Melting Behaviour of Ferronickel Slags

Abstract

The industrial manufacturing of ferronickel in electric furnaces produces large amounts of slag with strong acidic character and high melting points, which seriously stresses the furnace refractory lining. In this study, the melting behavior of synthetically produced ferronickel slags on magnesia as refractory material was determined by means of a hot stage microscope. Therefore, slags comprising the main oxides SiO 2 (35-70 wt.%), MgO (15-45 wt.%) and Fe 2 O 3 (5-35 wt.%) were melted in a graphite crucible and afterwards analyzed by a hot stage microscope. The design of experiments, which was created by the statistic software MODDE Ò , included 20 experiments with varying slag compositions as well as atmospheres. The evaluation of the test results occurred at three different characteristic states of the samples like the softening point according to DIN 51730 and the temperatures at which the area of residual cross-section of the samples amounted to 30% and 40%, respectively, of the original value depending of their SiO 2 /MgO ratio and iron oxide content. Additionally, the thickness of the zone influenced by the slag was measured and evaluated.

Decomposition of ferronickel slag through alkali fusion in the roasting process

“…Ferronickel slag is the by-product resulted from the lateritic nickel ore smelting process in the blast furnace or electric furnace. Generally, it contains SiO 2 , MgO and FeO as the main compounds [1][2][3], which are fused in the olivine phase [4], as well as small amounts of Al [3,[5][6][7] and Cr [4,8] that are fused in the spinel phase.…”

Effects of CaO Addition on the Iron Recycling from Nickel Slags by Oxidation-Magnetic Separation

“…Thus, it is necessary to investigate how the CaO affects the temperature. Because FactSage can be used for the prediction of phase evolution in various slag systems [16], and HSM was also used to measure the fusion temperatures [17][18][19]. Thus, both theoretical calculations and experiments were used for the investigations.…”

Recovering Magnesium from Ferronickel Slag by Vacuum Reduction: Thermodynamic Analysis and Experimental Verification

“…Depending on the cooling methods, ferronickel slag can be classified into three types, namely, slowly-cooled slag, wind-cooled slag, and water-quenched slag. 4 Among them, water-quenched slag is a major type in the industry. Many studies have been focused on the utilization of this type of ferronickel slag, 5−14 including those on making construction and building materials, 6,7 producing glass ceramics, 9 and recovering the contained metals (e.g., nickel, cobalt).…”