Ultrafiltration pretreatment technique for recovering pressed liquor electrodialysis alkali in viscose fiber production

The invention provides an ultrafiltration pretreatment technique for recovering pressed liquor electrodialysis alkali in viscose fiber production, which is characterized by comprising the following steps: passing pressed liquor with the NaOH content of 50-200 g/L through a prefilter to remove large granule impurities, and ultrafiltering to recover lignin and trap high-molecular-weight pollutants to obtain NaOH-containing permeation liquor for subsequent electrodialysis treatment. According to the characteristic that viscose fibers generate hemicellulose-containing high-concentration waste alkali in the pressing process, the alkali waste is firstly pretreated, so that the indexes of the waste alkali liquor are suitable for the subsequent electrodialysis alkali recovery technique, thereby lowering the viscosity of the waste liquor, effectively lowering the energy consumption and enhancing the permeation efficiency and operation stability.