Abstract Crude aqueous acidic phosphatic solution such as wet process weak phosphoric acid, 25% P2O5 to 35% P2O5, is passed through a layer of especially prepared perlite filter aid thereby removing substantially all of the finely divided organic and inorganic solids. The clarified solution may be processed as usual to produce merchant grade wet process acid or it can be concentrated to 38% P2O5 to 42% P2O5 and again passed through a fresh layer of especially prepared perlite filter aid for additional clarification. This clarified solution may be processed from this point as usual to produce merchant grade wet process acid or it can be further concentrated to 51% P2O5 to 53% P2O5, allowed to stand in a quiescent state for up to 90 minutes, decanted, and the overflow concentrated to 54% P2O5 to 62% P2O5 to produce a highly refined merchant grade wet process phosphoric acid.
A PROCESS FOR THE CLARIFICATION OF A WET PROCESS PHOSPHORIC ACID SOLUTION CONTAINING FROM ABOUT 25 TO ABOUT 35% P2O3 AND HAVING FINELY DIVIDED ORGANIC AND IGNORGANIC SOLIDS THEREIN COMPRISING THE STEP OF PASSING SAID SOLUTION THROUGH A LAYER OF PERLITE FILTER AID SO AS TO REMOVE SUBSTANTIALLY ALL OF SAID FINELY DIVIDED ORGANIC AND INORGANIC SOLIDS.
Claim 2
Dependent Claim
57 words
A PROCESS FOR THE CLARIFICATION OF A WET PROCESS PHOSPHORIC ACID SOLUTION CONTAINING FROM ABOUT 25 TO ABOUT 35% P2O3 AND HAVING FINELY DIVIDED ORGANIC AND IGNORGANIC SOLIDS THEREIN COMPRISING THE STEP OF PASSING SAID SOLUTION THROUGH A LAYER OF PERLITE FILTER AID SO AS TO REMOVE SUBSTANTIALLY ALL OF SAID FINELY DIVIDED ORGANIC AND INORGANIC SOLIDS.
Claim 3
Dependent Claim
33 words
The process of claim 1 wherein the wet process phosphoric acid solution is heated to a temperature in the range of from 80* to about 250*F and centrifuged through said perlite filter aid.
Claim 4
Dependent Claim
24 words
The process of claim 1 wherein the Wet process phosphoric acid solution contains calcium in a CaO/P2O5 ratio of from 0:1 to about 1:1.
Claim 5
Dependent Claim
74 words
The process of claim 1 comprising the further steps of dehydrating the filtered wet process phosphoric acid solution to a concentration of from about 51 to 53% P2O5, holding said concentrated acid solution quiescently for a time up to 90 minutes so as to settle additional solids, decanting the resulting concentrated acid solution from the settled solids and further dehydrating said decanted acid solution to a concentration of from about 54 to 62% P2O5.
Claim 6
Dependent Claim
59 words
The process of claim 1 comprising the additional step of adding a flocculating agent to the wet process phosphoric acid solution prior to the step of passing said solution through the layer of perlite filter aid, said flocculating agent being added in an amount sufficient to provide from about 0.001 to about 2 pounds thereof per ton of solution.