Acta Montanistica Slovaca (Nov 2005)
Flotation separation of PET from a PET, PVC and PS mixture by the hydrofilization of the PET surface in NaOH solutions
Abstract
Recycling is the most effective method of waste minimization created by the human activity. The idea of waste re-use as a result of environmental, social and economical factors is becoming very relevant in the last decades. The portion of plastics in the municipal waste is growing year by year as also is its use in the wrapping industry. A condition for recycling technologies is the input of highly pure plastics (without undesirable admixtures) suitable for recycling. Various separation technologies can be used which provide separation of particular components of plastic waste and contaminants. Flotation is one of the separation methods used especially for the ore beneficiation but recently is widely also used for the separation of various types of waste. Plastics, which are not possible to be separated by gravitational methods (because they have almost the same density), PET from beverage bottles, PVC from bottles and foils and PS from beverage beakers, were studied. By changing the surface properties of PET from naturally hydrophobic to hydrophilic by the adjustment in a NaOH solution, PET with the recovery of up to 99 % in the non-foamy product and with the product purity of up to 98 % was acquired by the flotation.
