Calcination Conditions Research Articles

Synthesis of a composite Fe–CaO-based sorbent/catalyst by mechanical mixing for CO2 capture and H2 production: An examination on CaO carbonation and tar reforming performance

A composite CaO-based sorbent/catalyst (Fe/CaO-CA, CA stands for Ca12Al14O33) with good cyclic CO2 uptake characteristics, mechanical stability and tar reforming performance for the carbon-negative biomass calcium looping gasification (CLG) technology is prepared by mechanical mixing method. Different synthesis parameters regarding cyclic CO2 capture and Fe/CaO-CA's mechanical strength have been investigated. Different reaction conditions, such as low carbonation temperature, high calcination temperature, long cycles, and large particle size, were also investigated using a thermogravimetric analyzer. Results showed Fe/CaO-CA performed better in mechanical strength and carbonation when it was prepared by calcination at 750 °C for 4 h. In the carbonation temperature range from 650 °C to 850 °C, 750 °C was more favourable to promote CO2 capture during cyclic reactions. Fe/CaO-CA still exhibited promising CO2 uptake characteristics under severe calcination conditions, including high CO2 partial pressure, high temperature and long-term response up to 40 cycles. Additionally, the effect of Fe/CaO-CA on tar removal enhancement was also studied via the reforming of 1-methyl naphthalene (1-MN) by using a self-designed fixed-bed reactor. Fe/CaO-CA presented the maximum 1-MN conversion and the highest H2 yield (0.15 mol h−1 g−1) compared to the other three candidate samples (CaO, CaO-CA and Fe/CaO). Furthermore, Fe/CaO-CA showed the largest CO2 uptake capacity and the least amount of coke deposition during tar reforming.

Ti-MWW Catalysts for Propylene Oxide Production: Influence of Si/Ti Ratio and Calcination Conditions

Titanium silicates of MWW structures with different Si/Ti ratios were prepared via hydrothermal synthesis using piperidine as the structure directing agent and boric acid as the crystallization agent. All the syntheses resulted in highly crystalline materials independent of the Si/Ti ratio. The observed morphology showed MWW-like well-defined thin hexagonal platelets. The synthesized Ti-MWW materials exhibited higher surface areas and partial meso-porosity compared to the commercial TS-1 catalyst. The coordination of the Ti-species was investigated by UV–vis- and IR-spectroscopy. The MWW titanium silicates were tested for the catalytic performance in the epoxidation of propylene in a laboratory-scale trickle bed reactor to compare their clear different physico-chemical properties with the commercial TS-1. The synthesized Ti-MWW materials showed significantly higher catalytic activities, up to 3.5 times, using acetonitrile as the solvent and enhanced epoxide selectivities partially up to 100% in methanol unlike TS-1. The effect of the Ti content in the MWW and the calcination conditions were investigated in propylene epoxidation, revealing the beneficial effect of a lower calcination temperature and an increased Ti content on the activity. The catalytic results were correlated with the physico-chemical properties of the synthesized materials.Graphical

Bifunctional Fe(III) metal-organic framework: A highly sensitive “turn-off” fluorescent probe and a precursor of magnetite nanoparticles for potential water decontamination

Nowadays growing concerns are rising toward water contamination caused by pharmaceuticals. Consequently, the design of optical sensors for their detection and analysis is extremely essential. In the current work, iron (III) aminoterephthalate-based metal-organic framework (Fe(III)-MOF) was synthesized by two approaches i.e. conventional and ultrasonication without the use of any organic solvents. Calcination of the synthesized Fe(III)-MOFs resulted in formation of different iron oxide phases i.e. magnetite and hematite depending on the calcination conditions. Magnetite NPs obtained from calcination of conventionally prepared MOF were efficiently utilized in the removal of daclatasvir (DAC), a hepatitis C antiviral drug, from water. Adsorption mechanism was investigated, and it was found that electrostatic interaction is the main force governing the adsorption of DAC on the magnetite NPs surface. Moreover, adsorption kinetics was studied, and it was established that adsorption of DAC on magnetite NPs surface follows pseudo-second order kinetics with R2 = 0.9970. The removal efficiency reached 99.9% after 220 min while using 5.0 mg/L of DAC. Furthermore, conventionally prepared Fe(III)-MOF showed higher fluorescence signal than ultrasonically-prepared MOF (∼3.0 times). This finding was exploited for utilization of conventionally prepared Fe(III)-MOF as a highly sensitive “turn-off” fluorescent probe for the analysis of nifuroxazide (NIFR) in domestic water. Parameters affecting sensing properties such as pH, solvent type and concentration of Fe(III)-MOF were optimized. The highest fluorescence quenching efficiency of NIFR was achieved while using 50 mg/L of Fe(III)-MOF in pH 9.0. Inner-filter effect was verified experimentally and mathematically to be the principal mechanism of the fluorescence quenching. The developed strategy showed high selectivity and sensitivity towards the analysis of NIFR with limit of detection and quantitation of 8.0 and 25.0 μg/L, respectively. Moreover, the designed sensor was successfully applied for determination of NIFR in domestic water without any interference from other tested antiviral, antidiabetic or antimicrobial drugs.

Perovskite-Like Strontium Bismuth Oxyhalides: Synthesis, Characterisation, Photocatalytic Activity and Degradation Mechanism

Recent studies have demonstrated that bismuth oxyhalides with a 2D structure inhibit the recombination of electron–hole pairs. Further, perovskite-like strontium bismuth-based compounds with a special layered Sillen X1 structure have shown potential for use as effective visible-light photocatalysts. Here, a series of strontium bismuth oxyhalide composites were prepared under different calcination conditions. The sample compositions were controlled by modulating the calcination temperature and the secondary calcination time. The synthesised catalysts were characterised by various techniques to identify the product compositions. Under visible-light irradiation, the degradation efficiencies and photocatalytic activities of the different catalysts towards rhodamine B (RhB) and 2-hydroxybenzoic acid (2-HBA) were measured via UV–Vis PDA and electron paramagnetic resonance analyses. To explore the degradation mechanism, scavengers were utilised to detect the radicals produced in the photodegradation test. SrBiO2Cl exhibited the best RhB degradation efficiency, of 0.0685 h−1, and SrBiO2Br exhibited a rate of 0.0984 h−1. At 25 °C and 1 atm, the CO2–CH4 photocatalytic conversion efficiencies of the optimised SrBiO2Cl and SrBiO2Br samples increased to 0.037 and 0.053 μmol g−1 h−1, respectively. The findings confirm that the catalysts are highly recyclable and effective for environmental remediation, achieving the objectives of green chemistry.

Application of ultrasound technology in the intensification of biodiesel production from bitter almond oil (BAO) in the presence of biocompatible heterogeneous catalyst synthesized from camel bone

ABSTRACT Although biofuels have many benefits, but their production costs are high. This challenge has caused researches to use waste materials and apply technologies to lower the cost of producing these fuels. In this study, a biocompatible heterogeneous catalyst created from calcining camel bones is employed to make biodiesel fuel from non-edible bitter almond oil (BAO). Additionally, using ultrasound technology was one way to increase the effectiveness of the biodiesel synthesis process. Additionally, the effects of the independent variables alcohol to oil molar ratio (6:1, 11:1, and 16:1), reaction time (10, 20, and 30 minutes), ultrasonic power (30, 65, and 100%), catalyst loading (4, 8, and 12 oil wt%), and reaction time (10, 20, and 30 minutes) on the production of methyl ester from BAO were examined. Camel bones were calcined at 400, 700, and 1000°C for 2, 3, and 4 hours. Optimum temperature and time conditions for camel bones calcination with maximum methyl ester production of 88% were obtained at 1000°C and 3 hours after measuring the morphology structure of camel bones catalyst using XRD and TGA methods. The maximum biodiesel conversion rate of 92.3% was obtained using the calcined catalyst with a molar ratio of 11:1, a catalyst loading of 8%, an ultrasonic power of 100%, and a reaction time of 20 minutes. Using the response surface methodology, tests and optimization were performed by Design-Expert software. Biodiesel yield and energy consumption were 88.13% and 248.18 kJ in the optimal conditions suggested by the software with the conditions of maximum production and minimum energy consumption with appropriate weighting. According to the results, waste camel bone can be used as a cost-effective biocompatible source with favorable catalytic activity for biodiesel fuel production.

Potential of bamboo leaf ash as supplementary binder materials - A systematic literature review

Concrete is one of the most used building materials in contemporary society; however, its production demands large amounts of raw materials and natural resources. Cement production is responsible for the highest CO2 emissions, causing major environmental impacts. The use of industrial waste as a supplementary cementitious material (SCM) has been increasingly studied to reduce and minimize these negative impacts. In this systematic literature review, we investigated the possible use of bamboo leaf ash (BLA) as a SCM. We analyzed 31 papers from four databases and evaluated the effects of calcination conditions of BLA as well as its chemical, physical, mechanical, and durability properties. The literature review demonstrates that BLA presents high pozzolanic reactivity and that composites with cement replacement by BLA present great mechanical properties and increased durability.

Chemical synthesis of magnesium oxide (MgO) from brine towards minimal energy consumption

The precipitation of magnesium from marine-derived feedstocks (e.g. waste brine discharged from desalination plants), has several environmental and economic advantages, if the right conditions are provided. In this work, the synthesis of reactive magnesium oxide (MgO) from the feedstock of simulated waste brine was demonstrated. One of the main challenges is the high energy consumption during the calcination of brucite, requiring the optimization of the calcination process to reduce this energy demand. To investigate this aspect, different calcination temperatures (400–550 °C) and durations (1−2 h) were examined and the synthesized MgO was evaluated for its chemical composition, specific surface area (SSA), reactivity and microstructure. The obtained results revealed the critical calcination condition that distinguished between low and high reactivity MgO, which also differentiated between plate-like and fiber-like morphology of MgO. Optimization of the calcination conditions led to SSA values as high as 167 m2/g. Calcination conditions with a minimum energy demand were identified for achieving MgO powders with a high reactivity, high SSA, and morphologies with a high propensity for hydration and/or carbonation reactions.

Tailored P2/O3 phase-dependent electrochemical behavior of Mn-based cathode for sodium-ion batteries

The development of mixed structures is increasingly becoming an efficient way to improve the performance of layered oxide cathodes for sodium-ion batteries. Herein, the Na0.8Mn0.6Ni0.3Cu0.1O2 (NMNC) cathodes with varying fractions of P2/O3-type phases are prepared by adjusting the calcination conditions. The Rietveld refinement of X-ray diffraction (XRD) data confirms the increase in O3 phase fraction from 7 % to 27 % with the increase in calcination temperature from 850 °C to 950 °C. The sample prepared at 850 °C (NMNC-850) exhibits the highest specific capacity (139 mAh g−1, 100 mAh g−1, and 80 mAh g−1 at 0.1C, 1C, and 4C, respectively) and best rate performance among all samples in addition to an excellent cyclability with capacity retention of ~85 % after 100 cycles in 1.5–4.2 V range. The increase in the O3 phase fraction leads to a drastic degradation of rate performance. The galvanostatic intermittent titration technique confirms a diffusion coefficient of 5.13 × 10−13–5.25 × 10−10 cm2 s−1 in biphasic NMNC-850 sample. Ex-situ XRD studies confirm a reversible P2/O3 → P2/P3 → P2/O3 transformation in NNMC-850 during cycling. The improved electrochemical performance is attributed to the presence of non-identical neighboring phases in suppressing the phase transformations during cycling.

Crucible Effect on Phase Transition Temperature during Microwave Calcination of a N-Doped TiO2 Precursor: Implications for the Preparation of TiO2 Nanophotocatalysts

Nitrogen-doped titanium dioxide (N–TiO2) is extensively studied in the literature and widely employed as a visible-light photocatalyst. The preparation of this nanomaterial often involves a final calcination step: in this paper, we used microwave technology as an efficient and environmentally friendly tool for the calcination of a mixed anatase/brookite phase precursor containing organic compounds arising from its synthesis. A wide study was performed, comparing results obtained in quartz fiber-made crucibles, porcelain crucibles, microwave (MW) and conventional heating, and also using a pristine TiO2 as a reference material. Weight percentages of the three main TiO2 polymorphs obtained in different calcination conditions were determined by X-ray powder diffraction (XRPD) data and Rietveld refinements, and the results are discussed. We found that the calcination’s outcome is dramatically affected by the crucible used: while mixed-phase nanomaterials were obtained when using classic porcelain crucibles, only the rutile phase was obtained when working in a quartz fiber crucible at temperatures as low as 250 °C. The direct material’s temperature measurement inside the microwave oven showed that this finding is not due to a microwave effect but to a thermal effect caused by the particular crucible employed that favors better combustion of organics and prompts rutile formation. Nitrogen doping of this material was inferred by ultraviolet–visible–diffuse reflectance spectroscopy (UV–vis–DRS).

Decomposition Mechanism and Calcination Properties of Small-Sized Limestone at Steelmaking Temperature

Limestone with a particle size of less than 5 mm was rapidly calcined in a high-temperature resistance furnace at 1623 K to simulate the conditions of rapid calcination of limestone at ultra-high temperature in a converter. In this study, the decomposition mechanism and calcination characteristics of small-sized limestone at steelmaking temperature were investigated. The study shows that the shrinking sphere or cylinder models with phase boundary reaction were found to be the best representation of limestone kinetic data, and the mechanism function equation is G(α) = 1 − (1 − α)n, n = 1/2 or 1/3. Limestone particles with a size of 0.18–1.0 mm can be quickly calcined to obtain a typical active lime microstructure and a high activity of more than 350 mL, which is the preferred limestone particle size range in the steelmaking process in which limestone powder is injected into the converter.

Feasible synthesis of magnetic zeolite from red mud and coal gangue: Preparation, transformation and application

A feasible synthesis of magnetic zeolite from the mixture of industrial solid wastes (red mud and coal gangue) was proposed. The preparation conditions, formation mechanism and adsorption performance of magnetic zeolite were investigated. Magnetic zeolite with uniform distribution of zeolite and magnetite could be successfully synthesized at the alkali reducing calcination conditions of n(Na:Al:Si) = 3.6:1:1, 600 °C, 1.5 h and the hydrothermal conditions of n(Na:H2O) = 2.8:1, 90 °C, 9 h. During this process, aluminosilicates in the mixture of red mud and coal gangue could be transformed into sodium-containing phases and zeolite A in turn; meanwhile, hematite in red mud could be reduced by carbon in coal gangue to transform into magnetite. The prepared magnetic zeolite showed excellent adsorption capacity and reusability for heavy metals. The maximum adsorption capacity for Cu2+, Cd2+ and Pb2+ reached 76.2, 92.2 and 178.4 mg/g, respectively, which could be attributed to the different ionic radius of heavy metals.

Extraction of Iron and Alumina from Red Mud with a Non-Harmful Magnetization Sintering Process

Red mud, which could cause numerous problems to the environment, is a hazardous waste generated from the alumina smelting industry. In general, the storage and harmless utilization of red mud are hard to implement due to its fine particle size and high alkalinity. This study put forward a novel process to separate iron (MgFe2O4) and alumina (Al2O3) in red mud by a magnetization sintering method. The magnesium oxide was added to transform the nonmagnetic Fe2O3 into magnetic MgFe2O4 to achieve physical separation of iron-bearing minerals, and the alumina-bearing minerals were converted into dissoluble NaAlO2 minerals in a one-step reaction. The atmospheric pressure leaching process was adopted in this study for alumina resource recovery. To achieve clean alumina production, the silicate in the leaching solution was removed by adding the slightly soluble CaSO4, and the entire process becomes clean and harmless. The feasibility of the process was verified by thermodynamic analysis, and a series of experiments were performed to detect the optimum MgO/(Fe2O3 + MgO) ratio and the calcining and leaching conditions. The morphological and mineralogical characteristics of modified red mud, leaching red mud, and magnetic separation product were studied by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) energy dispersive spectroscopy (EDS). It was observed that under the optimal conditions with MgO/(Fe2O3 + MgO) of 14.89% to recover iron and aluminum, the corresponding recovery rates were 67.54% and 73.01% respectively, and the iron grade was 30.46%. The EDS results showed that the obtained Mg/Fe ratio of the magnetic separation product was 0.4677–0.528, which is slightly different from that of the standard MgFe2O4 at 0.5. This new method can promote the development of comprehensive utilization of red mud and iron production.

Selective Solvent Extraction of Vanadium Over Chromium from Alkaline Leaching Solution of Vanadium Slag by D2EHPA/TBP

ABSTRACT A selective extraction process for recovering vanadium (IV) over chromium was proposed with use of a mixed extractant consisting of di(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP). The influence of various factors, which included the initial aqueous pH value, the concentration of leach solution and D2EHPA, phase ratio (O/A), extraction equilibrium time and extraction temperature in the extraction process on the separation of V and Cr was investigated. Under the condition of the optimum extraction, vanadium extraction was above 94.0%. Meanwhile, under the optimum stripping conditions, the vanadium stripping was above 93.0% utilizing 1.5 mol/L sulfuric acid as the effective stripping reagent. The regeneration and reusability of the loaded organic phases after stripping were discussed. In addition, continuous three-stage extraction and stripping strategy indicated that the aggregate loss of vanadium was 0.885% and that the purity of vanadium was more than 99.9%. Under the condition of the optimum precipitation, when the pH value of the stripping solution was adjusted to 7.0 with ammonia water, the precipitation efficiency reached 99.93%. The calcination conditions (above 680 °C in air) were finally determined by TG-DTA and TG-MS experiments, and the V2O5 obtained by calcination was characterized by XRD. Additionally, a method for detecting impurity elements in vanadium matrix without interference was established. The recovery technology has practical significance in enlarging production scale, reducing specific energy consumption and cost, and realizing automatic control in vanadium leaching process.

Cooperative Characterization of In Situ TEM and Cantilever-TGA to Optimize Calcination Conditions of MnO2 Nanowire Precursors.

Calcination plays a vital role during material preparation. However, the calcination conditions have often been determined empirically or have been based on trial and error. Herein we present a cooperative characterization approach to optimize calcination conditions by gas-cell in situ TEM in collaboration with microcantilever-based thermogravimetric analysis (cantilever-TGA) techniques. The morphological evolution of precursors under atmospheric conditions is observed with in situ TEM, and the right calcination temperature is provided by cantilever-TGA. The proposed approach successfully optimizes the calcination conditions of fragile MnO2 nanowire precursors with multiple valence products. The cantilever-TGA shows that a calcination temperature above 560 °C is required to transform the MnO2 precursor to Mn3O4 under an N2 atmosphere, but the in situ TEM indicates that the nanowire structure is destroyed within only 30 min under calcination conditions. Our method further suggests that heating the precursor at 400 °C using an H2-containing atmosphere can produce Mn3O4 nanowires with good electrical properties.

Band Engineering of Photocatalytic BiVO4 with Modified Vanadium States via Potassium Chloride Addition during Hydro-Thermal Synthesis and Post-Annealing

The monoclinic BiVO4 in a powder state was prepared via a hydrothermal method, with the addition of KCl as a structure-directing agent. The as-prepared sample was calcined at different temperatures (400–600 °C), either in the air or in Ar gas. It is found that, though the morphology and crystal structure mostly remain unchanged, the bandgap properties are modified during calcination. A detailed analysis of the surface chemical states and optical absorption properties reveals the involvement of tetravalent vanadium ions and oxygen vacancies as the cause of the band modification. The bandgap properties are to be found tunable via changing the calcination condition, as well as the KCl concentration in the precursor. The photocatalytic properties of BiVO4 samples are greatly enhanced with the addition of KCl in the precursor, but degraded by post-annealing, where the residual Cl in the calcined sample may act as an inhibitor. The enhanced photoactivity is explained in terms of favorable faceting, bandgap modification, and heterojunction of BiVO4/BiOCl.

Deformation and Cracking Resistance of MgO-Incorporated Cementitious Material: A Review.

In China, MgO-based expansive agent (MEA) has been used for concrete shrinkage compensation and cracking control for over 40 years. The expansive behavior of MEA in cementitious materials could be manipulated to some extent by adjusting the calcination process of MEA and influenced by the restraint condition of the matrix. It is key to investigate the factors related to deformation and cracking resistance so that the desired performance of MEA in certain concrete structures could be achieved. This paper reviews the influence of key parameters such as hydration reactivity, dosage, and calcination conditions of MEA, the water-to-binder ratio, supplementary cementitious material, aggregates, and curing conditions on the deformation and cracking resistivity of cement paste, mortar, and concrete with an MEA addition. The numerical simulation methods and deformation prediction models are then summarized and analyzed for more reasonable estimations.

Development of Red Ceramic Pigments with Perovskite Structure Prepared through a Traditional Route

Solid solutions of ceramic pigments of red shade have been synthesized based on YAlO3 perovskite structure doped with chromium by means of conventional synthesis; that is, the “ceramic route”. To optimize this synthesis, an emphasis has been made on the study of stoichiometry, calcination conditions and mineralizer incorporation. Various studies have demonstrated the high stability of perovskite structures, which ensures stable coloration at high temperatures. This is a highly important factor in the ceramic sector, given the scarcity of red glazes functional at temperatures close to those required of porcelain stoneware and their environmental constraints. Such a limitation makes it impossible in the European community to manufacture using toxic materials such as Se and Cd (cadmium sulfoselenide) that offer interesting colors at low temperatures. Pigments have been synthesized within the Y1−xCrxAlO3, YCrxAl1−xO3 and Y1−xAl1−yCrx+yO3 chromium-doped systems in molar ratios between n = 0.01 molar and n = 0.10 molar. The pigments obtained have been characterized by X-ray diffraction to identify the crystalline phases responsible for the shade; that is, the formation of the perovskite crystalline structure YAlO3 responsible for the red shade, together with lateral phases of garnet Y3Al5O12 of lower intensity. Visible ultraviolet spectrophotometry shows absorption bands corresponding to Cr(III) in octahedral position and the appearance of Cr(IV) in both octahedral and tetrahedral positions. The morphology of the samples was studied using a scanning electron microscope, obtaining information from the secondary and back scattered electrons. The viability of its use in ceramic glazes was verified after applying them mixed at 4% by weight in a glaze to an industrial porous single-firing cycle, collecting the L*a*b* chromatic coordinates using a visible ultraviolet spectrophotometer based on the CIE L*a*b* system, giving rise to red colorations.

On the disparity in reporting Li-rich layered oxide cathode materials.

Lithium-rich layered oxides are considered one of the most promising cathode materials for next generation lithium-ion batteries due to their extraordinary specific capacity of over 280 mA h g-1 and superior energy density of over 1000 W h kg-1. Despite the excellent performance, LRLOs still suffer from low Coulombic efficiency, serious capacity/voltage decay upon cycling, voltage hysteresis, short lifespan, and poor rate capability. Driven by the thirst for high-energy-density battery technologies, various strategies have been developed to address these issues with great progress being achieved in the past several years. However, the emerging disparity among the published results severely precludes meaningful comparisons between different LRLOs and material modification strategies, which has become an impediment to the development and commercialization of LRLOs. Although the significance of standardization has been recognized in the battery community, the standardization of LRLOs is worth particular attention due to their complicated compositions and unique electrochemical properties. This perspective analyzes the underlying parameters that can cause varied and even controversial results observed in LRLOs, from the synthesis procedure to the electrochemical evaluation procedure, followed by preliminary suggestions for the standard protocols of chemical compositions, synthesis pathways, calcination conditions, electrode preparation, battery fabrication, and battery testing. Hopefully, this perspective can help build a reliable baseline for LRLO research, thus aligning the huge research effort toward the practical applications of LRLOs.

Relationship between Transport Properties and Calcination Conditions in Low-Temperature Sintered Pr-Doped Bi2212 Superconductors

Relationship between Transport Properties and Calcination Conditions in Low-Temperature Sintered Pr-Doped Bi2212 Superconductors

Influence of additive surface area degradation on fine particle formation during biomass pulverised-fuel combustion

This study examined the surface area degradation of kaolin, coal fly ash and the resulting impact on the alkali capture efficiency in a pilot-scale real flame combustion test rig using beech wood as fuel. Experiments in an electrically heated furnace revealed the thermal surface area evolution of kaolin with residence times between 30and 3600 s and temperatures between 790 and 1400 °C under calcination conditions. Subsequent measurements of the resulting specific BET (Brunauer-Emmet-Teller method) surface area of the kaolin samples were carried out. The temperature profile in the top-down fired biomass combustion test rig (BoCTeR) was measured with a suction pyrometer when combusting natural gas and beech wood powder. Additional experiments were performed by injecting kaolin and coal fly ash particles directly into a natural gas flame at different reactor heights. Those kaolin particles exposed to high temperatures in the natural gas flame were collected and subsequently analysed for the specific BET area to evaluate the corresponding degree of surface loss. The main test series comprises a setup combusting beech wood with kaolin or coal fly ash injected at different positions of the combustion chamber. The alkali sorption capacity of the kaolin and coal fly ash used is indirectly measured by the combustion aerosol reduction performance determined with an electrical low-pressure impactor (ELPI). The goal of this work is to show the impact of surface area degradation phenomena of additives and the resulting optimisation potential when using Al/Si-based in-furnace additive during the pulverised-fuel combustion of biomass. The surface area development of the additives at high temperatures affects the most suitable temperature window for the additive injection. The results show an optimum for the kaolin injection. The coal fly ash reduced PM best when injected as early possible into the combustion chamber.