Innventia AB's LignoBoost process enables the extraction of high purity lignin efficiently from the black liquor in kraft mills. A stream of black liquor is taken from the evaporation plant and the lignin is precipitated by acidification and filtered. The filter cake is redispersed and acidified and the resulting slurry is filtered and washed. High purity lignin can be produced at several scales, namely 10g, 1kg, 10kg and over 1,000kg. Innventia has invested significantly to demonstrate the potential of lignin as a viable feedstock for carbon fibre manufacture. Initially, the fibre melt spinning performance of the lignin is assessed using single filament melt extrusion and then melt spinning is performed at the multifilament scale, where fine fibres can be produced for conversion to carbon fibre. Oxidative thermostabilisation of the lignin fibres is carried out so that carbonisation can proceed. The effects of thermal treatment programmes and tensioning have been studied by using either thermomechanical analysis or by using test equipment specially designed to monitor carbonisation profiles with either stress or strain control. In addition, continuous processes for the conversion of lignin fibre to carbon fibre are being developed.