Local mechanical and chemical engineer Professor Mulalo Doyoyo has developed a low-water brickmaking machine, acid-resistant bricks and chemical-resistant paints that consume industrial waste.

The brickmaking machine is adaptable to local conditions and uses vibration compaction to compress the mixture. Local boiler-making skills are sufficient to manufacture the machines.

However, the main benefit of the machine is that it uses industrial waste products and very little water to produce structurally robust bricks.

“The machine can use either fly ash – a waste product of coal burning, such as for power generation – or cement, if fly ash is unavailable. We require samples of the local materials, including the sands, aggregates and fly ash to determine and design a suitable mixing ratio.

“This enables us to provide producers with a mixing ratio based on their local materials that will produce strong bricks using little water. We also train buyers and operators on the correct use of the brickmaking machine,” Doyoyo explains.

Fly ash is an industrial waste product used as a component to reduce cement in producing concrete. Many power stations, mines and industries that burn coal for power have fly ash waste heaps that can be consumed to produce bricks for houses and infrastructure in South Africa.

“My goal was to produce an economically viable, yet high-productivity, brickmaking machine that can help to create sustainable small enterprises and jobs throughout the country.”

The machine requires two operators and 28 stock bricks can be cast within minutes. The low-water bricks require about a day to dry, and various oxides can be added as a top layer to colour the bricks. Entrepreneurs can, therefore, use the machines to produce aesthetically appealing bricks for commercial sale, while remaining cost effective.

Further, the machine can also produce wet-cast bricks, pavers, maxi bricks, Sabricks and clay bricks, enabling entrepreneurs and operators to produce a variety of building products.

The machines have garnered interest from the US and European markets, but these markets would use motorised systems, as they typically do not need labour-intensive equipment. Doyoyo has received samples of fly ash for testing and validation from US-based companies interested in the machines. Tests indicate that the fly ash is suitable.

Meanwhile, Doyoyo has developed acid- resistant bricks, which have received significant interest from petrochemicals multinational Sasol and the mining industry. The bricks are wet-cast and use a chemical called Solunexz mixed with fly ash to produce the bricks.

The materials for these bricks do not need to be calcined, which decreases the production costs, compared with conventional production techniques.

Doyoyo has also developed an Amoriguard-approved chemical- and heat-resistant paint that uses fly ash and paper pulp derived from waste paper sources.

The paint can be applied onto rough and abrasive surfaces, including cinder bricks and the dry-cast bricks without requiring a primer. The paint produces a smooth, visually appealing surface and can be used in industrial applications and for housing and infrastructure development.