Process for producing wet method phosphoric acid by medium low grade phosphorus mine

Abstract

A process for preparing phosphoric acid from low-and medium-grade phosphorus ore by wet method includes such steps as countercurrent decomposing of P core by excessive phosphoric acid to generate the solution of calcium dihydrogen phosphate, liquid-solid separation to obtain liquid extract, reacting on sulfuric acid to obtain bihydrated calcium sulfate crystal and phosphoric acid solution, liquid-solid separation to obtain phosphoric acid and phosphogypsum, returning the most of phosphoric acid back to decomposing step, and using the rest as finished product.

Description

technical field

[0001] The invention belongs to the field of phosphoric acid production, and relates to a process method for producing wet-process phosphoric acid by using medium and low-grade phosphorous rock. Background technique

[0002] Wet-process phosphoric acid is the basic intermediate product of the phosphate compound fertilizer industry and the phosphate industry. It has a very important position and is in great demand. At present, the production of phosphoric acid at home and abroad is to use high-grade phosphate rock (there is no strict standard for the grade of phosphate rock, and the industry is traditionally divided into: high-grade: P 2 o 5 ≥30%, medium grade: 24%≤P 2 o 5 <30%, low grade :P 2 o 5 <24%. Enterprise standards stipulate that phosphate rock used for wet processing should be ≥ 28% P 2 o 5 . ), with the gradual depletion of rich phosphate ore mining, the production cost is gradually increasing, and the utilization of low- and medium-g...

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