Japan: JFE Steel improves efficiency of converter in Chiba plant

JFE Steel has remodelled the converter at its East Japan Works in Chiba city in order to increase the productivity of its hot metal pre-treatment process that removes impurities from the hot metal. The investment amount is estimated to be several billion yen. The company has changed the hot metal pre-treatment process from the conventional torpedo car (hot metal transport vehicle) method to the converter type. It has reduced the amount of auxiliary raw materials used in the refining process and strengthened cost competitiveness. JFE Steel is working to expand the use of iron scrap as part of measures against global warming.

The part of the converter that was remodelled was from the third steel plant. Construction was completed last year and full-scale operation started in CY'22 in order to increase the productivity of high-grade steel such as steel sheets for automobiles, which is the mainstay of the Chiba area.

Conventionally, hot metal pre-treatment using a torpedo car as a reaction vessel was performed in a unit away from the factory. By switching to the converter type, the efficiency of removing phosphorus as an impurity is improved, and the effect of reducing the amount of quicklime used as an auxiliary material can be expected.

There is also the advantage of increasing the amount of cold iron sources used, such as iron scrap in converters. The converter-type hot metal pre-treatment can effectively utilise the heat of reaction associated with the removal of silicon impurities. Therefore, it is easy to secure sufficient hot metal temperature even when a larger amount of cold iron source is added.

JFE's converter type hot metal pre-treatment method is called Dissolved Reactive Phosphorus (DRP). This was introduced in the Fukuyama district of West Japan Steel Works (Fukuyama City, Hiroshima Prefecture), the Kurashiki District of the same steelworks (Kurashiki City, Okayama Prefecture), and the Keihin District of East Japan Steel Works (Kawasaki City) in CY'20. Currently, the application of DRP has expanded to all four integrated blast furnace steelworks by horizontally deploying this in the Chiba area.

Note: This Insight has been published in accordance with an article exchange agreement between SteelMint and Japan Metal Daily.