Production of diammonium phosphate from coke oven gas

Claim 1

A PROCESS FOR RECOVERING THE AMMONIA FROM COKE OVEN GAS AS CRYSTALS OF DIAMMONIUM PHOSPHATE WHICH COMPRISES CONTACTING SAID COKE OVEN GAS IN SEQUENCE WITH FIRST AND SECOND SOLUTIONS, SAID FIRST SOLUTION BEING SATURATED AS TO ITS CONTENT OF DIAMMONIUM PHOSPHATE AND CONTAINING FREE PHOSPHORIC ACID AT A PH VALUE OF FROM 6.0 TO 7.0 SO AS TO BE CONDUCIVE TO THE FORMATION OF DIAMMONIUM PHOSPHATE BY ABSORPTION OF AMMONIA FROM SAID GAS WHEREBY THE SOLUTION BECOMES SUPERSATURATES WITH DIAMMONIUM PHOSPHATE, WITHDRAWING SAID SUPERSATURATED FIRST SOLUTION FROM CONTACT WITH SAID GAS AND CONTACTING SAID SUPERSATURATED FIRST SOLUTION WITH PREVIOUSLY FORMED CRYSTALS OF DIAMMONIUM PHOSPHATE WHEREBY THE SUPERSATURATION OF DIAMMONIUM PHOSPHATE ON THE CRYSTALS AO AS TO LEAVE THE SOLUTION SUBSTANTIALLY SATURATED, AND RETURNING SAID SATURATED SOLUTION INTO CONTACT WITH SAID COKE OVEN GAS AS SAID FIRST SOLUTION, SAID SECOND SOLUTION BEING UNSATURATED AS TO ITS CONTENT OF AMMONIUM PHOSPHATE AND CONTAINING FREE PHOSPHORIC ACID OF A STRENGTH GREATER THAN SIAD FIRST SOLUTION AND OF A PH VALUE OF 3.5 TO 4.5 AS TO BE CONDUCIVE TO THE SUBSTANTIALLY COMPLETE ABSORPTION OF AMMONIA FROM THE GAS, ADDING WATER TO SAID SECOND SOLUTION TO MAINTAIN THE UNSATURATED CONDITION AS AMMONIA IS ABSORBED FROM THE GAS, AND FLOWING SAID SECOND SOLUTION TO SAID FRIST SOLUTION TO REPLACE WATER EVAPORATED FROM SAID FIRST SOLUTION BY THE CONTACT OF SAID SOLUTION WIHH SAID GAS.