The effect of NaOH (natrium hydroxide) to slag nickel pyrometallurgy in different temperature and additive ratio

¹ Center of Minerals Processing and Corrosion Research, Department of Metallurgical and Materials Engineering, Universitas Indonesia, Depok 16424, Indonesia
² Department of Mechanical Engineering, Politeknik Negeri Jakarta, Depok 16425, Indonesia

^* Coresponding author: jwsono@metal.ui.ac.id

Abstract

Nickel slag is one of the output from nickel ore smelting. In Indonesia itself, further utilization of valuable elements in it is needed to be processed. Nickel slag also has Fayalite (Fe₂SiO₄) content where nickel and copper are spread evenly on the iron matrix silica which then complicate the process of increasing nickel and copper content. The addition of Sodium Carbonate (Naoh) is used as a silica binder and as an alternative way to increase nickel and copper content. In this research, pyrometallurgy is done by coal as a reductor in 800°C, 900°C and 1000°C operating temperature and ratio between nickel slag and additive equal to 1:1, 1:2, and 2:1. Based on this study, it is obtained that with the increasing of temperature without additive, there is still found the presence of silica in a form of Fe-rich Forsterite (FeMgSiO₄) and Olivine (NiMgSiO₄). Whereas with the presence of additive in slag nickel pyrometallurgy with a different temperature and ratio, it is seen that there is a phase formation of Sdoium Magnesiosilicate (Na₂MgSiO₄), Magnesium Oxide (MgO) and Wustite (FeO) which proved the binding of silica and has liberate iron that helps the process of increasing nickel and copper content.