搅拌速率对旧报纸回用白水中微细胶黏物稳定性的影响

摘要

以实验室模拟旧报纸回用白水为研究对象,通过改变搅拌速率并实时监测其各项物理化学性能以及微细胶黏物数目、粒径、浊度、电导率、Zeta电位等,来揭示微细胶黏物失稳机理.实验结果表明,微细胶黏物的稳定性与搅拌速率有着明显的关系.搅拌速率低(小于300 r/min)时,胶体物质(CS)和微细胶黏物会因为不能有效的打散而聚合,微细胶黏物的总数从一开始的5.1509×106个/mL降到4.8491×106个/mL.随着搅拌速率的增加(从300 r/min增加到350 r/min),部分结合不牢固的微细胶黏物会分散成为更细小的颗粒,微细胶黏物的总数从5.0350×106个/mL (300 r/min)升到5.3153×106个/mL(350 r/min),总体积从0.64492 mm3/mL增长到0.73218 mm3/mL,当搅拌速率超过400 r/min之后,虽然打散强度变大,但是聚合能力也增强,数均粒径和质均粒径分别为1.85 ～ 1.92 μm和6.24 ～6.56 μm之间波动;当搅拌速率高于700 r/rain时,微细胶黏物的总数从5.7626×106个/mL (700 r/min)快速上升到6.3115×106个/mL (750 r/min),平均粒径减小,以分散为主.%The laboratory simulated whitewater of newspaper was studied to reveal the instability mechanism of microstickies,by changing the stirring speed and real-time monitoring various physical and chemical indexes,such as the number of microstickies,the turbidity,conductivity,Zeta potential.etc.The resultsof experiment shown that the stability of microstickieswas clearly related to stirring speed.The stirring speed lower than 300 r/min,colloidal substances (CS) and microstickies were aggregated due to they could not be effectively dispersed,the total number ofmicrostickies was decreased from 5.1509 × 106 pcs/mL to 4.8491 × 106 pcs/mL.With the increase of the stirring speed (in 350 r/min,400 r/ min),a part of the unstable bound microstickieswere dispersed into the smaller pellet,the total volume increasedfrom 0.64492 mm3/mL to 0.7321 mm3/mL,when stirring speed was higher than 400r/min,the dispersing and coagulation increased at the same time.But more than 700 rpm,many stickies were dispersed,the total number of microstickies increased from 5.7626 × 106pcs/mL to 6.3115 × 106pcs/mL.