Production and separation of anhydrous alkali metal sulfate and boric acid

Claim 1

IN A PROCESS IN WHICH BORIC ACID AND AN ANHYDROUS SULFATE OF AN ELEMENT SELECTED FROM THE CLASS CONSISTING OF SODIUM AND POTASSIUM ARE SELECTIVELY PRECIPITATED FROM AN AQUEOUS AND ORDINARILY ACID SOLUTION CONTAINING BORIC ACID AND THE SULFATE AS PRINCIPAL SOLUTES, THE SOLUTION ALSO CONTAINING DISSOLVED IRON IN SUFFICIENT CONCENTRATION TO STABILIZE SUPERSATURATION WITH RESPECT TO THE ANHYDROUS SULFATE, THE IMPROVEMENT WHICH COMPRISES TREATING THE SOLUTION WITH A CHEMCAL AGENT SELECTED FROM THE CLASS CONSISTING OF BASIC COMPOUND THAT WILL REACT WITH THE IRON TO PRODUCE FERRIC HYDROXIDE THEREFROM, AND REDUCING AGENTS THAT WILL REACT TO REDUCE FERRIC IONS TO THE FERROUS STATE, SO AS TO SUBSTANTIALLY SO REACT ALL OF THE DISSOLVED IRON TO PREVENT, BY TRANSFORMATION OF THE IRON TO SUCH REACTED STATE, INHIBITION OF PRECIPITATION OF ANHYDROUS SULFATE FROM THE SOLUTION, AND PRECIPITATION THE ANHYDROUS SULFATE FROM THE SOLUTION IN THE PRESENCE OF THE IRON IN SAID REACTED STATE, SAID PRECIPITATION BEING CARRIED OUT AT A TEMPERATURE AT WHICH THE SULFATE IS PRECIPITATED ONLY IN ANHYDROUS FORM.