Grey phosphorus sink-and-float separation method of sugaring mixed juice

The invention relates to a grey phosphorus sink-and-float separation method of sugaring mixed juice. Pressed mixed juice is firstly prelimed until pH is in the range of 7.2-7.4, and phosphoric acid is added; after the temperature is in the range of 60 to 75 DEG C through once heating, secondary preliming is performed immediately so that lots of impurities are agglomerated and separated out; next, the mixed juice is mechanically stirred for bubbling, and a flocculant is added for sink-and-float separation. A sugar juice settler separates clear juice, mud juice and scums from each other. The sludge and the scums are returned to a mud juice tank and mixed with the mud juice of the previous technical sedimentation basin, and then filtered together; the filtrate obtained after filtering is returned to a previous mixed juice tank, and the obtained clear juice also enters the previous mixed juice tank; in addition, phosphoric acid is added, and the final clear juice can be obtained through stoving by a sulfurous-met