The seventh factory study tour was held at June 9th 2010 at Nippon Steel Corporation, at its Kimitsu Works in Chiba. Nippon Steel Corporation is the world’s second largest steel producer. As the production base for Nippon Steel to serve the Kanto area, the Kimitsu Works ranks at the top in Japan for product quality, production equipment and production volume. Production areas of Kimitsu Works can be divided into four areas: iron making area, steel making area, hot-rolling area, and cold-rolling area.
The raw materials needed for iron making are sintered ore and coke. These materials are processed in blast furnace, producing pig iron. In the basic oxygen furnace, the impurities and carbon that remain after iron making process are removed from the pig iron. The final composition of the molten steel is then adjusted to user specifications. The molten steel is then poured into a mold and water-cooled from outside to form solidified steel. The solidified steels are then rolled by using hot rolling process and cold rolling process, and then shaped according to the user specifications.
Nippon Steel produces different kinds of products such as UO pipe and tubes, wire rod, wide-flange beam and sheet pile, spiral pipe and tubes, hot-dip galvanized sheets, and electro-galvanized sheets. Nippon Steel does not only produce steel but also do recycling jobs. The byproducts produced by the process of iron and steel making are recycled to be used again whether as the raw material, the energy source, cooler, or other functions in steel production. The recycling rate of these byproducts is as high as 98%.
Kimitsu Works has a plastic recycling equipment used to recycle plastic into coke. The plastic waste from society is gathered to be recycled in the plastic recycling equipment. After the plastic waste is transported from the municipalities, the plastic waste is put into feed conveyor to be unpacked. Then there will be manual sorting to sort things which are not plastics, and after that there will be rough crushing. The crushed plastics are sorted again by mechanical sorting, and then crushed again into smaller pieces and then put into a coke oven. Coal is added into it, and the thermal decomposition treatment process will make the plastics decompose into coke, coke oven gas, and hydrocarbon oil. The coke produced is then used as raw material in the blast furnace, while coke-oven gas is used for power generation. The hydrocarbon oil will then be used as raw material for producing plastic again.