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Microwave Heating and Acid Leaching Processes for Recovery of Gold and Other Precious Metals from E-Waste


Affiliations
1 National Institute of Technology, Mizoram - 796 012, India
2 SRM Institute of Science and Technology, Modinagar - 201 204, India
3 CSIR-Institute of Minerals and Materials Technology, Bhubaneswar - 751 013, India
 

The main aim of the present study is to develop a new method to recover gold and other precious metals such as copper, silver, etc. with the judicious combination of microwave heating and acid leaching of e-waste samples like printed circuit board of computers, mobiles, electronic devices, etc. In the present study, microwave heating is much required for segregation of melted plastics and metals from e-waste and it also generates high temperature in much lesser time. The investigation basically consists of seven stages, i.e. heating the e-waste using microwave energy, grinding, physical separation of molten plastics and metal slag followed by leaching in nitric acid, leaching in aqua regia for unreacted materials, removing with concentrated nitric acid and washing and purifying the metal deposits. The results obtained from XRD, FESEM-EDAX and TEM studies confirm that precious metals like gold and silver can be obtained with the new method, which is also an environmental friendly approach.

Keywords

Aqua Leaching, EDAX, E-waste Sample, FESEM, Image Mapping, Microwave Heating, TEM, XRD.
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  • Khanna, R., Cayumil, R., Mukherjee, P. S. and Sahajwalla, V., A novel recycling approach for transforming waste printed circuit boards into a material resource. Proc. Environ. Sci., 2014, 21, 42-54.

  • Cui, J. and Zhanga, L., Metallurgical recovery of metals from electronic waste: a review. J. Hazard. Mater., 2008, 158, 228-256.

  • Dey, S. and Jana, T., E-waste recycling technology patents filed in India -an analysis. J. Intell. Prop. Rights, 2014, 19, 315-324.

  • Buekens, Alfons and Jie, Y., Recycling of WEEE plastics: a review. J. Mater. Cycles Waste, 2014, 16, 415-434.

  • Balde, K., The Global E-waste Monitor 2014 -Quantities, flows and resources. United Nation University; https://i.unu.edu/media/ unu.edu/news/52624/UNU-1stGlobal-E-Waste-Monitor-2014-small.pdf

  • Pant, D., Joshi, D., Manoj Upreti, K. and Ravindra, K. K., Chemical and biological extraction of metals present in e-waste: a hybrid technology. Waste Manage., 2012, 32, 979-990.

  • Chaurasia, A., Singh, K. K. and Mankhand, T. R., Extraction of tin and copper by acid leaching of PCBs. Int. J. Metall. Eng., 2013, 2(2), 243-248.

  • Bala, I. A. K. and Hassan, M. A. A., Thermal plasma treatment of wastes: a review. Aust. J. Basic Appl. Sci., 2015, 9(31), 322-333.

  • Biswajit, R., Thermal plasma treatment of mobile phone waste under reduced condition. Int. J. Environ. Sci., 2012, 2(4), 1-8.

  • Cerqueira, N., Vandensteendam, C., Baronnet, J. M. and Girold, C., Heavy metals volatility during thermal plasma vitrification of mineral waste. Environ. Eng. Sci., 2004, 21(1), 83-92.

  • Abdul, K., Rhamdhani, M. A., Brooks, G. and Syed, M., Metal extraction processes for electronic waste and existing industrial routes: a review and Australian perspective. Resources, 2014, 3, 152-179.

  • Cheng, T. W., Chu, J. P., Tzeng, C. C. and Chen, Y. S., Treatment and recycling of incinerated ash using thermal plasma technology. Waste Manage., 22(5), 485-490.

  • Srikant, S. S., Mukherjee, P. S. and Rao, R. B., Morphological characterization of titania slag obtained from red sediment placer ilmenite using microwave energy. J. Inst. Eng. India Ser. D, 2015, 96, 43-49.

  • Srikant, S. S., Mukherjee, P. S. and Rao, R. B., Prospects of microwave energy in material and mineral processing. Turk. J. Eng. Sci. Technol., 2013, 2, 23-31.

  • Pickles, C. A., Microwaves in extractive metallurgy: Part 1 -A review of fundamental. Miner. Eng., 2009, 22, 1102-1111.

  • Srikant, S. S., Mukherjee, P. S. and Rao, R. B., Microwave energy for waste management. Mineral Process. Technol., 2013, 3, 948-953.

  • Srikant, S. S., Mahapatra, R. P. and Laxmi, T., Microwave energy for waste used engine oil. The Institution of Engineers (India) Odisha State J., 2015, 1, 255-261.


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  • Microwave Heating and Acid Leaching Processes for Recovery of Gold and Other Precious Metals from E-Waste

Abstract Views: 438  |  PDF Views: 120

Authors

Rajendra Prasad Mahapatra
National Institute of Technology, Mizoram - 796 012, India
Satya Sai Srikant
SRM Institute of Science and Technology, Modinagar - 201 204, India
Raghupatruni Bhima Rao
CSIR-Institute of Minerals and Materials Technology, Bhubaneswar - 751 013, India
Bijayananda Mohanty
National Institute of Technology, Mizoram - 796 012, India

Abstract


The main aim of the present study is to develop a new method to recover gold and other precious metals such as copper, silver, etc. with the judicious combination of microwave heating and acid leaching of e-waste samples like printed circuit board of computers, mobiles, electronic devices, etc. In the present study, microwave heating is much required for segregation of melted plastics and metals from e-waste and it also generates high temperature in much lesser time. The investigation basically consists of seven stages, i.e. heating the e-waste using microwave energy, grinding, physical separation of molten plastics and metal slag followed by leaching in nitric acid, leaching in aqua regia for unreacted materials, removing with concentrated nitric acid and washing and purifying the metal deposits. The results obtained from XRD, FESEM-EDAX and TEM studies confirm that precious metals like gold and silver can be obtained with the new method, which is also an environmental friendly approach.

Keywords


Aqua Leaching, EDAX, E-waste Sample, FESEM, Image Mapping, Microwave Heating, TEM, XRD.

References





DOI: https://doi.org/10.18520/cs%2Fv116%2Fi3%2F463-468