| The printed circuit boards were accumulated,burned or discarded with the rapid development of electronic science technology industry and continuous upgrading of electronic products.This would not only lead to a large number of waste metal and non-metallic materials but also heavy metals and organic flame retardants in the circuit board would be harmful to human health and environmental health and cause serious harm.This paper aims at the problems of the waste printed circuit board,such as the difficulty of resource recovery,the low utilization rate of the product,the high labor intensity,the low technology integration and the two pollution of the environment.The metal recovery and nonmetal resource utilization in circuit boards were researched,Solve the waste of printed circuit board waste and two pollution problems.The tin bath stripping method was used to disassemble the components,and the metal and nonmetal were separated by the hydraulic table.The non-metallic materials were used to modify the asphalt and prepare composite materials.Method of circuit board components dismantling were discussed firstly,the content of Cu,Sn,Fe,Al,Pb five kinds of metals in circuit boards were analyzed,The influence of crushing time on the yield of each size and the distribution of copper in different sizes were discussed.The best dosage of Twelve sodium dispersant to the particle size of powder in water dispersion effect and effect of the particle size of powders on the hydraulic shaking table separation were researched.In the end the utilization of nonmetal resources of PCB were studied and the feasibility and technological conditions for the preparation of asphaltmodified and filled PVC composites were analyzed.The following conclusions can be drawn from these findings.(1)The best effect of dismantling by using tin bath removal of tin when the bath temperature is maintained at 225? to 235 ?.The components on the circuit boards basically can be removed when the circuit board were immersed in a tin bath for about 1.5 min and disassembly efficiency can be reached 100%.(2)The content of copper in the main metal was about 25%,the content of tin was 5.4%,the content of iron was as high as 0.3%,the content of aluminum was about 1.5%,and the content of lead was about2.3%.(3)The size of the broken product is mainly distributed at 16-100 mesh,when the crushing time is about 180 s and the highest separation efficiency of the size range of powder by using hydraulic shaking table.(4)The particle board size of 32-100 mesh powder can be dispersed completely when twelve sodium at the concentration of 0.11%.The particle size of >100 mesh powder can be dispersed completely when twelve sodium at the concentration of 0.33%.(5)The recovery of copper can reach up to 98.7% when the particle size was >16 mesh.The recovery of copper can reach 98.3% when the particle size was >32 mesh.The recovery of copper was 96.1% when the particle size was >100 mesh.Metal and nonmetal in waste printed circuit boards circuit boards separation and recovery by electric hydraulic shaker.the distribution of particles in the range of >100 mesh should be reduced by controlling the grinding time and preventing over grinding.The powder of particle diameter range was more than 16 mesh for electric hydraulic shaker under the action of the dispersant.(6)The particle size of 8-16 mesh substrate powder was high separation efficiency by using high voltage electrostatic separator.<16mesh powder of metal and nonmetal be separation and enrichment by high voltage electrostatic separator.No complete dissociation of non metal be again crushed into a smaller particle size powder and be again sorted.(7)The optimal combination of asphalt modified process conditionsof non metal powder mesh number was 200,the dosage was 12%,the reaction temperature was 165?,the shear time was 25 min,dosage of silane coupling agent was 0.3%,The high temperature stability of modified asphalt was improved,and the temperature sensitivity was reduced.(8)The mechanical properties of the composites were more than that of the ordinary wood plastic composites and has a certain application prospect,which wide application prospect when the non-metallic powder particle size of nonmetal waste circuit board was of the order of 100 meshes,the filling amount was as high as 10%,the molding temperature was about 195 DEG C,and the molding pressure was 17 MPa. |
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