Method for improving property of dihydrate wet-process phosphoric acid reaction slurry

Abstract

The invention discloses a method for improving the performance of dihydrate wet methods phosphoric acid reaction stuff, which comprises the following steps: Classify treating the stuffs by a classifier, the ardealite crystal size of classification bottom current is: the proportion of particles of +40 um size is 90%-95%, 100 um size is 50%-65%, +150 um size is 20%-35%. Filtering and washing the classification bottom current in a filter. The ardealite crystal size of classification overflow is: the proportion of particles of -40 um size is 80%-85%, -100 um size is 100%. Growing and increasing further have the classification overflow in a seed crystal reaction tank and entering the next classified cycle. Taking the ardealite filtrated and washed to the slag ground, and taking the diluted phosphoric acid to the storage tank, returning the preliminary filter liquid and 1st cleaning solution to the reaction tank, and quadratic countercurrent washing the 2nd cleaning solution in the filter.

Description

technical field [0001] The present invention relates to the production method of dihydrate wet-process phosphoric acid, more specifically, the present invention relates to the improvement of the filtration and washing process in the production of dihydrate wet-process phosphoric acid. Background technique [0002] The production of wet-process phosphoric acid mainly includes four processes: dihydrate, hemihydrate, hemihydrate-dihydrate recrystallization, and dihydrate-semihydrate recrystallization. At present, the dihydrate process is dominant in the world. But no matter which process is used, the production of wet-process phosphoric acid needs to obtain coarse and neat phosphogypsum crystals, so as to improve the filtration and washing performance of the reaction slurry. premise of benefit. [0003] In the existing dihydrate wet-process phosphoric acid production technology, the reaction slurry is directly filtered into the filter, and then added ...

AI Technical Summary

Problems solved by technology

However, with the depletion of phosphate rock resources, the grade of phosphate rock used for wet-process phosphoric acid production (characterized by P 2 o 5 ), the quality (representing impurities) declines, resulting in finely crushed phosphogypsum crystals. When filtering, the gaps in the filter cloth and filter cake are blocked, which seriously affects the filtration and washing performance of the reaction slurry, resulting in the production capacity, washing rate, and phosphorus pentoxide of the device. The recovery rate drops and the consumption increases, seriously restricting the improvement of economic benefits

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