Process for recovering the alkali metal content of spent pulping liquor

Claim 1

A PROCESS FOR RECOVERING ALKALI METAL CONTENT FROM A SPENT PULPING LIQUOR COMPRISING: (A) INTRODUCING THE LIQUOR IN A FINELY DIVIDED STATE, AND AN OXYGEN CONTAINING GAS INTO A COMBUSTION ZONE TO EFFECT COMBUSTION OF THE LIQUOR AT A TEMPERATURE BETWEEN ABOUT 1700*F, AND ABOUT 2200*F., THE QUANTITY OF OXYGEN CONTAINING GAS INTRODUCED BEING SUFFICIENT TO MAINTAIN COMBUSTION IN A REDUCING ATMOSPHERE, SAID COMBUSTION CONVERTING THE LIQUOR TO AN INORGANIC SMELT CONTAINING AN ALKALI METAL CARBONATE AND A COMBUSTION GAS CONTAINING HYDROGEN SULFIDE; (B) REMOVING THE INORGANIC SMELT, AND THE COMBUSTION GAS FROM THE COMBUSTION ZONE; (C) SEPARATING THE SMELT AND THE COMBUSTION GAS TO THEREBY RECOVER THE ALKALI METAL CONTENT; AND (D) CONTACTING THE COMBUSTION GAS WITH AN ABSORPTION SOLUTION CONTAINING SODIUM HYDROXIDE SOLUTION TO REMOVE HYDROGEN SULFIDE THEREFROM.