Could zinc be the secret to a more sustainable future?

By Simon Norton, International Zinc Association, Africa Desk

In the next decade, the United Nations projects, the world population will grow to a staggering 8.5 billion people. Supporting a global citizenry of this size will necessitate economic development and the expansion of the global economy at an unprecedented scale.

Meeting these needs will place enormous strain on our finite natural resources. As such, it’s crucial that we think in “circles” when it comes to the use of metals and minerals to ensure optimisation in its mining, production, product life cycle and, eventually, the recycling thereof.

Think zinc 

One resource that is particularly versatile and abundant is zinc, an essential element for all living things and presenting useful metallurgical and chemical properties. Zinc features in our daily lives with applications in everything from agriculture and building to wellness, X-ray machines and much more.

Adding to zinc’s overall appeal is the fact that zinc can be recycled without losing or compromising any of its metallurgical properties or overall value, meaning it can be used over and over again. Zinc is not only a sustainable option during use, but the recycling thereof also works to reduce concentrate demand, energy use, emissions and reducing waste disposal.

According to the American Galvanizers Association zinc has a reclamation rate of 80%, while some 30% of the zinc currently in use is from reclaimed zinc sources. There is however scope for this number to increase significantly as the technology used in zinc recycling is becoming more sophisticated all the time. As the recycling process advances, reclaimed zinc becomes an increasingly viable source for sustainable use across industries.

The circular solution

A circular approach to the use of metals and minerals will help to reduce the strain on natural resources and, ultimately, prevent the depletion of these life-giving materials.

It’s an ethos that also takes the question of climate change into consideration. Key to reducing our impact on the environment, and reducing an industry’s contribution to climate change, is a keen understanding of a particular material’s – zinc in this case – life cycle. Unpacking what happens at each stage, from mining to production, product life time and recycling, is the foundation for developing measures of optimization that reduce costs and protect resources.

Economy and environment 

We’re at a crucial point in history where all resources need to be understood to be finite. It’s to this point that the maximum efficiency and re-use of resources, through the cycle of production, consumption and recycling, needs to take priority. Beyond the environment, the economy sets to benefit from the strategic use of zinc.

In both the construction industry and civil engineering sector, zinc, in the form of hot dip galvanising, is used as corrosion protection. Hot dip galvanising of steel structures and steel items such as concrete reinforcing steel is a cost-effective way to prevent premature corrosion of steel and to ensure a long life for steel in corrosive environments. While hot dip galvanising may cost more initially, it provides a long-term maintenance-free service life, saving significant sums of money normally spent on repainting or coating maintenance over the prescribed life of the project. Hot dip galvanised steel structures can give a trouble-free life of more than 30 years in the right environment. Its maintenance-free longevity offers both an environmental and economic benefit, and in a developing economy like South Africa, solutions that cost less mean more capital for other projects, and with the more widespread use of zinc this is possible without compromising on quality.

As such, when long-term and sustainability enjoys priority over the short-terms gains allowed by taking shortcuts, both the economy and the environment benefit.

Full circle?

Currently, one of the biggest barriers to greater sustainability is the linear economic model of “take-make-dispose”. It’s key to rethink this model to keep waste out of the system. Zinc’s inherent features make it possible to completely eliminate the “dispose” aspect of the model.

Environmentally Eco Friendly Readymixes Are Gaining Traction

Environmentally Eco Friendly Readymixes Are Gaining Traction

AfriSam, as part of its efforts to conserve the environment, perfected the art of producing composite cements using additives as partial replacement for cement.

AfriSam uses sustainably sourced materials coupled with environmentally friendly manufacturing processes

While Portland cement served industry for well over a century it has been superseded by composite cements. Using sustainably sourced materials coupled with more environmentally friendly manufacturing processes, these are blends of high performance cement with carbon neutral mineral components designed to achieve excellent cementitious properties.

Depending on the compressive strength, the carbon footprint is reduced by between 46% to 51% when compared to typical industry cement. An example of this is the AfriSam Eco Readymix brands – Starmix, Foundation Mix and Retainer Mix – which were developed to suit particular construction sector applications.

The performance of the Eco Readymix concretes is far superior to concrete made from pure cements. AfriSam can produce ultra-high performance Eco Readymix concretes with compressive strengths of above 70 MPa.”

AfriSam, as part of its efforts to conserve the environment, perfected the art of producing composite cements using additives as partial replacement for cement. Not only does this practice of recycling products from other industries minimise harm to the environment, these additives also enhance the performance of cement and offer advantages over ordinary Portland cement.

The additives include limestone, fly ash (a by-product of coal fired power stations) and ground granulated blast furnace slag from the steel industry. These products behave like pure cements in the presence of cement of lime.

AfriSam perfected the art of producing composite cements using additives as partial replacement for cement

Significantly despite the low carbon footprint, the performance of the Eco Readymix concretes is far superior to concrete made from pure cements. AfriSam can produce ultra-high performance Eco Readymix concretes with compressive strengths of above 70 MPa.

Years of research and development in cement products and in particular C-Tech technology has given several distinct advantages overs pure cements including improved workability, reduce heat of hydration, reduced susceptibility to chemical attack and increased erosion resistance. The resultant concretes are less permeable and more resistant to corrosion. They also continue to gain strength over time.