Alkalilignin made up in the scaling process is responsible for the colour of residual solutions resulting from sulphate cellulose fabrication technology. The present paper deals with the precipitation of alkalilignin in residual solutions by means of sulphuric acid. The experimental approach has taken into account the technological origin of residual solutions. Thus, both qualitative and quantitative determinations have been done for an accurate assessement of the composition of residual solutions gathered after washing cellulose.
