge iron.
(3) mineral processing technology, can provide a large amount of high grade ore, ore gangue content to restore a degree of removal does not need to be in the lead, thus simplifying the direct reduction technology.