Effect Of Hydrogen Peroxide And Lead Nitrate In The Cyanidation Leaching Of Gold Ore Sample

Ong , Pek Ling (2016) Effect Of Hydrogen Peroxide And Lead Nitrate In The Cyanidation Leaching Of Gold Ore Sample. ["eprint_fieldopt_thesis_type_phd" not defined] thesis, Universiti Sains Malaysia.

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Abstract

Bijih Au yang digunakan diperolehi daripada lombong bijih Au di Malaysia. Dalam proses pelarutlesapan sianida, keboleh-ekstrakan Au bergantung kepada sifat semulajadi bijih. Maka dengan itu, pencirian bijih melalui kajian mineralogi merupakan peringkat yang penting sebelum pengekstrakan Au. Kehadiran Fe, As, dan S telah dikesan dan taburan halus partikel Au dengan butiran bersaiz 10.0 μm didapati terperangkap dalam fasa aluminosilikat. Au yang hadir (Au pukal yang larut - boleh ekstrak) dalam bijih bebas kisar dan refraktori telah ditentukan melalui kaedah pensianidaan diikuti dengan cerakin api. Sebanyak 1.9368 g/t Au terekstrak. Bijih Au ini tidak mudah diekstrakkan dengan kaedah pensianidaan lazim disebabkan oleh kesan perencatan yang disebabkan oleh mineral sulfida. Oleh itu, H2O2 digunakan sebagai sumber O2 dan Pb(NO3)2 telah ditambah untuk menstabilkan Cu dan Fe daripada menjadikan permukaan Au itu pasif terhadap sianida. Ujian awal pensianidaan dijalankan pada pH 11 dengan 33.3 % pepejal sebelum kajian pengoptimaan menggunakan kaedah respon permukaan-rekabentuk komposit berpusat. Rangkuman jarak keadaan optimum adalah pada 467.3 ppm NaCN, 94.96 ppm Pb(NO3)2 dan 0.01M H2O2, dengan 1.7231 g/t (88.97%) Au terekstrak selepas menggunakan kaedah kenaikan mendadak. Pensianidaan lazim cuma boleh mengekstrak 62.02% Au, dimana ini menunjukkan Pb(NO3)2 and H2O2 membantu dalam pelarutan Au sianida. Dari kaedah perbezaan Van’t Hoff, tertib tindakbalas adalah tertib kedua dengan pemalar kadar 0.501/jam. Kompleks auro yang terbentuk daripada tindakbalas pensianidaan adalah bergantung kepada kepekatan sianida dan O2 terlarut dari H2O2. ________________________________________________________________________________________________________________________ The Au ore sample used was obtained from a local gold mine in Malaysia. In the cyanidation, the ease of Au extraction would depend on the nature of the ore. Hence, ore characterization via mineralogical studies plays a vital stage prior to Au extraction. The presence of Fe, As, and S were detected and the finely disseminated Au particle with the grain size of about 10.0 μm, was found to be interlocked in aluminosilicate. Au (bulk leachable extractable Au) present from the free milling and refractory ore was determined by cyanidation followed by fire assay respectively. About 1.9368 g/t Au was extracted. The Au ore samples were not amenable by conventional cyanidation due to the detrimental effects caused by the sulphide minerals. Therefore, H2O2 was used as a source of O2 and Pb(NO3)2 was added to stabilize the Cu and Fe from passivating the Au surface. Preliminary experiments of cyanidation were conducted at pH 11 with 33.3% solid before the optimization studies using response surface methodology–central composite design. The vicinity of the optimum condition was at 467.3 ppm NaCN, 94.96 ppm Pb(NO3)2 and 0.01M H2O2, with 1.7231 g/t (88.97%) Au extracted after using path of steepest ascent. Conventional cyanidation only able to extract 62.02% of Au, which indicates that Pb(NO3)2 and H2O2 assisted in the Au cyanide dissolution. From Van’t Hoff differential method, the reaction order was found to be of second order with the rate constant of 0.0501/hour. The auro complex formed from the cyanidation reaction is dependent on the concentration of cyanide and dissolved oxygen produced by H2O2.

Item Type: Thesis (["eprint_fieldopt_thesis_type_phd" not defined])
Additional Information: Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=3160
Subjects: T Technology
T Technology > TN Mining Engineering. Metallurgy > TN263-271 Mineral deposits. Metallic ore deposits. Prospecting
Divisions: Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Bahan & Sumber Mineral (School of Material & Mineral Resource Engineering) > Thesis
Depositing User: Mr Mohd Jasnizam Mohd Salleh
Date Deposited: 04 Sep 2018 08:40
Last Modified: 04 Sep 2018 08:40
URI: http://eprints.usm.my/id/eprint/41714

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