EFFECT OF SEAWATER USAGE IN LEACHING OF NICKEL LIMONITE ORE WITH HYDROCHLORIC ACID SOLUTION AT ATMOSPHERIC PRESSURE ON NICKEL EXTRACTION PERSENTAGE AND ACID CONSUMPTION

• Main Author: SAGITA AZWAR (NIM : 12512043), YOGI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31750
• Institution: Institut Teknologi Bandung

Mostly main mineral of nickel limonite ore in which nickel is found is goethite ((Fe,Ni)OOH). During leaching in acid solution, nickel is dissolved from goethite which occurs simultaneously with iron dissolution. In the acid leaching of nickel limonite at atmospheric pressure, dissolved iron is a major problem because it is not spontaneously re-precipitated during leaching and leads to a high acid consumption of this process. In this research, iron precipitation in hydrochloric leach solution of limonite ore was attempted by using seawater which contains Na+ and Ka+ which are able to form non-soluble complex of iron precipitate and simulataneously regenerates acid. The influence of seawater usage in hydrochloric acid leaching of limonite ore at atmospheric pressure on the nickel extraction percentage and acid consumption was investigated. <br /> <br /> Series of nickel limonite acid leaching in hydrochloric acid solution by using seawater were carried out for 12 hours under variations of temperature, solid percentage and the initial amount of the added hydrochloric acid. The best condition of the leaching experiment is determined at the highest nickel extraction percentage with relatively lower co-extracted iron. Leaching experiment of the nickel limonite ore without using of seawater was also performed to quantitatively determine the influence of seawater usage on the nickel extraction and acid consumption. Acid consumption was calculated from the data of mol acid reacted during leaching based on the data of metals extraction percentage and stoichiometry of the metals dissolution. <br /> <br /> Result of the leaching experiments demonstrated that the usage of seawater enhances nickel extraction percentage from 84.58% to 89.9%, reduces co-extracted iron from 92.01% to 61.57% and acid consumption for leaching from 951.2 kg/ton dry ore down to 644.2 kg/ton dry ore. The best result was obtained at leaching temperature of 95oC, solid percentage 10% (w/v), initial added acid of 900 kg/ton-ore at ore size fraction of -65+100#. The increased of temperature and the initial amount of added acid tend to increase nickel extraction, meanwhile the increased of solid percentage used in the leaching resulted in the lowerin of extracted nickel.