THE DECOMPOSITION OF BANGKA ISLAND MONAZITE USING CAUSTIC FUSION TECHNIQUE

• Main Author: Machruf, Bachtiar
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69394
• Institution: Institut Teknologi Bandung

Rare earth elements (REE) are a group of lanthanides that includes scandium and yttrium. In Indonesia, REE can be found as monazite on Bangka Island and in the Ketapang area of West Kalimantan. The REE process from minerals generally begins with beneficiation and continues with decomposition, leaching, precipitation, and purification. The decomposition process of treating rare earth minerals is unique because it is not common in hydrometallurgical processes. In this study, the caustic fusion method with NaOH was used to investigate the decomposition of monazite from PT Timah. A series of experiments on the decomposition of monazite using the caustic fusion technique was carried out to investigate the effect of baking temperature, baking time, and particle size on percent phosphate removal, REE, and thorium recovery. Each caustic fusion process was performed in a corundum crucible introduced into a muffle furnace at a NaOH/monazite ratio of 1:1. After the caustic fusion process, the experiment continued with the water leaching of the caustic fusion samples. After being separated, the water leaching residue was washed, calcined, and then sent for X-Ray Fluorescence analysis to determine the composition and content of the sample. The percentage of phosphate removed from monazite ore increased with increasing caustic fusion temperature, with an optimal value of 96.68% at 600oC. When the caustic fusion temperature was raised, the percent recovery of REE and thorium changed insignificantly. The percentage of phosphate removal increased from 96.68% to 97.22% at a baking time of 2 to 3 hours, then slightly decreased to 97.03% at a baking time of 4 hours. Reducing the particle size to 200# improved phosphate removal, REE, and thorium recovery.