基于碱液预处理的泡沫浮选法分离PVC/PET

Separation of PVC/PET by froth flotation with alkaline pretreatment

为优化聚氯乙烯(PVC)和聚对苯二甲酸乙二醇酯(PET)废旧混合塑料的浮选分离效果,采用碱液预处理的方式,结合松油醇(TP)作为浮选药剂,以PVC在上浮产物中的回收率及纯度为考核指标,详细考察了不同参数对浮选效果的影响。结果表明:分离PVC/PET混合物的最优工艺为Na OH质量分数2%,预处理时间15 min,预处理温度70℃,TP浓度35mg·L^(-1),浮选时间2 min。在上述最优工艺参数下,混合物中PVC作为上浮产物的回收率和纯度分别可达83%和100%。实验结果对PVC/PET分选的实际应用具有重要的指导意义。

In order to optimize the effect of separation by froth flotation of the mixed plastic poyvinyl chloride （PVC） and polyethylene terephthalate （PET） , using the method of treatment with alkaline, combined with ter- pineol （TP） as a flotation reagents. To clearify the mechanism influenced by different parameters, the recovery and purity of PVC in froth product were chosen as performance indicators. Results showed that the optimal process for the separation of PVC and PET was achieved under sodium hydroxide concentration of 2% , pretreat- ment time of 15 min,temperature of 70℃ ,terpineol concentration of 35 mg · L-1 and flotation time of 2 min. In these conditions, the flotation recovery and purity of PVC in floating product were 83% and 100% ,respectively. These results showed a significance meaning for improving the efficiency of separation of mixed PVC/PET. Key words plastics ; alkaline pretreatment ; flotation separation ; recovery rate ; purity