Incorporating trace elements in superphosphate fertilizers

Claim 1

IN A PROCESS FOR THE MANUFACTURE OF A PHOSPHATIC FERTILIZER IN WHICH PHOSPHATE ROCK IS TREATED WITH AN INORGANIC ACID TO PRODUCE A PHOSPHATIC FERTILIZER, THE IMPROVEMENT WHICH COMPRISES SUBSTANTIALLY COMPLETELY DISSOLVING AN ACID-SOLUBLE SALT SELECTED FROM THE GROUP DISSOLVING AN ACID-SOLUBLE SALT SECLECTED FROM THE GROUP CONSISTING OF SULFATES AND PHOSPHATES OF AT LEAST ONE OF THE TRACE ELEMENTS REQUIRED FOR NORMAL PLANT METABOLISM IN THE ACID PRIOR TO PRODUCING THE PHOSPHATIC FERTILIZER, SAID TRACE ELEMENT BEING SELECTED FROM THE GROUP CONSISTING OF COPPER, MANGANESE, ZINC, IRON, MAGNESIUM, ALUMINUM, BORON, COBALT, MOLYBDENUM, AND VANADIUM, ALUMINUM, BORON, COBALT, MOLYBDENUM, AND VADADIUM, AND THEREAFTER REACTING THE RESULTING SALT-CONTAINING ACID WITH PHOSPHATE ROCK TO PRODUCE A PHOSPHATIC FERTILIZER MATERIAL, WHEREBY A SMALL CONCENTRATION OF SAID TRACE ELEMENT IS UNIFORMLY DISTRIBUTED THROUGHOUT THE SAID FERTILIZER MATERIAL, THE AMOUNT OF THE ACID-SOLUBLE SALT DISSOLVED IN SAID ACID PRIOR TO FORMING THE FERTILIZER BEING SUFFICIENT TO OBTAIN A CONCENTRATION OF SAID TRACE ELEMENT IN THE FERTILIZER OF AT LEAST 0.01 PERCENT BY WEIGHT.