PDF Publication Title:
Text from PDF Page: 007
566 Yanhua Zhang et al. / Procedia Environmental Sciences 16 (2012) 560 – 568 Economic feasibility (B1) Environmental impact (B2) Research level (B3) Leaching rate(C11) Reagent cost(C12) Corrosive(C13) Toxicity(C21) Reliability(C31) Fig.2. Diagram of hierarchical structure Table 3 Comparing matrixes of different hierarchies A B1 B2 B3 Ki B2 C21 Ki B3 C31 Ki 2311 Ki B1 C11 C12 C13 i 1 i 1 i 1 i 1 5 C11 1 0 0 1 C21 1 1 C31 1 1 B1 1 2 2 B2 0 1 0 1 C12 2 1 2 5 B3 0 2 1 3 C13 2 0 1 3 Table 4 Judging matrixes of different hierachies A B1 B2 B3 T B1 C11 C12 C13 T B2 C21 T B3 C31 T B1 1 6 7/2 0.627315 C11 1 1/6 2/7 0.086749 C21 1 C31 1 B2 1/6 1 2/7 0.086749 C12 6 1 B3 2/7 7/2 1 0.285936 C13 7/2 2/7 Table 5 Weight of different indexes about leaching methods Evaluation index Leaching rate (C11) Reagent cost (C12) 7/2 1 0.627315 0.285936 Corrosive (C13) 0.179 0.087 Thiosulfate Chloride 2.711 3.251 Toxicity (C21) Reliability (C31) 0.286 Iodide 3.640 Weight 0.054 Table 6 Final scores of different leaching methods Leaching method Cyanide Aqua regia 0.394 Thiourea 4.000 Bromide 2.249 Scores 4.457 3.483 The analysis shows that cyanide leaching gains the highest points for its good economic feasibility and research level. But when the toxicity of reagents are taken into account, it is an inevitable trend for non- cyanide leaching to replace cyanide leaching. With further research, thiourea leaching and iodide leaching are both likely to reduce the cost of the process and to be more reliable in technology, so as to replace cyanide leaching. 4. Conclusions In summary, leaching technologies mentioned above are technically feasible. However, in order to develop an environment-friendly technique for recovery of precious metals from waste PCBs, we should pay more attention to evaluating the environmental impact of techniques. A critical comparison of seven leaching methods is analyzed based on three-scale AHP. The results suggest that thiourea leaching and iodide leaching make more possible to replace cyanide leaching. Along with the further studies on this field, those leaching process with potential environment benefits will be more economically feasible in the future. Feasible leaching method (A)PDF Image | leaching precious metals from waste printed circuit boards
PDF Search Title:
leaching precious metals from waste printed circuit boardsOriginal File Name Searched:
1-s20-S1878029612006159-main.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)