Statistical Analysis of the Effect of Na₂CO₃ as Additive on the Reduction of Vanadic-Titanomagnetite-Coal Mixed Pellets

Abstract

Vanadic-titanomagnetite-coal mixed pellets with minor addition of Na2CO3 were reduced isothermally at 900°C, 945°C, 1100°C, 1255.4°C and 1300°C. The variables parameters studied are temperature, the amount of carbon and the amount of Na2CO3 as additive. The experiment was designed with the technique of orthogonal regression in order to quantitatively assess the effect of each variable and the interactional effect of different variables. It is found that temperature, the amount of carbon and the amount of Na2CO3 as additive substantially influence the degree of reduction and metallization, and the presence of Na2CO3 can increase the reducibility of the pellets. The interaction of temperature and the amount of Na2CO3 have negative influences on the degree of reduction and metallization.

Review on Reduction Kinetics of Iron Ore–Coal Composite Pellet in Alternative and Sustainable Ironmaking

“…The presence of alkali carbonates such as K 2 CO 3, Na 2 CO 3, and CaCO 3 catalyzes the carbon gasification reaction and subsequently enhances the reduction rate [13,34,35]. Zhou and Zeng [36] suggested that the alkali metals can cause lattice distortion of iron oxide, which results in lattice transformation and formation of porous iron and subsequently enhances diffusion in the product layer. Sohn and Jung [37] have studied the effect of metal additions on the reduction of iron oxide composite pellets under hydrogen atmosphere in the temperature range from 700 to 900 °C.…”

Recovery of Iron from Cyanide Residues by Carbothermic Reduction-Magnetic Separation

“…It is generally believed that the alkali metal infiltrates and reacts with the pulverized coal particles, which promotes the gasification of carbon. At the same time, the alkali metal can change the mineral structure, and make it become more loose which is of great benefit for the reduction of magnetic minerals [6]. However, when the dosage of potassium carbonate is more than 4%, a sharp decrease of iron recovery was observed.…”

Effect of CaO on the reduction behaviour of iron ore–coal composite pellets in multi-layer bed rotary hearth furnace

“…It is well reported that the presence of alkali carbonates like K 2 CO 3 , Na 2 CO 3 and CaCO 3 catalyses the carbon gasification reaction and subsequently enhances the reduction rate. [4,11,13] Zhou and Zeng [14] reported that the alkali metals can cause lattice distortion of iron oxide, which results in lattice transformation and formation of porous iron and subsequently enhances diffusion in the product layer. Park and Sahajwalla [15] studied the effect of the CaO–SiO 2 –Al 2 O 3 ternary oxide system on the reduction behaviour of composite pellets and reported higher activation energy of 137 kJ mol −1 for silica-rich hematite–graphite composite pellet compared to 107 kJ mol −1 for alumina-rich composite pellet in the temperature range of 1350–1500°C.…”