Isothermal Kinetic Mechanism of Coke Dissolving in Hot Metal

The carburization of molten iron is close to saturation in the blast furnace process, while that in the flash ironmaking process is uncertain because there is no pressure from solid charge and no carburization reactions occurring between the deadman and hot metal. Some experiments were conducted to reveal the kinetic mechanism of coke dissolving in carbon-iron melts. Reduced iron powder, electrolytic iron as well as chemical pure graphite were used as experiment materials. With high-purity argon injected as the protective gas, the specimens were heated up to 1873 K in a tubular resistance furnace to study the isothermal mechanism. The results show that the composition of the ferrous sample affects the dissolution rate. When the FeO content of the iron-bearing material rises from 0% to 4.76%, the apparent dissolution rate constant, k_t, falls from 7.98 × 10⁻⁶ m/s to 5.48 × 10⁻⁶ m/s. There are some differences amongst the dissolution rate coefficients of different cokes despite interacting with similar carbon-iron melts, with coke 1 of 7.98 × 10⁻⁶ m/s, coke 2 of 5.17 × 10⁻⁶ m/s, and coke 3 of 3.77 × 10⁻⁶ m/s. Besides, this index decreases with the increase of the dissolution time and solely depends on the procedure of the mass transfer. A negative correlation is demonstrated between k_t and the sulfur content in the iron bath as well. The content of silicon dioxide in the coke has a significant influence on k_t. Additionally, the dissolution rate coefficient increases with the increase of the graphitization degree of coke.