Effect of Basicity on Metallurgical Properties of Fluxed Pellets with High MgO Content

Abstract

The basicity (CaO/SiO 2 ) has an important influence on the metallurgical properties of fluxed pellet with high MgO content. This paper studied the effect and function of basicity on metallurgical properties of fluxed pellet, such as compressive strength, reduction disintegration, reduction swelling and the softening-melting behaviour systematically with simulating BF conditions. From the results, with increasing basicity from 0.6 to 1.3, the compressive strength increases from 2 842 N to 3 532 N, the pore structure become more compact, and the following phase transformation is observed from Fe 2 SiO 4 → Ca 2 SiO 4 , Mg X Fe 2−X SiO 4 → MgFe 2 O 4. Additionally, the reduction properties of high magnesium fluxed pellets are improved, the low temperature disintegration index increases from 89.8% to 97.78%, and the reduction swelling index decreases from 19.02% to 8.45%. With the increase of basicity in the pellets, the softening interval and melting interval of the pellets decrease slightly, and the position of the cohesive zone shift down and gradually become thinner, which improve the permeability of the cohesive zone. In the basicity range of 0.6-1.3, the optimum metallurgical properties of pellets are observed for the basicity of 1.1.

Phase Evolution Behavior during the Reduction Process of Medium‐Silica Fluxed Pellets

“…Figure 8b,e shows that some of the silicate liquid phases containing Al 2 O 3 and MgO crystallized at higher temperatures, and clear streaky crystallization is observable. [ 30 ] This also contributes to the higher temperature of the melt droplets of fluxed pellet‐2.…”

Reinforcement of Pellet Consolidation Strength Based on Iron Filings: Microstructural Evolution and Mechanism

“…According to research, it can be seen that the energy consumption of pellet production is lower than that of sintering process, making it more ecologically friendly. [1][2][3] Therefore, increasing the proportion of pellets in blast furnace ironmaking process has become the primary method for iron and steel companies to develop green production, [3,4] and it has shown the positive application effects in some enterprises, [5,6] with many blast furnaces in North America and European countries achieving 100% pellet charge blast furnace smelting. [7,8] With the increase of pellet ratios and the trend of large-scale blast furnaces, [9] the demand for iron grade and higher quality blast furnace burden rises.…”

Structural Roles of TiO2 in CaF2-SiO2-CaO-TiO2 Submerged Arc Welding Fluxes

“…[25] The Q 0 to Q 4 are located at positions of ~850, ~900, 950 to 1000, ~1050, and ~1200 cm 1 , respectively. [26,27] These four types of Q i bands are labeled in Figure 2(a), and Q 4 is not observed in any samples due to its very low intensity in mixed silicate. As FTIR is not sensitive to Si-O symmetry stretching vibrations, [22,28] no noticeable changes with TiO2 addition are observed in the width and depth of this broad band in the high-frequency region.…”