Separating iron from aqueous aluminum salt solutions

Claim 1

THE CONTINUOUS PROCESS OF SEPARATING IRON FROM AQUEOUS ALUMINUM SULFATE SOLUTIONS WHICH COMPRISES PROVIDING AN AQUEOUS SOLUTION CONTAINING ALUMINUM SULFATE AND FERROUS SULFATE WHICH IS SUBSTANTIALLY SATURATED WITH ALUMINUM SULFATE AND WHICH HAS A PH OF 0.3 TO 3.0, PASSING THE SOLUTION THROUGH A SERIES OF IRON REMOVAL ELECTROLYTIC CELLS EACH OF WHICH CONTAINS AN ANODE, PASSING A MERCURY CATHODE MATERIAL CONTAINING FROM 0.02 TO 0.5% BY WEIGHT METALLIC IRON THROUGH THE SERIES OF IRON REMOVAL CELLS, ELECTROLYZING THE SOLUTION IN THE IRON REMOVAL CELLS WHILE MAINTAINING THE CONCENTRATION OF FERROUS SULFATE IN THE SOLUTION AT A LEVEL OF ABOUT 0.1% TO 0.3% BY WEIGHT AND THE METALLIC IRON CONTENT OF THE MERCURY CATHODE MATERIAL AT A LEVEL OF NOT LESS THAN 0.02% NOR MORE THAN 0.5%, THEREBY CAUSING THE SEPARATION OF IRON FROM THE SOLUTION AND ITS AMALGAMATION WITH THE MERCURY CATHODE, ELECTROLYZING THE RESULTING AMALGAM OF METALLIC IRON AND MERCURY IN AN IRON RECOVERY ELECTROLYTIC CELL, USING THE AMALGAM AS THE ANODE, UNTIL ITS IRON CONTENT HAS BEEN REDUCED TO A LEVEL NOT LESS THAN 0.02% BY WEIGHT, CYCLING THE RESULTING MERCURY CATHODE MATERIAL OF REDUCED IRON CONTENT BACK TO THE ELECTROLYSIS OF A FURTHER QUANTITY OF ALUMINUM SULFATE SOLUTION, AND FOLLOWING ELECTROLYSIS, SUBJECTING THE ALUMINUM SULFATE SOLUTION TO THE ACTION OF SULPHURIC ACID TO PRECIPITATE ALUMINUM SULFATE.