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The sustainability of galvanized steel G
alvanized steel is an integral part of everyday life and is all around us. But how does its prevalence today affect the environment of the future? How sustainable is it? What role does it play in the circular economy? And is the galvanizing process itself environmentally friendly? Steel is essential for housing, infrastructure, transport, manufacturing, and agriculture. Used as frames for our buildings, safety on our roads, and support for the bridges we cross, we must never waste the resources used to produce it by throwing it away when the original function is no longer valid. Instead, we must repurpose steel, especially if the world wants to move away from traditional business models of use-throw-away- remake to a more environmentally friendly, sustainable circular economy that aims to eliminate waste and repurpose resources.
What is a circular economy, and how can galvanizing play a part? A circular economy encourages materials to be made, used, reused, remade and recycled.
Hot dip galvanizing fits perfectly into a circular economy because it optimises the durability of steel (enabling it to be used again) and facilitates the ease of reuse. It can be recycled if there’s no immediate need to repurpose it. Here’s how:
Optimising durability When steel is galvanized, it is immersed in a bath of molten zinc, where it alloys with the iron in the steel to form zinc/iron alloy layers. These layers form the basis of the coating, which is covered with free zinc as the steel lifts from the galvanizing bath. The result is a robust, durable, corrosion-protective finish that will last many years. Without a galvanized coating, steel would corrode, and its lifespan would be short. However, with a galvanized coating, steel can last between 34 and 170 years before the base steel is exposed. This means that steel can be used for the original purpose for which it was fabricated, and – once the project is dismantled – the steel is still good enough to be used elsewhere.
Facilitating ease of reuse
Once a structure – such as a house or fencing – reaches its end of life, the steel can easily be repurposed if it has been hot dip galvanized. The galvanized coating protects the steel from impact and abrasion when disassembled and reassembled.
Recycling Finally, galvanized steel fits nicely into a circular economy because it can be melted and used repeatedly without losing quality if there is no immediate need for repurposing. The zinc coating can also be reused. Zinc and steel are recycled in well-established steel recycling processes. The zinc particulates are returned, without loss of properties, to zinc production plants, where they are incorporated into zinc ingots and reused in the galvanizing process.
How else does the galvanizing process enhance sustainability? A hot dip galvanized finish gives steel a long life and durability. In addition, it creates a
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03/10/2022 10:06 ADF OCTOBER 2022
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