Application of Gold Adsorption Kinetic Model to Find Out a Relationship between Carbon Transfer Rate with Gold Adsorbed on Activated Carbon and the Operation Variables of CIL Process at PT Antam Tbk UBPE Pongkor

• Main Author: ZAMZAM J. (NIM : 22109302), AGUS
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/19837
• Institution: Institut Teknologi Bandung

Carbon-in-leach (CIL) process is used to recover gold and silver at gold processing plant PT Antam Tbk UBPE-Pongkor. In the CIL process, cyanidation leaching and carbon-adsorption process occur simultaneously. Carbon management becomes an significant aspect in the operation of the CIL. Despite the simplicity of the process, the fluctuation of operation variable can be a very complex, so that it is not easy to predict the result of an operational change. Therefore, the modeling would be useful to predict the influence of major variable changes on the CIL circuit. The available adsorption kinetic models are evaluated to establish which one shall be used in this research. <br /> <br /> <br /> To determine the model equations that can be applied at the CIL circuit, several kinetic model have been selected. The selected model is the kn model, Nicol-Fleming model and Freundlich film-diffusion model (Johns model). In this research, the real plant operating data are examined if they are suitable with these models. For this aim, a Saymer mass balance equations were arranged to calculate the average CIL adsorption rate in each adsorption tanks. The adsorption rate obtained then plotted to each model parameters. The correlation coefficient R is used to validate the models. To complete model calculation, the adsorption isotherm parameters are required. The isotherm parameters were obtained from independent equilibrium tests. The suitability isotherm model is also determined by using the best value of the correlation coefficient R. <br /> <br /> <br /> Empirical adsorption kinetic model based on Johns model then can be obtained as the suiable model. The model has a good agreement with real CIL Plant#1 data. And as previously produce from an independent equilibrium test, Freundlich isotherm parameters have been used as appropriate equilibrium constant for Johns model, which is have Kf= 5040,8 m3/tonC and Freundlich parameter n=1.6. To illustrate its application, the model was used to investigate the effect of major operation variables such as mill feed rate, mill feed grade, and mill feed persen solid on the carbon transfer rate as a graphical functions. Gold grade of loaded carbon can be predicted. Moreover, the model can also be used to set the limit of critical gold loading on carbon as a different way for CIL operational control. Plant data verification then were performed, it can be seen that prediction for total adsorption time before elution process is 29 hours, which is fit with actual data of 28-32 hours in 2012. Average gold contained on Loaded Carbon of TNK#3 Plant#1 in 2012 is 8% lower than model calculation, and as a prediction this value is still acceptable. Gold concentration on carbon in CIL tanks in 2012 is about 70-72% of its limit critical concentration.