Production of pig iron with the use of coke iron

Abstract

The investigations on the production of coke iron and its appl icat ion for iron smelt ing were started during the Korean War. At first, by making use of the experience accumula ted during the investigation of the possibil i ty of the production of pig iron with the use of anthracite, and by ut i l iz ing the method of the manufacture of ore briquettes, we ~.~t0,5 carried out some e lementary experiments and thermody~aamic ~ ~ o O ~ 01ff ~ _ calculat ions which showed that i f the blast furnace is o ~ ~ ~ f i l led with briquettes made of a mixture of iron ore con~ = . centra te and coal then the iron oxide is rapidly reduced ~ . ~Yg~ ~ O t/ to a me ta l l i c state, provided that the strength of the bri~ ~ o O3 que~te is retained. Therefore, one can obtain pig iron from these briquettes in low shaft furnaces (during the war we were not in a position to build blast furnaces of a normal height but there was an urgent demand for pig iron). The workers and technica l pe r sonne lo f theKim Chak Iron and Steel Factory undertook to continue the invest igation of the production of pig iron in low shaft furnaces. In September~ 195!, we started to make briquettes from a mixture of Musan iron ore concentra te and various coals. These briquette~ were resistant to cold and high temperature and stood up well to the pressure in Iow shaft furnaces. They were ca l led "reducing i ron-ore briquettes." Under war eonditious, no exper imenta l apparatus Was ava i lab le for testing briquettes at a high tempera ture and, therefore, we carried out industrial tests direct iy in a small blast furnace during a tr ial smelt ing operation. To strengthen the briquette we subjected i t to thermal t rea t ment under pressure. The strongest briquettes were obta ined from a mixture of iron ore concentrate and coking coal. This is explained by the fact that, in the course of the thermal t reatment , the coal was converted into coke, and oxides of iron were reduced to m e t a l l i c iron. We ca l led such briquettes " i ron-conta in ing coke," and la te r on we gave it the name of coke iron. As a result of the laboratory preparat ion of coke iron the following facts were ascertained: 1. During the coking most o f the Musan iron ore concentrate is reduced to m e t a l l i c iron, the extent of the reduction being dependent on the conditions of coking. At the same t ime the grains of the reduced me ta l l i c iron adhere strongly to the neighboring grains of iron or carbon. Therefore, the mechan ica l strength of the coke iron produced depends on the content of iron ore concentra te in the charge prepared for coking. Up to a certain I imi t of the concentrate content the mechan ica l strength increases and then gradually decreases (F ig . ) . 2. When coke iron is used there is no need for high blast furnaces since the iron contained in the coke iron is a lready part ly reduced, 3. Cokei ron production makes i t possible to u t i l i ze pulvemlent iron ores.