Singapore is one of the most densely populated countries in the world with very little land and very few raw materials of its own. With this in mind, the Government of this Asian city-state is pushing ahead the development of a resource-efficient society. In line with this, Singapore’s first ever facility for processing waste incinerator slag is due to start operations in the near future. A REMONDIS Group company has been commissioned to build and operate the plant: REMEX Mineralstoff GmbH.
This new facility for processing slag from waste incineration plants and recovering ferrous and non-ferrous metals is a project initiated by the NEA (National Environment Agency) in Singapore. Having put out the project to tender, the agency awarded the contract to REMEX. This REMONDIS subsidiary has extensive experience of this type of work and already operates similar facilities in the Netherlands and Germany. In order to set up and operate the facility in Singapore, REMEX founded a local branch which is being run under the name, M/s REMEX Minerals Singapore Pte. Ltd.
“As industrialisation grows, so, too, does the demand for metals. By recycling metals from waste incineration processes, we are helping to ensure that the very most is made of our existing resources.”
Venkat Patnaik, Managing Director M/s REMEX Minerals Singapore Pte
REMEX is to begin construction work on the Singapore slag processing and metal recovery plant this October. The facility is due to start operations in the summer of 2015 and will be able to process approx. 650,000 tonnes of incinerator slag every year.
The project in Singapore to process slag and recover raw materials will be acting as a role model in Asia.
The slag will be coming from Singapore’s four waste incineration plants which are also the country’s biggest energy producers. At present, magnet separators are in use which are only able to recover larger pieces of ferrous metal. The disadvantage of this conventional process is that valuable non-ferrous metals, such as aluminium and copper, and small iron pieces remain in the slag residue and are lost forever.
Once REMEX’s facility is up and running, it will greatly increase the country’s recycling rates as it will also be able to filter out non-ferrous metals as small as one millimetre in size. Recovery rates of ferrous metals will also grow considerably as the facility will have the capability to recognise and remove pieces that are four millimetres or bigger. All in all, around 90 percent of the ferrous metals and over three quarters of the non-ferrous metals will be able to be recycled. To reach these targets, REMEX will be relying on both well-established machinery, e.g. magnet separators, as well as on state-of-the-art processes, such as the technology the company developed itself in the Netherlands. Moreover, it will be installing special eddy current separators to ensure even the smallest of metal pieces are recovered.
This new slag processing plant will not only be pushing forward metal recycling, which is so important to Singapore. The NEA is also looking ahead and has its eye on the largest material fraction: the leftover slag itself. If treated correctly, this material could be used as a substitute material in road and earthworks projects – for example as an aggregate in concrete products.
Special processes have been developed to treat waste incinerator slag enabling it to be used as a high quality building product so that it can substitute and conserve primary raw materials.
Such products include paving stones, concrete slabs for building paths, kerbstones, concrete blocks and armour stones for protecting river banks and coastlines. Recycling slag for use in construction projects is already practised in Europe and provides an alternative to sending such material to landfill.
“The construction of REMEX’s facility to recover metals is part of our long-term plan to improve resource efficiency.“
Ronnie Tay, CEO of the NationalEnvironment Agency (NEA), Singapore
The site selected for REMEX’s Singapore slag processing plant is an industrial area covering 1.4 hectares and located right next door to the Tuas Marine Transfer Station. The left-over slag residue will be transported from here by ship to the Island of Semakau. This island primarily consists of deposited slag covered in soil so that its surface area increases year on year. Singapore allows nature to take its natural course on the island, as previous projects have shown this to be the best solution. Today, Semakau has its own thriving biosphere with rich tropical vegetation and a wide variety of animal species.