Kappa number lignin content

Figure 6.1 The acid group content of pulps expressed as an ion exchange capacity as a function of kappa number (measure of lignin content) for Kraft and sulfite pulps.

J Value in parenthesis is kappa number corresponding to lignin content... 

Table 2.2.5. Relationships for the interconversion of lignin content and kappa, permanganate, and chlorine (hypo) numbers...

Kratzl K, Billek G (1957) Synthesis and testing of lignin precursors Tappi 40 269-285 Kyrklund B, Palenius I (1964) The total lignin content of sulphite pulps and its relation to the kappa number Pap Puu 46 513-520... 

Srinivasa Rao Y, Shukla RN, Maheshwari S, Kulkarni AY, Jivendra Y (1983) Determination of permanganate and kappa number of pulp with high ash content. IPPTA 20(3) 55-56 Stewart CM, Foster OH, Cohen WE, Leslie RT, Watson AJ (1951) The selection and preparation of a reporducible wood sample for chemical studies. Appita 5 267- 311 Swan B (1965) Isolation of acid-soluble lignin from the Klason lignin determination. Sven Papperstidn 68 791-795... 

Semichemieal pulps produced by the sodium bisulphite and neutral sulphite-anthraquinone pulping processes at 75% yields have properties that are rather similar to a lower yield chemical pulp shown in Table 13.4. The pulp eharaeteristies from this proeess are of considerable interest, since it has been shown that ehemical pulps made by the so-ealled ASAM process, in which the wood is delignified with a liquor containing sodium sulphite, sodium carbonate or sodium hydroxide and methanol (c. 40% of the liquor by volume) with a trace of anthraquinone ean be delignified more rapidly and to a lower kappa number (this surrogate measure of the lignin content of pulp is explained in the appendix) than pulps made in the absenee... 

In chemical pnlping, the kappa nnmber is frequently used as a process control parameter for nnbleached and partially bleached pulps. It has been found empirically that there is a relationship between the kappa number and the Klason lignin content [23] and, therefore, the kappa number is often used to describe the degree of delignifica-tion in (for example) kraft pulping. 

J Li, G Gellerstedt. Oxymercuration-Demercuration-Kappa Number An Accurate Estimation of the Lignin Content in Chemical Pulps. Nordic Pulp Pap Res J 17 410-414, 2002. 

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