Effect of alumina on slag–metal separation during iron nugget formation from high alumina Indian iron ore fines

Abstract

Iron nuggets can be obtained from ore-coal composite pellets by high temperature reduction. Alumina in the ore plays a vital role in slag-metal separation during nugget formation, as it increases the liquidus temperature of the slag. In this study, the effect of carbon content, reduction temperature and lime addition on slag-metal separation and nugget formation of varying alumina iron ore fines were studied by means of thermodynamic modelling. The results were validated by conducting experiments using iron ore fines with alumina levels ranging from 1?85 to 6?15%. Results showed that increase in reduction temperature enhances slag metal separation, whereas increasing alumina and carbon content beyond the optimum level adversely affects separation. Carbon below the required amount decreases the metal recovery, and carbon above the required amount reduces the silica and alters the slag chemistry. Optimum conditions were established to produce iron nuggets with complete slag-metal separation using iron orecoal composite pellets made from high alumina iron ore fines. These were reduction temperature of 1400uC, reduction time minimum of 15 min, carbon input of 80% of theoretical requirement and CaO input of 2?3, 3?0 and 4?2 wt-% for 1?85, 4?0 and 6?15 wt-% alumina ores respectively.

Effects of Agitation and Morphology of Primary Crystalline Phase on Crystallization Behavior of CaO–SiO2–CaF2 Supercooled Melts

“…18) Furthermore, in comparison with the density, [19][20][21] surface tension, and other properties, viscosity can vary in a wide range depending on the temperature and composition. Viscosity is also greatly influenced by the existence of a solid phase generated by the crystallization of supercooled molten slag and flux in the temperature region between its liquidus and glass transition temperatures.…”

Carburization Degree of the Iron Nugget Produced by High Al₂O₃ Iron Ore

“…The chemical compositions of the ores and anthracite coal were shown in Table 1 3 is only a little. The particle sizes the ores are all below 0.5 mm.…”

“…The basicities of the slag compositions of the pellets ranged from 0.6 to 1.2 with the addition of chemical CaCO 3 . The pelletizing process was performed through a manual ball press under the pressure of 20 MPa.…”

“…Consequently, some researchers believe DRI process, especially the iron nugget process, will be one of the possible choices to effectively use high Al 2 O 3 iron ore resource. [2][3][4] The iron nugget process is an environmentally friendlier, economical alternative to the traditional blast furnace process. [5][6][7] It aims to produce pig iron nugget which has similar chemical and physical properties to blast furnace pig iron using fine iron ores and noncoking coals.…”

Melting Separation Process of High Chromium Vanadium-bearing Titanomagnetite Metallized Pellet and its Optimization by Multi-Index Synthetic Weighted Scoring Method

“…[5][6][7] Recently, the technology of direct reduction followed by melting separation applying to dispose special metallurgical resources has attracted increasing attention. [8][9][10][11] Jun et al 8) studied the carbothermal reductionmelting separation process for copper slag. In Guang et…”