Recycling of Wastepaper(V): -Calcium Hardness Control of Process Water for Zero-Discharge System-

고지재상연구 (제5보) -공정수 폐쇄화를 위한 칼슘경도 조절-

  • 지경락 (한국화학연구소 펄프제지연구센터) ;
  • 류정용 (한국화학연구소 펄프제지연구센터) ;
  • 신종호 (한국화학연구소 펄프제지연구센터) ;
  • 송봉근 (한국화학연구소 펄프제지연구센터) ;
  • 오세균 (한국화학연구소 펄프제지연구센터)
  • Published : 1999.06.01


A new technique for recycling of white water was developed in order to reduce the calcium hardness in a closed OCC recycling system. Calcium ions present in the white water were precipitated as calcium carbonate by reacting with sodium carbonate, and the precipitated $CaCO_3$ was removed from the system using a flotation fractionation method, which has been commonly used in deinking process. In the flotation stage, a mixed gas of $CO_2$-air was purged into the flotation cell because the pH of $Na_2CO_3$-treated white water was reduced to neutral by $CO_2$ gas. Since $CaCO_3$ precipitate tends to stick onto fine fiber surface and then selectively removed from the white water, a proper amount of suspended solid in white water acts as an important factor for deciding the removal efficiency. By the application of $Na_2CO_3$ addition-$CO_2$ flotation to the short circulated white water, the calcium hardness was significantly reduced by 87% and more. Removal of calcium ions with fine fibers led to a drainage improvement, reduction of fresh water consumption, and enhanced efficiency of wet-end chemicals.



  1. Water reduction in the pulp and paper industry v.1-9 H. A. Simons Ltd.;NLK Consultants Inc.;Sandwell Inc.
  2. Tappi. J. v.76 no.7 Michalowski, R.
  3. Tappi. J. v.60 no.12 Alexander, S. D.;Dobbins, R. J.
  4. Nordic Pulp and Paper Res. J. v.2 no.258 Hedborg, F.;Lindstrom, T.
  5. Appita J. v.51 no.4 Malton, S.;Kuys, K.;Parker, I.;Vanderhoek, N.
  6. Progress in Paper Recycling v.6 no.11 Friberg, T.
  7. Factory Manager of Zulpich Papich Papier GmbH. Personal Communication with H. Trowski
  8. Korea Patent Appl. No., 98-53566 Ryu, J.-Y.;Ji, K.-R.;Kim, J.-D.;Shin, J.-H.;Song, B.-K.;Ow, S.-K.
  9. Korean Patent Appl. No., 98-24526 Ryu, J. -Y.;Seo, H.-I.;Ji, K.-R.;Kim, J.-D.;Shin, J.-H.;Song, B.-K.;Ow, S.-K.
  10. Korean Patent Appl. No., 98-24525 Ryu, J. -Y.;Seo, H.-I.;Ji, K.-R.;Kim, J.-D.;Shin, J.-H.;Song, B.-K.;Ow, S.-K.
  11. Proceedings of Kor. Soc. Ind. Eng. Chem. Shin, J.-H.;Lee, J.-M.