【正文】 mped into a skip car which rides on rails up the inclined skip bridge to the receiving hopper at the top of the furnace. The cables lifting the skip cars are powered from large winches located in the hoist house . Some modern blast furnace acplish the same job ith an automated conveyor stretching from the stockhouse to the furnace top. At the top of the furnace the materials are held until a charge usually consisting of some type of metallic (ore, pellets or sinter), coke and flux (limestone) have accumulated. The precise filling order is developed by the blast furnace operators to carefully control gas flow and chemical reactions inside the furnace. The materials are charged into the blast furnace through two stages of conical bells which seal in the gases and distribute the raw materials evenly around the circumference of the furnace throat. Some modern furnaces do not have bells but instead have 2 or 3 airlock type hoppers that discharge raw materials onto a rotating chute which can change angles allowing more flexibility in precise material placement inside the furnace. Also at the top of the blast furnace are four uptakes where the hot, dirty gas exits the furnace dome. The gas flows up to where two uptakes merge into an offtake . The two offtakes then merge into the downer . At the extreme top of the uptakes there are bleeder val ves which may release gas and protect the top of the furnace from sudden gas pressure surges. The gas descends in the downer to the dustcatcher, where coarse particles settle out, accumulate and are dumped into a railroad car or truck for disposal. The gas then flows through a Venturi Scrubber which removes the finer particles and finally into a gas cooler where water sprays reduce the temperature of the hot but clean gas. Some modern furnaces are equipped with a bined scrubber nd cooling unit. The cleaned and cooled gas is now ready for burning. The clean gas pipeline is directed to the hot blast stove . There are usually 3 or 4 cylindrical shaped 9 stoves in a line adjacent to the blast furnace. The gas is burned in the bottom of a stove and the heat rises and transfers to refractory brick inside the stove. The products of bustion flow through passages in these bricks, out of the stove into a high stack which is shared by all of the stoves. Large volumes of air, from 80,000 ft3/min to 230,000 ft3/min, are generated from a turbo blower and flow through the cold blast main up to the stoves. This cold blast then enters the stove that has been previously heated and the heat stored in the refractory brick inside the stove is transferred to the cold blast to form hot blast. The hot blast temperature can be from 1600176。F. Oil, tar, natural gas, powdered coal and oxygen can also be injected into the furnace at tuyere level to bine with the coke to release additional energy which is necessary to increase productivity. The molten iron and slag drip past the tuyeres on the way o the furnace hearth which starts immediately below tuyere level. 3 Conclusion The blast furnace is the first step in producing steel from iron oxides. The first blast furnaces appeared in the 14th Century a