磷酸废水封闭循环处理的实验研究

本法由４个化工单元操作组成：旋流离心分离、絮凝、重力沉降和混合稠浆过滤。实验结果表明：第１级旋流离心分离效率在８０％以上。第２级含固相细粒的旋流溢流采用絮凝预处理后，沉降速度提高近３０倍，清液含固量在２００×１０－６以下。１、２级稠浆在混合比为１．５可达良好的过滤性能。本实验结果为磷酸废水封闭循环处理工艺设计、设备设计，以及操作控制提供了理论依据。

Pilot Study on an Enclosed Circulation System for Treating the Wastewater from Phosphoric Acid Production Process

n enclosed circulation system comprising fouroperation units,i.e.,spiral flow centrifugeseparation, flocculation, gravity settling, andmixed thick sludge filtration, has been developedfor the treatment of wastewater from a wet process of phosphoric acid production. The resultsfrom a pilot study on this system show that thespiral flow centrifuge separation in stage 1 had anefficiency of over 80%.The overflow containingfine solid particles from the spiral flow process instage 1 was subject to a flocculation pretreatmentin stage 2, allowing the settling rate to be increased by near 30 times and the supernatant tocontain less than 200 ppm of solid. The thicksludge from stage 1 and that from stage 2 weremixed at a ratio of 1. 5, resulting in a good performance of filtration.