Min Heating Rate Research Articles

Effect of different acids during the synthesis of urea‐formaldehyde adhesives and the mechanical properties of medium‐density fiberboards bonded with them

ABSTRACTThe characteristics of urea‐formaldehyde (UF) adhesives condensed by catalysis with four different acids, namely formic (HCOOH), hydrochloric (HCl), phosphoric (H3PO4), and sulfuric (H2SO4) acids, under alkaline–acidic–alkaline conditions at a molar ratio F/U = 1.12 were studied. The thermal curing properties of UF adhesives catalyzed with acid were characterized by differential scanning calorimetry at 10 °C/min heating rate. The resin structure examined by 13C‐NMR spectroscopy showed that the resin catalyzed with HCl had a lower proportion of methylol groups, resulting in a lower level of formaldehyde emission. It was interesting to note that HCOOH resulted in the best overall mechanical properties of the medium‐density fiberboard (MDF) panels. The HCl catalyst resulted in the poorest performance, providing the lowest internal bond strength, modulus of elasticity, and thickness swelling, with the exception of the free formaldehyde content. The resin catalyzed with H2SO4 had the highest free formaldehyde and the highest formaldehyde emission. H2SO4 and H3PO4 resulted in MDF mechanical properties relatively lower than for HCOOH. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47256.

The effect of calcination rate on the structure of mesoporous bioactive glasses

Mesoporous bioactive glasses (MBGs) are designed to have high specific surface area. They are formulated by a sol–gel process to formulate the glass followed by calcination. This study evaluates how calcination heating rate influences the porous architecture, and thereby the specific surface area, of MBGs. MBGs of molar ratio 80:15:5 for SiO2:CaO:P2O5 were calcined using both low (1 °C/min) and high (20 °C/min) heating rates, termed as L-MBG and H-MBG, respectively. The results obtained from small-angle X-ray diffraction (SAXRD) confirm that the MBGs possess 2D hexagonal (P6mm) spacing groups and wide-angle XRD confirms the amorphicity of both MBGs. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirm that both batches of MBGs have similar chemical composition. Fourier transform infrared spectroscopy identifies the same functional groups present in both batches. However, transmission electron microscopy indicates that H-MBG samples exhibited discontinuities in their ordered channel structure, confirmed by the lower SAXRD peak intensity of H-MBG compared to L-MBG. These discontinuities led to a reduced surface area. L-MBG exhibits more than quadruple the surface area and double the pore volume (373.87 m2/g and 0.27 cm3/g) of H-MBG (85.91 m2/g and 0.13 cm3/g), measured through Brunauer, Emmett, and Teller nitrogen adsorption analysis. This higher surface area resulted in a significant (p < 0.05) increase in the quantity of ion release from the L-MBGs compared to the H-MBGs. It is concluded that the application of a low heating rate during calcination, of the order of 1 °C/min, is more likely to result in ordered mesoporous bioactive glasses with high surface area and pore volume than MBG samples processed at a higher heating rate.

Large Improvement in Magnetic Properties of Hot-Deformed HREE-Free Nd–Fe–B Magnets Using the Rapid Heating Technique of the Powder

Nd–Fe–B magnets for electric vehicles are required to have high coercivity, and heavy rare earth elements are added. However, it is necessary to reduce the heavy rare earth element that is a scarce resource. Decreasing the grain size is an effective method of increasing $H_{\mathrm {cj}}$ , and hot-deformed magnets which are consisted of rapidly quenched powders are known to have fine grains. This paper focused on coarse grains observed in the microstructure of hot-deformed magnets. Measuring the local magnetic properties by XMCD, it was shown that the coarse grain areas had lower magnetic properties than those of the fine grain areas. The coarsening was located at the powder interface. Therefore, the crystal growth behavior in the powder was investigated in detail. Due to the Fe concentrated in the powder along the wheel side of the melt-spun, Nd2O3 and $\alpha $ -Fe were grown as the primary crystals. It is considered that the coarsening of hot-deformed magnets originates in those heterogeneous crystallizations. In order to prevent the coarsening, this paper focused on the heating rate of heat treatment of powders. The coarsening was prevented under the conditions, over 400 °C/min of heating rate and over 600 °C of heating temperature. The rapid heating of powders using the free-fall-type furnace prevented the coarsening in hot-deformed magnets. As a result of decreasing the coarse grains, $H_{\mathrm {cj}}$ was increased from 1584 to 1614 kA/m and $M_{r}$ was increased from 1.33 to 1.40 T.

Liquid fuels from used transformer oil by catalytic cracking using bentonite catalyst

In this study, the main target was to obtain the liquid fuel‐like product from the catalytic cracking of the used transformer oil over bentonite as a low‐cost catalyst. For this aim, a series of cracking runs were performed under certain experimental conditions (450 °C cracking temperature, 10 °C/min of heating rate, and catalyst in the range of 0–8.0 wt %) in a fixed‐bed reactor. In catalytic cracking runs, the use of bentonite as a catalyst led to a considerable increase in yield of the cracking oil comparable to that of the noncatalytic oil. The highest yield value of 98.64 wt % was achieved at catalyst ratio of 4.0 wt %. Furthermore, the liquid product obtained in the highest yield was characterized by FTIR and GC–MS to evaluate its composition in terms of compound distributions as a comparison with the noncatalytic run. Also, its fuel properties such as cetane index, higher heating value, viscosity, density, water content, elemental content, and so forth were analyzed using standard test techniques. Based on these results obtained, the catalytic liquid product can be utilized to prepare liquid fuel blends with diesel for the diesel engines. © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13080, 2019

Influence of Presintering Parameters on the Mechanical Properties of Presintered Dental Zirconia Block

This study aimed to investigate the effects of presintering parameters on the mechanical and microstructural properties of presintered zirconia block. The zirconia block was prepared using colloidal and cold isostatic pressing techniques and subsequently subjected to various presintering procedures at 850 °C, 900 °C, and 950 °C with two different heating rates (3 and 10 °C/min). All samples were evaluated in terms of hardness, density, and morphology. Results showed that the sample porosity decreased with increment in the presintering temperature. On the contrary, the Vickers hardness increased from 1.8 GPa at 850 °C to 2.7 GPa at 950 °C at 10 °C/min heating rate. The sintering temperature of 950 °C with 3 °C/min heating rate was considered the most suitable parameter among presintering procedures, with high theoretical density (96.2%) and appropriate hardness (1.27 GPa) that are within the range of commercial zirconia block hardness values for restoration milling procedure. Furthermore, to sinter the block samples successfully without considerable failure, the heating and cooling rates should be lowered to ≤3 °C/min. Therefore, on the basis of these results, the forming methods and the sintering temperature influence the resultant mechanical and microstructural properties of the final sample.

SiO2 particles effect on the mechanical properties of the starch/PVA blends

The present work studies the mechanical properties of SiO2 μPs, and NPs in St/PVA blends. The samples were prepared by casting method as PVA, St/PVA blends at different concentrations (30, 40, 50, and 60 %). DSC and TGA tests were carried out to the samples evolved. The result showed a single glass transition temperature (Tg) for all St /PVA blends that was attributed to the good miscibility of the blends involved. It was found that (Tg) decrease with starch ratio increase. It was seen that (PVA) of (Tg=105 oC); The glass transition temperature which was decrease with starch ratio that was attributed to glass transition relaxation process due to micro-Brownian motion of the main chain back bond. The endothermic peak at 200 oC was attributed to melting point of (PVA). Thermal properties of PVA; and St /PVA blends at different concentration (30, 40, 50, and 60 %) were evaluated by thermo gravimetric analysis (TGA). The analyses were carried out from 20 to 600 oC at 10 oC)/min heating rate in air oxygen atmosphere. The weight loss stages depended on polymer system. The starch addition causing shifting in the second degradation temperature to the higher temperature; which result in overlapping between the two main degradation steps, these result was attributed to the St/ PVA blend compatibility. The mechanical properties results showed a decrease in ultimate strength with starch ratio increase. The ultimate strength of (PVA) was (47 MPa), whereas the ultimate strength of 60 %St/PVA was (11 MPa) and for 30 %St/PVA was the highest ultimate strength of blends involved (26 MPa). SiO2μPs (753.7 nm), and NPs (263.1 nm) were added at different concentrations (1.5, 2, and 2.5 %). 1.5% SiO2μPs, and NPs of the best ultimate strength (69 MPa), (86 MPa) respectively then it was decreased by SiO2μPs, and NPs increase. Optical microscope of the samples involved was investigated. It was concluded the prepared samples were suggested to be used as packaging materials for agriculture application and its ultimate strength could be controlled by SiO2μPs, and NPs addition.

Effects of activation conditions on the structural and adsorption characteristics of pinecones derived activated carbons

ABSTRACTThis study was conducted to understand and optimize the activation process for the production of a low-cost activated carbon (AC) using a renewable and plentiful biomass waste, pinecones. This was achieved by tracking the changes in porous structure, surface chemistry and adsorption properties of the AC produced using different activating agents, activation temperatures, holding times and heating rates. Generally, produced ACs were predominantly microporous with small external surface area and were different in terms of H/C and O/C ratios. Study of Pb2+ cations adsorption on these samples proved the high affinity of the pinecones derived ACs to this cation. The best adsorption behaviour was recognized in sample prepared by impregnation with H3PO4 at weight ratio of 2, then heating at 400 °C for 2 h at 5 °C/min heating rate. This sample possessed the highest BET surface area (1335 m2/g). The adsorption process obeyed the pseudo-first-order and Freundlich model slightly better than the pseudo-second-order kinetics and Langmuir model. The high Langmuir maximum adsorption capacity of 418 mg/g supports the applicability of the produced AC for the removal of Pb2+ cations from wastewater.

Phase Diagrams of Polymer-Dispersed Liquid Crystal Systems of Itraconazole/Component Immiscibility Induced by Molecular Anisotropy

Liquid crystalline (LC) materials and their nonmedical applications have been known for decades, especially in the production of displays; however, the pharmaceutical implications of the LC state are inadequately appreciated, and the misunderstanding of experimental data is leading to possible errors, especially in relation to the physical stability of medicines. The aim of this work was to study LC phases of itraconazole (ITZ), an azole antifungal active molecule, and for the first time, to generate full thermodynamic phase diagrams for ITZ/polymer systems, taking into account isotropic and anisotropic phases that this drug can form. It was found that supercooled ITZ does not form an amorphous but a vitrified smectic (vSm) phase with a glass transition temperature of 59.35 °C (determined using a 10 °C/min heating rate), as is evident from X-ray diffraction and thermomicroscopic (PLM) experiments. Two endothermic LC events with the onset temperature values for a smectic to nematic transition of 73.2 ± 0.4 °C and a nematic to isotropic transformation at 90.4 ± 0.35 °C and enthalpies of transition of 416 ± 34 J/mol and 842 ± 10 J/mol, respectively, were recorded. For the binary supercooled mixtures, PLM and differential scanning calorimetry showed a phase separation with birefringent vSm persistent over a wide polymer range, as noticed especially for the hypromellose acetate succinate (HAS) systems. Both, smectic and nematic, phases were detected for the supercooled ITZ/HAS and ITZ/methacrylic acid-ethyl acrylate copolymer (EUD) mixtures, while geometric restrictions inhibited the smectic formation in the ITZ/poly(acrylic acid) (CAR) systems. The Flory-Huggins lattice theory coupled with the Maier-Saupe-McMillan approach to model anisotropic ordering of molecules was successfully utilized to create phase diagrams for all ITZ/polymer mixtures. It was concluded that in a supercooled ITR/polymer mix, if ITZ is present in a LC phase, immiscibility as a result of molecule anisotropy is afforded. This study shows that the LC nature of ITZ cannot be disregarded when designing stable formulations containing this molecule.

Kinetic study for the co-pyrolysis of lignocellulosic biomass and plastics using the distributed activation energy model

The characteristics of bio-oil produced from biomass pyrolysis can be improved by co-feeding waste materials. In this work, co-pyrolysis of lignocellulosic biomass with six different waste plastics (waste tyre (WT), polylactic acid (PLA), polystyrene (PS), polyethylene terephthalate (PET), polypropylene (PP) and high density polyethylene (HDPE)) were conducted in a thermogravimetric analyser to study thermal decomposition of the mixtures. The distributed activation energy model (DAEM) was applied to pure feedstocks at 5 and 10 °C/min heating rates to fit the kinetic parameters. The model was used to simulate the co-pyrolysis of biomass/plastic mixtures assuming additive effect of components at different weight proportions and heating rates. Profiles of the fraction of mass remaining for mixtures at 100 °C/min were reproduced with a remarkable agreement. Discrepancies between the experimental and calculated profiles were considered as a measure of the extent of interactions occurring in the co-pyrolysis. Projections of the behaviour of mixtures under flash pyrolysis conditions were performed to study important aspects of the process, such as radical interactions and optimum working temperature.

Thermo-chemically tuning of active basic sites on nanoarchitectured silica for biodiesel production

In the design of catalysts, an extremely important point is to determine, control and increase the availability of active sites on the surface. In the present work, active sodium oxide species have been identified and it is demonstrated how its dispersion can be suitably improved by combining sodium loading degree and calcination heating rate in order to increase the catalyst basic character and consequently, its performance. The different synthesized materials were characterized by: small-angle X-ray scattering (SAXS), high angle X-ray diffractions (XRD), atomic absorption spectroscopy (AA), BET method (specific surface determination), Fourier-transform infrared spectroscopy (FT-IR), carbon dioxide temperature programed desorption (CO2 TPD) and X-ray photoelectron spectroscopy (XPS). The obtained catalyst using 10 wt% of sodium loading followed by calcination at 500 °C, employing an 8 °C/min heating rate, showed the highest activity towards the transesterification of sunflower oil reaction (5 h, 60 °C, 14:1 methanol to oil molar ratio, 2 wt% catalyst, vigorous magnetic stirring), achieving a 90% biodiesel yield.

A Study of the Production and Combustion Characteristics of Pyrolytic Oil from Sewage Sludge Using the Taguchi Method

Sewage sludge is a common form of municipal solid waste, and can be utilized as a renewable energy source. This study examines the effects of different key operational parameters on sewage sludge pyrolysis process for pyrolytic oil production using the Taguchi method. The digested sewage sludge was provided by the urban wastewater treatment plant of Tainan, Taiwan. The experimental results indicate that the maximum pyrolytic oil yield, 10.19% (18.4% on dry ash free (daf) basis) by weight achieved, is obtained under the operation conditions of 450 °C pyrolytic temperature, residence time of 60 min, 10 °C/min heating rate, and 700 mL/min nitrogen flow rate. According to the experimental results, the order of sensitivity of the parameters that affect the yield of sludge pyrolytic oil is the nitrogen flow rate, pyrolytic temperature, heating rate and residence time. The pyrolysis and oxidation reactions of sludge pyrolytic oil are also investigated using thermogravimetric analysis. The combustion performance parameters, such as the ignition temperature, burnout temperature, flammability index and combustion characteristics index are calculated and compared with those of heavy fuel oil. For the blend of sludge pyrolytic oil with heavy fuel oil, a synergistic effect occurs and the results show that sludge pyrolytic oil significantly enhances the ignition and combustion of heavy fuel oil.

Self-catalyzing pyrolysis of olive pomace

In thisstudy, catalytic effect of intrinsic inorganics was evaluated by comparing pyrolysis end products obtained from pyrolysis of olive pomace (OP) in three different initial weights (30,100 and 200 g). Pyrolysis of OP with higher weights led to self-catalyzing pyrolysis resulting in approximately 20% bio-oil quantity increment when pyrolyzed OP weight increased from 30 g to 200 g. Additionally, both intrinsic inorganic percentages remained in pyrolysis chars and organic compounds in pyrolysis liquids altered with pyrolyzed OP weights. While the lowest inorganic percentage in chars was found at the pyrolysis of the highest OP weight, the highest belonged to 30 g OP pyrolysis. Moreover, while oxygenated compounds, namely aldehydes and ketones, in pyrolysis bio-oil decreased explicitly at 200 g OP pyrolysis, variety in alkane and alkene compounds enhanced at higher weights OP pyrolysis. Finally, the effects of temperature, heating rate and retention time on pyrolysis products were evaluated. Results showed that liquid products increased at 5 °C/min heating rate and decreased at 1 °C/min heating rate as pyrolysis temperature increased from 450 to 600 °C in the pyrolysis without retention time. However, reverse tendency was observed in liquid product quantities in the case of pyrolysis with retention time. Furthermore, while effect of temperature increment on pyrolysis gas and liquid was mostly opposite to each other in all pyrolysis conditions, bio-chars' quantity irregularly altered as to pyrolysis conditions.

A comparative study of Schiff base chelating resins: synthesis, uptake of heavy metal ions, and thermal studies

Two new chelating resins (Rciaa91 and Rciaa73) with different compositional chelating groups and degree of cross-linking were prepared by free radical copolymerization of Schiff bases obtained from condensation reaction of cinnamaldehyde (ci) with anthranilic acid (aa) and 1,4-phenylenediamine (pn) monomers. The synthesized materials were characterized using CHN analyses, FTIR, 1H-NMR, and thermal analyses (TGA, DTA). Batch technique was applied, and the contact time, pH and initial concentration of the metal ions were investigated as factors affecting the uptake behavior. The results obtained indicated that the chelating resin with larger compositional ratio of chelating moieties and lower degree of cross-linking showed lower optimum reaction time and higher uptake affinity towards the metal ions Cu(II), Cd(II), Co(II), Zn(II), Hg(II), and Pb(II), under the same conditions. Both the chelating resins showed uptake behavior of the metal ions in the following order Hg2+ &gt; Cu2+ &gt; Zn2+&gt;Pb2+&gt;Co2+ &gt; Cd2+ each metal at its optimum pH and at the same reaction time and ion concentration. The thermal degradation behavior and stability of the resins were investigated by using non-isothermal thermogravimetric analysis (TGA/DTG/DTA), at 10 °C min-1 heating rate and under nitrogen. The Coats-Redfern method was used to evaluate the kinetic and thermodynamic parameters (ΔG*, ΔH* and ΔS*) for the prominent degradation steps in the TGA curves at 450-660 °C range.

Determination of kinetic parameters and thermodynamic properties for ash (Fraxinus) wood sawdust slow pyrolysis by thermogravimetric analysis

ABSTRACTAsh (Fraxinus) wood sawdust pyrolysis under nitrogen was conducted using 2, 5, 10, 15, and 20°C/min heating rates. Friedman and Starink methods were used for kinetic analysis while y(α) master plots were used for pyrolysis mechanisms prediction. The mean activation energy were 198 and 202 kJ/mol for Friedman and Starink, respectively. The master plots predicted that the pyrolysis process could be a combination of diffusion, geometrical contraction, nucleation, and reaction order models. The pre-exponential factors were in the range 1012 to 1019 s−1. Gibbs free energy was 180 −185 kJ/mol. The entropy values were negative up to α = 0.75 indicating high orderliness of products relative to reactants but changed to positive at higher conversions implying likely disorderliness of the products compared to reactants. The calorific value of Ash (Fraxinus) wood sawdust was 18.3 MJ/kg.

Pyrolysis of human feces: Gas yield analysis and kinetic modeling

Pyrolysis of human feces renders the waste free of pathogens and is a potential method of treating fecal sludge waste collected from non-sewered systems. Slow pyrolysis experiments were conducted on human feces and the char yield and gas evolution quantified at 1–10 °C/min heating rates. Char yield ranged from 35.1 to 35.8% (dry mass basis), while the gas yield ranged from 17.2 to 29.6% (dry mass basis). The pyrolysis gases detected were CO, CO2, CH4, C2H6, and H2. These non-condensable gases contained a higher heating value (HHV) ranging from 7.2 to 22.8 MJ/Nm3. Kinetic analysis was done by a pyrolysis reaction model free method (Isoconversional) as well as a DAEM (Distributed Activated Energy Model) method that assumes many irreversible first order reactions. Both yielded very close values for activation energy ranging from 141 kJ/mol to 409 kJ/mol, with half of the biomass conversion happening at 241.5 ± 2.9 kJ/mol. The findings of the research provide useful technical information that can guide the design of a pyrolysis system to treat fecal waste. Social acceptance and scale-up issues need to be addressed through further research.

Properties and environmental impact of the mosaic sludge incorporated into fired clay bricks

This paper presents fundamental information on the utlization of mosaic sludge waste from industrial mosaic activities into building materials. The study greatly benefits solid waste management and industries that produce waste with high heavy metal concentration by providing insights on ways to dispose waste by minimizing heavy metal leaching potential whilst providing a new formulation of low-cost and environmentally friendly building materials. Therefore, an alternative disposal method is to incorporate mosaic waste such as bodymill sludge (BS) and polishing sludge (PS) into fired clay brick. The bricks were incorporated with different percentages (0%, 1%, 5%, 10%, 20% and 30% by weight) of sludge waste and fired at 1050 °C (0.7 °C/min heating rates). The optimization results showed that the incorporation of up to 30% of mosaic sludge into fired clay bricks is capable of improving its physical and mechanical properties. Moreover, the incorporation of mosaic sludge waste into clay bricks has a positive effect on firing shrinkage, density and compressive strength. However, a decreased performance was reported for certain aspects. Hence, this study demonstrated that BS and PS can be alternative low-cost and environmentally friendly which can be used to improve the physical and mechanical properties of fired clay bricks.

Prediction of the Products Yield of Delayed Coking for Iranian Vacuum Residues

In this work, new correlations are proposed to predict the products yield of delayed coking as a function of CCR and temperature based on the experimental results. For this purpose, selected Iranian vacuum residues with Conradson carbon residue (CCR) values between 13.40-22.19 wt.% were heated at a 10 °C/min heating rate and thermally cracked in a temperature range of 400-500 °C in a laboratory batch atmospheric delayed coking reactor for 2 hours. The amount of distillate (C5+-500 °C) and coke yield were measured in all the experiments, and the gas (C1-C4) product yield was calculated based on mass balance between products and feedstock in each experiment. According to the developed functions, products yield changes with CCR value linearly and is a power function of temperature. The further investigation of the results show that by a 1 wt.% increase in CCR value, the distillate yield decreases by about 2.1 wt.%, but the amount of coke and gas yields rise by 1.2 wt.% and 0.9 wt.% respectively.

Microwave co-pyrolysis of waste polyolefins and waste cooking oil: Influence of N2 atmosphere versus vacuum environment

Microwave co-pyrolysis (MCP) of waste cooking oil (WCO) and waste polyolefins (WP) was examined for its potential to convert these wastes into liquid fuel. The influence of performing the pyrolysis process under N2 atmosphere and vacuum environment was investigated with emphasis on the temperature profile, heating rate, and the yield and properties of the liquid oil obtained. Different ratios of WP to WCO (1:2, 1:1.5, 1:1, 1.5:1, and 2:1) were also investigated. MCP performed under vacuum environment recorded higher heating rates (20–24 °C/min) and higher yield of liquid oil (up to 62 wt.%) compared to that performed under N2 atmosphere (18–22 °C/min of heating rate and 24–50 wt.% of liquid oil). The high heating rate resulted in shorter reaction time and lower power consumption, leading to lower energy consumption by the pyrolysis process. The liquid oil comprised C13–C24 hydrocarbons (aliphatics, aromatics) within the hydrocarbon range of diesel fuel. It also showed promising green properties comprising low nitrogen and oxygen content, and free of sulphur. Combined with the detection of high energy content (42–49 MJ/kg) and low moisture content (<1 wt.%), the liquid oil shows great potential to be used as a fuel. Our results show that MCP performed under vacuum environment shows potential as a promising pyrolysis approach with improved heating performance and production of hydrocarbon fuel with desirable fuel properties.

Synthesis of Large Mesoporous-Macroporous and High Pore Volume, Mixed Crystallographic Phase Manganese Oxide, Mn2O3/Mn3O4 Sponge.

The controlled synthesis of mixed crystallographic phase Mn2O3/Mn3O4 sponge material by varying heating rates and isothermal segments provides valuable information about the morphological and physical properties of the obtained sample. The well-characterized Mn2O3/Mn3O4 sponge and applicability of difference in reactivity of H2 and CO2 desorbed during the synthesis provide new developments in the synthesis of metal oxide materials with unique morphological and surface properties. We report the preparation of a Mn2O3/Mn3O4 sponge using a metal nitrate salt, water, and Dextran, a biopolymer consisting of glucose monomers. The Mn2O3/Mn3O4 sponge prepared at 1 °C·min-1 heating rate to 500 °C and held isothermally for 1 h consisted of large mesopores-macropores (25.5 nm, pore diameter) and a pore volume of 0.413 mL/g. Furthermore, the prepared Mn2O3/Mn3O4 and 5 mol %-Fe-Mn2O3/Mn3O4 sponges provide potential avenues in the development of solid-state catalyst materials for alcohol and amine oxidation reactions.

Thermal conductivity of MgO-C refractory ceramics: Effects of pyrolytic liquid and pyrolytic carbon black obtained from waste tire

In the present study, thermal conductivity and mechanical properties of MgO-C refractory ceramic bricks were investigated. Pyrolytic liquid and pyrolytic carbon black obtained from pyrolysis of waste tires were used as a resin and carbon source, respectively. The pyrolysis of the tires was conducted in a fixed bed reactor at the temperature of 500 °C with a 15 °C/min heating rate under nitrogen flow (0.5 lt/min). Before using in MgO-C refractory ceramic blends, pyrolytic products were purified with the acidic extraction methods which resulted in 61and 66 wt%. decreases in sulfur and ash contents in pyrolytic carbon, respectively. After this treatment of pyrolytic liquid, the sulfur content was reduced by 24 wt%. Eight different blends of MgO-C refractory ceramics consisting of different pyrolytic product contents were prepared, pressed, and tempered at 250 °C, and then characterized in terms of porosity, thermal conductivity, and density. The mechanical behavior of the samples was tested using a three-point bending test. Archimedes test was employed to determine the porosity and density. Surface properties of the bricks were analyzed by scanning electron microscopy (SEM). The obtained results were compared with a reference consisting of graphite and resin. The results revealed that mechanical and thermal properties of the developed bricks were highly sensitive to the porosity and the carbon source as well as the type of binder.