Coal ash proves it's friendly

The Hong Kong University of Science and Technology (HKUST) is to develop and manufacture novel coal ash-based building materials and products in collaboration with 3E Envirotech Products.

The joint project involves an investment of HK$8 million by 3E, a newly established company specialising in the development of environmental technology with commercial value.

Dr Zongjin Li, Associate Professor of HKUST's Civil Engineering Department, will employ extrusion technology in the development of novel building materials with pulverized coal ash, an industrial waste produced by electricity-generating plants.

He will work with 3E to recycle coal ash into high strength bricks, wall panels, light-weight aggregate, high-quality filler materials and masonry blocks with two-way joints.

'Compared to the traditional casting method, extrusion is a flexible technology, showing great improvement in strength, toughness, ductility and durability,' says Dr Li, who is also the Director of the Advanced Cement-Based Building Products Cooperative Research Center at HKUST. 'Wall panels created by extrusion can replace plaster splints and bricks. They are water- and fire-proof, and can be mass-produced in different shapes and sizes.'

Under the agreement, both sides will develop an extruder for the manufacture of coal ash-based wall panels and other building materials. The collaboration will help recycle coal ash, estimated to be in millions of tons each year, greatly minimising the pollution caused by this industrial by-product. It will also minimise construction waste, save land, energy and production costs.

'The applications of coal ash have not been fully utilized in Hong Kong. Tapping the strengths of Dr Li's extrusion technology, we can develop a whole series of advanced building materials that will benefit the construction industry and the environment eventually,' says Mr Wang Ding.