Soda bagasse spent liquor

Lignin was obtained from an industrial soda bagasse spent liquor as before (5). The lignin was initially evaluated as a thermosetting adhesive by the beech strip test. Prior to its application as adhesive, the lignin was reacted with formaldehyde in alkali at temperatures below 60 °C to afford a hydroxymethylated lignin (fi). The hydroxymethylation reaction was done at pH 12 and 13, and samples of the reaction mixtures were evaluated on beech strips with overlaps of 25 x 25 mm, cured for 4 hours at 90 °C and 12% equilibrium moisture content. 

Soda bagasse spent liquor thus contains two useful renewable polymeric chemical feedstocks hemicellulose and lignin. The uses developed so far for these materials are depicted graphically in Figure 1. The use of the hemicellulose as a corrugated board adhesive is discussed in this chapter. 

Venter, J.S.M Van der Klashorst, G. H. The Recovery of By-Products and Pulping Chemicals from Industrial Soda Bagasse Spent Liquors. Paper presented at TAPPI Environmental Conference, Portland, OR, April 1987. 

Hemicellulose was reclaimed from industrial soda bagasse spent pulping liquor by precipitation with methanol as was done in earlier studies 2-5). The hemicellulose precipitate obtained was submitted to different degrees of washing with 50% aqueous methanol, resulting in hemicellulose preparations containing different quantities of ash and lignin. The pH of the hemicellulose was adjusted and borax or CaCh added, after which it was dried and ball-milled to the indicated particle sizes. 

Figure 1. Products from industrial soda sugarcane bagasse spent pulping liquors.

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