Scholarlink

<p>To ensure the safety of workers, the public, and the environment, the limit for the content of technologically enhanced natural radioactive materials (TENORM) as by-product metals such as uranium and thorium in mineral processing products is 500&#xa0;ppm. For safe application in the industry sector, La<sub>2</sub>O<sub>3</sub> nanoparticles with high purity and low TENORM (U and Th &lt; 500&#xa0;ppm) are required. This study aims to obtain high-purity and TENORM-free La<sub>2</sub>O<sub>3</sub> nanoparticles from monazite sand as raw material. The synthesis of La<sub>2</sub>O<sub>3</sub> nanoparticles consisted of decomposition of monazite sand with NaOH, partial dissolution with HCl at pH 3.7, precipitation of U and Th at pH 6.3, precipitation of rare earth metal hydroxide [RE(OH)<sub>3</sub>] at pH 9.8, leaching of RE(OH)<sub>3</sub> with dilute HNO<sub>3</sub>, separation of Ce-hydroxide at pH 4, hydroxide precipitation of Y, Nd, Pr, Sm, Gd at pH 8.25, precipitation of lanthanum oxalate at pH 8.25 with oxalic acid, formation of commercial La<sub>2</sub>O<sub>3</sub>, precipitation of La(OH)<sub>4</sub> at pH 8 with NaOH and calcination. XRF, XRD, FTIR, FE-SEM-EDS, and PSA characterized La<sub>2</sub>O<sub>3</sub> nanoparticles. The research results obtained La<sub>2</sub>O<sub>3</sub> nanoparticles with high purity, La content 98.173%, TENORM free with OH–, CO<sub>3</sub><sup>2−</sup>, and La–O functional groups, and a hexagonal crystal structure with a particle size of 5.69&#xa0;nm. This synthesis method can increase the La concentration from 11.22 to 98.173% and is TENORM free (U from 2530&#xa0;ppm becomes undetectable and Th from 5.52% becomes undetectable).</p> Graphical Abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Synthesis of TENORM-Free And High Purity Lanthanum Oxide Nanoparticles From Monazite Sand

  • 期刊论文

  • 发表日期：

    2025年7月9日

查看全文
  • Samin,
  • Suyanti,
  • Widi Astuti,
  • Amru Daulay,
  • Hafni Lissa Nuri,
  • Kurnia Trinopiawan,
  • Septian Nafiatul Khasanah,
  • Kharistya Rozana

摘要

To ensure the safety of workers, the public, and the environment, the limit for the content of technologically enhanced natural radioactive materials (TENORM) as by-product metals such as uranium and thorium in mineral processing products is 500 ppm. For safe application in the industry sector, La2O3 nanoparticles with high purity and low TENORM (U and Th < 500 ppm) are required. This study aims to obtain high-purity and TENORM-free La2O3 nanoparticles from monazite sand as raw material. The synthesis of La2O3 nanoparticles consisted of decomposition of monazite sand with NaOH, partial dissolution with HCl at pH 3.7, precipitation of U and Th at pH 6.3, precipitation of rare earth metal hydroxide [RE(OH)3] at pH 9.8, leaching of RE(OH)3 with dilute HNO3, separation of Ce-hydroxide at pH 4, hydroxide precipitation of Y, Nd, Pr, Sm, Gd at pH 8.25, precipitation of lanthanum oxalate at pH 8.25 with oxalic acid, formation of commercial La2O3, precipitation of La(OH)4 at pH 8 with NaOH and calcination. XRF, XRD, FTIR, FE-SEM-EDS, and PSA characterized La2O3 nanoparticles. The research results obtained La2O3 nanoparticles with high purity, La content 98.173%, TENORM free with OH–, CO32−, and La–O functional groups, and a hexagonal crystal structure with a particle size of 5.69 nm. This synthesis method can increase the La concentration from 11.22 to 98.173% and is TENORM free (U from 2530 ppm becomes undetectable and Th from 5.52% becomes undetectable).

Graphical Abstract