Delignification of sawdust of the wood species corai (Albizzia Lebbeck)

Abstract

All the cellulosic materials except pure cotton contain lignin as the cementing material to link the cellulose microfibrils. Delignification is the first step in the preparation of paper and board from fibrous raw materials. Chemical treatments of these materials remove most of the lignin and isolate the fibre in a relatively purer form with improved colour and fibre characteristics. This process is known as delignification. The delignified materials may be subsequently used for paper and board making. In course of pulping studies carried out in different laboratories over the last few decades, attempts were made to shorten the duration of delignification and the pulping and bleaching steps were combined using sodium hypochlorite. An interesting result was obtained when jute was used as a raw material. It appeared worthwhile therefore to subject sawdust to Ca-hypo made by passing into Ca(OH)2 solution in situ and also subsequently by using pure Ca-hypochlorite solutions. In this study a novel idea of combining pulping and bleaching in one step was tried using Ca- hypochlorite. If successful this would give enormous economic benefit.