Post-consumer Blended Textile Separation and Recycling by Hydrothermal Treatment

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With a huge amount of textile waste produced annually, great pressure was imposed on landfill and the fiber supply chain. HKRITA is conducting an on-going project (ITP-103-15TP) for chemically recycling textile materials (e.g. PET and cotton) from their blends. Chemical methods are the focus, particularly hydrothermal treatment and dissolution treatment. Recently, positive results on hydrothermal treatment have been obtained. The PET and cotton/cellulose recovered show great potential in being applicable for textile applications, hence fulfilling the goal of “end-to-end recycling” where post-consumer textiles are recovered as the raw materials of the production cycle. Hence, a complete treatment process and a pre-industrial scale system are proposed to be developed for verifying the treatment performance by generating PET and cellulose samples of reproducible qualities, before further up-scale production proceeds.
Application

The whole process uses only heat, water and less than 15% of green chemical with a recovery rate of over 97% for polyester fibres in 2 hours.
Industry Benefit

A pre-industrial scale hydrothermal system is now set up in a Tai Po factory to evaluate the parameters for scale-up, such as the treatment conditions in a scale of 500L, energy consumption, and optimisation of operation. This will facilitate the system industrialisation in the future.
Technological Breakthrough

The separated fibres with no depolymerisation are ready for spinning and manufacturing of new fabric, while the cellulose powders, decomposed from the cotton, can be applied to functional products such as super-absorbency materials and regenerated cellulose fibres.
Project Name (ITF)
Hydrothermal Treatment to Recycle PET and cellulose from the cellulose and PET Blends Phase II
Project Number (ITF)
ITP/025/17TP