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Utilising innovative rotary kiln technology to recycle waste into synthetic aggregate

Objective



This proposal, which was prepared with the help of an exploratory award which incluced a research feasibility study, is specifically aimed at using an innovative design of rotary kiln to provide a solution to two modem day dilemmas which confront both disposers of waste & users of natural aggregate for the production of concrete: 1. how to overcome the conflicting problems of dealing with the increasing amounts of domestic & industrial wastes &, at the same time, effect a reduction in the numbers of landfill sites being used for disposal 2. how to limit the use of irreplaceable natural resources & still satisfy the growing demand for aggregate. This innovative design of rotary kiln, which is currently undergoing development by the Prime SME Proposer, Sherwen Engineering Company Ltd, represents startling advances in terms of both operating efficiency & overall cost when compared with the traditional heavyweight, inefficient & expensive rotary kiln alternative. The unique properties of the Trefoil rotary kiln (so called because of its triple lobed internal cross section) make it possible to recycle a much greater range of waste material than is possible with conventional kilns. It presents an economical way of combining the thermal & bonding properties of such freely available & often toxic waste as; power station ash; household waste; sewage sludge; river & marine silts; quarry & mine tailings; construction waste & the residue of paper & cardboard production to create synthetic aggregate. A pilot trefoil plant at the Prime SME Proposer's Darford headquarters has already demonstrated its ability to produce synthetic aggregate from a variety of waste. Indications are that a full scale plant will be capable of producing 250,000 cubic metres of synthetic aggregate annually for use in manufacturing structural concrete from approximately the same volume of waste material without any adverse environmental implications. The flexibility, efficiency & relative low cost of a turn key Trefoil plant purpose built to suit a specific waste site will enable synthetic aggregate to be produced in volume at a market price which will be approximately comparable to that of the natural aggregate which currently represents the vast bulk of the EU market. For the first time quantities of synthetic aggregate will be available to the construction industry at prices which will transform the use of these materials which can be similar in strength & are generally lighter than natural aggregates but which have so far been classified as a premium product which inhibited their widespread use. There are very obvious commercial risks inherent in a 2 year research project such as this which is geared to carrying out a comprehensive programme of qualitative research into the synthetic aggregate end product & the process by which it is created whilst also fabricating a full scale prototype Trefoil plant in order to be able to properly & effectively demonstrate the technology Involved & disseminate the best operational practices. However, the potential rewards have attracted a closely integrated group of SMEs & a prestigious team of research providers (to be co ordinated by the University of Leeds) which is ideally suited to carry out the comprehensive 2 year work programme into the composition, characterisation & thermo processing of waste & the allied environmental implicationsfactors which are of vital interest to prospective users of the process. The SME's acknowledge that it will require at least an additional 12 month period to effectively disseminate the intelligence gathered during the research programme & bring the Trefoil Plant & Process to the market.

Funding Scheme

CRS - Cooperative research contracts

Coordinator

Sherwen Engineering Company Ltd.
Address
Mile End Green
DA2 8EB Dartford
United Kingdom

Participants (7)

Dublin Institute of Technology
Ireland
Address
8,Kevin Street
8 Dublin
Gregory Demolition Limited
United Kingdom
Address
24,London Road
CR4 4NA Mitcham
HYDRO International Limited
Ireland
Address
Trim Road
37 Navan
Hanley Control Systems Ltd.
Ireland
Address

Monknewtown - Slane
MBI Beton A.J. Van der Meijden B.V.
Netherlands
Address
10,Taylorweg
5460 AG Veghel
Netherlands Energy Research Foundation
Netherlands
Address
3,Westerduinweg 3
1755 LE Petten
UNIVERSITY OF LEEDS
United Kingdom
Address
Woodhouse Lane
LS2 9JT Leeds