PRELIMINARY STUDY OF LEAD EXTRACTION FROM ESP DUST, S-FURNACE (S-EP) OF PT. SMELTING GRESIK THROUGH DUST LEACHING IN AMMONIUM ACETATE SOLUTION UNDER ATMOSPHERIC PRESSURE

• Main Author: ZULKARNAIN AZWAR , MUHAMMAD
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/12436
• Institution: Institut Teknologi Bandung

PT. XYZ uses Mitsubishi Process to treat copper concentrate to produce copper anode. This process implements three furnaces that work continuously (i.e. Smelting Furnace, Slag Cleaning Furnace, and Converting Furnace). In addition to concentrate, dust recycled from the previous smelting process is also introduced to the S-Furnace. In the recent times, PTS has been facing problems due to the increase of impurities contents in the concentrate and the decrease of Cu content of the concentrate. One of the impurities that causes the problems is lead (Pb). High level of lead in the concentrate would result in copper anodes with high content of lead. The high content of lead in the copper anode can generate the problems during copper electrorefining, such as anode passivation and produces anode slimes which are not suitable with market specification. Moreover, the high content of lead in the concentrate increases the lead content of S-EP dust, so that the dust cannot be recycled to the S-Furnace increasing content of impurities especially Pb in anode copper impact from high content of Pb in dust S-furnace which recycled to S-Furnace. Several research projects have been carried out by PTS to extract Pb from S-EP dust which include Pb reduction in dust by coke and leaching of dust in sulfuric acid solution under atmospheric pressure. The results of the dust leaching in sulfuric acid are not satisfactorily in which lead content in the leach residues is only about 32% (targeted 80%). The low percentage of lead in the leach residues is due to the high amount of undissolved elements in the dust such as Fe, As, Sb, Se, Ni, Zn that makes the high concentrations of these elements in the leach residues. This research is a preliminary study, aimed at extracting Pb from the S-EP dust through hydrometallurgical route by means of dust leaching in ammonium acetate solution (CH3COONH4) under atmospheric pressure. The objective of the dust leaching in the ammonium acetate solution is to selectively dissolve Pb as much as possible under which the dissolutions of the other elements in the dust are limited. The leaching of the dust samples have been performed in two stages in order to maximized Pb recovery. Series of experiments have been done to study the influences of ammonium acetate concentration, leaching temperature, and solid percentage on the lead recovery and the dissolutions of other elements in the dust especially Cu and Zn. The investigation results show that the highest extraction percentage of Pb (i.e. 95%) is obtained from the two-stage leaching with particle size fraction of -200#, 20% solid percentage, 3M CH3COONH4 and leaching temperature of 40 degrees C. Increasing ammonium acetate concentration above 3M did not significantly affect Pb extraction and even increased the dissolutions of Cu and Zn. From kinetic study, it has been found that the leaching process is controlled by CH3COONH4 diffusion through un-reacted solid product with activation energy of 3,03 kcal.