1
|
Xie G, Liu L, Suo Y, Zhu M, Yang P, Sun W. High-value utilization of modified magnesium slag solid waste and its application as a low-carbon cement admixture. J Environ Manage 2024; 349:119551. [PMID: 37988896 DOI: 10.1016/j.jenvman.2023.119551] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 10/17/2023] [Accepted: 11/04/2023] [Indexed: 11/23/2023]
Abstract
A large amount of magnesium slag solid waste, insufficient comprehensive disposal capacity, high disposal costs, and uncertain environmental stability hinder the low-carbon, green, and sustainable development of magnesium and magnesium alloy smelting. Therefore, this study proposed a high-quality, large-scale, and industrialized disposal method for modified magnesium slag (MMS). Through relevant experimental tests and microscopic characterization methods (physical and chemical performance, hydration heat, resistivity, and microstructure tests), the physical and chemical properties, curing mechanism, and social benefits of MMS low-grade magnesium slag were investigated. The physical and chemical properties, curing mechanism, and social benefits of modified magnesium slag low-carbon Portland cement (MMSPC) produced by MMS as a cement admixture were elucidated. The results showed that (1) the physical and chemical properties of MMSPC met the requirements of the GB 175-2007 "General Portland Cement" standard. (2) A significant difference was observed in the early hydration heat release of fresh MMSPC slurry, confirming a hydration composite effect between MMS and clinker, which was also the key reaction mechanism of MMS replacing clinker to produce MMSPC. (3) The resistivity of MMSPC increased, decreased, and then increased with time, which was mainly controlled by the settling of the aggregate, the dissolution of the binder, and the hydration reaction of the system. However, the variation in resistivity with time and value was influenced by the mixing ratio of the system. (4) MMSPC could also offer certain environmental and economic benefits. Carbon emissions per ton of cement produced were reduced by 7.95%, and the total cost per ton of cement produced was reduced by more than 10%. This study provided a theoretical basis for the high-value disposal of MMS and the reduction of carbon emissions in the cement industry.
Collapse
Affiliation(s)
- Geng Xie
- Energy School, Xi'an University of Science and Technology, Xi'an, 710054, China; Research Center for Functional Backfill Technology in Mine, Xi'an, 710054, China.
| | - Lang Liu
- Energy School, Xi'an University of Science and Technology, Xi'an, 710054, China; State Key Laboratory of Green and Low-carbon Development of Tar-rich Coal in Western China, Xi'an, 710054, China; Research Center for Functional Backfill Technology in Mine, Xi'an, 710054, China.
| | - Yonglu Suo
- Energy School, Xi'an University of Science and Technology, Xi'an, 710054, China; State Key Laboratory of Green and Low-carbon Development of Tar-rich Coal in Western China, Xi'an, 710054, China.
| | - Mengbo Zhu
- Energy School, Xi'an University of Science and Technology, Xi'an, 710054, China; Research Center for Functional Backfill Technology in Mine, Xi'an, 710054, China.
| | - Pan Yang
- Energy School, Xi'an University of Science and Technology, Xi'an, 710054, China; Research Center for Functional Backfill Technology in Mine, Xi'an, 710054, China.
| | - Weiji Sun
- Energy School, Xi'an University of Science and Technology, Xi'an, 710054, China; Research Center for Functional Backfill Technology in Mine, Xi'an, 710054, China.
| |
Collapse
|
2
|
Zhan X, Wang L, Wang L, Wang X, Gong J, Yang L, Bai J. Enhanced geopolymeric co-disposal efficiency of heavy metals from MSWI fly ash and electrolytic manganese residue using complex alkaline and calcining pre-treatment. Waste Manag 2019; 98:135-143. [PMID: 31446253 DOI: 10.1016/j.wasman.2019.08.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/25/2019] [Accepted: 08/15/2019] [Indexed: 06/10/2023]
Abstract
The predominant heavy metals in MSWI fly ash and electrolytic manganese residue (EMR) were determined to be Zn, Pb, Cd, and Mn, with lesser amounts of Cu and Cr. The curing efficiency of heavy metals in MSWI fly ash and EMR was improved using complex alkaline activators (NaOH and KOH), base addition (calcium hydroxide and complex Portland cement), and EMR calcining (at 800 °C for 3 h) based on a geopolymeric system. The best formulation of the geopolymeric system was composed of 75 wt% MSWI fly ash and 25 wt% EMR with a KOH/NaOH (1:1) complex solution (7.5 M OH-)/solid of 0.5. Calcium ions were dissolved aluminosilicate under the strongly basic conditions to form complex products (ternesite) which further improved the strength. The primary curing mechanism of heavy metals (Pb, Zn, Cd, Mn, Cr, and Cu) mainly was primarily influenced by the acid-base buffering capacity of geopolymers, followed by the physical encapsulation of geopolymeric gels.
Collapse
Affiliation(s)
- Xinyuan Zhan
- Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, PR China; College of Resource and Environmental Science, Chongqing University, Chongqing 40044, PR China
| | - Li'ao Wang
- Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, PR China; College of Resource and Environmental Science, Chongqing University, Chongqing 40044, PR China.
| | - Lei Wang
- Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, PR China; College of Resource and Environmental Science, Chongqing University, Chongqing 40044, PR China
| | - Xiang Wang
- Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, PR China; College of Resource and Environmental Science, Chongqing University, Chongqing 40044, PR China
| | - Jian Gong
- Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, PR China; College of Resource and Environmental Science, Chongqing University, Chongqing 40044, PR China
| | - Lu Yang
- Chong Qing Municipal Solid Waste Resource Utilization & Treatment Collaborative Innovation Center, Chongqing 401331, PR China
| | - Jisong Bai
- Chong Qing Municipal Solid Waste Resource Utilization & Treatment Collaborative Innovation Center, Chongqing 401331, PR China
| |
Collapse
|