Ion exchange process for recovery of monovalent ions from waste sulfite pulping liquor

Claim 1

AN ION EXCHANGE METHOD OF TREATING THE WASTE SULFITE LIQUOR RESULTING FROM MONOVALENT CATION SULFITE PULPING OF WOOD WHEREIN THE MONOVALENT CATION IS SELECTED FROM THE GROUP CONSISTING OF AMMONIA AND ALKALI METALS OR SELECTIVELY SEPARATING SAID MONOVALENT CATIONS FROM MULTIVALENT CATIONS CONTAINED IN THE LIQUOR COMPRISING THE STEPS OF PASSING THE WASTE LIQUOR SUCCESSIVELY THROUGH A PAIR OF FIRST ION EXCHANGE RESINS HAVING MONOVALENT CATIONS THEREON SELECTED FROM THE GROUP CONSISTING OF AMMONIA AND ALKALI METALS, TO EFFECT PREFERENTIAL EXCHANGE OF MULTIVALENT CATIONS IN THE WASTE LIQUOR FOR SAID MONOVALENT CATIONS ON THE RESINS AND PRODUCING A LIGNOSULFONATE EFFLUENT THEREFROM, SAID PASSAGE OF THE WASTE SULFITE LIQUOR SUCCESSIVELY THROUGH SAID FIRST RESINS BEING CONTINUED UNTIL A PREDETERMINED PROPORTION OF MULTIVALENT CATIONS BEGIN TO LEAK WITH THE EFFLUENT FROM THE FIRST AND SAID PAIR OF FIRST RESINS; SUBSEQUENTLY PASSING THE LIGNOSULFONATE EFFLUENT FROM THE LAST OF SAID PAIR OF FIRST RESINS THROUGH AT LEAST ONE SECOND ION EXCHANGE RESION HAVING HYDROGEN IONS THEREON TO EFFECT EXCHANGE OF SAID MONOVALENT CATIONS IN THE LIGNOSULFONATE EFFLUENT FOR HYDROGEN IONS ON THE SECOND