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Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent
Published on: February 21, 2017
Process envelopes for stabilisation/solidification of contaminated soil using lime-slag blend
Reginald B Kogbara1, Yaolin Yi, Abir Al-Tabbaa
1Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, UK. rbk22@cam.ac.uk
Environmental Science and Pollution Research International
|March 17, 2011
Summary
Stabilisation/solidification (S/S) using hydrated lime and slag binders can treat contaminated soil. Higher binder dosages improve mechanical strength and reduce heavy metal leaching, meeting landfill criteria.
Area of Science:
- Environmental Engineering
- Geotechnical Engineering
- Waste Management
Background:
- Stabilisation/solidification (S/S) is an effective method for treating contaminated soils.
- Optimizing S/S treatment is complex due to intercorrelated variables influencing performance.
- Developing process envelopes is crucial for designing effective S/S treatment processes.
Purpose of the Study:
- To develop process envelopes for S/S treatment of heavy metal and petroleum hydrocarbon-contaminated sand.
- To evaluate the performance of a hydrated lime (hlime) and ground granulated blast furnace slag (GGBS) binder blend (1:4 ratio).
- To determine optimal binder dosages and water contents for effective soil treatment.
Main Methods:
- Soil treatment using 5%, 10%, and 20% binder dosages at varying water contents.
- Assessment of treatment effectiveness through unconfined compressive strength (UCS), permeability, and acid neutralisation capacity.
- Evaluation of contaminant leachability (cadmium, nickel) using pH-dependent tests.
Main Results:
- UCS values reached approximately 800 kPa, and permeability was around 10(-8) m/s after 28 days.
- The binder significantly reduced the leachability of cadmium and nickel.
- A 20% binder dosage met waste acceptance criteria for inert waste landfill and environmental quality standards for both metals.
Conclusions:
- Greater than 20% binder dosage is needed for a balance of mechanical and leaching properties.
- Process envelopes are dependent on the intended end-use of the treated soil.
- Further research may refine S/S treatment design for specific applications.
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