Perpustakaan Digital ITB

Solvent extraction is currently the most dominant purification technique to separate individual rare earth elements (REE) from aqueous solutions. Industrially, the REE separation process is performed in multiple stages in a series of interconnected cascade mixer-settler circuits to achieve a specified recovery and purity target. Mathematical modeling for piloting circuits enables optimal design and parameter determination. A separation route that utilizes fuzzy technology has been developed and claimed to be superior at separating La and Nd from light REE solutions at an early stages. Due to a limited number of articles detailing the deployment of this technique, this study provides simulations and assessments of the earlier stages of a fuzzy separation route based on the operation of the SGS Minerals Services pilot plant in Lakefield, Canada. The simulation begins with establish empirically a model of equilibrium equations based on laboratory data in the existing literature. The model verification utilized data from cascade solvent extraction at the Idaho National Laboratory, USA. Subsequently, the appropriate software with best iteration capability is determined to perform simulations under certain conditions. This study employs three different software, including Microsoft Excel, MATLAB R2022a, and SIMULINK 10.5. Afterwards, a set of simulations is performed to determine the optimum process parameters on the separation of La and Nd in a cascade mixersettler circuit. The process parameters include the organic and aqueous (O/A) ratio of the extraction stage ranges by 1, 2, and 2.5; the O/A ratio of the scrubbing stage varies by 4, 6, and 10; the pH of the extraction stage differs by 1, 1.25, and 1.5; the acid concentration of the scrub solution diverges by 0.5, 1, and 2M; and the reflux ratio from stripping to scrubbing alters by 5%, 10%, and 20%. The process performance is evaluated from extraction and scrubbing efficiency, as well as purity of raffinate, and organic product resulted from scrubbing. Determination of optimum parameters is performed by utilizing grey relational analysis (GRA). This research exhibit results the reaction equilibrium equations empirical model has the equilibrium constants for La, Ce, Pr, and Nd extraction -3.3733, -2.648, - 2.2943, and -2.1093, respectively. Microsoft Excel is selected for extraction simulation for an O/A ratio of 2.0 at pH 1.5 and an O/A ratio of 2.5 in all pH variation. MATLAB R2022a is decided to perform all scrubbing simulations. SIMULINK 10.5 is chosen to perform extraction simulation for an O/A ratio of 2.0 at pH 1 and 1.25 and an O/A ratio of 1 in all pH variation. The optimum condition to separate La and Nd based on simulation results and GRA is extraction with an O/A ratio of 2.0 at pH 1.5 followed by scrubbing with an O/A ratio of 6 and acid concentration of 1 M. For this separation, reflux from stripping to scrubbing insignificantly increases product purity.