Research on Preparation of Coal Waste-Based Geopolymer and Its Stabilization/Solidification of Heavy Metals

Xu, Zhongzi; Dongdong, Ye; Dai, Tao; Ding, Yan

doi:10.1080/10584587.2021.1911314

Cited by 9 publications

(4 citation statements)

References 18 publications

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“…When CG was used to replace low-calcium fly ash and metakaolin to produce CGG, the leaching toxicity of Zn 2+ , Cr 3+ , Ni 2+ , and Co 2+ solidified bodies increased steadily with the increase in ion dose (as shown in Figure 17). The maximum leaching concentration was below 1.5 mg/L, which is far below the national standard value of leaching toxicity [115]. The leaching toxicity of heavy metals of CGG cured for 90 days is lower than that of CGG cured for 30 days.…”

Section: Heavy Metal Solidificationmentioning

confidence: 74%

Activation Mechanism of Coal Gangue and Its Impact on the Properties of Geopolymers: A Review

et al. 2022

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Coal gangue is one of the industrial solid wastes that may harm the human body through the ecosystem for a long time. Using coal gangue in geopolymer preparation can effectively reduce cement output and meet the sustainability requirements. In this paper, the physical and chemical characteristics, including the heavy metal content, of coal gangue from different producing areas are described. Then, the mechanism of physical activation (mechanical and thermal activation), chemical activation, and compound activation of coal gangue are illustrated. The machinability, as well as the mechanical, microscopic, and toxicity consolidation properties of geopolymers prepared from coal gangue, are summarized and analyzed. The results indicate that the coal gangue geopolymers can have higher mobility and mechanical strength than cement-based composites by adjusting high calcium element material, alkali activator content, Na2SiO3 modulus, and curing condition. After physical activation, coal gangue is used in geopolymer preparation with a chemical activator (alkali excitation agent), which effectively forms a three-dimensional silicon aluminate polymer network. The pore structure is dense, the physical fixation and chemical bonding are strengthened, and the solidification and adsorption of heavy metal ions are improved. Further, it can also be applied to solidifying radioactive waste, which is following the future development direction.

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Section: Heavy Metal Solidificationmentioning

confidence: 74%

Activation Mechanism of Coal Gangue and Its Impact on the Properties of Geopolymers: A Review

et al. 2022

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“…Geopolymer like ground granulated blast-furnace slag (an industrial waste produced from the cement production) and kaolin clay (natural occurring waste) (Abdullah et al, 2020a;Pooria et al, 2021;Rivera et al, 2020;Zhu et al, 2020b). Whereas rice husk fibre is waste from agricultural (Abdullah, 2021;Xu et al, 2021;Zhu et al, 2020a). Besides, globally, ground granulated blast-furnace slag and rice husk fiber produced by cement factories and rice industries have been increasing for the past few years (Adeyanju et al, 2020a;Alshaba et al, 2018;Wang et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Compactability of Agro based Geopolymer using Sodium Silicate Activator

Agashua¹,

Ogbiye²,

Amu³

et al. 2023

IJWPDS

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The strength of a fine-grained lateritic soilfrom three (3) different localities on Abuja – Lokoja road where road failure happen was treated with rice husk ash (RSA), cement andsodium silicate activator (SSA), with varying percentage examined by means of Atterberg, Compaction and triaxial shear tests. The addition of optimum cement with additives changes laterite sample of plasticity index (PI) into non-plastic and resulted in a minimum of 11.90 % reduction in PI of lateritic soil which led to the belief that additives decreases plasticity of soils, and this is an advantage, because reduction in PI contents indicates animprovement.Thecompaction characteristics of the natural lateritic soils were altered with the addition of optimum contents of OPC with each of RHA, KCP and SSA. The MDD of cement-stabilized residual soil slightly increased with the increase in cement content, whereas by adding RHA, KCP and cement, the OMC is decreases steeply. Also, CBR results shows that CBR of the soil-cement-SSA content increases upon adding sodium silicate activator content up to 4% SSA content before the value experiences reduction at much higher SSA content. But, theRHA-treated residual soils decrease the CBR value from 6% upwards. This, again, alludes that RHA alone is not suitable as stabilizer.

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“…Solidification/stabilization (S/S) methods can prevent harmful chemicals from being released into the environment though chemical or mechanical binding using curing agents [6,[58][59][60]. Magnesium oxychloride cement (MOC), known as Sorel cement, comprises MgO and MgCl 2 ; it is typically used as a curing agent for S/S of solid waste, because of its good engineering and mechanical properties, fast curing, air hardening, good resistance to abrasion and fire, and so on [61][62][63][64][65][66][67].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties and Water Resistance of Magnesium Oxychloride Cement–Solidified Residual Sludge

Liang

Wang

et al. 2023

Processes

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As a solid waste, the amount of residual sludge produced by the municipal wastewater treatment process is escalating. How to dispose it properly is attracting much attention in society. Herein, solidifying residual sludge using magnesium oxychloride cement (MOC) is promising for converting it into building materials. Various factors of mass ratio (RW/S) of liquid to solid, molar ratio (Rn) of MgO to MgCl2 in MOC, mass ratio (Rm) of residual sludge to MOC, the mass concentration of Na2SiO3 (DNa2SiO3), and dosage of fly ash (DF) influenced the unconfined compression strength (RC) of the as–obtained MOC–solidified residual sludge, and it was characterized using SEM and XRD analysis. The results show that the value of RC for MOC–residual sludge solidified blocks increased initially and then decreased as Rn and Rm increased, respectively, for 60–day curing. At 10–day curing, equilibrium RC was reached at all RW/S values except 1.38, and at 60–day curing, RC decreased with RW/S increasing. The maximum RC of 60 days of 20.90 MPa was obtained at RW/S = 0.90, Rn = 5.0, and Rm = 1.00. Furthermore, adding Na2SiO3 or fly ash in the solidifying process could improve RC. The water resistance test showed that SM13 and NF5 samples exhibited good alkaline resistance after immersion for 7 and 14 days in an aqueous solution with pH = 7.0–11.0. The water resistance of MOC–residual sludge solidified blocks decreased with increase in immersion duration in aqueous solutions. The fly ash could also help improve water resistance of MOC–solidified residual sludge in neutral and basic aqueous solutions. This work provides an important theoretical basis and possibility for the efficient disposal and comprehensive utilization of residual sludge through solidification/stabilization technology using MOC from the perspective of mechanics and water resistance.

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Research on Preparation of Coal Waste-Based Geopolymer and Its Stabilization/Solidification of Heavy Metals

Cited by 9 publications

References 18 publications

Activation Mechanism of Coal Gangue and Its Impact on the Properties of Geopolymers: A Review

Activation Mechanism of Coal Gangue and Its Impact on the Properties of Geopolymers: A Review

Compactability of Agro based Geopolymer using Sodium Silicate Activator

Mechanical Properties and Water Resistance of Magnesium Oxychloride Cement–Solidified Residual Sludge

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