Suchergebnisse

Dua sumber LTJ berasal dari mineral seperti monasit dan senotim. Ketersediaan LTJ di kerak bumi relatif sedikit, tersebar dan jarang terjadi dalam bentuk bijih. Dalam penelitian ini bahan baku yang digunakan adalah campuran konsentrat LTJ yang berasal dari PT. Monokem Surya. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh konsentrasi H2C2O4, kecepatan pengadukan dan suhu terhadap kemurnian dan pemungutan LTJ dari campuran konsentrat LTJ. Percobaan dilakukan dalam lima langkah: (1) Fusi alkali, proses dilakukan selama 3 jam pada suhu 450oC, dengan rasio padatan NaOH terhadap campuran konsentrat LTJ sebesar 1:1, untuk memutuskan ikatan fosfat; (2) ) Pelindian fosfat dalam produk fusi alkali menggunakan aquadest pada suhu 80oC; (3) Residu pelindian aquadest dilakukan proses perlindian menggunakan 6 M HCl selama 2 jam untuk melarutkan LTJ pada 90oC; (4) Menghilangkan kotoran seperti uranium dan thorium dengan mengendapkannya menggunakan NH4OH pada pH 1; (5) Presipitasi LTJ dari filtrat yang dihasilkan dari butir (4) menggunakan H2C2O4. Didapatkan hasil LTJ dengan kemurnian 96% dan pemungutan sebesar 95% pada konsentrasi H2C2O4 8,11%, kecepatan putar pengaduk 500 rpm, dan suhu 70oC.Two sources of REEs are from mineral monazite and xenotime. The availability of REEs is relatively abundant in the earth's crust, typically dispersed, and rarely occur in ores. In this study as raw material was a mixed rare earth concentrate from Monokem Surya Ltd. The purposes of this research were to determine the effect of concentration H2C2O4, stirring speed, and temperature regarding to purity and recovery REEs from the mixed rare earth concentrate. The experiments were conducted in five steps:(1) Alkaline fusion, the process was performed about 3 hours at 450oC, with ratio of NaOH solid to the mixed rare earth concentrate sand was 1:1, in order to break phosphate bonds;(2) Leaching of phosphate in alkaline fusion product using aquadest at 80 oC; (3) Aquadest leaching residue was leached using 6 M HCl for 2 hours to dissolve REEs at 90 oC; (4) Removal of impurities such as uranium and thorium by precipitating them using NH4OH at pH 1; (5) Precipitation of REEs from filtrate produced from point (4) using H2C2O4. The results of REEs with 96% purity and 95% recovery was obtained at concentration H2C2O4 8,11%, stirring speed 500 rpm, and temperature 70oC.

The increasing need of REY has been observed in industries such as catalyst industry, metallurgy, military, health and renewable energy resources. REY such as Ce, Nd, Y, and Eu has a prominent evidence to improve material properties such as high electropositive, good conductivity and renewable energy. Due to this increasing need of REY, exploration of alternative source has been conducted. One of the promising alternative sources is coal fly ash. The conventional method to recover REY from coal fly ash using inorganic acids is harmful to the environment. Thus, the exploration of REY extraction from coal fly ash using organic acid has been proposed in this study. The leaching agent was acetic acid applied for all operating condition. Regarding to the mineralization of REY in the form of siliceous minerals (non-magnetic coal fly ash). Silicate digestion was conducted using sodium hydroxide 8 M with solid-to-liquid of 25% to decompose the siliceous mineral. Further, the REY bound siliceous mineral will change to REY(OH)3. Temperature as one of the operating conditions was varied. The maximum recovery of leaching 20.58 %, 43.53 %, 17.38%, 40.96 %, 18.45 % and 32.74 % were achieved for Ce, Dy, La, Nd, Y and Yb respectively at temperature of 90 0C pH 1.74 and 120 minutes. For some metals, increasing the temperature higher than 70 0C does not provide any significant effect for REY recovery such as La and Ce.