Incinerator Ash Research Articles

Prospect for recycling critical elements in combustion residues of coal, lignite, and biomass feedstocks

The combustion residues derived from coal, lignite, biomass, and spent wash could be recycled to extract critical elements required for energy transition. To recycle these elements from the combustion residues, it is necessary to understand their chemical mode of occurrence in the ash. This study presents the content of critical elements and their chemical mode of occurrence in coal, lignite, biomass, and incinerator ash. Lignite ash, rich in Ca and Si, offers Sc (31 mg/kg) and Nd (212 mg/kg), while coal ash, dominated by Si and Al, contains Ga (44.8 mg/kg). Biomass and spent wash ash, characterized by K, Ca, and S, present substantial potential for potash and Sc. Lignite ash primarily contains rare earth elements (REEs) in metal oxide-bound fractions, whereas in coal ash, the REEs are associated with the hard mullite or quartz phase. Biomass and incinerator ashes have significant water-soluble potash, and the Sc is associated with metal oxides. Green acids can extract critical elements from lignite, biomass, and incinerator ashes, but extracting from coal ash requires harsh conditions. Future research should concentrate on green extraction processes considering the chemical patterns of occurrence of critical elements.

Aerated Concrete Made of MSW Incineration Ash: Effect of Blending Materials and CO2 Curing Condition

Municipal solid waste (MSW) incineration ash is used to produce aerated concrete blocks (ACB). To reduce cement usage and improve ACB quality, steel slag and blast-furnace slag were tested as cement substitutes, and CO2 mineralization technology was applied to cure ACB. The effect of steel blending ratios (MSW incineration ash, cement substitutes, water, aluminum powder) and CO2 curing conditions (temperature, pressure) on ACB properties was investigated. Under different conditions, the compressive strength, CO2 uptake and microstructure of ACB were determined. Higher fly ash content in ACB increases CO2 uptake but reduces compressive strength; ACB shows better mechanical properties when the cement is completely replaced by blast-furnace slag, but steel slag will cause ACB to fail to form; the optimal water-to-solid ratio enhances carbonation rate and compressive strength, and reducing aluminum powder content improves compressive strength. As the CO2 curing temperature increases from 25 to 105ºC, the carbonation rate and compressive strength of the ACB initially increase and then decrease, with the maximum CO2 uptake ratio of 20.0% and peak compressive strength occurring at 65ºC. When CO2 pressure increases from 0.2MPa to 1MPa, the carbonation rate rises to 23.4%, and the compressive strength first increases and then decreases, reaching 1.86MPa at a curing pressure of 0.6MPa, meeting the GB/T 11968-2020 B03 A1.5 grade standard. Approximately 0.58 tons of CO2 emissions can be reduced for every ton of ACB produced. This study established an innovative method to produce an environmentally friendly, low-carbon building material.

Utilization of Textile-Dyeing Sludge Incineration Ash in Autoclaved Aerated Concrete

Utilization of Textile-Dyeing Sludge Incineration Ash in Autoclaved Aerated Concrete

Variation in the Composition of Municipal Solid Waste Incineration Ash

Unlike municipal solid waste bottom ash (MSWBA), fly ash (MSWFA) is landfilled due to its toxicity. However, MSWFA may also be a source of elements. Ash samples collected from a Portuguese MSW incinerator from different locations and over six months were analyzed. Their geochemical composition was normalized to the upper continental crust (UCC) and compared since metal enrichment may be used as an indicator for potential recovery. The potential recovery economic viability was also assessed for metals K, Sb, Cu, Pb, and Zn, considering the ore cut-off grade and minimum industrial grade (MIG) from Chinese geological and mineral industry standards. Compared to the global samples, only the Baghouse 1 FA size fraction’s coarse fraction showed a slight enrichment (1- to 5-fold) in Bi, Nb, and Zr. After wet sieving, most trace elements were enriched in all fractions, but Sb, Bi, Pb, Zn, Ag, As, Cd, Sn, Se, and Hg were depleted in the coarse fractions and enriched in the fine ones. For Baghouse 1 samples collected over 6 months, the normalization to the UCC showed enrichment of Zn and Pb between 10× and 50×, Zr, Cu, In, and Se between 50× and 100×, and Ag, Mn, Cd, Sb, and Bi at more than 100×. Over six months, the Baghouse 1 FA soluble fraction ranged between 21 wt.% and 30 wt.%, and its precipitates comprised 27% CaO, 6% Na2O, and 9% K2O. The K concentration in the MSWFA was above the cut-off and the MIG, and K could be concentrated in precipitates via simple washing.

Valorization of Poultry Litter Incineration Ash as a Sustainable and Balanced Fertilizer Source

Valorization of Poultry Litter Incineration Ash as a Sustainable and Balanced Fertilizer Source

Study on rutting performance of synthetic zeolite based warm mix asphalt using railway carriage workshop incineration ash as filler

Study on rutting performance of synthetic zeolite based warm mix asphalt using railway carriage workshop incineration ash as filler

Remanufacturing construction and demolition waste and incineration ashes into eco-blocks: Quantitative sustainability assessment

This study performed a sustainability evaluation of a proposed business for remanufacturing concrete materials from construction and demolition waste (CDW) and ash from the combustion of municipal solid waste (MSW) to produce eco-blocks for construction applications. Six possible industrial remanufacturing alternatives are proposed based on commercially available industrial machinery and their economic sustainability was compared by a cost and profit feasibility study. Furthermore, the technical feasibility was evaluated by considering the maturity of the selected machinery based on the relationships among the cost–productivity, power–productivity, and number of workers–productivity pairs. The proposed remanufacturing business achieves a maximum profit of 17,643 USD/day with a minimum remanufacturing cost of 30.65 USD/t for the production of 529 t of eco-blocks in an 8-h factory shift. A quantitative environmental sustainability assessment was performed using the remanufacturing cost, profit, concrete savings, energy savings, CO2 emission savings, and eco-cost savings as criteria based on demographic statistics from the literature for current and predicted CDW and MSW generation. CDW and incineration ash are widely available, so the proposed process is viable worldwide. Based on the technical, economic, and environmental sustainability results, a final sustainability index of 0.874 was calculated, which exceeds literature thresholds for a sustainable business, indicating that the proposed eco-block remanufacturing process has the potential to generate substantial profits, while positively contributing to reducing waste and energy usage by recovering valuable resources and producing value-added products. The remanufactured eco-blocks are prepared in the same way as typical concrete blocks and can be used for all of the same residential, commercial, and industrial construction and landscaping applications. The remanufactured eco-blocks have several advantages over typical concrete blocks, including a much lower manufacturing cost (∼50 % lower), significant environmental and resource savings by avoiding the use of new sand and gravel resources, and improved mechanical properties.

Utilizing chicken manure incineration ash as a phosphorus and silicon source to mitigate boron absorption in barley grown on boron-contaminated soil

Excessive boron (B) levels in soil can lead to toxicity in plants, impacting their growth and productivity. Effective strategies to reduce B uptake are important for improving crop performance in contaminated soils. This experiment aimed to investigate the effects of chicken manure incineration ash (CMA) and triple superphosphate (TSP) on B uptake in barley plants grown in B-contaminated soil. Before the experiment, the chemical composition and molecular structure of CMA were analyzed using XRF, XRD and SEM. The soil was contaminated with 15 mg kg−1 of B, and both TSP and CMA were applied at rates of 40, 80, and 160 mg kg−1 of phosphorus (P). Neither P source had a significant impact on plant dry weight. However, increasing doses of applied TSP and CMA increased plant P concentration while significantly decreasing B concentration. Particularly with CMA applied at 160 mg kg−1 P dose, plant B concentration decreased to the lowest level of 194 mg kg−1. Increasing P doses led to a slight decrease in plant silicon (Si) concentration. The pH of soil samples taken after the experiment slightly increased with CMA treatments compared to TSP. The available P concentration in soils increased with increasing P doses. The available B concentration decreased with increasing P doses, especially reducing to the lowest level of 2.52 mg kg−1 in soils with a 40 mg kg−1 P, CMA. In conclusion, in addition to the effect of P, the molecular structure of P is also important in reducing B uptake in barley.

Evaluation of Radioactivity Concentration and Hazard Indices in ash Some Hospitals Incinerators in Baghdad / Al Resafa

Due to their harmful effects on human health and their tendency to cause cancer, radionuclide concentrations and risk indicators have been measured in hospital incinerator ash. This was done by collecting samples ash of Hospitals Incinerators, examining them, and identifying the risks that emerged from the examination. Three samples Only taken for the study from certain hospitals affiliated with the Baghdad Al-Rusafa Health Department. High purity germanium gamma spectrometer (HPGe) were used to analyze the samples. The concentrations of potassium isotopes (K-40) range from (147.1±16.5 to 214.4±21.1 Bq/kg), While the range of concentrations for Ra-226 isotopes is (7.52±1 to 19±1.8 Bq/kg), and lead (Pb-212) isotope concentrations ranged from (10.1±1.1 to 11.1±1.5 Bq/kg). In addition, the isotope concentration of actinium (Ac-228) is 8.05±1. Radium equivalent (), risk index , annual effective dose equivalent radioactivity level index ), absorbed dose rate D, and lifetime cancer risk were calculated. The results showed that no radiation risk Only indicated by any of the risk indicators. This indicates that the ash from the hospital incinerator does not pose any radioactive danger.

Leaching behavior of sustainable concrete made with coal ash wastes as replacement of cement and sand.

The coal-fired power plant fly ash (FA) and bottom ash (BA) are gradually used as alternative materials in the concrete. However, knowledge of the leaching characteristics of using both incinerator ashes in concrete production is lacking. This work aimed to evaluate the leaching behavior of the FA and BA used in concrete production by employing batch and tank leaching tests. The outcomes of both leaching tests showed that there was no considerable leaching of any trace elements to the environment, and it remains much lower than standard limitations for utilization as construction materials. The results of cumulative mass discharge showed that the slope of flux time for all elements was less than 0.4 and because of that, primary surface wash-off was the main discharge process of all the heavy metals. Strength test results revealed that there was not much difference between coal ash concrete (CAC) and the control mix at the initial age of curing time. Despite that, at a long period of curing time (180 days), the compressive strength of CAC containing 20% FA as cement replacement and 100% BA as fine aggregate replacement increased by 76% due to the pozzolanic reaction of BA and FA in comparison to the normal concrete, while, due to the high porosity of BA, the workability of CAC decreased by 50%. The outcomes of the current work revealed that the combined use of FA and BA can be counted as a promising alternative in the production of sustainable concrete for structural applications toward sustainable development.

A method of pretreating incineration ashes containing metallic aluminium using NaOH to mitigate volume expansion under highly alkaline conditions

Globally, millions of tonnes of incineration ashes are produced with a substantial portion remaining underutilized in low-value applications or disposed in landfills. Many types of fly ashes and bottom ashes contain metallic aluminium (Al0), which causes volume expansion when the ashes are used in alkali-activated materials and as a supplementary cementitious material due to the generation of hydrogen gas at high-pH conditions. This phenomenon significantly restricts the potential applications of these ashes. To address this issue, ashes can be pretreated with NaOH to oxidize the metallic aluminium (Al0) before their utilization. This study focuses on investigating the effect of the NaOH pre-treatment duration on fly ashes from the co-combustion of recovered solid fuel, peat, and wood. A pre-treatment process was conducted using 8 mol/L aqueous NaOH solution to treat the fly ash for up to 60 minutes. The formed slurry was subsequently used to prepare alkali-activated material by mixing it with bottom ash and employing either sodium silicate or sodium carbonate as an alkali activator. The NaOH pre-treatment demonstrated a 100 % metallic aluminium conversion into oxidized form resulting enhancement in mechanical performance, microstructure, and water absorption properties. The proposed method offers a highly efficient and rapid solution for eliminating the drawbacks caused by the presence of metallic aluminium and it can be conveniently implemented on construction sites. Concurrently, this study also explores the leaching behaviour of heavy metals during alkali-activation. Significant reductions in the leaching of Ba, Cr, Cu, Mo, and Pb were observed, highlighting the environmental remediation potential of alkali-activation methods.

Development of sustainable self-compacting concrete: Replacement of sand with municipal solid waste incineration ash molten slag and recycled fine aggregate

The purpose of this study is to develop self-compacting concrete using MSWA and RA as fine aggregates, supplemented with fly ash and GGBS that can modify the workability of the concrete. To evaluate the performance of sustainable self-compacting concrete, its mechanical properties, workability, drying shrinkage, and pore structure were comprehensively analyzed. The results demonstrate the feasibility of producing self-compacting concrete by replacing 50–100 % of sand with MS and RA, as all mixes in this experiment achieved the target slump flow of 600 ± 20 mm. The compressive strength remained unaffected for MS contents below 25 %, but at 50 % MS, it was 10 % lower than that of normal concrete. The drying shrinkage deformation of all specimens was below 700 μ, meeting the requirements for practical engineering applications. Incorporating fly ash increases porosity but transforms micropores larger than 100 nm into those smaller than 100 nm. Incorporating GGBS not only reduces porosity but also converts pores of 10–100 nm into gel pores smaller than 10 nm. Additionally, the suitability of various formulas correlating compressive strength and static elasticity modulus, recommended by American Concrete Institute (ACI 363), European Practice (EN 1992), and the Architectural Institute of Japan (JASS 5), was evaluated, and appropriate formulas were determined through regression analysis.

Production of hydroxyapatite utilizing calcium and phosphorus in sewage sludge incineration ash

Sewage sludge incineration ash (SSIA), enriching the most of phosphorus (P), could be named as promising P source for P recycling and management. The novel strategy including extraction of P from SSIA by acid (HCl), purification and separation to obtain Ca liquid and Al-P liquid that could produce hydroxyapatite was investigated in this study. The P acid leaching rate was 97.9 % from SSIA at 0.2 mol/L HCl for 2 h. In P purification, P combined with Fe and Al to form precipitation (Al-P and Fe-P) with the increase of pH (<4.0). At a pH of around 4.0, the separation of Ca in the liquid phase was maximized, while Al-P and Fe-P precipitated out. Then, the Al-P precipitation could be dissolved in NaOH solution (0.2 mol/L) to separate Fe-P precipitation, that obtaining the Al-P liquid. What’s more, the high P content (P2O5, 25.5 %) in P product could be produced directly under 1.5 Ca/P molar ratio, which could be used in P fertilizer. The heavy metal content in the P product were far below the Chinese, American and EU fertilizer regulation, indicating that its environment safety. The Ca and P elements leached out during the acid leaching process were eventually recombined to form hydroxyapatite by wet-chemical purification. The cost of P recovery from SSIA was $3.06/kg P product demonstrating commercial potential of this strategy.

Recycling and optimization of poultry manure incineration ash as a source of phosphorus and balanced mineral fertilization

Recycling and optimization of poultry manure incineration ash as a source of phosphorus and balanced mineral fertilization

Valorizing waste activated sludge incineration ash to S-doped Fe2+@Zeolite 4A catalyst for the treatment of emerging contaminants exemplified by sulfamethoxazole

The global attention towards waste management and valorization has led to significant interest in recovering valuable components from sludge incineration ash (SIA) for the synthesis of functional environmental materials. In this study, the SIA was converted to an S-doped Fe2+-zeolite type catalyst (FZA) for the treatment of emerging contaminants (ECs), exemplified by sulfamethoxazole (SMX). Results demonstrate that FZA effectively catalyzed the activation of peracetic acid (PAA), achieving a remarkable degradation of 99.8% under optimized conditions. Mechanistic investigations reveal that the FZA/PAA system can generate ·OH, 1O2, O2·－, and Fe(Ⅳ), with ·OH playing a dominant role in ECs degradation. Additionally, the doped S facilitated electrochemical performance, Fe2+ regeneration and fixation in FZA. Practical application elucidated that the FZA/PAA system can work in complex environments to degrade various ECs without generating high-toxicity ingredients. Overall, valorizing SIA to FZA provides dual achievement in waste management and ECs removal.

Preparation of sludge-derived spinel ferrite nanoparticles for highly efficient adsorption of Pb(II) from water: Adsorption behaviour and mechanism interpretation via advanced statistical physics model

Because proper disposals of municipal sewage sludge and lead-containing wastewater are still open questions, the novel sludge-derived mesoporous nanospinel ferrite adsorbents were prepared from municipal sewage sludge (S-MZF) and its incineration ash (A-MZF) for Pb(II) removal from water. S-MZF and A-MZF had similar mesoporous structures with an average pore size at around 4.13–5.51 nm. A-MZF displayed a larger specific surface area (254 m2/g) and pore volume (0.3 m3/g) but inferior magnetic property, while S-MZF showed abundant surface functional groups and higher saturation magnetization (12.3 emu/g). The adsorption capacity of S-MZF and A-MZF for Pb(II) was close to each other at 50 °C, reaching 160 mg/g. Initial adsorption of A-MZF for Pb(II) was dominated by intraparticle diffusion, while the evident liquid film diffusion existed in that of S-MZF. Advanced statistical physics modeling found that multiple divalent lead ions were anchored simultaneously by each site of S-MZF mainly via multi-interactions where physical force and precipitation played a key role, while each site of A-MZF anchored only one Pb(II) ion by the physical interaction. As a result, the adsorption capacity of S-MZF mainly depended upon the number of Pb(II) ions adsorbed by each active site, while the available density of active sites on the surface of A-MZF primarily controlled its adsorption capacity for Pb(II).

Enhancing microstructural integrity and mechanical strength of mortar containing incinerated ash using carbon nanotube, graphene nanoplatelet and nano silica reinforcements

Incineration ash contains metallic aluminium that can react with cement alkalis, producing hydrogen gas, which can affect the strength of cementitious materials. In this study, we aimed to improve the technical properties of incinerated ash-based mortar using three different nanomaterials: carbon nanotubes, graphene nanoplatelets, and nano-silica. These nanomaterials were incorporated at concentrations of 0.025 wt%, 0.05 wt%, 0.1 wt%, 0.25 wt%, 0.5 wt%, and 1 wt% of the cement mass, respectively. Comprehensive analysis indicates that the type of nanomaterials and their doses play a significant role in early age hydration, shortening the induction period and promoting the formation of C-S-H. Study results show evidence up to a 45 % enhancement in compressive strength. Sustainability assessment reveals that a dose of 0.025 % graphene nanoplatelets is the most sustainable from an environmental perspective, with approximately a 25 % improvement in compressive strength of incinerated ash mortar. Findings of the study will contribute to the understanding of nanomaterial-reinforced cementitious systems incorporating incinerated ash and offer valuable guidance for improving the performance of incinerated ash-based cementitious materials in construction applications.

Valorization of sewage sludge incineration ash as a novel soilless growing medium for urban agriculture and greenery

Limited open areas for urban agriculture and greenery have led to the search for innovative, sustainable growing media to strengthen the food supply and improve atmospheric quality for a resilient city. Rampant land developments have caused soil to become increasingly scarce. Sewage sludge incineration ash (SSIA), the by-product of waste-to-energy (WtE) incineration of sewage sludge, is a major municipal waste containing phosphorus-fertilizing nutrients. For the first time, we investigated the novel application of SSIA as a soilless plant-growing medium with built-in fertilizer. SSIA outperformed topsoil in bulk density, water-holding capacity, porosity, and nutrient content. However, it was found that SSIA has a high salinity and should be treated first. Wheatgrass (Triticum aestivum L.), a fast-growing glycophyte, thrived in the desalinated SSIA, showing growth and nutrient content comparable to the topsoil case. Simultaneously, it demonstrated phytoremediation. The SSIA residue was then recycled into cementitious materials, using desalinating water for mixing. SSIA upcycle into a growing medium facilitates urban resource management by utilizing nutrients in sewage waste for eco-friendly plant cultivation, benefiting urban agriculture and greenery. It is also a prudent valorization step before further recycling SSIA to reduce landfill requirements.

Unlocking Value from Municipal Solid Waste Incineration Ash: Electrochemical and Chemical Approaches for Materials Recovery

Nowadays, in the U.S. more than 6.6 million tons of hazardous solid residue, called municipal solid waste incineration (MSWI) ash is annually generated in waste-to-energy (WTE) plants for producing electricity and reducing landfill volume. This ash cannot be further utilized for beneficial applications, so it is mostly buried and has a negative value with the cost of a disposal fee. Moreover, the economics of MSWI is challenged by the decreasing cost of renewableelectricity. However, WSWI ash represents a unique opportunity for valuable element recovery, with the embodied value ranging from $100-400/tonne. We propose an electrochemical and chemical process for mining MSWI ash that utilizes electricity from the WTE plant toelectrolytically produce acid and base streams for materials recovery and refining. We establish a sequential process of electrochemical extraction and chemical precipitation, and successfully recover Cu, Pb, Zn, Mg, Ca, Fe, Al, with a purified silica co-product. Recovery of >90% of the targeted elements at purities >90% is demonstrated. The industry-scale technoeconomic analysis shows our proposed technology will realize the possibility of extracting the embodied mineral value with net positive returns that significantly exceed the combined value of WTE electricity sales and landfilling cost.

Municipal sludge-based low-carbon phase-change composite towards energy storage: Fabrication and investigation

The integration of municipal sludge with phase change materials for composite energy storage material fabrication benefits to sludge significant reduction and recycling, heavy metal fixation, and minimizing environmental pollution. This groundbreaking work proposed municipal sludge-derived phase-change composites utilizing potassium nitrate as phase change material to produce cost-effective, low-carbon thermal energy storage materials. Five samples with varying mass fractions of municipal sludge incineration ash and potassium nitrate were prepared through a cold-compression & hot-sintering process and then thermal properties, microscopic structure, mechanical strength, and chemical compatibility between components was investigated extensively to explore the feasibility of municipal sludge recycling for composite energy storage material fabrication. The results revealed successful encapsulation of heavy metals within the phase change composites, and the composite with a 50:50 ratio of ash to potassium nitrate exhibited superior overall performance, which boasts a thermal energy storage capacity of 330.34 J/g with temperature rising from 100 up to 380 °C, a peak thermal conductivity of 1.04 W/(m·K), remarkable mechanical strength of 153.78 MPa, and excellent thermal stability. In addition, the components of the municipal sludge incineration ash and potassium nitrate displayed exceptional chemical compatibility. This novel phase change composite holds significant potential for engineering application compared to traditional alternatives.