Effect of different gypsums on the workability and mechanical properties of red mud-slag based grouting materials

Li, Zhaofeng; Zhang, Jian; Li, Shucai; Gao, Yifan; Liu, Chao; Qi, Yanhai

doi:10.1016/j.jclepro.2019.118759

Cited by 113 publications

(36 citation statements)

References 32 publications

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“…BRM is a kind of strong alkaline industrial solid waste, which is discharged from the process of alumina production from bauxite. Normally, 1.0–1.5 tons of BRM will be produced for every ton of alumina [ 1 , 2 , 3 ]. The emission of BRM is increasing rapidly with the increase of global alumina production.…”

Section: Introductionmentioning

confidence: 99%

Tailings after Iron Extraction in Bayer Red Mud by Biomass Reduction: Pozzolanic Activity and Hydration Characteristics

Wang

Liu

et al. 2021

Materials

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Bayer red mud (BRM) is a kind of solid waste with high hematite content, and its effective utilization is difficult due to the special physicochemical properties. In this work, Fe2O3 in BRM was reduced to Fe3O4 by biomass, and iron concentrate and high activity tailings were obtained after magnetic separation. The pozzolanic activity and hydration characteristics of the tailings were systematically studied. The results showed that the relatively stable polymerization structures of Si-O and Al-O in BRM are destroyed under the effect of biomass reduction at 650 °C, and some fracture bonds and activation points are formed in the structures. The aluminosilicate phases in the BRM were easy to transform into the active substances of Si and Al. The pozzolanic activity of tailings is greatly improved, and its pozzolanic activity index is 91%. High polymerization degree of gel and ettringite are formed since more active substances and alkali in the tailings promote the hydration reaction of cement-based cementitious materials, which made cementitious materials have dense matrix, good mechanical properties, and environmental performance. This work has realized the full quantitative utilization of BRM and provided a feasible way for the resource utilization of BRM.

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Section: Introductionmentioning

confidence: 99%

Tailings after Iron Extraction in Bayer Red Mud by Biomass Reduction: Pozzolanic Activity and Hydration Characteristics

Wang

Liu

et al. 2021

Materials

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“…Due to the frequent occurrence of some disastrous safety accidents in the process of ore mining, a series of safety problems have arisen as a result, which often have a certain negative effect on production. For the maintenance of goaf and underground roadway, the conventional support methods such as long anchor cable, anchor rod, and shotcrete have played an important role, but for the huge mined-out area, the conventional support is no longer applicable at this time, so it is necessary to deal with the mined-out area permanently [19][20][21][22]. In recent years, great changes have taken place in the goaf filling technology, filling materials, and transportation methods, such as the continuous transportation technology of filling slurry and the development of new cementitious materials and filling aggregates; in order to make the filling process smooth, reduce the cost of filling, and reduce the collapse of the goaf rock, maintaining the safety of the goaf played a supporting role [23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Sampling and Mechanical Testing of Backfill in Large Mined-Out Area

Deng

Jiang²,

Duan

2021

Geofluids

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To investigate the physicomechanical properties of stope backfill and to explore the mining conditions for an adjacent pillar, four boreholes, namely, GZK1, GZK2, GZK3, and GZK4, were constructed for taking the backfill core in the test stope. During borehole sampling, it is found that the strength of backfill is usually lower than that of the rock and ordinary concrete, and its resistance to tensile and compressive loads is limited. Therefore, the drilling speed should not be too fast, and a small amount of water is needed to continue drilling smoothly. For backfill with high strength, the sampling process is relatively smooth, and the backfill samples are relatively complete. GZK1 is located on the upper part of the stope near the footwall of the orebody, and the test results show that the backfill quality of this part is poor; thus, a complete backfill core cannot be obtained. GZK2 is located at the bottom of the stope close to the footwall of the orebody, GZK3 is located at the bottom of the stope close to the hanging wall of the orebody, and GZK4 is located at the top of the stope close to the hanging wall of the orebody. The average compressive strength and average tensile strength of the backfill samples obtained from the three boreholes, namely, GZK2, GZK3, and GZK4, are 2.928 to 3.583 MPa and 0.328 to 0.523 MPa, respectively, indicating that the backfill near the upper part and bottom close to the hanging wall of the orebody is good, while the backfill near the upper part close to the footwall of the orebody is poor. Special attention should be paid to the backfill with the range of GZK1 in the future second-step pillar mining process, and the sublevel method can be adopted to ensure the safety of the mining process. The backfill samples in the large goaf of No.17 room were obtained by geological drilling. Segregation occurred in the upper part of the No.17 room near the area of the footwall. The concentration and flow rate of the filling slurry were reasonably adjusted and controlled with the improvement of backfill quality. Therefore, the backfill strength of the No.17 room is generally good, which can meet the requirements of pillar mining, and also creates a good condition for the resource utilization of waste tailings of Caolou Iron Mine.

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“…However, this typology of studies on the hardening and setting of gypsum materials have generally focused more on the achievement of new dosages to improve certain properties than on monitoring and continuous monitoring of the setting process. This has led to the fact that most of the tests were carried out on days set by the reference regulations, evidencing the continuous variations in humidity experienced by the samples, their relationship with the variations in the physical properties of the material, and the performance in most studies of only some complementary chemical tests to study the evolution of the dihydrate and the hemihydrate [ 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Low-Cost Sensors for Determining the Variation in Interior Moisture Content in Gypsum Composite Materials

et al. 2020

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Non-destructive testing can be used to determine some of the most relevant physical properties of building materials. In this work, two low-cost measuring devices were developed capable of determining the variation in real-time of the percentage of humidity that is produced in the construction of gypsum and plaster during the hardening process. For this, an Arduino resistive sensor and a capacitive sensor of our design were used. The results show how it is possible to determine the variations in mixing water content during the seven days of curing established by the UNE-EN 13279-2 standard as well relate to the mechanical resistance of the test specimens with the same percentage of humidity. Additionally, the study was completed with the determination of the formation of the dihydrate compound linked to this setting process in the test specimens by conducting X-ray diffraction and thermogravimetric analysis tests at different ages of the samples.

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Effect of different gypsums on the workability and mechanical properties of red mud-slag based grouting materials

Cited by 113 publications

References 32 publications

Tailings after Iron Extraction in Bayer Red Mud by Biomass Reduction: Pozzolanic Activity and Hydration Characteristics

Tailings after Iron Extraction in Bayer Red Mud by Biomass Reduction: Pozzolanic Activity and Hydration Characteristics

Sampling and Mechanical Testing of Backfill in Large Mined-Out Area

Low-Cost Sensors for Determining the Variation in Interior Moisture Content in Gypsum Composite Materials

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