Reaction between CO₂–O₂ Mixture Gas and Fe–C Melts by Isotope Tracing Method

Abstract

In order to clarify the role of O 2 and CO 2 which are applied to steelmaking, the isotope tracing method has been used to study the decarburization reactions between CO 2-O 2 mixed gas and Fe-C melts containing different carbon contents at 1 873 K. When the mixture of two isotope gases of 18 O 2 and 13 CO 2 reacts with melts, the isotopic composition of the reacted gas is monitored online by a mass spectrometer. According to the change of isotopic gas composition, the ratio of various reactions and the decarburization rate can be calculated, and the effects of gas flowrate and carbon content on the decarburization reaction can be discussed. The results showed that the utilization of CO 2 was more than 97%, and approximately 52% of oxygen formed to CO, 17% to CO 2 , and 31% for post combustion under the conditions of 30 ml/ min of flowrate, 1 cm of the gas injection height and the 4.00 to 1.00 wt% of original carbon content. And with the increase of the flowrate from 30 ml/min to 40 ml/min, the amount of CO 2 generated by O 2 increased, while the amount of CO decreased. In particular, the post combustion ratio improved significantly from 47% to 77%. KEY WORDS: decarbonization; isotope tracing method; CO 2-O 2 mixture; mass spectrometry analysis technique.

Decarburization Kinetics of Fe–C Melt with CO₂–O₂ Mixed Gas by Isotope Tracing Method

“…As for CO, there were two sources and one destination: generation by O 2 and [C], generation by CO 2 and [C], and the consumption of post combustion, which flowrates were assumed as Q z1 , Q z2 and Q z3 (mL(STP)•min -1 ) respectively. Moreover, the flow monitoring converts different gases based on gas viscosity [32]- [34]) , when CO 2 -based gas, 1 mL(STP)•min −1 O 2 , CO and Ar (SCCM) can be converted into 1.38 mL(STP)•min -1 ,1.20 mL(STP)•min -1 and 1.50 mL•min -1 CO 2 (SCCM), respectively. Therefore, the relationship based on the chemical reaction can be established simultaneously:…”

“…The experimental apparatus was followed by the previous work [32]) . An alumina tube containing 25.00±0.01 g of a metal sample heated in a high-temperature vertical tube furnace with argon (Ar, Purity ≥ 99.999%).…”

“…Thus, reasonable control of injection conditions can reduce the disturbance of post combustion and two oxygen decarburization reactions so as to real-time quantitative analysis of interface reaction. In our previous works [32]- [34]) , 13 CO 2 -18 O 2 dual isotope tracing method was established to study the reaction behavior of Fe-C melt with CO 2 -O 2 mixed gas. In this paper, the mixed gas composition and flowrates were changed to analyze the CO 2 -O 2 decarburization utilization, and the rate-limiting step was determined during the decarburization process.…”

CO Desorption and Absorption in Molten Steel: A Review

“…According to the experiment, the reaction rate constant is estimated to be 1.5 × 10 − 5 mol•cm − 2 s − 1 at 1 600°C. Fan et al 53) studied the decarburization rate of Fe-C melts with a CO 2 -O 2 mixture by employing the isotope tracing technique. Their results indicate that the utilization rate of CO 2 exceeds 97%.…”

Oxidation Mechanism During Pyrometallurgical Vanadium Extraction Process Using CO2-Containing Gas

“…6 Emission reduction and recycling of carbon dioxide in metallurgical processes have become more prominent and urgent. 7 In recent years, Zhu and co-workers [7][8][9] conducted a series of industrial experiments to study the CO 2 -O 2 mixed injection (COMI) process in the basic oxygen furnace (BOF). It was found that the dust generation rate of the COMI process was reduced by about 19.3%, and the dephosphorization rate was increased by 7.53-13.39%, compared with the conventional steelmaking process.…”