The effect of pre-treatments to the nickel limonite leaching using dissolved gaseous SO₂-air

The Effect of Alkali Roasting Pretreatment on Nickel Extraction from Limonite Ore by Using Dissolved SO2-Air

“…The leaching process was carried out at pH 1 and 3, a temperature of 55 and 80 °C for 180 min. As a reference, the optimum condition of Ni selectivity over iron was identified as pH 3 and temperature of 80 °C in a previous study [14]. The current work investigates the effect of lower pH and temperature.…”

“…The dissolved SO 2 -air method does not require the use of strong acids. The dissolved SO 2 -air approach for limonitic ore extraction has been proved in a previous study by the Authors [14,17]. Conducted at very mild conditions, including a low temperature of 55 to 80 • C and atmospheric pressure, a leaching recovery as high as 21% was obtained.…”

“…While the recovery values summarized in Table 3 give the impression that the dissolved SO 2 -air to be not very promising, an economic assessment may nevertheless be needed to verify the overall economics of the processes in Table 3. During the leaching process, there are proposed mechanism reaction of SO 2 occurred in the solution [27] (Equations (9)- (14)). The formation of a peroxo-monosulfate species (SO 5…”

“…The utilization of dissolved SO 2 -air during the extraction of nickel from laterite ore at atmospheric pressure has been known to provide a high nickel to iron selectivity [14]. Iron and other impurities may also be leached from laterite and are therefore regarded as unwanted byproducts in the nickel hydrometallurgical recovery process.…”