Colour change with the alkaline extraction reaction
Last week we took some video of the alkaline extraction process step. This is where we clean up the stock after the first R3 reaction. The R3 reactions oxidize the biomass and the main byproducts of the reaction are various organic acids. We use caustic soda to clean up these organic acids. These acids, when too prevalent, interfere with our crystallization reaction. The resulting reaction leaves a dark brown liquor. When we dewater the mixture, the resulting solids are very clean and ready for the final crystallization reaction.