Studi Pemisahan Thorium dari Besi dan Logam Tanah Jarang dalam Larutan Asam Nitrat dengan Ekstraksi Pelarut Menggunakan Ekstraktan Trioctylphosphine Oxide
Authors: Briliant Briliant , Mubarok Mohammad Zaki , Trinopiawan Kurnia , Prassanti Riesna 
Published: January 2018

AbstrakSerangkaian percobaan ekstraksi pelarut untuk memisahkan thorium dari besi (Fe) dan logam tanah jarang (LTJ) menggunakan trioctylphosphine oxide (TOPO) dilakukan dengan variasi konsentrasi asam nitrat, waktu ekstraksi, nisbah ekstraktan terhadap diluen (g/mL), dan variasi nisbah volume larutan organik terhadap volume larutan aqueous (O/A) serta variasi konsentrasi asam pada proses stripping. Konsentrasi awal thorium, besi, dan LTJ dalam larutan umpan diukur masing-masing dengan Inductively Coupling Plasma (ICP), Atomic Absorption Spectroscopy (AAS), dan Ultraviolet Visible Spectroscopy (Spektro UV-VIS). Konsentrasi asam nitrat divariasikan pada 1M, 2M, 3M, 4M, dan 5M. Waktu ekstraksi divariasikan pada 2, 5, 10, 15, dan 20 menit, sementara nisbah ekstraktan terhadap diluen (g/mL) divariasikan pada 2:100, 3:100, 4:100, 5:100, dan 6:100 dengan variasi nisbah O/A yaitu 1:3, 1:2, 1:1, 2:1, dan 3:1. Pada tahap stripping dilakukan variasi konsentrasi asam nitrat pada 0,1 M; 0,2 M; 0,3 M; 0,4 M; dan 0,5 M. Hasil percobaan menunjukkan kondisi terbaik dicapai pada konsentrasi asam nitrat 3M, waktu ekstraksi 10 menit, nisbah ekstraktan terhadap diluen sebesar 5:100 (g/mL), dan nisbah O/A sebesar 1:1 sehingga didapatkan persen ekstraksi Th sebesar 97,26%, Fe sebesar 7,97%, dan LTJ sebesar 62,15% dengan nilai βTh-Fedan βTh-LTJ masing-masing sebesar 273,62 dan 14,43. Pada percobaan stripping didapatkan persen stripping Th tertinggi sebesar 51,37% pada konsentrasi asam nitrat 0,3M dengan persen stripping Fe dan LTJ masing-masing sebesar 2,72% dan 2,55%. AbstractA series of solvent extraction experiment to separate thorium(Th) from iron (Fe) and rare earth metals (REE) using trioctylphosphine oxide (TOPO) conducted with variations of nitric acid concentration, extraction time, ratio between exctractan and diluent (g/mL), and ratio between organic solution and aqueous solution volumes (O/A), and variation of nictric acid concentration in stripping process. Thorium, iron and rare earth metals early concentration in solution feed were measured by using Inductively Coupling Plasma (ICP), Atomic Absorption Spectroscopy (AAS), dan Ultraviolet Visible Spectroscopy (UV-VIS Spectro) respectively. The nitric acid concentration was varied at 1M, 2M, 3M, 4M, and 5M. The extraction time was varied at 2, 5, 10, 15, and 20 minutes, meanwhile the ratio between extractan and diluent (g/mL) was varied at 2:100, 3:100, 4:100, 5:100, and 6:100 with O/A ratio at 1:3, 1:2, 1:1, 2:1, and 3:1. At stripping stage, the nitric acid concentration was varied at 0.1M; 0.2M; 0.3M; 0.4M; and 0.5M. The result of the experiments show that the best condition was obtained on 3M nitric acid concentration, 10 minutes extraction time, 5:100 (g/mL) extractan and diluent ratio, and 1:1 O/A ratio, that resulted in 97.26% Th extraction, 7.97% Fe extraction, and 62.15% rare earth metals extraction with βTh-Fe and βTh-REE value 273.62 and 14.43 respectively. On the stripping experiment, the highest Th stripping percentage obtained as much as 51.37% at 0.3M nitric acid concentration with Fe and REE stripping percentage up to 2.72% and 2.55% respectively.