The purification of pre-concentrated up to 80 wt.% H 3 PO 4 phosphoric acid (PA) obtained from Kola apatite in one of the Polish plants by the wet processing route was carried out by sulphate precipitation, desorption of volatile components (SiF 4 , HF) and liquid-liquid extraction method using 4-methyl-2-pentanone (MIBK). The experiment was carried out on a laboratory scale. The effects of the reagent grade Ca(H 2 PO 4 ) 2 . H 2 O, CaHPO 4 . 2H 2 O, Ca 3 (PO 4 ) 2 , and technical grade calcium oxide, the molar ratio of Ca 2 + to SO 4 2 - (0.8-1.5), the temperature (343-363 K), and the duration of precipitation time (1800-7200 s) on the extent of purification from SO 4 2 - were determined. The most efficient precipitant was CaHPO 4 . 2H 2 O. The precipitation using CaHPO 4 . 2H 2 O purified phosphoric acid from the initial SO 4 2 - concentration (1.5-1.8%) to a level of 0.1-0.2 wt.%. The use of 100% excess of SiO 2 over the stoichiometric ratio (in relation to SiF 4 ), while air bubbling and very intensive stirring of the phosphoric acid at 403 K was carried out, allowed the fluorine concentration to decrease to a level below 0.005 wt.% of F. Purification from metals was carried out at room temperature using 1:1.22 mass ratio of PA to MIBK. The stripped phosphoric acid, with a concentration of about 50 wt.% of H 3 PO 4 and 1.5 wt.% of MIBK, contained Fe and Al at a level of 0.01-0.005 wt.% each, Pb, Th <1 ppm, Cr, Co, Ni <0.1 ppm, As, Cd-not detected.