Method for the manufacture of superphosphate

Claim 1

A PROCESS FOR INTIMATELY MIXING FINELY DIVIDED PHOSPHATE ROCK WITH ACID IN THE PREPARATION OF FERTILIZER WHICH COMPRISES CONTINUOUSLY INTRODUCING A STREAM OF FINELY DIVIDED PHOSPHATE ROCK AT PREDETERMINED VELOCITY INTO A MIXING ZONE HAVING THE GENERAL SHAPE OF THE FRUSTUM OF A CONE HAVING ITS APEX AT THE BOTTOM; DIRECTING THE STREAM OF FINELY DIVIDED PHOSPHATE ROCK SUBSTANTIALLY VERTICALLY DOWNWARD TO A CENTRAL LOCATION ADJACENT TO THE BOTTOM OF SAID ZONE; CONTINUOUSLY INTRODUCING A PLURALITY OF STREAMS OF LIQUID ACID INTO AN UPPER PART OF SAID ZONE IN A DIRECTION DOWNWARD AT AN ACUTE ANGLE TO THE AXIS OF SAID FRUSTUM AND SUBSTANTIALLY TANGENTIAL TO THE LATERAL BOUNDARIES OF SAID ZONE; CONTROLLING THE RATE OF FLOW AND VELOCITY OF SAID STREAMS OF LIQUID ACID TO MAINTAIN A LAYER OF RAPIDLY MOVING LIQUID ACID OF SUBSTANTIAL THICKNESS UPON THE LATERAL BOUNDARIES OF SAID ZONE, SWIRLING AND DESCENDING SPIRALLY ALONG SAID BOUNDARIES OF SAID ZONE AT A CONTROLLED RATE; CONTROLLING THE RATE OF FLOW OF SAID STREAM OF PHOSPHATE ROCK IN CONJUNCTION WITH THE RATE OF DESCENT OF SAID LIQUID ACID TO MAINTAIN A SWIRLING, TURBULENT POOL OF FLUID ACIDROCK MIXTURE IN THE LOWER PART OF SAID ZONE; DROPPING SUBSTANTIALLY ALL OF SAID STREAM OF FINELY DIVIDED PHOSPHATE ROCK DIRECTLY INTO SAID SWIRLING, TURBULENT POOL OF FLUID WITHOUT CONTACT WITH ACID HIGHER IN SAID MIXING ZONE; AND CONTINUOUSLY WITHDRAWING THE RESULTING INTIMATELY MIXED ACIDROCK FLUID SUBSTANTIALLY VERTICALLY DOWNWARD BY GRAVITY FROM THE LOWER END OF SAID ZONE.