BENEFICIATION STUDY OF HIGH SILICA CONTENT BAUXITE FROM TAYAN – WEST KALIMANTAN BY REVERSE FLOTATION METHOD

• Main Author: Rahman Abdillah, Fatur
• Format: Final Project
• Language: Indonesia
• Subjects: Metalurgi
• Online Access: https://digilib.itb.ac.id/gdl/view/49141
• Institution: Institut Teknologi Bandung

Bauxite is the principal ore of alumina and the main raw material in aluminum industry. Bauxite is a mineral mainly composed from the mixture of hydrous aluminum oxyde and aluminum hydroxide such as Gibbsite, Boehmite, and Diaspore. Indonesia is one of the countries with high bauxite reserves and in 7th place together with China. In Indonesia, lateritic type bauxite is predominantly occur in Kalimantan island especially in West Kalimantan Province. Processing alumina with Bayer Process is the first step in producing aluminum. There are some requirements of feed for Bayer Process that must be considered such as grade of Al2O3 > 51%, SiO2 <7%, and A/S ratio >10. Bauxite from Tayan, Kalimantan Barat has a fairly high silica content which will reduce the capacity of Bayer Process and will be the main impurity contained in residue of digestion process that is red mud, so the beneficiation method is needed to reduce the silica content in the bauxite. This study can be used as one of the alternative bauxite beneficiation method using reverse flotation. The aim of this study is to reduce the silica content and increase the alumina in bauxite so that it qualifies as a Bayer Process feed. This experiment was started with bauxite preparation to obtain the fraction size; -63 +53 µm, -53 +44 µm, -44 +37 µm, and -37 µm followed by first characterization using X-Ray Diffraction (XRD), X-Ray Flourescence (XRF), SEM-Mapping, and Atomic Absorption Spectroscopy (AAS) to know the dominant mineral, chemical compound, and the presentation of chemical elements contained in bauxite. This experiment were carried out in 1375 mL flotation cell with 400 gr/ton Dodecylamine (DDA) reagent used as the collector, 0.1 mL of Dowfroth 1012 as the frother, 1500 gr/ton sodium hexametaphosphate as the dispersant, Na2CO3 as the pH modifier for produces a pH of 10, and modified starch as the depressant is used one of the variables in the experiment. There were three variables in this research, those were solid percentage, size fraction of the feed, and the depressant dose. Solid percentage of the feed in this research varied; 15%, 20%, 25%, 30%. The size fraction of the feed varied, started from -63 +53 µm, -53 +44 µm, -44 +37 µm and -37 µm. The depressant dose varied; 200 gr/ton, 400 gr/ton, 600 gr/ton, and 800 gr/ton. The results showed that percent increase in solid was able to give the best result in 25% solid with alumina content and recovery in concentrates were 54,9% and 67.34%. The use of various sizes of fraction as the experimental feed showed that the finer size of the feed, the higher content and recovery of alumina in concentrate. The fraction with size -37 µm was able to produce alumina contents and recovery in the highest concentrations about 55.76% and 69.52%. The increase of depressant did not give significant effect on the separation of alumina and silica in bauxite despite there was tendency of increasing contens and recovery of alumina in the concentrate.