Causticized muddy white liquid purifying technique

The invention discloses a causticized muddy white liquid purifying technique which is characterized by comprising the steps: causticized muddy white liquid enters a centrifugal separating device at the flow rate of 2.0 to 2.5 m/s for centrifugal swirling for 6 to 10 min; particle impurity with the diameter of larger than 20 Mum in the causticized muddy white liquid deposit downward into a hopper-shaped sludge concentration device; particle impurity in the causticized muddy white liquid, which is not separated under centrifugal action, flows up with the swirling flow into a gravity settling device for gravity separation for 30 to 40 min so as to enable the particle impurity with the diameter of larger than 2 Mum to deposit downward by gravity settling into the hopper-shaped sludge concentration device; and particle impurity which is not separated by gravity settling flows into a fiber filter with the water flow for deep filtration separation, wherein the suspended particle impurity in the purified causticized