metals Review Nickel Laterite Smelting Processes and Some Examples of Recent Possible Modifications to the Conventional Route Ender Keskinkilic Department of Metallurgical and Materials Engineering, Atilim University, 06830 Ankara, Turkey;
[email protected]; Tel.: +90-533-302-9510 Received: 16 July 2019; Accepted: 1 September 2019; Published: 3 September 2019 Abstract: The treatment of laterites has been a research hotspot in extractive metallurgy over the past decades. Industrially, the pyrometallurgical treatment of laterites is mostly accomplished with a well-established method, namely, the rotary kiln–electric arc furnace (RKEF) process, which includes three main operations—calcination, prereduction, and smelting—followed by further refining for the removal of impurities from the raw ferro-nickel. As indicated in many studies of the RKEF process, the major downside of this method is its high energy consumption. Efforts have been made to lower this consumption. Furthermore, several new processes have been proposed. Among these, low-grade ferro-nickel production is regarded as the most widely and industrially used process after traditional RKEF operation. Although not widespread, other alternative processes of industrial scale have been generated since the start of the millennium. Recently, certain innovative processes have been tested either in the laboratory or at pilot-scale. In this paper, a literature review related to the smelting of laterites is made, and an emphasis on new processes and some examples of new developments in the RKEF process are presented. Keywords: laterite; smelting; RKEF process; low-grade ferro-nickel 1. Introduction According to a review published by Diaz et al., oxide-type nickel ores accounted for 64% of land-based nickel ores, but more than 60% of nickel production was based on the matte smelting of sulfide ores in 1988 [1].