Recycling gold and copper from waste printed circuit boards using chlorination process

RSC Advances ◽  
2015 ◽  
Vol 5 (12) ◽  
pp. 8957-8964 ◽  
Author(s):  
Yuchen He ◽  
Zhenming Xu
Keyword(s):  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Selective Recovery ◽  
Printed Circuit ◽  
Efficient Process ◽  
Chlorination Process ◽  
Waste Printed Circuit Boards ◽  
Waste Pcbs ◽  
Pretreatment Processes

This study provides a less-polluted and more efficient process for selective recovery of gold and copper from waste PCBs through pretreatment processes.

A Novel Flowsheet for the Recycling of Valuable Constituents from Waste Printed Circuit Boards

2011 ◽  
pp. 296-306
Author(s):  
Jingfeng He ◽  
Yaqun He ◽  
Nianxin Zhou ◽  
Chenlong Duan ◽  
Shuai Wang ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Separation Efficiency ◽  
Precious Metals ◽  
Metal Recovery ◽  
Recovery Ratio ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Waste Pcbs ◽  
Impact Crushing

Waste printed circuit boards (PCBs) contain a number of valuable constituents. It is of great significance to separate precious metals and non-metallic constituents from waste PCBs with appropriate methods for resource recycling and environment protection. A novel flowsheet for the recycling of waste PCBs using physical beneficiation methods was constructed. Waste PCBs were disassembled into substrates and slots firstly. The substrates were crushed to the size below 1mm through wet impact crushing and separated with a tapered column separation bed. The results indicated that products with integrated separation efficiency of 93.9% and metal recovery ratio of 93.7% were obtained by the primary separation with the water discharge of 5.5 m3/h, feed-rate of 250g/min and inclination angle of 35°. Waste PCBs slots components were crushed to the size of 0.5-5mm through impact crushing and separated with an active pulsing air classifier. The separation results showed that products with integration separation efficiency of 92.4% and metal recovery ratio of 96.2% were obtained with the airflow velocity of 2.90m/s and pulsing frequency of 2.33Hz. Precious metals could be obtained by further separation and purification of the metal components and the non-metal components could be used as refuse derived fuel. The flowsheet has great potential to be applied in the field of waste PCBs treatment and recycling.

scholarly journals Gold recovery from waste printed circuit boards of mobile phones by using microwave pyrolysis and hydrometallurgical methods

2022 ◽  
Vol 32 (1) ◽  
Author(s):  
Yu-Fong Huang ◽  
Szu-Ling Chou ◽  
Shang-Lien Lo
Keyword(s):  
Hydrogen Peroxide ◽  
Solvent Extraction ◽  
Printed Circuit Boards ◽  
Gold Recovery ◽  
Circuit Boards ◽  
Microwave Pyrolysis ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Waste Pcbs ◽  
Oxidative Precipitation

AbstractRecycling of waste printed circuit boards (PCBs) has attracted increasing attention because of its high annually produced amount and high content of gold. In this study, gold recovery from waste PCBs was carried out by using the processes including microwave pyrolysis, acid leaching, solvent extraction and oxidative precipitation. The leaching efficiency of copper was approximately 95% when using a lixiviant composed of sulfuric acid and hydrogen peroxide, and the leaching efficiencies of gold were approximately 59, 95 and 95% by using thiourea, thiosulfate and aqua regia, respectively. The gold ions contained in the leachate previously produced by the leaching processes were not satisfactorily extracted by using organic solvents including di-(2-ethylhexyl)phosphoric acid, tributyl phosphate, dibutyl carbitol and trioctylamine, so the leachate was decided to bypass solvent extraction and directly apply to the oxidative precipitation process. By using the oxidants of hydrogen peroxide and perchloric acid, the precipitation efficiencies of gold were approximately 95 and 99%, and the final recovery rates were approximately 90 and 93%, respectively. The high recovery rates of gold can be attributable to the use of microwave pyrolysis that prevents the loss of gold caused by shredding and grinding processes. In addition, perchloric acid can provide higher selectivity for gold recovery than hydrogen peroxide. The maximum processing capacity of microwave pyrolysis of waste PCBs would be approximately 1.23 kg. The gold recovered from 1 t of waste PCBs can be sold for approximately USD 10,000, and thus the return on investment can be as high as approximately 1400%.

Progress in the Preparation of Composites Based on the Nonmetallic Fractions Recycled from Waste Printed Circuit Boards

2010 ◽  
Vol 160-162 ◽  
pp. 518-523 ◽  
Author(s):  
Wei Qiao Liu ◽  
Xing Xing Wang ◽  
Wei Ning Lei ◽  
Tong Ming Shang ◽  
Quan Fa Zhou
Keyword(s):  
Renewable Resources ◽  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Research Directions ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Inorganic Composites ◽  
Metals Recovery ◽  
Waste Pcbs ◽  
Properties Of Composites

From the use of renewable resources and environmental protection, recycling of waste printed circuit boards (PCBs) receives wide concerns as the amounts of scrap PCBs increases dramatically. However, the recycle technology for waste PCBs in China is still immature. Previous studies focused on metals recovery, but resource utilization for nonmetallic fractions (NMFs) is relatively fewer. In this paper, the physical properties of the recovered nonmetallic powder is briefly introduced. The preparation of composites including organic and inorganic composites through the recycling NMFs was reviewed. In addition, the research directions of preparation of composites based on recycling NMFs were put forward. Firstly, the study on the reaction mechanism of composites preparation should be strengthened to explore the reasons why the additional quantity and particle size of NMFs powder have effects on the properties of composites. Secondly, a suitable coupling agent should be chosen to improve the the interface compatibility between the NMFs and matrix.

A Green Process for Copper Recovery from Waste Printed Circuit Boards

2014 ◽  
Vol 878 ◽  
pp. 374-379 ◽  
Author(s):  
Zhi Yuan Zhang ◽  
Fu Shen Zhang
Keyword(s):  
Printed Circuit Boards ◽  
Copper Recovery ◽  
Synthesis Process ◽  
Cuprous Chloride ◽  
Cupric Sulfate ◽  
Circuit Boards ◽  
Green Process ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Waste Pcbs

In the present study, a green process for cuprous chloride synthesis from waste printed circuit boards (PCBs) was developed. High value-added cuprous chloride (98.7% purity) was obtained by treating metallic particles of waste PCBs with solution of cupric sulfate and sodium chloride. Typical noble metal (Pd) was dissolved by forming a stable chloride complex during the synthesis process as Cu2+ played the role of oxidant or concentrated in the residue. Under the optimum condition (VNaCl/mCuSO4 ratio = 6, [C/[Cu2+] mole ratio = 1.05, treatment time = 30 min, operation temperature = 60 °C), yield of cuprous chloride was 74.0% and approximately 98.5% of the copper could be recovered. It is believed that the process proposed is effective and practical for Cu recovery from waste PCBs.

LEACHING OF METALS FROM WASTE PRINTED CIRCUIT BOARDS (WPCBs) USING SULFURIC AND NITRIC ACIDS

2014 ◽  
Vol 13 (10) ◽  
pp. 2601-2607 ◽  
Author(s):  
Jae-chun Lee ◽  
Manoj Kumar ◽  
Min-Seuk Kim ◽  
Jinki Jeong ◽  
Kyoungkeun Yoo
Keyword(s):  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards
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