Presentation for Challenges in Metal Recycling

Presentation for Challenges in Metal Recycling

Challenges in Metal Recycling

Before diving into the challenges facing metal recycling, one must define what exactly recycling means. Recycling is a process to change materials (waste) into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, reduce energy usage, reduce air pollution (from incineration) and water pollution (from landfills) by reducing the need for “conventional” waste disposal, and lower greenhouse gas emissions as compared to plastic production. (Wikipedia)

What are the three most important findings you can take from this paper?

1. Over the past few decades the number of elements in the periodic table used in products has increased to the point where almost every stable element in the table is now being used for its chemical or physical properties in small amounts in products to make the devices strong/faster etc.  The elements that are not used that often but are used for their functional uniqueness that separates them from other metals are known as specialty metals and these metals are harder to recycle and replacements for these metals are hard to come by due to their uniqueness.
2. The EOL-RR (End of Life – Recycling Rate) is defined as the ‘fraction of metal in discarded products that is reused in such a way as to retain its functional properties’. The EOL-RR of the specialty metals is <1% where as for metals such as Iron and copper the EOL-RR is >50% (although it is not massively over 50%). The table below shows the EOL-RR of each of the stable metals in the periodic table.
3.  An example of where consumers have been educated and the efficient methods of recycling the element is used is the Zinc in car batteries where there is an EOL-RR of 90-95%. This shows that if the public and businesses know how to recycle them and the correct procedures are in place, the loop can almost be closed loop system.

Why do specialty metals have such low recycling rates?

The processes involved in recycling are

1. Collection (gathering used metals to be recycled)
2. Pre-processing (repeated sorting using manual, magnetic, optical etc.)
3. End-processing (thermo-dynamic processes optimised for each metal)

Specialty metals have low recycling rates as the recycling process for those metals is not optimised. Since the amount of the elements being used in the products are minute, in order to make it economical to extract the metals, a lot of the products must be collected for processing. Consumers are not fully aware of the elements used in the products they are using, so do not know how to recycle products with a long life time as they are not disposed enough to warrant educating people to sent these to the correct recycling plant and this is why collection rates are so low for these materials. Also with recycling the pre-processing state of the cycle is very labor intensive so is not as scale-able  as the end processing stage, this is also a reason why specialty metals have low recycling rates.

What are the activities with the greatest potential for improving metal recycling?

Collection is the biggest downfall for most of the metals. Because the customers do not know what is in their products, when recycled, the specialty metals are not extracted because not enough of these metals are collected to warrant having a process to remove them because of the lack of benefit and the fact that it is only a small amount that they are using in the next product also. If all products were collected and sorted into different categories depending on their chemical make up, the collection rates would be a lot higher and as a result, there would be a greater benefit in improving the processing of both the specialty and widely used metals.