Technologies for recycling of materials using dry-ice

The reusing of plastics on line is not a problem at most of plastic processors. It's not so easy with industrial complex products where the recycling on line is very often impossible because most of plastic materials are not compatible, the reusing of the complex materials in the same production line is always a big problem. The only solution is to separate the products. Some systems exist to separate the different materials in a complex part. The goal of this research is to separate the plastics by a simple method without using complex processes which use polluting products such as solvents for example. A common solution is the grinding of materials and separation by density. It works in few cases where the difference of density is large by floatation in water. Unfortunately, most of plastics have a density close 1. The aim of this research is to adapt a well known technology cryo grinding (-196°C) but adapted to specific materials by using CO2 (-50°C to -80°C). In fact at this temperature some materials come brittle while others remain soft. The problems met in the cryo grinding are distribution of N2 (liquid) and the cost of such an installation. In this project, the novelty is to use a solid cooling agent whose distribution is easy to insure and which doesn't give any pollutant product. Moreover, the dry-ice can be stored in a simple insulated container. The final result of the research will be the setting up of a device (grinder) using dry-ice for the sorting of plastic complex products in order to optimise the recycling.