Reduction kinetics of magnetite concentrate particles by carbon monoxide

Abstract

In this study, the reaction kinetics of carbon monoxide reduction of magnetite ore concentrate in the temperature range of 973-1173 K (700-900°C) has been investigated using the thermalgravimetric analysis. Various methods were used to obtain the governing mechanism and reaction rate constant of this reaction. It was observed that the sintering phenomenon affects the concentrate particles' reduction at temperatures higher than 1173 K (900°C). CO reduction of magnetite concentrate to pure iron or iron carbide occurred as a single-step reaction. The first-order reaction model and diffusion models are two important mechanisms for this reaction in the operating temperature range. The following equation is the result of our research work relevant to carbon monoxide reduction of the magnetite concentrate particles in order to predict the progress of the reduction reaction (with R 2 about 0.98):1/1.078 = 3.27 × 10 −3 d −1.871 P C 2.738 CO exp( − 2.438 × 10 5 /RT)t ARTICLE HISTORY

Hydrogen reduction of magnetite concentrate particles

“…In the previous investigation pertinent to CO reduction of the magnetite concentrate (Abolpour et al 2018), the obtained value of α was equal to −1.871. Since this value is a function of physical structure of the solid particles, α is changeable only by 4 with the hydrogen reduction experimental data at different temperatures.…”

“…These conditions, which chemical reactions controls overall rate of the reduction process, were used to study kinetics of the chemical reactions. More descriptions about the effects of gas flowrate, particles size, characters of solid bed and sintering phenomenon have been presented in our previous study (Abolpour et al 2018).…”

Numerical Analysis of Flash Ironmaking Process in a Newly Proposed Counter-Current Downer

“…The reactor structure, material amounts, and gas-particle compositions were simplified as the idealized conditions to obtain the fundamental characteristics. Also, predecessors have repeatedly verified the basic flow, 26 particle dynamics, 2,27 and gas homogeneous reactions. 28 Also, the necessary verification for our model was conducted in the author's previous works, 8,29 in which the experimental and numerical results were compared.…”

Kinetic and Mechanism of Cellulose Thermal Degradation

“…The reason of existed variations in calculated E at different x can be found in the complexity of the investigated phenomenon and also tolerance of the experimental system. The minor variations in this value arise from the experimental system tolerance and the major variations indicate the degradation mechanism changing (Abolpour et al, 2021;Abolpour et al, 2018).…”

“…Several investigations have been presented for obtaining the thermal properties of cellulose such as the glass transition temperatures and the melting points of cellulose esters (Morooka et al, 1984;Sealey et al, 1996;Jandura et al, 2000). Huang and Li (1998) However, it is necessary to present a complete, accurate, and deep investigation for obtaining the mechanism of the degradation of cellulose and also obtaining the kinematic parameters of this phenomenon using the novel developed methods for investigating solid phase thermal treatments (Abolpour, 2021;Abolpour et al, 2021;Abolpour et al, 2018;Abolpour and Shamsoddini, 2020). The objective of the present work is to study this mechanism and obtaining the mentioned parameters for thermal degradation of cellulose in the temperature ranges among 580 to 610 K. The experiments are carried out at conditions with at least effect of diffusion.…”