A Fundamental Research on Comprehensive Recycling of Waste Compact Disc

　　A Fundamental Research on Comprehensive Recycling of Waste Compact Disc
　　Along with the compact disc technology development, the compact disc obtains more and more widespread utilization, so its annual output increases rapidly, but the environment questions caused by it also gradually appear. If simply carried on burying or burning, not only it can increase the environmental pollution, but can waste the massive precious resources in compact disc. After referred to domestic and foreign related treatment and recycling methods, this article was proposed that the recycling of compact disc can be divided into 3 step: separating the surface and reflection layers and recycling the metal, separating the dye layer and recycling the dye, recycling the PC, Neodymium Magnets according to different organizational structure of compact discs and different ingredient in its functional layers.Then lots of related experiments were done, including1. Testing metal in compact discs: It was found that every CD-R includes about 7mg silver or more than 8mg gold by the atomic absorption spectrophotometer method, and every CD-RW includes many kinds of precious metal and rare metal with ICP-AES. This also indicates recycling compact disc may obtain precious resources as well as good economic efficiency.2. Recycling metal from compact discs: Using the method of solvent to dispose compact disc surface and reflection layers: After compared with many kind of processing method, the appropriate method-chemical dissolving method was chosen. Through the experiment, it appears that using 15% sodium hydroxide with 10% sodium chloride mixed solution or 60% sodium hypochlorite with 10% sodium hydroxide mixed solution under the appropriate temperature and mixing speed condition may separate compact discs’ surface layer and completely dissolve reflection layer, then metal can been recycled by simple methods.3. Recycling dye layer: Using the method of eluting dye layer by organic solvent. The eluting effects of many kinds of organic solvent on dye as well as the influence to PC have been demonstrated. After selecting three kind of organic solvent for experiment, it was proved alcohol had many kinds of merits so it is the first choice solvent, considering of eluting time and effect.
　　The eluted dye can be recycled in the mechanical and refined strainer, and then it may separate and purify all kinds of dye by many other methods.4. Recycling PC: Using the temperate method to depolymerize PC. In the compact disc, PC occupies the total weight above 98%;therefore recycling PC is most important. Although there are many methods to dispose or recycle PC, none of them is satisfied. In this article, the method of depolymerizing PC in mixed http://www.999magnet.com solvent under the moderate condition was designed. In the mixed solvent of methyl alcohol and toluene(1:3), joined 0.4mol/L sodium hydroxide,PC may be depolymerized to bisphenol A (BPA) and diethyl carbonate (DMC) and its product has high purity above 99% at 60 °C after research.When experiments were over, the mechanisms of recycling metal with NaCIO solvent, eroding compact disc and depolymerizing PC had been clarified after referred to related information and summarized tested data and phenomena in tests.Finally, considered of the questions appeared in the experiment and possible difficulties in the actual engineering utilization, a cleanly craft of recycling compact disc was conceived. It may completely separate all layers of compact disc, and recycle different useful resources from different functional layers. Not only has the treatment of waste water and waste residue which possibly appear been taken into account but the water and solvent used in this craft had been circularly reused to achieved the minimal harmless to the environment and the maximum use of resource.