STUDY OF THORIUM EXTRACTION FROM MAMUJU’S THORITE ORE BY ACID DIGESTION AND RECOVERY OF THORIUM HYDROXIDE BY CHEMICAL PRECIPITATION METHOD

• Main Author: IQBAL NUR SAID (NIM : 12513051), MOCH
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/28987
• Institution: Institut Teknologi Bandung

Thorium is a radioactive metal that can be utilized as an energy source for nuclear power plants, as an alternative to substitute uranium. Based on the data from National Nuclear Energy Agency of Indonesia (BATAN) in 2015, Indonesia has 130,947 tons of thorium reserves. According to Presidential Regulation No. 22 of 2017 about the General Policy of National Energy, Indonesia is targeted to have a total power plant capacity of 430 Giga Watt by Year 2050 in which 31% of the total capacity must be originally from Renewable Energy. This situation has promoted thorium-fueled nuclear power plants as one of the considerable options to realize that target. In this research, extraction of thorium from thorite ore of Mamuju Regency, West Sulawesi Province through acid digestion and precipitation method is studied. <br /> <br /> <br /> <br /> A series of experiments has been performed to extract thorium from Mamuju’s thorite ore at various conditions. The experiments started with ore size reduction process by crushing using jaw crusher and milling with a rod mill. The ore sample was then acid digested using 95% sulfuric acid (H2SO4) at 160°C to convert thorium (Th), iron (Fe) dan rare earth metals (REE) within the ore into sulfate compounds which are soluble in water. The acid digestions were carried out under variations of stirring time and solid/liquid ratio (g/mL). The thorium recovery from leaching solution is carried out by precipitation by pH neutralization using ammonium hydroxide (NH4OH) under variations of pH and precipitation temperatures. Dissolved iron(II) as impurities was pre-oxidized by addition of H2O2 in order to obtain lower pH for precipitation. <br /> <br /> <br /> <br /> The experimental results showed that the best conditions of the acid digestion were obtained at solid/liquid ratio (g/mL) of ½ for 60 minutes with Th, Fe and LTJ extractions of 82.47%, 80.08%, and 83.31%, respectively. The highest thorium precipitation percentage of 95.47% was obtained at pH 4.5 at room temperature (26±1°C). At pH 3.5, the increased of temperature from roomtemperature to 80 oC with and without pre-oxidation did not significantly influence iron precipitation and tend to reduce Th and REE precipitation. The pre-oxidation by using hydrogen peroxide (H2O2) solution with a dosage of 2&#61620; stoichiometry for 1.5 hours at room temperature increased Fe precipitation percentage from 93.08% to 99.93% at pH 4.5 and decreased percentage of REE precipitation from 21.05% to 1.25% at pH 3,5 at temperature 80oC. <br />