报废汽车内饰件塑料浮选技术研究

Research on Flotation Technique for End-of-Life Vehicle Interior Plastics

报废汽车内饰件塑料品种复杂、难以分选,为此,以分离汽车内饰件中4种主体塑料——PP(聚丙烯)、ABS(丙烯腈-丁二烯-苯乙烯)、PC(聚碳酸酯)、PVC(聚氯乙烯)为目标,利用实验室自制浮选设备,考察了浮选液流量、溶气罐压力、润湿液浓度等因素对浮选效果的影响.结果表明:当溶气罐压力为0.22 MPa、浮选液流量为10 L/min、润湿液中ρ(单宁酸)为15 mg/L时,一级浮选PP、ABS、PC、PVC效果达到最佳,其中PP和ABS为上浮料,二者上浮率分别为100%和98.63%;PC和PVC为下沉料,二者下沉率分别为98.95%和100%.当溶气罐压力为0 MPa、浮选液流量为6 L/min、润湿液中ρ(单宁酸)为10 mg/L时,二级浮选完全分离PP/ABS;当溶气罐压力为0.24 MPa、浮选液流量为10 L/min、润湿液采用10 mg/L单宁酸和10 mmol/L癸二酸二丁酯时,二级浮选分离PC/PVC效果达到最佳,PC上浮率为92.87%,PVC下沉率为91.41%.通过二级浮选分离,PP、ABS、PC、PVC的最终分离率分别达到100%、98.63%、92.87%和91.41%,显示出该二级浮选工艺在报废汽车内饰件塑料分选方面具有较为广阔的应用前景.

It is difficult to separate interior plastic components in end-of-life vehicles（ ELVs） due to their complex types. As flotation has been considered one of the most efficient techniques for plastic separation,efficiency of separating interior plastic components of ELVs with flotation technique was explored. Aiming at separating four kinds of interior plastic components of ELVs,a designed flotation column was used in the laboratory to investigate the effects of parameters such as flotation fluid flow,dissolved-air tank pressure and wetting agent concentration on the flotation behaviors. The results showed that the primary flotation of PP/ABS/PC/PVC achieved the optimal effect with PP/ABS as floating materials and PC/PVC as sinking materials under 15 mg/L of tannic acid as wetting agent,0. 22 MPa of dissolved-air tank pressure and 10 L/min of flotation fluid flow. Floating rates of PP/ABS were 100% and 98. 63% respectively,while sinking rates of PC/PVC were 98. 95% and 100% respectively. In the secondary flotation,PP and ABS were separated completely under 10 mg/L of tannic acid as wetting agent,0 MPa of dissolved-air tank pressure and 6 L/min of flotation fluid flow. PC/PVC separation in the secondary flotation achieved the optimal effect with PC floating rate being 92. 87% and PVC sinking rate being 91. 41% under 10 mg/L of tannic acid and 10 mmol/L dibutyl sebacate as wetting agent,0. 24 MPa of dissolved-air tank pressure and 10 L/min of flotation fluid flow. After two stages of flotation screening,the separating rates of PP,ABS,PC and PVC finally reached 100%,98. 63%,92. 87% and 91. 41%respectively. This indicated that the two-stage flotation process developed could achieve effective separation of the four kinds of mixed plastics. The two-stage flotation process developed has broad application prospects in separating interior plastic components of ELVs.