US 12,441,617 B2
Method for purification of at least one aqueous solution of phosphoric acid
Bernard Heptia, Engis (BE); Hubert Halleux, Engis (BE); and Damien Gabriel, Engis (BE)
Assigned to PRAYON, Engis (BE)
Appl. No. 18/724,077
Filed by PRAYON, Engis (BE)
PCT Filed Dec. 23, 2022, PCT No. PCT/EP2022/087733
§ 371(c)(1), (2) Date Jun. 25, 2024,
PCT Pub. No. WO2023/126349, PCT Pub. Date Jul. 6, 2023.
Claims priority of application No. 2021/6073 (BE), filed on Dec. 27, 2021.
Prior Publication US 2025/0109020 A1, Apr. 3, 2025
Int. Cl. C01B 25/00 (2006.01); C01B 25/237 (2006.01)
CPC C01B 25/237 (2013.01) 20 Claims
 
1. A method for purifying at least one aqueous solution of phosphoric acid continuously (hereinafter, PA solution) comprising at least the following steps:
step 1: providing, in at least one vessel, at least one PA solution derived from at least one phosphoric acid obtained by a wet process for production of phosphoric acid, said PA solution having a temperature of between 65° C. and 98° C.; said PA solution comprising, before said step 1:
between 50% and 63% by weight of P2O5 and
between 0.15% and 0.6% by weight of SO3 relative to the total weight of said PA solution;
step 2: adding barium carbonate to said vessel; said barium carbonate having a particle size distribution such that:
less than 1% by weight of said barium carbonate passes through a 45 μm mesh sieve;
between 0% and 2% by weight, of said barium carbonate passes through a 63 μm mesh sieve;
between 2 and 11% by weight of said barium carbonate passes through a 250 μm mesh sieve;
between 25 and 60% by weight of said barium carbonate passes through a 500 μm mesh sieve;
at least 85% by weight of said barium carbonate passes through a 1000 μm mesh sieve;
step 3: mixing said barium carbonate and said PA solution in said vessel;
step 4: removing from said vessel said PA solution formed during step 3 after a residence time of said PA solution in said at least one vessel of between 15 and 240 minutes;
step 5: purifying said PA solution removed from said at least one vessel in step 4, by solvent extraction to obtain a purified PA solution.