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Utilization of phosphogypsum and phosphate tailings for cemented paste backfill
Qiusong Chen1, Qinli Zhang2, Andy Fourie3
1School of Resources and Safety Engineering, Central South University, Changsha, 410083, People's Republic of China; School of Civil, Environmental and Mining Engineering, The University of Western Australia, Crawley, 6009, WA, Australia.
Journal of Environmental Management
|June 21, 2017
Summary
This study explores using phosphogypsum (PG) and phosphate tailings (PTS) for cemented paste backfill. Optimal results were achieved using Portland cement as a binder and CaO as an additive, yielding over 4 MPa UCS without gas generation.
Area of Science:
- Geotechnical Engineering
- Materials Science
- Environmental Engineering
Background:
- Phosphogypsum (PG) and phosphate tailings (PTS) are industrial byproducts requiring sustainable disposal solutions.
- Cemented paste backfill (CPB) is a common method for mine waste management.
- Investigating novel material combinations for CPB is crucial for resource utilization and environmental protection.
Purpose of the Study:
- To assess the feasibility of using PG and PTS as aggregates in cemented paste backfill.
- To evaluate the impact of different binders (slags, Portland cement) and additives (CaO) on backfill performance.
- To analyze the influence of PG ageing time on backfill consolidation and strength.
Main Methods:
- Experimental preparation of CPB samples using various combinations of PG, PTS, slags, Portland cement, and CaO.
- Testing of unconfined compressive strength (UCS) after 7 and 28 days of curing.
- Analysis of generated gases (CO2, SO2, H2S) and microstructural characteristics using Scanning Electron Microscopy (SEM).
Main Results:
- CPB with PG and PTS alone had low UCS (<1.0 MPa) and generated significant CO2 and SO2.
- Incorporating slags improved UCS threefold but increased gas generation (CO2, SO2, H2S).
- Adding CaO alone reduced UCS significantly, but with Portland cement and 2% CaO, UCS reached 4.44 MPa (28 days) with no gas generation. PG ageing beyond 4 days had negligible effect on UCS.
Conclusions:
- PG and PTS are viable aggregates for cemented paste backfill.
- Portland cement as a binder and CaO as an additive are effective in achieving desired backfill strength and preventing harmful gas emissions.
- This approach offers a sustainable method for managing PG and PTS, contributing to circular economy principles in mining.
Keywords:
Cemented paste backfillPhosphate tailingsPhosphogypsumSlagsUnconfined compressive strengthWaste treatmentMore Related Videos
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