Muffle Furnace Research Articles

Coping during the COVID-19 pandemic in the cleaning staff of a public hospital

The present work aimed to evaluate the effectiveness of Ca(OH)2 obtained from eggshells as a catalyst in the transesterification of first-generation oil compared to catalysts such as Na(OH) and Ca(OH)2.GR. The eggshells were subjected to thermal treatment in a muffle furnace with temperature intervals to reduce CaCO3 to CaO. Once the calcium oxide was obtained, it was mixed with distilled water, which evaporated over time due to the exothermic reaction of CaO conversion to produce Ca(OH)2. The results showed that Ca(OH)2.GR has greater efficacy than Ca(OH)2 obtained from eggshells, while Na(OH) proved superior to the other catalysts used in the study

Innovative Structural Characterization of Natural Villiaumite Crystal

The work presents the latest scientific research on the far infrared spectrum of the natural mineral villiaumite (chemical formula NaF). The three samples of villiaumite examined came from the Khibiny Mountains in the Kola Peninsula (Russia) and from Mon Saint Hilaire in Quebec (Canada). The tested villiaumite samples began to change color very slowly after being heated above 300 °C in a muffle furnace. Subsequent color changes required heating at increasingly higher temperatures for approximately 48–72 h. Samples of the reddish mineral villiaumite turned orange, pink and finally colorless (at approximately at 430 °C). Because the color of villiaumite changes under the influence of temperature, far infrared spectra were measured for the samples at room temperature and for the sample heated to 100, 200, 300, 400 and 500 °C. Additionally, using density functional theory (DFT/B3LYP/6-31+g*), the spectrum of NaF (125-atom model of crystal structure) was simulated for the first time and compared with the experimental spectrum of pure sodium fluoride (a chemical reagent) and the mineral villiaumite.

Evaporation rates of water droplets with soluble and insoluble additives

The relevance. Caused by a wide practical use of water with typical soluble and insoluble additives in the following technologies. They are: thermal and fire purification of liquids, polydisperse fire extinguishing, combustion of waste-derived slurry fuels, cleaning of heat-loaded surfaces, creation of heat agents based on combustion products. Any change in liquid component composition leads to a change in its thermophysical properties, heating rates and phase transformations. So far, there is not enough experimental data on evaporation rates of water droplets with typical soluble and insoluble additives. The aim. Experimental determination of evaporation rate of water droplets with typical additives under various heating methods. The methods. To register sizes of moving droplets, optical registration methods based on a high-speed video camera were used. To register the temperature of combustion products, a measuring complex, consisting of an NI 9219 board and four chromel-alumel fast-response thermocouples, was used. The authors used four methods of droplet heating: in the flow of combustion products with the dominance of convective heat transfer, in a tubular muffle furnace with the dominance of radiative heat transfer, on a solid surface with the dominance of conductive heat transfer, and in a flame with the dominance of mixed (convective and radiative) heat transfer. The results. The authors have determined the ranges of change in evaporation rates of water droplets with typical (soluble and insoluble) additives for various heating methods with the dominance of convective, radiative, and conductive heat transfer. The effect of an additive type and concentration, heating method and heating medium temperature on of droplet evaporation characteristics was established.

Study on photoluminescence of integrated nano-calcium carbonate (CaCO3) enhanced with dysprosium (Dy) doped calcium borophosphate (CBP) phosphor

Purpose There is a strong inducement to develop new inorganic materials to substitute the current industrial pigments, which are known for their poor ultraviolet absorbent and low photoluminescence (PL) properties. The purpose of this paper is to invent a better rare-earth-based pigment material as a spectral modifier with good luminescence properties to enhance the spectral response for photovoltaic panel application. Design/methodology/approach Different phosphor samples made of nano-calcium carbonate (CaCO3) with varied wt.% of the dopant Dysprosium doped calcium borophosphate (CBP/Dy) as (W0 – 0%, W1 – 3,85%, W2 – 7.41%, W3 –10.71% and W4 –13.79%) were prepared via the solid-state diffusion method at 600 °C for 6 h using a muffle furnace. The structural, morphological and luminescence properties of the CaCO3:CBP/Dy powder samples were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and PL test. Findings The XRD, SEM and FTIR results verified the crystalline formation, morphological behaviour and vibration bonds of synthesized CBP/Dy-doped CaCO3 powder samples. XRD pattern revealed that the synthesized powder samples exhibit crystalline structured materials, and SEM results showed irregular shape and porous-like structured morphologies. FTIR spectrum shows prominent bands at 712, 874 and 1,404 cm−1, corresponding to asymmetric stretching vibrations of CO32− groups and out-of-plane bending. PL characterization of CBP/Dy-doped CaCO3 (sample W) shows emission at 427 nm (λmax) under the excitation of 358 nm. The intensity of PL emission spectra drops due to the concentration quenching effect, while the maximum PL intensity is observed in the W3 phosphor powder system. Research limitations/implications This phosphor powder is expected to find out the potential application such as a spectral modifier which is applied to match the energy of photons with solar cell bandgap to improve spectral absorption and lead to better efficiency. Originality/value The introduction of a nano-CaCO3:CBP/Dy hybrid powder system with good luminescence properties to be used as spectral modifiers for solar cell application has been synthesized in the lab, which is a novel attempt.

Biodiesel Synthesis from Waste Vegetable Oil Utilizing Eggshell Ash as an Innovative Heterogenous Catalyst

The objective of this research is to explore the production of biodiesel using Waste Vegetable Oil (WVO) as the primary feedstock and calcined eggshell ash as an environmentally sustainable catalyst. The WVO, characterized by a Free Fatty Acid (FFA) content of 2.86%, serves as the primary feedstock for biodiesel production through transesterification. The eggshell ash undergoes a rigorous process, including washing with distilled water to remove impurities, drying at 100ºC for 24 hours, crushing into fine particles, and final calcination in a muffle furnace at 900ºC. Process optimization is achieved by varying key reaction parameters, including temperature, catalyst loading, and the methanol-oil molar ratio. The optimal conditions are identified at 65°C, utilizing a methanol-oil molar ratio of 6:1 and a 5wt% catalyst loading. Under these optimized reaction conditions, a substantial biodiesel yield of 91.3% is obtained. The produced biodiesel meets the stringent quality requirements specified by the American Standard (ASTM D 6751) and European Standard (EN 14214) for biodiesel fuel, ensuring its suitability for various applications. This study demonstrates the potential of utilizing calcined eggshell ash as an eco-friendly catalyst for sustainable biodiesel production from WVO.

Production and Characterization of Biodiesel from Castor Seed Oil Using Cocoa Pod Ash as Catalyst

AbstractA major problem retarding the commercialization of biodiesel is the derivation of catalysts and feedstocks from high‐cost materials. Hence, the following proposal is being put forward to mitigate this challenge: Extract and characterize castor oil, synthesize and characterize cocoa pod ash as the base catalyst, and apply the base catalyst for biodiesel production. Cocoa pods were heated at 600 °C for 35 min in a muffle furnace and the product sieved to obtain ash with uniform size distribution. The yield of castor oil extracted was 42 %, and the synthesized catalyst was capable of transesterifying the extracted oil. Castor oil was converted to biodiesel with cocoa pod ash as catalyst. A biodiesel yield of 88 % was obtained. The catalyst was characterized by various methods to confirm the presence of active sites. The physicochemical properties of the biodiesel product are consistent with literature values.

Hot corrosion behaviour of mullite thermal barrier coatings for marine diesel engines

Mullite's inherent qualities have made it a potential material for the application of thermal barrier coatings (TBCs) for diesel engine components. Hot corrosion at 600–800 °C can cause TBC degradation, thus significantly affecting the performance of engine components and reducing their service life. This work examines the hot corrosion behaviour of atmospheric plasma-sprayed (APS) mullite coating over NiCrAlY bond coat on mild steel substrates. The coated specimen surface was covered with a mixture of Na2SO4 (sodium sulphate) and V2O5 (vanadium pentoxide) in the form of paste and heated in a muffle furnace at 700 °C for up to 300 h. SEM, EDS, and XRD characterisations were used to investigate the mechanism of hot corrosion. Coatings remained intact after corrosion tests; however, it had reacted with corrosive salts, particularly sodium sulphate. This was evidenced by the removal of amorphous silica, followed by the formation of nosean as a major phase. During the reaction between sodium sulphate and mullite coating, vanadium pentoxide was found to be acting as a flux and mineraliser.

Gas Phase-Heat Absorption-Condensate Phase Stepwise Flame Retardant Strategy to Prepare Coal Tar Pitch-Based Porous Carbon for Supercapacitor.

Porous carbon is widely used in energy storage-conversion systems, and the question of how to explore an efficient strategy for preparation is very significant. Herein, the flame retardant capability of (NH4 )2 SO4 /Mg(OH)2 that contains gas phase-heat absorption-condensate phase components is assisted to carbonize coal tar pitch in air and obtain the porous carbon. The mechanism of stepwise inflaming retarding is systematically investigated. In the carbonization process in a muffle furnace, (NH4 )2 SO4 decomposes releasing gases at below 400°C to act as the role of gas phase flame retardant. Mg(OH)2 starts to decompose at ≥ 400°C, and it has the effect of heat absorption and condensed phase flame retardation (MgSO4 and MgO). What's more, the flame retardant also serves as an N, S source and template. The obtained porous carbon possesses an ultrahigh carbon yield of 56.9wt.%, hierarchical pore structure, and multi-heteroatoms doping. It can still reach up to 244.7Fg-1 even loaded 20mg of active material. In addition, the (NH4 )2 SO4 /agar gel electrolyte is synthesized, and the fabricated flexible ammonium ion capacitor exhibits a superior energy density of 40.8Whkg-1 . This work uncovers a new way to construct porous carbon, which is expected to synthesize more carbon materials using other carbon sources.

Enhancing the Catalytic Performance of Platinum-Doped Lanthanum Hexaaluminate through Reduction Method Variation

The development of a catalyst for the ammonium dinitramide (ADN)-based monopropellant system has been of growing interest in space research. In this study, we investigated the development methodology for the platinum hexaaluminate (Pt–LHA) catalyst. The reduction of Platinum was performed in muffle and tubular furnaces by considering the different heating rates, with or without hydrogen gas flow conditions. The dispersion of Platinum on LHA was confirmed by using SEM analysis; the particle size of Platinum in Pt–LHA-1 and Pt–LHA-11 was 5.1–9.1 μm and <100 nm, respectively. Notably, agglomeration of Platinum was observed when the catalyst was calcinated in a muffle furnace without air or H2 gas flow. Interestingly, the even dispersion of Platinum was revealed when the catalyst was calcinated in a tubular furnace at 4% H2 in N2 gas flow. As a result, Pt–LHA-7 to Pt–LHA-11 exhibited higher catalytic activity than Pt–LHA-1 to Pt–LHA-6 under H2O2 reactor conditions. The catalyst Pt–LHA-9 was further tested in a 1 N ADN thruster, demonstrating its capability to decompose the ADN-based monopropellant in an operation thruster.

Facile Extraction of Natural Hydroxyapatite (HA) from Biowaste and Its Characterizations

Natural Hydroxyapatite (HA) with chemical formula Ca10(PO4)6(OH)2 is a major mineral storage form of calcium and phosphorous in bone and it has been applied in many fields. In the present study, HA was extracted from biowaste; namely the buffalo bone by alkaline hydrolysis process followed by calcination at 900°C with holding time 6 hrs. in muffle furnace. The isolated material was analyzed by X-ray Diffraction (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR) and Field Emission Scanning Electron Microscopy (FESEM) etc. The SEM image suggested the isolated material had rod shaped and agglomerated. FTIR study indicated the phosphate and hydroxide were the major functional groups along with carbonate present in it. Further, XRD analysis inferred that the isolated material was only HA phased. The specific surface area of the isolated HA was determined by methylene blue adsorption method and it was found to be 141.12 m2 /g and pH point of zero charge (pHPZC) of the extracted biomaterial was determined to be 6.8 by pH the drift method. Thus the pure HA powder was synthesized by an environmentally friendly, cost effective method and may be applicable in many fields including waste water treatment and biomedicine etc.

Effect of coconut shell ash substitute with cement on the mechanical properties of cement concrete

The production of ordinary portland cement results in a great amount of carbon dioxide emissions, which has serious consequences for the environment. The building industry has been urged to make use of soil waste from industries or secondary materials in order to cut down on the amount of natural raw materials needed to make cement and concrete. Increases in population, economic activity, and social progress have all contributed to a rise in global garbage output. The investigation of waste reduction and reuse is one of the most alluring possibilities for handling such waste. It is becoming increasingly unaffordable to use cement in concrete works, despite the fact that the demand for homes and other constructions that rely on this material continues to rise in combination with the expansion of the human population; as a result, it is necessary to identify and develop alternative binding materials that can be used either wholly or partially in place of cement. In order to produce coconut shell ash (CSA), an agricultural waste material and environmental pollutant that is used as pozzolana in partial replacement of cement in the production of concrete, coconut shells are collected, burned in the open air (uncontrolled combustion) for three hours, and then incinerated in a muffle furnace at 800oC for seven hours. On the order of 0%, 5%, 10%, 15%, 20%, and 25% OPC was replaced with CSA in the concrete used to cast the specimens. Coconut shell ash is a viable cement replacement. The impact of CSA on mechanical qualities was investigated using a range of coconut shell ash replacements.

Quantification of silicon concentration in sugarcane ash using the neutron activation technique with an isotopic source

In the realm of agronomic research, the neutron activation technique has gained traction, particularly in regions such as Paraguay, for its capability to deploy an isotopic source for the quantification and identification of agriculturally pertinent minerals. Within the ambit of sugarcane cultivation, both silicon (Si) and silica (SiO2) emerge as paramount, owing to their efficacy in fortifying the sugarcane plant's resistance to phytopathogens and pests, as well as their role in mitigating lodging phenomena. Notably, an uptick in silica accumulation has been correlated with amplified biomass and sucrose production metrics. This underscores the imperative for a meticulous quantification of Si and SiO2 within sugarcane derivatives, catering to both agronomic and industrial directives. Addressing the extant lacuna in regional datasets, this investigation endeavored to elucidate the inherent concentrations of Si and SiO2 within distinct anatomical segments of sugarcane, viz., leaves, entire stems, bark, and bagasse. A total of eight sugarcane cohorts, each encompassing 10 specimens, were subjected to the experimental paradigm. Adhering to a fully randomized design, each cohort was trialed in triplicate. Post desiccation at 105°C, the resultant specimens underwent calcination in a muffle furnace at an approximation of 500°C for a sextet of hours. The experimental variables under scrutiny encompassed mass (in grams), Si concentration (in percentage), and SiO2 content. Subsequent quantifications of Si and SiO2 within the ash specimens were operationalized using a nuclear analytical modality coupled with an isotopic neutron source. Post-acquisition, the data were subjected to a unidirectional analysis of variance, with an ensuing post-hoc DMS comparative analysis. Empirical findings highlighted that ash derived from integral sugarcane stems registered a preeminent mass juxtaposed against other segments. Intriguingly, leaf-derived ash manifested the zenith of Si and SiO2 concentrations, quantified at 24% for Si and 51.5% for SiO2. In summation, the neutron activation technique, undergirded by an isotopic source, has manifested its robustness in pinpointing Si concentrations within sugarcane ash, thereby accentuating the potential of leaf ash as a quintessential fount for silica extraction. Such insights bear salient implications for nations, such as Paraguay, where the evolution of agronomic modalities remains an ongoing endeavor.

257 Survey of Biological Measurements Used to Determine Bone Mineralization in Pigs Across the US Swine Industry

Abstract Pigs (n = 192) from 64 commercial sites across 14 production facilities in the Midwest USA were used to evaluate baseline biological measurements used to determine bone mineralization in pigs. There were 3 pigs selected from each site representing: 1) a clinically normal pig, 2) a pig with evidence of clinical lameness, and 3) a pig with a history of recent low feed intake within a hospital pen (sick pig). Pigs ranged in age from nursery to market weight, with the three pigs sampled from each site representing the same phase of production. For each pig, blood, urine, and the right and left metacarpal, fibula, 2nd rib, and 10th rib were collected and analyzed. Serum was analyzed for Ca, P, and 25(OH)D3 as part of the serum chemistry profile. and. Each bone was measured for bone density and ash (non-defatted and defatted methods). Bone density was measured on each bone based on Archimedes principle. For defatted bone ash, all bones were cleaned of tissue and then placed in Soxhlet extractors containing petroleum ether for 7 days as a means of removing water and fat. Bones were then dried at 105°C for 7 days and then ashed in a muffle furnace at 600°C for 24 h. Healthy pigs had increased (P < 0.05) serum calcium and 25OHD3 compared with sick pigs, with lame pigs intermediate (Table). Healthy pigs also had increased (P < 0.05) serum phosphorus compared with sick and lame pigs, with no differences between the sick and lame pigs. For defatted bone ash and bone density, there was a pig type × bone interaction (P < 0.001). There were no differences between pig types for the fibulas, 2nd rib, and 10th rib, but metacarpals from healthy pigs had greater bone ash compared with sick pigs, with lame pigs intermediate. For bone density, healthy and lame pigs had greater (P < 0.05) bone density than sick pigs for the metacarpals and fibulas, with no difference observed for the ribs. In summary, there appear to be differences in serum analysis between a healthy, lame, and sick pig. Differences in bone mineralization between pig types were observed in the metacarpal and fibula, but not ribs. The metacarpal appears to be the most sensitive bone to detect differences in bone mineralization between pig types. There was also considerable range in values within pig type across production sites.

64 Determining the Phosphorus Release Curve for Sunphase HT Phytase from 250 to 2,000 FTU/kg in Nursery Pig Diets

Abstract A total of 280 pigs (DNA 241 × 600, initially 10.4 ± 0.24 kg BW) were used in a 21-day growth study to determine the available P (aP) release curve for Sunphase HT phytase (Wuhan Sunhy Biology Co., Ltd., Wuhan, P.R., China). At approximately 19 d of age, pigs were weaned, randomly allotted to pens, and fed common starter diets. On d 21 post-weaning, considered d 0 of the study, pigs were blocked by average pen body weight (BW) and randomly allotted to 1 of 7 dietary treatments with 5 pigs per pen and 8 pens per treatment. Dietary treatments were derived from a single basal diet and ingredients including phytase, monocalcium P, limestone, and sand were added to create the treatment diets. Treatments included 3 diets containing increasing (0.11, 0.19, and 0.27% aP) inorganic P from monocalcium P, or 4 diets with increasing phytase (250, 500, 1,000, or 2,000 FTU/kg) added to the diet formulated to 0.11% aP. All diets were corn-soybean meal-canola meal-based and were formulated to contain 1.24% SID Lys and an analyzed Ca:P ratio of 1.10:1. Before the beginning of the study, all pigs were fed a diet containing 0.11% aP for a 3-d period (d 18 to 21 post-weaning). At the conclusion of the study, 1 pig, closest to the mean weight of each pen, was euthanized and the right fibula, rib, and metacarpal were collected to determine bone ash and density. After cleaning, bones were submerged in ultra-purified water under vacuum for 4 h. Weights were then collected, and bone density was calculated. For bone ash, bones were placed in a drying oven at 105oC for 7 d and then ashed in a muffle furnace at 600oC for 24 h (Table 1). For the overall experimental period, feeding increasing levels of aP from inorganic P improved (linear, P ≤ 0.014) ADG, G:F, and final BW. Similarly, feeding increasing phytase increased (linear, P ≤ 0.011) ADG and final BW as well as improved (quadratic, P = 0.023) G:F. For fibula bone ash weight and percentage bone ash, rib bone ash weight and bone density, and all metacarpal bone properties, pigs fed increasing levels of aP from inorganic P exhibited a linear improvement (P ≤ 0.019), with a quadratic response (P ≤ 0.030) for fibula bone density and rib percentage ash. Additionally, pigs fed increasing phytase had increased (P < 0.05) bone ash weight, percentage bone ash, and bone density in either a linear or quadratic fashion depending on the bone analyzed. The available P release curve generated for Sunphase HT phytase for percentage bone ash combining values from right fibula, rib, and metacarpal is: aP = (0.360 × FTU) ÷ (2,330.250 + FTU).

225 The Effect of Different Analytical Methods on Assessment of Bone Mineralization of Various Rib Bones in Response to Dietary P, Phytase, and Vitamin D in Nursery Pigs

Abstract Pigs (n = 350; initial body weight = 11.9 ± 0.56 kg) were used to evaluate the effects of different bones and analytical methods on the assessment of rib bone mineralization response to dietary P and vitamin D in nursery pigs. Currently, there is little information available describing the effect of rib location (2nd through 10th) on measures of bone mineralization including density and ash. Pens of pigs (5 pigs/pen) were randomized to 6 dietary treatments in a randomized complete block design with 10 pens/treatment. Pens of pigs were assigned dietary treatments consisting of: 1) P at 0.19% STTD P (deficient); 2) P at 0.33% STTD P (NRC requirement) using monocalcium phosphate; 3) P at 0.33% STTD P using monocalcium phosphate and phytase; 4) P at 0.44% STTD P (industry level) using monocalcium phosphate, phytase, no vitamin D; 5) diet 4 with vitamin D (1,653 IU/kg), and 6) diet 5 with additional 2,000 IU/kg 25(OH)D3 (HyD). After feeding diets for 28-days, eight pigs/treatment were harvested for bone analysis. The 2nd, 3rd, 5th, 7th, and 10th ribs were collected from each pig and analyzed for bone density and non-defatted bone ash. All bones were cleaned of tissue and then dried at 105°C for 7 d and then ashed in a muffle furnace at 600°C for 24 h. Bone density was measured on each bone based on Archimedes principle. There was no interaction between bone and dietary treatment for bone density and non-defatted bone ash (P > 0.05; Table). Therefore, interpretation of results will focus on the effect of bone and treatment on measures of mineralization. Pigs fed deficient P (0.19%) had less bone density and ash percent compared with treatments fed NRC and industry levels of P. For bone density, there was a significant main effect of bone (P = 0.001), with the 10th rib having greater bone density than all other treatments and the 3rd rib having greater bone density than the 5th rib. Bone density of the 2nd and 7th ribs did not differ (P >0.05) from either the 3rd or 5th ribs. For non-defat bone ash, 10th rib had the greatest (P < 0.05) bone ash, followed by the 2nd rib which was greater (P < 0.05) than the 3rd rib, with the 5th and 7th ribs having the least non-defat bone ash percent. In summary, bone density and ash responses varied depending on the bone being measured. When measuring all of the bones, the 10th rib has the greatest value for bone density and bone ash percent, while the 5th rib has the least value for both bone density and bone ash percent compared with the rest of the bones analyzed. These results can help guide diagnostic investigations and aid in comparing results across different bones used to measure bone mineralization.

Study on lightening of coal tar with metal oxide supported γ-Al2O3 catalyst

In this experiment, a fixed bed of pyrolysis was used to conduct pyrolysis with coal and a mixture of coal and catalyst, and the distribution and composition of tar products were studied. The pyrolysis of raw coal was carried out at different temperatures and at different constant temperature times, and the effects of pyrolysis temperature and constant temperature pyrolysis time on tar product formation from raw coal pyrolysis were studied. γ-Al2O3 was used as the carrier, and 4 kinds of alkaline earth metal oxides (MgO, CaO, SrO, BaO), 3 kinds of subgroup metal oxides (Fe2O3, Co2O3, NiO) and 5 kinds of VIII metal oxides (Cr2O3, MnO2, CuO, ZnO, MnO2) were selected as active components. The supported γ-Al2O3 catalyst was prepared by the method of equal volume impregnation and roasting in a muffle furnace. The γ-Al2O3 catalyst was characterized by means of XPS, BET and SEM, and the mechanism of the mixed pyrolysis of coal with different metal oxide supported catalysts to generate tar was studied. The results showed that: (1) under the conditions of 450 °C, 500 °C, 550 °C and 600 °C, the maximum tar yield was 0.32 g at 600 °C, and the tar yield was higher at constant temperature for 15 min than at final temperature of 600 °C, with an increase of 15.63%. (2) Fe2O3/γ-Al2O3 catalyst resulted in the highest tar yield of 0.75 g, which was 134.38% higher than that of coal pyrolysis. (3) From the increase of light oil and phenol oil and the decrease of anthracene oil and asphalt, Co2O3/γ-Al2O3, Fe2O3/γ-Al2O3 and Cr2O3/γ-Al2O3 can improve the tar quality better.

The Effect of Leaching Time on ZrO<sub>2</sub> Synthesis through Alkali Fusion and Acid Leaching

Zircon (ZrSiO4) is one of Indonesia's most abundant mineral reserves that have yet to be fully utilized since zircon mine production in Indonesia is only 110.000 tons/year while Australia produces zircon up to 500.000 tons/year. Indonesia has 167 million tons of zircon sand reserves, especially in West Kalimantan. One of the most efficient methods of zircon sand processing in terms of energy use and environmental pollution is the alkali fusion of NaOH. This study used zircon sand with NaOH, a stoichiometric ratio of 1:4 (excess 1.5), to be roasted in a muffle furnace at 600°C for 120 min. The following process is washing the frit with water, and the frit is dissolved with aquades with ratio frit: H2O=1g:10 ml at 30°C and stirring 300 rpm for 60 min. The frit leaching solution is filtered to obtain Na2ZrO3. The water-wash product is leached using HNO3 as the leaching agent with the ratio of water-wash product: HNO3=1:5, the acid concentration is 6 M, at 90°C, agitation use 260 rpm with the variation of time 60, 120, 180, 240, and 300 minutes. The pregnant leach solution is deposited with NH4OH and calcinated. According to the results of this experiment, the optimum time to obtain high Zr extraction is 240 minutes. This research produced single-phase zirconia with a cubic crystal structure containing 91.23% ZrO2 and 1.18% SiO2.

Color modification of ceramics with controlled firing

This study explores vacuum firing to achieve a dark color of ceramics produced with iron-bearing clays. Four local low-quality clays were used as the ceramic body. The clay samples were ground, compacted into pellets, and fired at 1150 °C in either a conventional muffle or vacuum furnace. The resulting ceramics were evaluated by visual observation, optical microscopy, XRD, TGA, and nanoindentation to assess their color, chemical, and micromechanical properties. The study revealed that vacuum firing produced dark grey ceramics, and longer vacuum retention during cooling led to a darker shade. Metastable phases were decomposed, and mullite and cristobalite were formed from the kaolinitic constituent. More magnetite existed under vacuum firing, contributing to the dark shade of the ceramics. However, the indentation elastic modulus was lower under vacuum firing due to more formation of the softer magnetite and less of the stiffer hematite. The findings have implications for the large-scale production of dark-color ceramics with low-quality clays.

Thermoelectric properties of Yb-La-Nb-doped SrTiO3

Yb2Ti2O7 exhibits ferromagnetic and magnetic properties, which are expected to exert a discernible influence on the thermoelectric properties of SrTiO3 composite. The La-Yb-Nb-doped SrTiO3 powders, synthesized via the hydrothermal method, were prepressed and then buried in carbon powder before being sintered in a muffle furnace at 1573 K for 5 h. The Yb dopant precipitated during the sintering process, leading to the in-situ formation of Yb2Ti2O7. The content of Yb2Ti2O7 increased with an increasing Yb concentration, resulting in a reduction in thermal conductivity and grain boundary potentials, and an increase in the peak electrical conductivity. The La and Nb dopants affect the electrical conductivity and the Seebeck coefficient. Therefore, by controlling the La, Nb, and Yb ratios, the La8Yb2Nb15 sample achieved the largest power factor (PF) value of 0.9 mWm−1K−2 and a low thermal conductivity of 2.9 W m−1K−1, resulting in a high ZT value of 0.32 at 1000 K.

Scavenging Efficiency of Activated Charcoal of Sweet Corn Cop and Areca Nut Shell for Carcinogenic Salicylic Acid and Methylene Blue

Activated plant charcoal plays major role in adsorption chemistry and finds a huge application in industry, pharmaceuticals, cosmetics and water treatment. Present work planned to utilize waste sweet corn cop and areca nut husk to prepare charcoal by chemical method. The charcoal was carbonized at 8000C using muffle furnace. The adsorption efficiency of the experimental activated carbon adsorbents towards the model organic compounds methylene blue and salicylic acid were assessed by UV-Vis spectrophotometric method. Experimental results clearly indicates that sweet corn cop charcoal recorded maximum absorption for salicylic acid 640ppm/g in compare to areca nut shell husk charcoal 480ppm/g. Sweet corn cop charcoal recorded optimum absorption for methylene blue 240 ppm/g in compare to areca nut shell husk charcoal 240ppm/g. The experimental charcoal projects noticeable results in scavenging salicylic acid and methylene blue from polluted samples. This experimental results and affordable cost the raw material made the sweet corn cop and areca nut husk activated carbon a powerful alternative for the adsorption of carcinogenic organic compounds salicylic acid and methylene blue.