How is hot dip galvanizing sustainable?
One of zinc’s most exceptional qualities is its ability to protect steel from corrosion. When left unprotected, in almost any environment, steel will corrode.
Galvanizing protects steel by providing a physical barrier, as well as cathodic protection for the underlying steel, allowing the steel’s service life to be significantly extended. For more information, see How Zinc Protects Steel and Durability and Service Life.
Attention to the durability of steel structures and components has important environmental, economic and social consequences. Some of these are less obvious than others. The overall economic cost of corrosion has been studied in several countries and is commonly estimated at up to 4% of gross domestic product.
By protecting steel from corrosion, galvanizing performs an invaluable service. It helps to save natural resources by significantly prolonging the life of steel and capital investments. The long-term durability provided by galvanizing is achieved at a relatively low environmental burden in terms of energy and other globally relevant impacts, especially when compared to the energy value of the steel it is protecting.
Lack of attention to optimal corrosion protection can leave a damaging economic legacy of repeated maintenance costs. For example, in social housing projects, future maintenance costs will be borne by the local authorities. In public infrastructure projects, use of galvanized steel can lead to lower maintenance budgets, releasing public funds for other purposes.
Hot-dip galvanizing works in a circular economy. By-products of the galvanizing process such as zinc dross, zinc ash or acids are recycled or used for the production of zinc preparations. Typical process consumables, such as hydrochloric acid and flux solutions, are recycled or recycled in the recycling process; for example, “spent” hydrochloric acid solutions are used to produce ferric chloride, which is used in the treatment of urban wastewater.