An Experimental Study on the Kinetics of Fluidized Bed Iron Ore Reduction.

Abstract

To optimize existing iron ore reduction processes or to develop new ones, it is necessary to know the reduction kinetics of the iron ore of interest under the relevant operating conditions. In this work the reduction kinetics of hematite fine iron ore was studied for industrial-scale processes using the fluidized bed technology. Especially designed batch tests were performed in a laboratory-scale fluidized bed reactor fluidized with H 2 , H 2 O, CO, CO 2 , N 2 at atmospheric and elevated pressures to simulate the relevant process conditions. To obtain the reduction rates and the degree of reduction, the concentrations of H 2 O, CO, and CO 2 in the outlet gas were analyzed by FT-IR spectroscopy.Preliminary reduction tests showed a strong effect of the sample weight on the reduction rates, especially in the early stages of reduction. The optimum sample weight was determined by partly replacing the hematite with silica sand. Additionally, the silica sand provided a constant and stable flow pattern throughout the reduction tests. The effects of temperature, gas composition, particle size and pressure on the rates of reduction were tested and discussed.Rate analysis showed the existence of two phases with different rates during the reduction tests. Additional investigations (microscope analysis, SEM) demonstrated that in the first phase the rates were controlled by mass transport in the gas phase and in the second phase by the reduction process within the small grains of the iron ore particles.KEY WORDS: iron ore reduction; high temperature fluidized bed; reduction kinetics; elevated pressure; H 2 -CO gas mixture.

The limitations on organic detection in Mars-like soils by thermal volatilization–gas chromatography–MS and their implications for the Viking results

“…and This process takes place at temperatures of Ͻ1,000°C (27)(28)(29), but the reduction is kinetically controlled by hydrogen pressure (29) and temperature (27,28,30). We have experimentally studied the oxidation of hydrogen to water by the hematite present in the NASA Mars-1 martian soil simulant in the temperature range from 200°C to 1,200°C.…”

Thermal Decomposition Behaviour of Fine Iron Ore Particles

“…It was stated that at high temperatures, the oxygen removed by thermal decomposition before the start of the reduction corresponds to a degree of reduction of about 18%. The equation for calculating the equivalent reduction degree R due to thermal decomposition 11) and thermal decomposition reactions of iron oxides are as follows. The equivalent reduction degree R of the iron ore is defined as the ratio of weight loss of oxygen Δmoxygen to the total initial mass of oxygen in the iron oxides in the iron ore sample m tot-oxygen as shown in Eq.…”

Characterization of Precipitated Carbon by XPS and Its Prevention Mechanism of Sticking during Reduction of Fe2O3 Particles in the Fluidized Bed

“…[1][2][3][4] However, the industrialized development of the fluidized bed in iron-making was limited, [5][6][7] which was mainly attributed to the defluidization resulted from sticking among iron ore particles. [8][9][10][11] To prevent sticking problem during reduction of iron ores in the fluidized bed, some methods were proposed by previous researchers.…”