A Study was made on the manufacture of active carbon with sodium bisulfate as activative agent both in the laboratory and pilot scale.
Laboratory results showed that the optimum conditions of active-carbonization temperature was obtained at 800°C with NaHSO
4 from a mixture of H
2SO
4 and Na
2SO
4 at the same mole ratio.
These conditions were applied to the pilot plant, but the satisfactory results were not obtained because of the unsuccessful active-carbonization and then, the temperature was raised to 900950°C in the pilot plant.It was found that the active carbon obtained in a pilot scale had an intermediate decoloring ability of commercial steam and ZnCl
2 activated carbons.Na
2S deoxidized from Na
2SO
4 while active carbon is formed can be used as one of the kraft cooking chemicals and its yield was approximately 70%. It was found that yields of active carbons which had more than 90% of decoloring ability to caramel were approximately 24% for sawdust and 20% for bark, respectively.
It was examined in the laboratory if the spent liquor containing considerable amount of NaHSO
4 from R-2 process which was used for the production of chlorine dioxide as bleaching agent was able to be employed as activative agent. We have found that the effect of spent liquor was comparable to NaHSO
4 used as the above described activative agent. We have also studied on the decoloring ability of active carbons to kraft spent liquor and found that the active carbon obtained in the laboratory by R-2 spent liquor had the same decoloring ability compared with those of higher grade commercial active carbons. Therefore, it seems that the active carbon by NaHSO
4 is satisfactorily utilizable in the effluent treatment.
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