Caustic Soda Recovery Plant

タイトルまたは説明

During the mercerisation process, cotton yarn or fabric (mainly woven fabric but also knit fabric) is treated in a solution of concentrated caustic soda (**0 - **0 g NaOH/l, or also **0 - **0 g NaOH/kg textile substrate) for about *0 - *0 seconds. The textile substrate is then rinsed in order to remove caustic soda. This rinsing water is called weak lye (*0 - *0 g NaOH/l) and can be concentrated by evaporation for recycling. The principle is shown in the figure below.

After removal of lint, fluff and other particles (using self-cleaning rotary filters or pressure micro-filtration), the weak lye is first concentrated, for instance in a three-stage evaporation process. In many cases, purification of the lye is required after evaporation. The purification technique depends on the degree of lye contamination and can be simple sedimentation or oxidation/flotation with injection of hydrogen peroxide.