【摘要】 针对二步湿法腈纶生产过程中硫氰酸钠(Na SCN)溶液经纳滤膜分离净化后浓液的进一步净化和回收利用,采用混凝-沉淀法对Na SCN膜分离浓液的净化处理效果进行了试验,并研究和分析了聚合氯化铝(PAC)、聚丙烯酰胺(PAM)、石灰乳等的投加量以及初始p H、搅拌强度对Na SCN膜分离浓液净化的影响。结果表明:当PAC、PAM和石灰乳投加量分别至其浓度为200、2.5和25 mg/L,初始p H为7.5,搅拌转速为80 r/min,速度梯度(G)为48.9 s-1,GT为58.7×103时,浓液中浊度和CODCr去除率可达到最高值,分别为85%±2%和30%±5%;此时SCN-流失率仅为20%~25%,表明混凝-沉淀工艺能很好地去除Na SCN膜分离浓液中的杂质,使SCN-回收效率达75%以上,适合用于该生产浓液净化过程的预处理。更多还原

【Abstract】 To further purify and recycle the concentrated solution of Na SCN excreted from the nanofiltration membrane in the two-step wet production of acrylic fiber,the coagulation-sedimentation method was applied to the treatment of concentrated solution of Na SCN membrane separation. Different dosages of polyaluminium chloride( PAC),polyacrylamide( PAM),lime milk,etc.,and variable initial p H,stirring intensity were tested to analyze the purification effect of concentrated solution of Na SCN membrane separation. The results showed: when the dosage of PAC,PAM,lime milk was 200 mg/L,2. 5 mg/L,25 mg/L separately,initial p H was 7. 5,stirring intensity was 80 r/min,velocity gradient( G) was 48. 9 s- 1,GT was 58. 7 × 103,the turbidity and CODCrremovalrates of the concentrated solution were 85% ± 2%,30% ± 5%,respectively; the SCN-turnover rate was only20% under the above conditions,and the recovery rate of SCN-was more than 75%. It showed that the method was suitable to the pretreatment of the concentrated solution.更多还原