Effect of Sodium Carbonate on the Reduction Process of Nickel Slag from Sulawesi

Abstract

Nickel slag is one of the results of the nickel ore smelting process which is still a waste and has not been used optimally. Considering the amount of nickel slag waste in Indonesia, the effort to utilize it into a more valuable product becomes very important. Therefore, in order to extract the precious metal content in nickel slag, this study aims to analyze the effect of adding sodium carbonate in the reduction process of nickel slag. In this study, the reduction process is carried out using coal as a reducing agent, where the variation of the reduction temperature is 800, 900, and 1000°C; while the variation of the ratio between nickel slag and additives is 1:1, 1:2, and 2:1. The XRD analysis results show that the temperature rise up to 1000 °C and the addition of sodium carbonate will increase the amount of sodium magnesiosilicate up to 29.4% and also hematite up to 25.1%. The same thing happened in samples with a ratio of 1:1 and 1:2 where the amount of sodium magnesiosilicate increased from 29.4% to 30.0% and hematite from 25.1% to 28.8%.

Reverse leaching of magnesium from ferronickel slag using alkali solvent NaOH

“…1 that the three strongest diffraction peaks are forsterite (Mg 2 SiO 4 ), fayalite (Fe 2 SiO 4 ) and enstatite (MgSiO 3 ) compounds. This XRD result is appropriate with previous researchers who have characterized the ferronickel slag [15,18,22]. Moreover, morphological structure and mapping from SEM-EDS analysis, Fig.…”

“…Research that has been done to process ferronickel slag waste has been carried out by several researchers, both with pyrometallurgical, hydrometallurgical processes and a mixture of both pyro-hydrometallurgy. Several studies with pyrometallurgical processes are by roasting or reducing ferronickel slag with a mixture of additives NaOH [13], Na 2 CO 3 [18] and Na 2 SO 4 [12]. The roasting process is carried out by adding an additive of Na 2 CO 3 for the decomposition of forsterite and enstatite into magnesium oxide and sodium silicate so that it will facilitate the process of separating precious metals, especially magnesium [4].…”

The Product Characteristics of Treated-Ferronickel Slag Produced by Alkali Fusion and Carbothermic Process

“…The compounds contained in the product from alkali fusion, which is named as a roasted product in this study, are quartz (SiO2), sodium silicate (Na2SiO3), fayalite (Fe2SiO4), and hematite (Fe2O3). The sodium silicate (Na2SiO3) appears to form during the alkali fusion process; this was not identified in the previous study [4]- [5].…”

“…Arum Cahyanurani S. et al, [4] reported that the valuable metals in the slag are difficult to be separated due to their bonding in the silica-iron matrix in the fayalite phase, which is a dominant phase in ferronickel slag. Moreover, M. D. Alfariz et.…”