How Do We Recycle?
- Collection and dismantling – Recover & Reuse
- Here spare parts are recovered and parts that can be directly reused are collected.
- There is a variety of approaches for the collection of waste materials (glass, paper) and end-of-life products (electronics, vehicles) that are distinguished by the logistical approach (e.g. waste separated and sorted in every home, at recycling depots where people travel to deposit the waste, or at waste management facilities, where the recyclable material is collected by waste removal companies and sorted on site at the regional waste facilities). Different regions and countries use different tactics for the initial collection of these materials, each has its own merit and the economics and socio-political dimensions of these decisions are worth studying.
- Disintegration and breaking down the material
- Especially for end-of-life products like electronic devices, disintegration is highly important. In this step the connections between components and building blocks of the devices as well as connections between different materials are destroyed by breaking, cutting, shredding, ablating or detaching.
- Separation of materials
- Here the materials that are still mixed together are separated by their different physical properties. Separation techniques include density separation, magnet separation, eddy-current separation and electrostatic separation. In these processes the classified materials are separated into concentrates that are processed further in the conversion step.
- Coarse metal can be separated using a magnet.
- Shredded material can be sieved by size fractions. To meet technical and economical requirements, process parameters such as the design of the sieving machine as well as the retention time can be varied.
- After sieving, material of the same size can be separated based on their density differences.
- Further separation
- At this point electrolysis, precipitation and leaching, crystallisation and ion-exchange processes on solid or liquid phases (solvent extraction) are applied to separate out specific elements.
- Smelting and purification
- The concentrates produced can be combined with other components and relatively pure waste materials from other sources (e.g. production scraps) and processed in pyro-metallurgical (smelting) processes.
- To separate pure materials from the resulting alloys by using the chemical behaviour of the different metals.
The recycling process occurs in steps.