Aiming at recovering sodium compounds from KP black liquor, separation of sodium and lignin has been made by means of electrodialysis of ion exchange membranes which have the characteristics of ion selectivity and concentrating capacity. The aparatus consists of 25 cells each of which being Cation exchange membrane - Spacer - Anion exchange membrane - Spacer, and platine-plated stainless electrodes were used.
The separation was done at dilute section circulating the sample black liquor with batch process, and its total sodium decreased from initial concetration of 44.7g/l (as Na₂O) to 5.6g/l (as Na₂O) after the period of 8 hours, and it was found that the balance between the two alkali concentrations had migrated to the side of the concentrated black liquor.
In addition, there are several experimental methods for accelerating the velocity of sodium removal from spent sulfate liquor.

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Economical making of active carbon having good qualities from spent sulfite liquor has been studied.
The purpose has been accomplished by using ZnCl₂ and CaCl₂ together as activating agent, but not by using ZnCl₂ only.
Effects of using CaCl₂ resulted in decreasing the use of ZnCl₂, increasing the active carbon yield and easy treatment of ash elimination.

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