Method for removing impurities in phosphoric acid

Abstract

The invention discloses a method for removing the impurities in phosphoric acid. The method for removing the impurities in the phosphoric acid is characterized by comprising the following steps that firstly, a phosphoric acid precipitation groove is installed and an efficient thickener is further installed in the precipitation groove; secondly, a cone precipitator is arranged at the bottom of the phosphoric acid precipitation groove, the precipitated impurities are discharged for one time every 0.5-1.5h, and the precipitated impurities are discharged into a residue acid groove; finally, the precipitated impurities are pumped into a extraction groove through a residue acid pump. The method for removing the impurities in the phosphoric acid has the advantages that the color of the finished phosphoric acid is greatly improved, the original amount of solid is reduced from 1-2 to below 0.05, the color of the finished phosphoric acid is obviously whitened, and the fineness is good; due to the fact that the gypsum content of the finished phosphoric acid is small, most of other metallic oxide and gypsum impurities are precipitated at the bottom of the phosphoric acid precipitation groove and are discharged into the extraction reaction groove to be recycled, the impurity content of slurry added into an ammonium phosphate heater is relatively smaller, the frequency of the heater scaling phenomenon is obviously reduced, the concentration effect is good, and steam is greatly saved.

Description

technical field [0001] The invention relates to an improved method for carrying out sedimentation and filtration of gypsum in a phosphoric acid solution, improving the quality of phosphoric acid, and recycling the gypsum to an extraction reaction system, in particular to a method for removing impurities in phosphoric acid. Background technique [0002] Before the improvement, the finished phosphoric acid directly enters two 9000×9000×7000 square storage tanks (with stirring paddles). Since the four corners cannot be stirred for a long time, the gypsum will accumulate over time, and the gypsum will slide down after a certain period. Can cause the color of finished ammonium phosphate to turn gray, and total nutrient also reduces thereupon, and the product can't meet the high standard requirement of the market. Contents of the invention [0003] In order to overcome the defects of the above-mentioned prior art, the present invention provides a method for removing impurities i...

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Problems solved by technology

[0002] Before the improvement, the finished phosphoric acid directly enters two 9000×9000×7000 square storage tanks (with stirring paddles). Since the four corners cannot be stirred for a long time, the gypsum will accumulate over time, and the gypsum will slide down after a certain period. It will cause the color of the finished ammonium phosphate to be gray, and the total nutrient will also decrease accordingly, and the product cannot meet the high standard requirements of the market

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