More civil and design engineers should specify the use of galvanised steel structures and hot-dip galvanised reinforcing steel for road and bridge infrastructure, says industry organisation International Zinc Association Africa (IZA Africa) director Simon Norton.

This would help to support the local steel and galvanising industries while enhancing road infrastructure’s longevity.

Expanding on the role that zinc can play in the protection of road and bridge infrastructure, Norton explains that refined zinc is typically used in hot-dip galvanising to coat structural steel, road-sign gantries, and reinforcing steel used in concrete bridges.

“With Africa boasting many major cities along its coastline, there is a great need for all the road-sign gantries to be galvanised and painted, demonstrating zinc’s role in ensuring the longevity of steel and concrete structures.”

Norton adds that zinc galvanising is a “powerful corrosion protection medium”.

Road infrastructure is essential for transporting people and goods, thereby supporting economic development, and empowering communities.

However, such infrastructure is often exposed to various environmental factors that can cause corrosion, which, in turn, compromises the safety, performance and durability of the infrastructure, leading to increased maintenance costs, reduced service life and potential accidents, he explains.

“IZA Africa gets out into the South African and African marketplace and highlights the benefits of zinc in the galvanising sector, zinc-rich paints, and zinc thermal spray for steel structures.

“There are so many players involved in this multi-stage process that no single player can be isolated as having a singular impact on roads and bridges. However, what IZA Africa highlights to industry stakeholders is: without zinc and galvanised steel, the roads and bridges being built will have a very short life span,” Norton highlights.

However, he highlights that Africa, a continent with more than one-billion people, does not have a single zinc ore refinery and, consequently, imports all its refined zinc. He suggests, therefore, that this must change “very soon” so that Africa can beneficiate its own zinc resources and improve its trade balance.

Norton also cites the need to initiate and rapidly progress chemical engineering and mineral processing research on the continent to advance new zinc ore-processing techniques that are clean, green and cost effective. This will ensure that any eventual zinc refinery will produce ingots of sufficient quality and ensure that its operations are globally competitive.

Production Process, Environmental Impact

Zinc production is a multi-stage process encompassing the zinc orebody being geolocated using advanced geochemical detection methods and being assessed before a zinc mining operation is erected on site, and the ore is extracted and processed into a concentrate.

Thereafter, the zinc concentrate is transported to a refinery and chemically processed into high-grade zinc, ready for sale to hot-dip galvanisers.

Norton notes that the mining of orebodies means that a non-renewable resource is being depleted and that the processing of zinc ore into concentrates at mine sites results in environmental impacts.

There could also be environmental consequences associated with the transportation of zinc ore, such as truck emissions, and the refining of zinc ore often requires substantial water and process chemicals consumption.

Although many of zinc’s applications create or facilitate benefits that outweigh the environmental impacts of mining zinc ore, Norton reiterates that research into cleaner, greener mining and refining processes will help mitigate the effects of or eliminate these impacts.

He notes that the primary objective of IZA Africa and IZA worldwide is to promote the use of zinc in sectors where it could benefit people the most, including those of medicine, agriculture and infrastructure development.

“Africa is not a booming economic miracle, and a variety of economic parameters point to [its] . . . needing to maximise the benefits . . . from large capital expenditure. Roads and bridges are large capital spend projects, so countries in Africa that shell out for transport projects must ensure that the infrastructure that’s built lasts a very long time –that is where zinc comes into its own,” Norton concludes.