Increasing nickel from nickel slag with Na₂SO₄additives and palm kernel shell charcoal reductors using the pyrometallurgical method

Indonesia has rich deposit of nickel ore and nickel slag is one of the hazardous waste from nickel smelting industries. The nickel slag has valuable elements in it, therefore further utilization is needed. In this research, the valuable elements was beneficiated by pyrometallurgical process where the palm kernel shell charcoal was used as reducing agent which considered as better option because of its environmental friendly characteristic and the functional properties resemble to fossil fuels. The pyrometallurgical process is done by heating the nickel slag size #200 mesh using furnace Carbolite CWF 11/13 with the mass ratio palm kernel shell are 5%,10%, 15%, 20% respectively and the addition of sodium sulfate 10% with reduction temperature at 1000°C for 60 min. The result of the reduction then follows with magnetic separation using Nippon magnetic dressing type 39000. The result was tested with AAS which showed the content of nickel and copper decline as the ratio of palm kernel shell charcoal increases. Based on the result, optimal parameter for nickel content is obtained by 15% palm kernel shell at 1000°C for 60 min, the optimum dosage of palm kernell shell charcoal with the addition sodium sulfate is 15% where the valuable content is obtained with 0.126%Ni and 5.13% Fe.