Study on Precipitation and Dissolution Mechanisms of Graphite in Hot Metal of Blast Furnace

Abstract

Graphite precipitation in the hot metal of a blast furnace (BF) has a significant effect on the low permeability zone of the deadman. In this work, the precipitation mechanisms of graphite in the hot metal of BF were investigated and discussed. Furthermore, the theoretical flame temperature of tuyere raceway, the center temperature of the deadman, and the critical temperature of graphite precipitated from the hot metal, were calculated and the graphitic carbon cycle and graphite enrichment mechanisms in the void of the deadman were analyzed. The results showed that the theoretical flame temperatures of the two BFs used in this study varied from 2100 ∘C to 2200 ∘C and the average center temperatures of the deadman in 4350 m3 and 1280 m3 BFs were 1329.08 ∘C and 1386.74, respectively. Moreover, graphite can precipitate from the hot metal and be enriched in the void of the deadman under certain conditions. It was assumed in this work that graphite is precipitated in the form of a 2 mm sphere and the precipitation rate of graphite in hot metal is approximately 1.01 × 10−8 kg/s. With variation in BF conditions, the precipitation–enrichment–dissolution process of graphite occurs continuously in the deadman of the BF.

Keywords

• low permeability zone
• graphite
• precipitation and dissolution
• hot metal
• blast furnace