Simon Norton | Director | Africa | International Zinc Association (IZA) | mail me |
From the tyres on vehicles to ceramic tiles, protective coatings, sunscreens and agricultural products, zinc oxide ranks among the most versatile forms of zinc. It has applications across several commercial sectors relevant to Africa. Manufacturers can produce zinc oxide through several processes.
The primary route is the indirect French process. Manufacturers melt metallic zinc ingots or high-purity scrap in a furnace and vaporise the zinc at temperatures above its boiling point of 907°C. The resulting zinc vapour reacts with oxygen in a combustion chamber. It rapidly oxidises and forms fine, high-purity “ZnO” particles upon cooling. This process produces high-grade industrial and rubber-grade zinc oxide.
The second route is the direct American process. Manufacturers mix zinc ores, such as roasted zinc concentrates or secondary zinc residues, with carbonaceous fuels like coal or coke. They then reduce the mixture in a furnace. Air immediately oxidises the zinc vapour produced during reduction within the same reactor system. This process yields a lower-purity, pigment-grade material containing trace metallic impurities.
The third route involves wet chemical hydrometallurgical processing. Manufacturers dissolve zinc feedstocks, zinc ash, or scrap in acid, such as sulphuric acid, to create a purified zinc salt solution. They then add alkaline reagents, including sodium carbonate or ammonia, to precipitate zinc carbonate (ZnCO₃) or zinc hydroxide, Zn(OH)₂. Next, they filter and wash the precipitate before calcining it at temperatures between 400°C and 800°C. This process yields ultra-high-purity, pharmaceutical-grade or active nanostructured zinc oxide.
Zinc oxide derives its versatility from a combination of physical and chemical properties. These properties allow it to perform different roles across industrial, agricultural, and medical applications.
Zinc oxide is a good example of how a relatively simple zinc compound can become an essential ingredient in products that are fundamental to modern life. Its applications span manufacturing, agriculture and medicine, making it particularly relevant to the diverse needs of all economies, including many in Africa.
Putting the bounce into tyres
One of zinc oxide’s major industrial applications is its role as a vulcanisation activator in rubber production. It is particularly important in tyre manufacturing, where it contributes to rubber’s resilience and elasticity. Consequently, zinc oxide has a direct connection to transport and mobility.
These sectors are critical to Africa’s economic development, from passenger vehicles and commercial transport to the movement of agricultural and mineral products. However, tyres represent only one part of the story. Zinc oxide also plays an important role in ceramics, where it contributes to the production of frits, artistic glass and enamels. Its properties help improve the durability and appearance of ceramic tiles, cookware and tableware. In paints and coatings, zinc oxide can function as a pigment while improving lightfastness and hardness.
Furthermore, zinc oxide can contribute to corrosion protection and provide anti-fouling and antimicrobial properties. These applications have particular relevance in Africa, where infrastructure and industrial assets often face challenging environmental conditions.
Durability is an important consideration wherever resources are constrained, and infrastructure has to deliver value over a long operating life. Zinc oxide contributes to the performance of a wide range of products, from rubber and coatings to ceramics. These applications can support more resilient manufacturing and infrastructure.
From the factory to the farm
Some of the most important African applications of zinc compounds extend beyond conventional industrial markets into agriculture. Zinc is an essential micronutrient for plants, yet zinc deficiency remains widespread in African soils.
For example, we note that average zinc deficiency rates range from 24% in Nigeria to 66% in Zambia. Soil zinc deficiency can also contribute to zinc deficiency in human populations, particularly where diets rely heavily on cereal crops.
Zinc-containing fertilisers can therefore address two interconnected challenges. They can improve crop productivity while increasing the zinc content available through food. We also note that zinc fertilisers can improve crop resilience to environmental stresses, including drought and heat. They can also increase zinc concentrations in grain. On farms, zinc oxide plays a vital role in animal health and crop production.
Zinc oxide acts as a micronutrient fertiliser additive. It corrects zinc deficiencies in soils and promotes enzymatic activity, protein synthesis, and chlorophyll formation in crops, thereby supporting healthier crop growth. Alternatively, zinc oxide can protect crops through its antimicrobial and antifungal properties. It can also serve as a UV protectant in modern agrochemical and nanopesticide formulations.
Finally, zinc oxide functions as a livestock feed supplement. Farmers and feed manufacturers add it to swine, poultry, and cattle feeds as an essential trace element. It helps enhance gut health, boost immune responses, and support growth performance.
Food security is not simply about producing more food; it is also about producing nutritious food. The relationship between zinc-deficient soils, crop performance, and human nutrition makes zinc an important part of the wider conversation around agricultural productivity and health in Africa.
A compound with a human dimension
Zinc oxide also has important medical and topical skincare applications. Manufacturers include it in skin lotions and ointments, where it serves as a mild astringent, skin barrier, and antiseptic. Common applications include baby rash creams, calamine lotions, and burn ointments. These products help promote wound healing and reduce inflammation.
Under intense sunlight, zinc oxide provides broad-spectrum UV protection. It acts as a physical UV filter in sunscreens and dermatological products by reflecting both UV-A and UV-B radiation. Even more interestingly, zinc oxide also has applications in dentistry. When mixed with eugenol, it forms zinc oxide-eugenol cements. Dental professionals use these materials for temporary tooth restorations, root canal sealers and pulp-soothing dressings because of their sedative and antibacterial properties.
For Africa, food security, crop resilience and access to healthcare remain closely connected to economic development. Consequently, the wider zinc value chain presents numerous opportunities. Zinc compounds may not always be visible to the end user, but their contribution is vital to human well-being and health.
From the products that support mobility and manufacturing to agriculture and healthcare, zinc oxide and zinc compounds demonstrate the breadth of applications that this essential element offers Africa.