Neodymium (Nd) is one of the rare-earth elements (REEs) found in significant amount within monazite and bastnasite minerals. Nd is a ferromagnetic metal that is often used as a material to produce magnet, commonly known as a permanent magnet. Neodymium is alloyed with other metals such as iron and boron to form one of the strongest types of permanent magnet. This research aim is to study the reduction process of Nd-oxide into Nd-metal through the metallothermic process. The Nd metal product is expected to fulfill the material specification for a permanent magnet. Thermodynamics simulation of Nd reduction into its metal was conducted using ITB"s licensed Factsage software. A validation experiment was conducted only to the Nd metal resulting simulation. The simulations involved some parameters, i.e. temperatures (600, 700, 800, 900, 1000, 1100 and 1200 °C), types of fluxes (CaCl2 and Ca(OH)2), composition of the reducing agent (1x, 2x dan 3x of the stoichiometric calculations), types of the reducing agents (Ca and Mg), and types of feeds used (Nd-oxide and Ndchloride). The thermodynamic simulation shows that Nd metal was produced in a condition where the temperature should be1100-1200 °C using Ca as the reducing agent and CaCl2 as the flux, while the amount of reducing agent has no effect on the resulted product. Validation result of the simulations shows that the Nd metal is formed up to 49% metal in a non-oxidative condition.

SARIMonasit yang banyak ditemukan bersama dengan mineral kasiterit dan mineral zirkon, dapat diolah menjadi campuran logam tanah jarang oksida kemudian dipisahkan menjadi masing masing logam oksida yang selanjutnya dapat diproses menjadi logamnya. Logam tanah jarang ini banyak digunakan untuk bahan material maju. Dalam penelitian ini, ytrium oksida yang diektrak dari monasit diperoleh dari Pusat Sains dan Teknologi Akselerator-Badan Tenaga Atom Nasional (PSTA-BATAN) mempunyai kadar 73,53%, dilarutkan dalam asam klorida dengan variasi konsentrasi dan waktu kemudian diendapkan dengan amonia klorida menjadi ytrium klorida. Ytrium klorida kemudian dilebur melalui proses peleburan metalometri menggunakan logam Ca atau Mg serta NaCl dan CaCl2 sebagai aditif, menghasilkan logam ytrium. Hasil percobaan menunjukkan bahwa pembetukan YCl3 diperoleh pada kondisi pelarutan HCl 0,4 N dengan waktu pelarutan 45 menit. Selanjutnya, peleburan dengan proses metalotermik, menggunakan reduktor Mg (1:1) dengan aditif NaCl dan CaCl2, didapat logam yttrium. Hasil analisis SEM menunjukkan teridentifikasinya logam ytrium sebanyak 5,40 gram. Proses metalotermik ini dapat diterapkan untuk reduksi logam tanah jarang lainnya.Kata Kunci: monasit, logam tanah jarang, ytrium, proses metalotermik. ABSTRACT Monazite which is commonly associated with cassiterite and zircon minerals, can be processed into