Sains Malaysiana 34(1): 45-50 (2005)

Concentration of Uranium and Thorium in the Product and

by-Product of Amang and Ilmenite Tailings Process

(Kepekatan Uranium dan Torium dalam Hasil dan Hasil Sampingan

 Proses Tahi Timah Amang dan Ilmenit)

Husin Wagiran, Lim Say Eng & Lee Siak Kuan

Physics Department, Faculty of Science

Universiti Teknologi Malaysia

81310 UTM, Skudai, Johor, D.T.

Mohamad Yasin Sudin

Lembaga Perlesenan Tenaga Atom

Batu 24, Jalan Dengkel

43800 Dengkel, Selangor, D.E.

ABSTRACT

Amang are by-products obtained when tailings are processed into concentrated ores and other economical products such as monazite, (Ce, La, Th)PO₄; zircon, ZrSiO₄; ilmenite, FeTiO₃; struverit; and xenotime, YPO₄. Its could be extracted from amang for further usage. Tailings from these ores may have a significant potential to cause elevated radiation exposures. This project was carried out to measure the concentration of uranium and thorium in the waste and products produced after the processing of the amang and ilmenite ore. The concentration of uranium and thorium was determined using gamma ray spectrometer with HPGe detector. The concentration of uranium was determined by measuring the intensity of gamma ray emitted from its daughter nuclei ²¹⁴Pb at 352 keV and ²¹⁴Bi at 609 keV while the concentration of thorium was determined by measuring the intensity of gamma rays emitted from its daughter nuclei ²²⁸Ac at 911 keV and ²⁰⁸Tl at 583 keV. The concentration of uranium and thorium in ppm obtained in this study are as follows: raw amang (83 -383) and (174 - 1566); ilmenite (149 - 290) and (301- 575); monazite (2303 - 4070) and (9641 – 60061); zircon (963 - 1192) and (353 - 583) and waste (22 - 98) and (44 - 223) respectively. Rutile and iron oxide was obtained from ilmenite. The concentration of uranium and thorium in rutile was 50 and 72 ppm and from iron oxide was 336 and 379 ppm respectively. These values are considered high compare to normal sand and could pose danger to the surrounding.

Keywords: Amang, Uranium, Thorium, Ilmenite

ABSTRAK

Amang adalah hasil sampingan yang diperoleh semasa pengekstrakan tahi timah kepada logam tulennya. Pelbagai hasil yang berekonomi seperti monazit, (Ce,La,Th)YPO₄; zirkon, ZrSiO₄; ilmenit, FeTiO₃; struverit; dan xenotim, YPO₄ boleh diekstrak daripada amang bagi kegunaan seterusnya. Pemprosesan tahi bijih ini berkeupayaan mendatangkan pendedahan sinaran yang tidak diingini. Kajian ini dijalankan untuk menentukan kandungan uranium dan torium yang terkandung dalam sisa dan hasil yang dikeluarkan semasa pemprosesan amang dan ilminit. Kepekatan kandungan uranium dan tarium ditentukan menggunakan spektrometer sinar gama dengan pengesan HPGe. Kandungan uranium ditentukan dengan mengukur keamatan sinar gama yang dipancarkan daripada nukleus anaknya, iaitu  ²¹⁴Pb pada tenaga 352 keY dan ²¹⁴Bi pada tenaga 609 keY, manakala kandungan torium ditentukan dengan mengukur keamatan sinar gama yang dipancarkan oleh nukleus anaknya, iaitu ²²⁸Ac pada tenaga 911 keY dan 208Tl pada 583 keY. Kandungan uranium dan torium dalam ppm yang diperoleh daripada kajian ini masing-masing adalah seperti berikut: amang mentah (83 - 383) dan (174 -1566); ilmenit (149 - 290) dan (301 - 575); monazit (2303 - 4070) dan (9641 - 60061); zirkon (963 -1192) dan (353 -583) dan sisa (22 - 98) dan (44 - 223). Kandungan uranium dan torium dalam rutil masing-­masing ialah 50 and 72 ppm, manakala dalam ferum oksida ialah 336 dan 379 ppm. Nilai yang diperolehi ini adalah tinggi berbanding dengan pasir biasa semula jadi dan berpotensi mendatangkan kemudaratan kepada persekitaran.

Kata kunci: Amang, llmenit, Uranium, Torium

RUJUKAN/REFERENCES

Cohen S. and Associates, Inc., & Rogers and Associates Engineering Corp. 1993.  Diffuse NORM Wastes–Wastes Characterization and Preliminary Rosk Assessment. United States Environmental Protection Agency, EPA.

Hu, S.J. Chong C.S. & Subra S. 1981.  238U and 232 Th in Cassiterites Samples and Among  By-Products. Health Physics 40: 248-250.

Minerals and Geosciences Department Malaysia. 2002, Exploration and mining.

Myrick T.E. Berven B.A. & Haywood F.F. 1983.  Determination of Concentration of selected radionuclides in sirface soil in U.S.A.  Health Physics 45(3): 631-640.