The present invention discloses a method for improving
phosphorus yield by defluorination, purification and separation of wet-process
phosphoric acid, and belongs to the field of wet-process
phosphoric acid production. The method comprises the following steps: a, adding a reaction amount of a defluorination agent to wet-process
phosphoric acid to carry out a compete reaction; b, adding the material
slurry from the step a to a scroll
discharge sedimentation centrifuge to carry out
solid-liquid separation, and adding the separated liquid to a defluorinated phosphoric acid
storage tank; c, adding hot water to the
solid-liquid separated
solid from the step b to carry out
slurry conditioning, wherein density of the material
slurry is 1.35-1.50 g / ml; and d, conveying the conditioned material slurry from the step c to a
belt filter to carry out
filtration and countercurrent washing, wherein the liquid after
filtration and countercurrent washing enters the defluorinated phosphoric acid
storage tank, and the solid after
filtration and countercurrent washing is the by-product
sodium fluorosilicate. With the method of the present invention,
phosphorus yield in the defluorination purification process can be increased to more than 99% from 95%, and pure
sodium fluorosilicate by-product can be obtained, such that comprehensive utilization of resources is achieved.