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Physical process to sort construction and demolition waste (C&DW) fines components using process water.
Taillard Vincent1, Mercier Guy1, Pasquier Louis-César1
1Institut national de la recherche scientifique (Centre Eau Terre Environnement), Université du Québec, 490 rue de la Couronne, Québec, Qc G1K 9A9, Canada.
Waste Management (New York, N.Y.)
|March 3, 2022
Summary
Construction and Demolition Fines (C&DF) recycling is challenging. This study introduces an efficient physical sorting process for C&DF, enabling the recovery of valuable materials like gypsum and aggregates.
Area of Science:
- Environmental Science
- Materials Science
- Waste Management
Background:
- Modern societies generate substantial Construction and Demolition Wastes (C&DW).
- Existing recycling methods are inefficient for C&DW fines (<10 mm), which constitute a third of C&DW.
- Landfilling of C&DW fines poses environmental concerns, necessitating alternative recycling solutions.
Purpose of the Study:
- To develop an efficient sorting process for Construction and Demolition Fines (C&DF).
- To enable the segregation and recovery of valuable materials from C&DF.
- To design a process adaptable for integration into existing recycling facilities.
Main Methods:
- A novel sorting process train utilizing physical separation techniques from mining and soil treatment industries.
- Application of process water for segregation and concentration of gypsum from 2-12 mm C&DF.
- Hydraulic classification and physical sorting based on density, size, and shape for other constituents.
Main Results:
- Successful segregation of gypsum into a fraction with 55-65% content, representing 40% of the total mass.
- Separation of other C&DF components into high-potential recycling fractions: coarse aggregates (15%), fine aggregates (9.4%), organic and inorganic fibers (10.8%), and light organic compounds (24.8%).
- The developed process is designed for integration into existing facilities with an evaluated cost of 38 CAN$/t.
Conclusions:
- The presented physical separation process train offers an efficient solution for recycling C&DW fines.
- The method allows for the recovery of multiple valuable material streams from C&DF, promoting a circular economy.
- The process is cost-effective and adaptable for industrial implementation, addressing a critical gap in C&DW management.
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