Thioureation of chalcopyrite ore and gold-thiourea adsorption by Chlorella vulgaris and rice husk

การใช้ไทโอยูเรียในการสกัดทองจากแร่ชาโคไพไรด์และการดูดซับทองไทโอยูเรีย โดยใช้ Chlorella vulgaris และแกลบ

Name: Woranan Nakbanpote

Organization : King Mongkut's University of Technology Thonburi. School of Bioresources and Technology. Biotechnology

Name: Woranan Nakbanpote

keyword: การดูดซับ

; แกลบ

Abstract: Bioleaching of chalcopyrite ore by Thiobacillus fevrooxidans could extract copperand iron but not gold. However, bioleaching process enhanced gold extracted frombioleached-chalcopyrite ore. The percentage of gold extracted from chalcopyrite oreunder optimum condition (Thiourea concentration 15 g/L, pH 3.5) was only 40 %.Whereas, the percentage of gold extracted from bioleached-chalcopyrite under optimumcondition (Thiourea concentration 20 g/L, pH 3.0) was 70%.Immobilised Chlorella vulgaris heated at 400?C and then treated with 2.0 M HCI(IMcell-400 - T) was selected as an adsorbent from C. vulgaris. Its maximum goldadsorption was 10.34 mg Au/g adsorbent. In addition, rice husk heated at 300?C andthen treated with 2.0 M NaOH (RHA300-T) was used as an adsorbent from rice husk.The maximum gold thiourea adsorption of RHA300-T was 42.76 mg Au/g adsorbentwhich was higher than that of activated carbon, 35.88 mg Au/g adsorbent. Mechanism ofgold-thiourea adsorption by C. vulgaris and rice husk was chemical adsorption. Themechanism concerned donation a pair of electron from oxygen of ketone (>C=O),carboxylate (>Cod and esters (-COO-) on surface of IMcell-400-T, ketone,carboxylate, Si-O-Si stretching, Si-O-C and Si-O-Phenyl on surface of RHA300 andketone, carboxylate and esters on surface of RHA300-T to coordinate covalent bondingwith gold from gold-thiourea complex. While gold adsorption mechanism of activatedcarbon was mainly physical adsorption. From elution test, gold adsorbed ontoC. vulgaris and rice husk could be eluted to 80-100% by 0.5 M Na2S203. Whereas, goldadsorbed onto activated carbon could be eluted only 40%. Therefore, RHA300-Tis suitable to be used as an adsorbent in gold-thiourea preconcentration instead ofactivated carbon.

King Mongkut's University Technology Thonburi. Library

Address: กรุงเทพมหานคร (Bangkok)

Email: info.lib@mail.kmutt.ac.th

Name: Paitip Thiravetyan

Role: Advisor

Name: Chatvalee Kalambaheti

Role: Advisor

Created: 2000

Issued: 2007-12-27

Modified: 2017-07-17

วิทยานิพนธ์/Thesis

CallNumber: BIT328

eng

DegreeName: Doctor of Science

Level: Doctoral Degree

Descipline: Biotechnology

Grantor: King Mongkut's University of Technology Thonburi

©copyrights King Mongkut's University of Technology Thonburi

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