Optimization of flotation columns to provide added value of local sphalerite ore

Abstract

Sphalerite is the most important mineral in the formation of zinc metal. According to regulation of Ministry ESDM No.5/2017 stated that the minimum grade of zinc concentrates to be exported is 51%. Therefore, it is necessary to do a beneficiation process for sphalerite ore to fulfil the requirements. Sphalerite is hydrophobic mineral, therefore it is the best way to processed sphalerite by flotation. Flotation is the process of concentrating valuable minerals from impurities based on the nature of the mineral surface. Column flotation is a flotation technology without an agitator as a producer of air bubbles like conventional flotation machines. Recovery is the most important factor in flotation and it shows the rate of acquisition of the flotation process. The purpose of this research was to determine the effect of air flow rates (2, 2.5, 3, 3.5, and 4 L / min.), percent solid (7.5%, 10%, 12.5%, and 15%), dose of reagent frother (10, 20, 30 and 40 ppm), and particle size of ore (-80 + 100 #, -100 + 140 #, -140 + 200 #, -200 #) on ZnS recovery. The research was carried out by using a laboratory scale flotation column with 4.6 cm in diameter and 150 cm column height. The flotation reagent used was activator (CuSO4), pH regulator (NaCO3), collector (PAX), and frother (dowfroth 1012). The highest recovery (90.29%) was achieved at a flow rate of 4.0 L/min, while on variation of particle size the highest recovery was 85.55% at (-100+140) #. The increase in percent solid or dilution of pulp is not always followed by an increase in recovery and the highest recovery ((71.26%) was achieved at 7.5% solid. In addition, recovery increases with increasing doses of frother, the highest recovery (86.04%) was achieved at 40 ppm doses of frother.