Phosphogypsum pretreatment with CaCO3 to improve the backfill performance
When acid phosphogypsum (APG) is recycled as aggregate of cemented backfill in mines, pretreatment is usually needed to reduce its adverse impact on the backfill. In this study, a new approach of using a neutral salt (CaCO3) to pretreat APG has been proposed to enhance the strength development of th...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-07-01
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| Series: | Case Studies in Construction Materials |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S221450952300133X |
| _version_ | 1797798967815176192 |
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| author | Ying Shi Yanmei Song Chendi Min Jing Du Xiaolin Wang Jie Min Shaofeng Wang |
| author_facet | Ying Shi Yanmei Song Chendi Min Jing Du Xiaolin Wang Jie Min Shaofeng Wang |
| author_sort | Ying Shi |
| collection | DOAJ |
| description | When acid phosphogypsum (APG) is recycled as aggregate of cemented backfill in mines, pretreatment is usually needed to reduce its adverse impact on the backfill. In this study, a new approach of using a neutral salt (CaCO3) to pretreat APG has been proposed to enhance the strength development of the cemented PG backfill. The role of CaCO3 in cemented PG backfill acting as a reactant is explored. In the pretreatment stage, CaCO3 reacted with the residual acid in PG, and the generated calcium ions could solidify the impurities, such as soluble phosphate and fluoride, with solidification rates reaching 90% and 99%, respectively. This neutral modifier buffered pH values of PG aggregate from 1.8 to about 5.0, and excess dosage of CaCO3 did not adjust the pH value of aggregate to an excessively high level. Hence, there was no interference with the hydration reaction of the binder (cement). Using PG pretreated with CaCO3 as aggregate for cemented backfill effectively accelerated the setting process of backfill and increased the unconfined compressive strength (UCS) of the backfill matrix from 0.14 MPa to 2.27 MPa at 28-day age. The present results suggest that CaCO3 pretreatment is an effective way to improve the accessibility of PG as aggregate, thus significantly increasing the utilization rate of PG and enhancing the backfill performance. |
| first_indexed | 2024-03-13T04:11:51Z |
| format | Article |
| id | doaj.art-c2c4025244d34fd3836e9d3ed85b18bc |
| institution | Directory Open Access Journal |
| issn | 2214-5095 |
| language | English |
| last_indexed | 2024-03-13T04:11:51Z |
| publishDate | 2023-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Case Studies in Construction Materials |
| spelling | doaj.art-c2c4025244d34fd3836e9d3ed85b18bc2023-06-21T06:53:56ZengElsevierCase Studies in Construction Materials2214-50952023-07-0118e01954Phosphogypsum pretreatment with CaCO3 to improve the backfill performanceYing Shi0Yanmei Song1Chendi Min2Jing Du3Xiaolin Wang4Jie Min5Shaofeng Wang6School of Resources and Safety Engineering, Central South University, Changsha, Hunan 410083, PR ChinaSchool of Resources and Safety Engineering, Central South University, Changsha, Hunan 410083, PR ChinaSchool of Resources and Safety Engineering, Central South University, Changsha, Hunan 410083, PR ChinaSchool of Materials Engineering, Changshu Institute of Technology, Changshu, Jiangsu 215500, PR China; Suzhou Sinoma Design and Research Institute of Non-metallic Minerals Industry Co., Ltd, Suzhou, Jiangsu 215151, PR ChinaSchool of Resources and Safety Engineering, Central South University, Changsha, Hunan 410083, PR ChinaSchool of Resources and Safety Engineering, Central South University, Changsha, Hunan 410083, PR ChinaSchool of Resources and Safety Engineering, Central South University, Changsha, Hunan 410083, PR China; Corresponding author.When acid phosphogypsum (APG) is recycled as aggregate of cemented backfill in mines, pretreatment is usually needed to reduce its adverse impact on the backfill. In this study, a new approach of using a neutral salt (CaCO3) to pretreat APG has been proposed to enhance the strength development of the cemented PG backfill. The role of CaCO3 in cemented PG backfill acting as a reactant is explored. In the pretreatment stage, CaCO3 reacted with the residual acid in PG, and the generated calcium ions could solidify the impurities, such as soluble phosphate and fluoride, with solidification rates reaching 90% and 99%, respectively. This neutral modifier buffered pH values of PG aggregate from 1.8 to about 5.0, and excess dosage of CaCO3 did not adjust the pH value of aggregate to an excessively high level. Hence, there was no interference with the hydration reaction of the binder (cement). Using PG pretreated with CaCO3 as aggregate for cemented backfill effectively accelerated the setting process of backfill and increased the unconfined compressive strength (UCS) of the backfill matrix from 0.14 MPa to 2.27 MPa at 28-day age. The present results suggest that CaCO3 pretreatment is an effective way to improve the accessibility of PG as aggregate, thus significantly increasing the utilization rate of PG and enhancing the backfill performance.http://www.sciencedirect.com/science/article/pii/S221450952300133XPhosphogypsumCalcium carbonate (CaCO3)Cemented backfillPretreatment |
| spellingShingle | Ying Shi Yanmei Song Chendi Min Jing Du Xiaolin Wang Jie Min Shaofeng Wang Phosphogypsum pretreatment with CaCO3 to improve the backfill performance Case Studies in Construction Materials Phosphogypsum Calcium carbonate (CaCO3) Cemented backfill Pretreatment |
| title | Phosphogypsum pretreatment with CaCO3 to improve the backfill performance |
| title_full | Phosphogypsum pretreatment with CaCO3 to improve the backfill performance |
| title_fullStr | Phosphogypsum pretreatment with CaCO3 to improve the backfill performance |
| title_full_unstemmed | Phosphogypsum pretreatment with CaCO3 to improve the backfill performance |
| title_short | Phosphogypsum pretreatment with CaCO3 to improve the backfill performance |
| title_sort | phosphogypsum pretreatment with caco3 to improve the backfill performance |
| topic | Phosphogypsum Calcium carbonate (CaCO3) Cemented backfill Pretreatment |
| url | http://www.sciencedirect.com/science/article/pii/S221450952300133X |
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