The variation of Na₂SO₄mass percentage on the content and recovery of Ni and Fe in the direct reduction process of Indonesia's low-grade laterite nickel ore

The trade for stainless steel is continually increasing. Nickel is one of the decisive elements of stainless steel making. Nickel can be produced through the pyrometallurgical process route from its ore. However, coeval, nickel sulfide ore reserves which are the essential source of high-grade nickel are increasingly rare. So, the alternative processing route from laterite-type of nickel ore is a solution. One of the alternative methods to process laterite-type of nickel ore is by direct reduction. The direct reduction process utilizes CO gas as a reductant. This study was conducted by directly reducing the low grade of laterite nickel ore with the variation of Na2SO4 dosage. This research aimed to determine the content and recovery of nickel and iron elements in the direct reduced product. First, the mixture of low-grade laterite nickel ore, coal, Na 2SO4 with a ratio of 100: 50: 17 was formed into pillow-like shape briquettes. Starch was used as a binder. The variations of Na2SO4 dose of as selective agent used in this research were 10% wt, 20 wt%, and 30 wt%. The direct reduction process was conducted within the silicon carbide crucible at 1400°C for 6 hours. The Then, the direct-reduced products were tested by using EDX and XRD. The nickel contents in the direct reduced products were 5.75%, 1.23%, and 4.31% for 10, 20, and 30 wt% Na2SO4, respectively. Differently, the iron contents in the direct reduced products were 52.84%, 11.07% and 11.26% for 10, 20, and 30 wt% Na2SO4, respectively. The Ni recovery were 95.66%, 93.1%, and 91.86% for 10, 20, and 30 wt% Na2SO4, respectively. The phase of nickel and iron contained in the direct reduction product is an alloy of Fe-Ni.