#TITLE_ALTERNATIVE#

• Main Author: AGUNG PITOYO (NIM : 12104027); , WAHYU
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/19636
• Institution: Institut Teknologi Bandung

Low grade of limonite ore has not been processed in Indonesia yet; most of them have not been mined and parts were exported as nickel price increases. Processing of the low grade limonite ore within the country would increase the added value, and improving the optimization and conservation of the nickel laterite resources in Indonesia. Heap leaching is considered as one of the cost-effective to treat the low grade limonite ore due no requirement to provide milling facilities, agitation, counter current decantation thickeners and tailing dam, more simple operation, cheaper maintenance and control system. In this research, the possibility of implementing heap leaching method for the extraction of nickel from Pomalaa limonite ore was investigated by means of column leaching test and simulation using METSIM 17.07 software. <br /> <br /> Series of column leaching test have been performed using agglomerated ore samples under the variations of sulphuric acid concentrations, ore type and the height of ore heap in column for 55 days. The flow rate of leaching agent through the column was adjusted at a constant value by using a peristaltic pump from Ismatec. The concentration of sulphuric acid during leaching were measured by acid-base titration and maintained at a constant value. Analysis of dissolved nickel, cobalt and iron were periodically performed by AAS (Atomic Absorption Spectrophotometer). The simulation by METSIM were carried out by varying sulphuric acid concentration, chemical and mineral compositions of the ore to predict extraction percentages of nickel and cobalt and dissolved iron, magnesium and aluminium as well as sulphuric acid consumption per ton dry ore. <br /> <br /> From the limonite column leaching test, nickel extraction percentages of respectively 51.6% and 57.6% were obtained by the leaching with 0.5 and 0.75 molar of sluphuric acid after 52 days. Under the same ore composition, sulphuric acid concentrations and leaching duration, nickel extraction percentages of respectively 52.4% and 53.2 were obtained from the simulation. Dissolved iron by the column leaching at acid concentration of 0.5 and 0.75 molar were 43.5 and 54.3, respectively. The column leaching of saprolite ore sample at the acid concentration of 0.5 molar, exhibited faster dissolution rate of the saprolite ore, however, extraction percentage of nickel from the saprolite ore was only slightly higher than that of limonite after 55 days of leaching. The simulation result showed the maximum nickel extraction percentage of 78.6 using 2 molar of sulphuric acid, after a 254 day of leaching which was unchanged significantly by the increased of the leaching duration. The increased of sulphuric acid concentrations of the leaching duration from 0.5 molar to 2 molar, enhanced the acid consumption per ton of dry ore from 71 Kg/ton to 330 Kg /ton. The content and ratio of goethit (&#945;-FeOOH) to hematite (Fe2O3) was found to increase the extraction percentage nickel and also the sulphuric acid consumption.