Biomass Ash Research Articles (Page 1)

Concrete is the second most consumed material after water, with cement as its primary binder. However, cement production accounts for nearly 7% of global CO2 emissions, posing a major sustainability challenge. This review critically evaluates 35 agricultural biomass ashes (ABAs) as potential supplementary cementitious materials (SCMs) for partial cement replacement, focusing on their effects on concrete strength and durability and highlighting performance gaps. Using a systematic methodology, rice husk ash (RHA), sugarcane bagasse ash (SCBA), and wheat straw ash (WSA) were identified as the most promising ABAs, enhancing strength and durability—including resistance to chloride ingress, sulfate attack, acid exposure, alkali–silica reaction, and drying shrinkage—while maintaining acceptable workability. Optimal replacement levels are recommended at 30% for RHA and 20% for SCBA and WSA, balancing performance and sustainability. These findings indicate that ABAs are viable, scalable SCMs for low-carbon concrete, promoting greener construction and contributing to global climate mitigation.

Wood biomass ash, municipal solid waste ash, and recycled concrete from construction demolition waste as supplementary cementitious materials in fine graded granular mixtures

Study on the superiority of biomass ash composite activation in blast furnace slag-coal gangue-fly ash system: A novel high-strength alkali-activated cementitious material

Biomass plays an important role in the energy transformation aimed at carbon neutrality, with its potential estimated at 1/3rd of the entire energy mix. One of the main ways of using biomass is combustion or co-combustion, which enables the production of heat and electricity while maintaining low emissions. A promising path to utilize the combustion by-product—ash—is the possibility of using it as a natural and cheap catalyst that can effectively support the process of solid fuel gasification. This paper reviews scientific studies on the properties of biomass ash and its use to support the gasification process. The issues related to the genesis of mineral matter in plants are presented, emphasizing the importance of its transformations during biomass combustion. Particular emphasis is placed on the characterization of biomass ash, which was carried out on the basis of a comprehensive overview of the results regarding its chemical composition. An analysis of the physicochemical and surface properties relevant to the use of biomass ashes as catalysts in the gasification process was performed. In addition, a review of studies on catalytic gasification of solid fuels using biomass ash was conducted, taking into account the impact of biomass ash on the most important parameters characterizing the course of the gasification reaction, i.e., reactivity, quality of the gaseous products, and the kinetics reaction. The summary compares the most important advantages and disadvantages of using biomass ashes in the gasification process along with recommendations for future research.

The increasing demand for sustainable alternatives in civil construction has spurred the development of cementitious materials with reduced environmental impact. In this context, alkali-activated materials have emerged as a promising solution, enabling the partial replacement of Portland cement with industrial by-products, such as biomass ash and fly ash. This paper investigates the use of biomass ash from the ceramic industry (CBA) and the cellulose industry (PBA), in binary mixtures with fly ash (FA), in the production of alkaline-activated cementitious pastes. Mini-slump, setting time, compressive strength, water absorption and scanning electron microscopy (SEM) tests were performed. CBA with a high calcium content (86.23%), showed greater reactivity and better mechanical performance in the pastes. In contrast, PBA, characterized by a high silica content (65.9%) and a low calcium content (6.54%), exhibiting higher compressive strength (30,66 MPa), but lower workability indices. The results demonstrate that these ashes are viable alternatives to Portland cement, contributing to sustainability and the circular economy by reusing industrial waste. However, the variability in ash properties requires strict control to ensure consistency and optimization of composites.

Effective transformation of ammonia nitrogen in the soil from rare earth mining areas by amendments of biomass ash.

Biomass ash chemistry in oxygen carrier aided combustion: effect of steam on potassium and red mud agglomeration behavior

The construction sector has a prominent role in raw materials consumption and environmental depletion due to waste and emissions connected to the production of construction materials and construction/demolition operations. Thus, research is pushing to develop sustainable construction materials, mainly recycling waste and by-products. Following this trend, the present study explores the possible use of two different blends of cement-based waste powder and biomass ashes as filler for the production of asphalt concretes. The materials have been tested following the EN 13043 standard requirements for fillers for bituminous mixtures. Still, the basic performances of hot mix asphalts produced with the recycled materials have been evaluated on a laboratory scale. The physical, chemical, and mechanical characterization of the waste fillers and the bituminous mixtures showed advantages and downsides in the use of the recycled powders for hot mix asphalt production. Despite final performances in line with traditional hot mix asphalt, the chemical composition of the proposed fillers has a negative influence mainly on the water susceptibility of the mixture. However, the findings of the study open new perspectives on future possible applications of the recycled fillers in the road pavements sector.

Biomass ashes are considered to be sustainable alternatives for fly ashes from hard coal combustion for the use as supplementary cementitious material (SCM). However, their diverse composition and properties are impeding their standardized use. This study aims to gain a better understanding of how composition affects performance. It investigates three wood ashes (one bottom ash, two fly ashes), one spelt husk ash and a mineral residue from sewage sludge ash after wet-chemical phosphorus recovery for their suitability as SCM. After characterization of the materials including the determination of environmentally relevant parameters, the reactivity was tested using the R3 test and mortar compressive strength with different substitution levels. The effect on hydration was studied in blends with Portland cement using isothermal calorimetry and X-ray diffractometry (XRD). The composition of the ashes differed significantly, also between the wood ashes. The wood ashes showed no significant reactivity (cumulative R3 heat lower than 125 J/g SCM after 7 days), while the spelt husk ash and the sewage sludge ash residue showed distinct reactivity with a cumulative R3 heat of 249 and 181 J/g SCM after 7 days, respectively. Following an initial period of unaffected hydration, the wood fly ashes were found to impede clinker reactivity. In contrast, the other materials exhibited no significant influence on the hydration process, aside from the consumption of portlandite by the reactive ones. The wood fly ashes also impaired strength development in blended mortar formulations (e.g., relative compressive strengths with a cement substitution level of 20 wt% after 28 days were <0.6), whereas the reactive spelt husk ash and the mineral residue were associated with a measurable contribution to strength gain (e.g., relative compressive strengths with a cement substitution level of 20 wt% after 28 days were >0.85). The wood bottom ash was the only material investigated which perfectly sustained mortar workability and rather acts like a nearly inert addition. The results show both the potential and the limitations of using different types of ash, which cannot be generalized due to the wide variation in raw materials and combustion conditions.

Eight biomass ashes (BAs) generated from agricultural, herbaceous, woody and aquatic biomass types were studied for the occurrence of 14 nutrient elements (NEs) and 6 contaminant elements (CEs) to evaluate their significance for potential soil fertilization. For that purpose, a combination of different mineralogical and chemical analyses, and leaching procedures was used. The data show that the contents of NEs in BAs are highly variable; however, the concentrations of B, Ca, Cl, Cu, K, P, S, and Zn, and, to a lesser extent, Mg, Mn, Mo, Na, and Ni in BAs are perspective for potential soil fertilization or soil conditioners. The inorganic matter of BAs comprises amorphous matter and different minerals among carbonates, silicates, chlorides, sulphates, oxyhydroxides, and phosphates. BAs have high yields of water-soluble solutions with alkaline character, which are favourable for BA use. NEs such as Ca, Cl, K, Mg, Na, P, and S occur significantly in water-soluble and bioavailable salts. Various NEs and CEs in BAs fulfilled the available regulation limits for fertilizing products, excluding some problematic concentrations of Cd, Co, Cr, Fe, Mo, Ni, and P for specific BAs. Therefore, each BA needs to be studied on a case-by-case basis for that purpose. The establishment of advanced regulatory framework for BA utilization as fertilizing products is required to generate strict limit values of NEs and CEs in BA leachates. The water-extractable proportions of elements from BA and their release in time are very important to predict the supply of bioavailable NEs or CEs for crops.

Use of biochar and coal ash as passive sorbent barriers for long-term mitigation of chlorinated solvent vapours.

Shrinking-melting mechanism of biomass ashes induced by phase transformation of alkali metal minerals for entrained flow gasification

Abstract Slag deposition and high-temperature corrosion are major ash-related issues in biomass-fired boilers. Protective coatings are used as countermeasures to these challenges. The coatings are produced by methods such as slurry spray and thermal spray. Nevertheless, studies on the comparative performance of these coatings on slag deposition and corrosion resistance are limited. Furthermore, there is currently no standard method to evaluate the anti-slagging capabilities of boiler coatings. Therefore, this study investigated and compared the slag and high-temperature corrosion resistance of a slurry spray coating and its thermally sprayed counterparts: atmospheric plasma spray and suspension plasma spray coatings. Anti-slagging evaluation of the coatings was conducted using an in-house “slag testing rig”, which was designed to investigate coating performance under simulated boiler conditions. A suspension plasma spray coating with a cauliflower-like surface exhibited the largest biomass fly ash reduction of ~ 12% by weight, which was contributed by the formation of air pockets at the interface between the biomass ash deposit and the coating. The slurry spray coating provided the highest corrosion resistance capability against molten salts with a linear corrosion rate constant of 3.40 × 10-4 mg/cm2·s (p = 0.003).

The transition towards renewable energy necessitates large-scale, cost-effective energy storage solutions. Carnot Batteries (CBs), which store electricity as thermal energy, offer potential advantages for medium-to-long-duration storage, including geographical flexibility and lower energy capacity costs compared to electrochemical batteries. This article examines the evolution and current state-of-the-art of CB technologies, including Pumped Thermal Energy Storage (PTES) and Liquid Air Energy Storage (LAES), discussing their performance metrics, techno-economics, and development challenges. Concurrently, the increasing generation of biomass ash (BA) from bioenergy production presents a waste valorization challenge. This article critically evaluates the potential of using BA, particularly from woody biomass, as an ultra-low-cost thermal energy storage (TES) medium within CBs systems. We analyze BA’s typical composition (SiO2, CaO, K2O, etc.) and relevant thermal properties, highlighting significant variability. Key challenges identified include BA’s likely low thermal conductivity, which impedes heat transfer, and poor thermal stability (low ash fusion temperatures, sintering, corrosion) due to alkali and chlorine content, especially problematic for high-temperature CBs. While the low cost is attractive, these technical hurdles suggest direct use of raw BA is challenging. Potential niches in lower-temperature systems or as part of composite materials warrant further investigation, requiring detailed experimental characterization of specific ash types.

The utilisation of agrifood waste ashes has the potential to enhance the nutrient content of cereal crops, thereby optimising both yield and grain quality. This study investigated rye grain composition, the fermentation efficiency, and volatile compounds in mashes made from crops fertilised with agrifood waste ashes derived from the combustion of corn cob, wood chips, and biomass with defecation lime. The ashes were applied at 2, 4, and 8 t/ha, separately and as mixtures of corn cob (25%) with wood chips (75%) and corn cob (50%) with biomass and defecation lime (50%). Rye mashes were prepared using the pressureless starch liberation method. The starch content in the majority of the rye grains was comparable to the control sample (57.12 g/100 g). The range of ethanol concentrations observed in the fermented mashes was from 55.55 to 68.12 g/L, which corresponded to fermentation yields of 67.25-76.59% of theoretical. The lowest fermentation yield was exhibited by the mash derived from rye cultivated on soil fertilised with a 50:50 mixture of ashes from corn cob and biomass with defecation lime at 8 t/ha. This mash contained more than double the acetaldehyde concentration and total aldehyde content compared to the other samples. These findings demonstrate the potential of using waste biomass ash as a source of macro- and microelements for rye cultivation, enabling the production of agricultural distillates. To ensure high fermentation efficiency and low aldehyde levels, ash dosage and composition need to be established based on experimental optimisation.

Valorization of industrial wastes as alternative liner materials: A review.

Influence of biomass ashes on the structural evolution and oxygen-donating capacity of red mud during chemical looping gasification.

Mechanistic insights into alkali metal migration and slagging behavior in K-type biomass ash during thermal conversion

This study investigated the effects of macronutrient type and concentration on the biomass yield and biochemical composition of hydroponically grown wheat sprouts (HWS), with the aim of identifying fertilization strategies that optimize both productivity and feed quality. HWS were cultivated using a nutrient film technique over a 7-day period under controlled environmental conditions, with treatments including calcium nitrate (CN1–CN3), potassium phosphate (CP1–CP3), potassium sulfate (CK1–CK2), and a balanced NPK 20–20–20 fertilizer (NPK1–NPK3), each applied at three increasing concentrations. The quantitative parameters assessed included biomass yield per unit of dry seed (DP, kg kg−1) and dry matter content (DM, %), while qualitative traits included crude protein (CP), ether extract (EE), crude fiber (CF), and ash content. Results indicated that balanced NPK fertilization significantly enhanced performance, with NPK3 achieving the highest biomass yield (6.39 kg kg−1), CP (24.26%), CF (5.63%), and ash (16.0%) content. In contrast, CN3 treatments reduced yield (4.84 kg kg−1) despite increasing CP (19.65%), indicating trade-offs between nitrogen enrichment and vegetative expansion. Phosphorus-based treatments (CP2–CP3) improved nutrient density without suppressing yield. Regression analyses revealed strong correlations between DM and both CF (R2 = 0.81) and ash (R2 = 0.71), supporting their utility as indirect indicators of feed quality. EE content remained stable (2.07–2.67%) across all treatments, suggesting its limited responsiveness to macronutrient manipulation. These findings highlight the importance of nutrient synergy in hydroponic systems and provide a practical framework for tailoring fertilization regimes to meet specific agronomic and nutritional objectives in precision livestock feeding and provide practical guidance for optimizing hydroponic livestock feed production.

This research paper provides new insights into the impact of accelerated mineralization of alkaline waste materials on the physical and mechanical behavior of low-carbon cement-based mortars. Standardized eco-cement mortars were prepared by replacing Portland cement with 7% and 20% proportions of three alkaline waste materials (white ladle furnace slag, biomass ash, and fine concrete waste fraction) that had been previously carbonated in a static reactor at predefined humidity and CO2 concentration. The mortars’ physical (total/capillary water absorption, electrical resistivity) and mechanical properties (compressive strength up to 90 d of curing) were analyzed, and their microstructures were examined using mercury intrusion porosimetry and computed tomography. The results reveal that carbonated waste materials generate a greater heat of hydration and have a lower total and capillary water absorption capacity, while the electrical resistivity and compressive strength tests generally indicate that they behave similarly to mortars not containing carbonated minerals. Mercury intrusion porosimetry (microporosity) indicates an increase in total porosity, with no clear refinement versus non-carbonated materials, while computed tomography (macroporosity) reveals a refinement of the pore structure with a significant reduction in the number of larger pores (>0.09 mm3) and intermediate pores (0.001–0.09 mm3) when carbonated residues are incorporated that varies depending on waste material. The construction and demolition waste (CCDW-C) introduced the best physical and mechanical behavior. These studies confirm the possibility of recycling carbonated waste materials as low-carbon supplementary cementitious materials (SCMs).