Production of high purity sodium chloride brine by multistage leaching

Claim 1

THE METHOD OF CONTINUOUSLY MAKING AT A HIGH FLOW RATE WITH NO SHUTDOWN TIME, A HIGH PURITY SODIUM CHLORIDE BRINE FROM A SOURCE OF SODIUM CHLORIDE CONTAINING IMPURITIES HAVING A DISSOLUTION RATE LESS THAN THE DISSOLUTION RATE OF SODIUM CHLORIDE, WHICH COMPRISES: INTERMITTENLY DISSOLVING SODIUM CHLORIDE FROM SOURCE SALT THROUGH AT LEAST THREE STAGES INCLUDING AS A FIRST STAGE, CONTINUOUSLY COCURRENTLY FLOWING A HIGH PURITY DILUTE SODIUM CHLORIDE BRINE FROM A NEXT SUCCEEDING INTERMEDIATE STAGE INTO CONTACT WITH SOURCE SALT AT A FLOW RATE SUFFICIENT TO ENTRAIN A QUANTITY OF SOURCE SALT IN EXCESS OF THAT REQUIRED FOR SODIUM CHLORIDE SATURATION OF THE DILUTE BRINE, CONTINUOUSLY AND POSITIVELY SEPARATING THE FLOWING BRINE FROM THE SOLIDS ENTRAINED THEREIN SUBSTANTIALLY IMMEDIATELY UPON ATTAINMENT OF SODIUM CHLORIDE SATURATED BRINE AND DISCHARGING SAID BRINE, CONTINUOUSLY INTRODUCING THE SOLIDS SEPARATED IN THE INITIAL STAGE TO A NEXT SUCCEEDING STAGE, AS AN INTERMEDIATE STAGE CONTINUOUSLY COCURRENTLY FLOWING THE SEPARATED SOLIDS FROM A NEXT PRECEDING STAGE WITH DILUTE BRINE FROM A NEXT SUCCEEDING STAGE IN A RATIO OF SOLIDS TO DILUTE FEED BRINE SUCH AS TO DISSOLVE ONLY SOME OF THE UNDISSOLVED SODIUM CHLORIDE TO FORM A DILUTE BRINE AND AT A FLOW RATE TO ENTRIN AND CARRY ALONG THE SOLIDS, SUBSTANTIALLY IMMEDIATELY CONTINUOUSLY AND POSITIVELY SEPARATING THE DILUTE BRINE AND THE SOLIDS AND DIRECTING SAID DILUTE BRINE INTO CONTACT WITH SOURCE SALT IN A NEXT PRECEDING STAGE, AS A FINAL STAGE, CONTINUOUSLY COCURRENTLY FLOWING THE SOLIDS FROM A NEXT PRECEDING INTERMEDIATE STAGE WITH SODIUM CHLORIDE SOLVENT IN A RATIO OF SOLIDS TO SOLVENT SUCH AS TO DISSOLVE SUBSTANTIALLY ALL OF THE UNDISSOLVED SODIUM CHLORIDE TO FORM DILUTE BRINE AND AT A FLOW RATE TO ENTRAIN AND CARRY ALONG THE UNDISSOLVED IMPURITIES, AND SUBSTANTIALLY IMMEDIATELY CONTINUOUSLY AND POSITIVELY SEPARATING THE DILUTE BRINE FROM THE UNDISSOLVED IMPURITIES AND DISCHARGING THE LATTER TO WASTE AND THE DILUTE BRINE AS FEED BRINE IN THE NEXT PRECEDING INTERMEDIATE STATE, WHEREBY THE FLOW OF BRINE IS COUNTERCURRENT FROM THE FINAL TO THE INITIAL STAGE AND COCURRENT WITHIN THE INDIVIDUAL STAGES.