Steel recycling improved at Leeds
5 Jun 2000
A radical new method of recycling steel has been developed by scientists at Leeds University. The method is cheaper, requires no pre-sorting of scrap, and may even produce a stronger material.
Steel recycling has hitherto been plagued by problems caused by impurities, particularly in the light of new EU targets. The Leeds team has discovered that the controlled addition of aluminium to the molten steel during recycling forms alloys with the tin and/or copper rendering both harmless.
The new alloy may even be improved by this patented process. Initial studies show that the presence of aluminium causes an increase in the hardness of the steel, implying an increase in mechanical strength. These encouraging findings are being evaluated, and once this has been completed, the team intends to replicate the process at pilot plant scale.
The addition of a metal as alloying agent is a radical departure from conventional treatments, which extract the unwanted metals by chemical or electrochemical methods in de-tinning plants. These methods are expensive and use environmentally-unfriendly chemicals. De-tinning plants also have limited capacity, and environmental considerations are increasingly putting constraints on their expansion.
Furthermore, Professor Cochrane thinks that a combination of tin plate scrap, aluminium scrap and domestic incinerator scrap may serve to produce a 'master alloy' or stepping stone to produce a higher quality material compared to remelted steel scrap.
This would be particularly advantageous to countries that currently have no indigenous steel industry. The team is actively seeking collaborative partnerships to develop this innovation through pilot studies.
