ANALISIS KESETIMBANGAN FASA-FASA OKSIDA PADA PELEBURAN BIJIH NIKEL LATERIT SEBAGAI FUNGSI DARI NISBAH SIO2 DAN MGO DENGAN PENAMBAHAN KALSIN DOLOMIT PADA TEMPERATUR 1450-1550 °C

• Main Author: Maranata Pandia, Darmi
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/65829
• Institution: Institut Teknologi Bandung

The use of nickel is spread in various sectors so that the need for production continues to increase. In ferronickel smelting, the operating temperature determines the effectiveness and efficiency, economy and safety of the process. Operating temperature define by liquidus temperature of slag. The main compositions of ferronickel smelting slag are SiO2 and MgO, so that the ratio of SiO2 and MgO determines the operating temperature in the ferronickel smelting process. In this study, an experiment was carried out to study the effect of calcined dolomite addition on various ratios of SiO2 and MgO on nickel ore in ferronickel smelting on the composition and phase present in slag and its effect on the liquidus temperature of slag. The experiment began with the addition of calcined dolomite variations to nickel ore, namely 2% and 4%, then coal reductors with a stoichiometric composition were added to produce slag with content 8-10% FeO. The smelting process of calcined nickel ore and calcined dolomite is carried out in a platinum envelope with a vertical tube furnace with calcined dolomite variations at temperatures of 1450 °C, 1500 °C, and 1550 °C, respectively. After the melting reaches a time of 120 minutes, the sample is quenched to maintain the phases present in the melting oxide. The experimental specimens are then prepared in the form of mounting using resin. The mounting is then polished for analysis with scanning electron microscope-energy dispersion spectroscopy (SEM-EDS). The results of the experiment showed that solids in the form of olivine in the smelting of nickel ore with SiO2/MgO 1.46; 1.77 and 2.36, as well as solids in the form of silica at the smelting of nickel ore with SiO2 /MgO 2.85 and 3.02. At a ratio of SiO2/MgO below 2.36, 1.46 and 1.77, the addition of dolomite increase the formation of the mass of phases of olivine. This implies that the addition of dolomite to the smelting of nickel ore with a low SiO2/MgO has an impact on an increase in liquidus temperature. Meanwhile, the relatively high ratio of SiO2/MgO, namely SiO2/MgO 2.36; 2,62; 2.85 and 3.02 additions of dolomite decreased the formation of silica. This implies that the addition of dolomite to nickel ore with high SiO2/MgO has an impact on the occurrence of a decrease in liquidus temperature.