Sulfuric Acid → Phosphoric Acid

Participants

Reaction Steps

Method presented in this example is effected in an identical system as that described in the first example the only difference being that it has only three washing zones, the sulphuric acid for the filter liquors being introduced to the stream of a condensate K behind the scrubber 7. Washing in the first zone 10 is effected with filter washings FP obtained from the second washing zone 9 and the last washing zone 4, whereas to the second washing zone 9 there is supplied solution R obtained in the filter cloth washing zone 6. Condensate K in the amount of 42 cu. m. per hour is used for washing cloths within zone 6 to which after hydrolysis waste sulphuric acid OKS of 1.56 t per cu. m. density is introduced containing 0.8 percent by weight of Fe2O3 in the amount of 4 cu. m. per hour from a titanium oxide manufacturing plant. To the last washing zone 4 there is supplied water in the amount of 20 cu. m. per hour. Filter washings FP from zones 4 and 9 contain 5.6 percent by weight of H2SO4 and 10.9 percent by weight of P2O5. For decomposition of phosphoric raw material FS at a rate of 48 t per hour there is used sulphuric acid of a concentration of H2SO4 equal to 98 percent by weight in the amount of 20 cu. m. per hour, dilluted with washings FP from the first washing zone 10 in the amount of 146 cu. m. per hour of a concentration of P2O5 equal to 22.3 percent by weight and concentration of H2SO4 equal to 2.3 percent by weight. In the course of this process there is obtained wet phosphoric acid EKF of a concentration of P2O5 equal to 29.0 percent by weight in the amount of 30.4 cu. m. per hour and waste phosphogypsum F of moisture content equal to 23 percent by weight of H2O in the amount of 99 t per hour containing 0.22 percent by weight of P2O5 in a form soluble in water; 0.28 percent of P2O5 by weight in a substitutive form and 0.3 percent by weight of P2O5 in the form of a non-decomposed phosphoric raw material in terms of dry matter.

Provenance & Evidence