| For the low nickel content of laterite,the pyrometallurgical process can be substituted by a hydrometallurgical technical approach.The goal of this probe is to characterize the effect of atmospheric pressure acid leaching on different ore layers,namely limonite ore and saprolite ore in Morowali ore.This study also aims to describe the extraction of laterite nickel ore using sulfuric acid.This study employed the leaching atmospheric approach with modifications in acid to ore ratio,temperature,duration,solid/liquid ratio,and leaching stirring rate.Mineralogy investigation using XRD(X-Ray Diffraction)revealed the existence of goethite,hematite,and lizardite minerals in limonite,whereas antigorite and quartz were found in saprolite ore.The findings of chemical analysis employing the impact of acid to ore parameter on-time reaction revealed that the extraction of nickel content in the sample could reach 98.86% for limonite ore and 99.19% for saprolite ore with acid to ore ratio of 1.75 for 6 hours.The leaching study revealed that the increase in acid concentration was directly proportionate to the increase in nickel recovery.The comparison of the extraction rate of limonite ore and saprolite ore with the influence of temperature revealed that a temperature of 80 ℃ could dissolve 96.11% Ni in limonite ore while saprolite had a Ni recovery of 98.02%.The leaching findings revealed that increasing the leaching temperature was directly related to increasing nickel recovery.Stirring speed rates in the range of 100-500 rpm depicted no distinguishable impact on nickel and cobalt leaching rates.The results showed that under the optimized leaching conditions(1.5 acid to ore ratio,leaching duration: 5 hours,leaching temperature 80 ℃,solid to liquid ratio 1:3,and stirring speed 300 rpm)it was possible to extract 96.12% of nickel in limonite ore,while for saprolite,the optimum condition(1.25 acid to ore ratio and leaching duration for 4 hours)is possible to get 98.20% nickel recovery.ANOVA(Analysis of Variance)calculation is used to determine the most influential factors in the leaching process of limonite and saprolite ore.The most influential factors for atmospheric leaching of limonite were the ratio of acid to ore,temperature,and quadratic value of temperature,while for saprolite were ratio of acid to ore,temperature,and quadratic value of acid to ore ratio.Based on the contour plot and response surface,the optimum leaching conditions for limonite ore were obtained at a temperature of 85℃,an acid to ore ratio of 1.42 in 2.6 hours with a nickel recovery of 94.68%.While the optimum condition of saprolite was obtained at a temperature of 72.27 ℃,the ratio of acid to ore was 1.12 in 2.4 hours with nickel recovery 95.84%.35 figures,14 tables and 60 references included in this thesis. |
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