Amount Of Na2CO3 Research Articles

Investigation of damage on FeCr26Ni36Co15W5 alloy reduction furnace tube during service

ABSTRACT The microstructure and mechanical properties of tungsten powder reduction furnace tube are investigated in this work. After service, the lamellar and skeleton-shape primary carbides of FeCr26Ni36Co15W5 alloy coarsened and formed a continuous network, much fine secondary carbide precipitated in the dendrite interior. The tensile strength and ductility of FeCr26Ni36Co15W5 alloy decreased. And, the creep strength of FeCr26Ni36Co15W5 alloy has reached the end of the service life. Meanwhile, the corrosion products were studied by XRD and XRF. It was found that the corrosion products were Na2WO4·2 h2O, Na2CO3·H2O and Cr4Ni15W，and the evaporation of catalyst (Na2CO3) results in a large amount of Na2CO3·H2O in the corrosion products. The hot corrosion mechanism of the reduction furnace tube is Type I hot corrosion.

Extraction of Vanadium from High Phosphorus Vanadium Containing Waste Residue via Carbonation: Optimization Using Response Surface Methodology

Vanadium (V) was successfully extracted from a high phosphorus vanadium residue (HPVR) through a carbonation process. Vanadium within HPVR substitutes for Fe in the mineral structure of Ca9(Fe,V)(PO4)7 at elevated temperatures, Na2CO3 reacts with V to form sodium metavanadate (NaVO3), concurrently generating calcium carbonate (CaCO3) through its interaction with Ca9(Fe,V)(PO4)7. Subsequently, V is liberated and leached by water, dissolving in the aqueous phase as metavanadate ions (VO3−). Crucial factors influencing V leaching efficiency include roasting time, roasting temperature, and the amount of Na2CO3 utilized. Response Surface Methodology (RSM) was employed. The optimized parameters determined were as follows: a roasting temperature of 850 °C, a roasting duration of 120 min, a Na2CO3 dosage of 8.01%, a liquid-to-solid ratio (L/S) of 3, and a leaching time of 60 min. Under these conditions, a remarkable V leaching efficiency of 83.82% was achieved. This study underscores the viability of a simplified approach for treating solid waste containing metal slag, which not only mitigates environmental pollution but also yields valuable metals.

Kinetics study on the low-temperature soda roasting of boron-rich blast furnace slag

The method of preparing borax by low-temperature soda roasting and water leaching of boron-rich blast furnace slag (BRBFS) is a novel method for extracting boron from BRBFS. In order to further improve the water leaching rate of boron, this article mainly studied the low-temperature soda roasting kinetics of BRBFS. The effects of roasting temperature and Na2CO3 addition on the water leaching rate of boron were investigated. The results demonstrate that when the amount of Na2CO3 added is four times of the theoretical amount, the kinetics of NaBO2 formation can be described by the Nucleation (Avrami) model in the temperature range of 600–700 °C. The corresponding apparent activation energy is 54.45 kJ/mol, and the apparent frequency factor is 215.16 h−1. It was found that at a roasting temperature of 700 °C,when the amount of sodium carbonate added is twice, three times, and four times of the theoretical amount, the kinetics of NaBO2 formation matches with 3-D Diffusion (Jander) model, Nucleation and Growth (Avrami-Erofeev) model, and Nucleation (Avrami) model, respectively. With an increase in the amount of Na2CO3 added, the rate-controlling step for the formation of NaBO2 transitions from being diffusion-controlled to nucleation-controlled.

Corrosion, permeation and mass transfer mechanisms of alkali metals in corundum refractories

During the operation of the waste liquid incinerator, the alkali metal slag might adhere to the surface of the refractory material to form an inhomogeneous solid slag layer, causing the furnace lining to be simultaneously corroded by three phases of alkali metals: vapor, molten salt, and slag. This phenomenon intensifies the damage to the refractory material. Therefore, this paper investigates the mass transfer and permeation process, phase change process and corrosion rate of Na2CO3 inside corundum refractory materials in three phases: Na vapor, molten Na2CO3 and Na-slag. The results showed that alkali vapor penetrated the interior through the pores, and the NaAlO2 and β-Al2O3 generated by the reaction led to the volume expansion and microcracks. Na vapor continued to penetrate the interior along the cracks and eroded the sample, and the higher the temperature the greater Na vapor penetration. In vapor phase corrosion, the effect of corrosion time on the erosion resistance of corundum refractories is less than that of temperature, and the increase in corrosion time does not lead to the formation of additional new phases. In the molten salt corrosion experiments, it was found that the molten salt corrosion was accompanied by vapor phase corrosion at 1100 °C, and the amount of Na2CO3 has a greater effect on the corroded mass than the temperature. Comparing the corrosion of refractory materials by the three phases of Na2CO3, the molten salt corrosion rate was the highest, followed by the vapor phase corrosion, and finally the slag corrosion. It is concluded that the slag layer can effectively prevent the corrosion of the refractory material by alkali metal molten salts and vapors, thus prolonging the service life of refractories.

Highly functional molten sodium hydroxide-BaZrO3 composite electrolyte with hybrid ionic conductivity for low-temperature solid oxide fuel cells

Proton-conducting barium zirconate perovskite attracts considerable attention as an electrolyte for solid oxide fuel cells (SOFCs). To obtain BaZrO3-based electrolytes with high ionic conductivity at low temperatures, composite electrolytes named BaZrO3+x wt% NaOH are designed and synthesized. A study is conducted to explore the effects of molten-state NaOH and a small amount of Na2CO3 generated during SOFC operation on the performance of composite electrolytes systematically. As a result of the addition of NaOH, the composite electrolyte is created with rich surfaces and solid-liquid interfaces, compared to traditional condensed electrolytes.The solid-liquid interface can serve as a high-speed ion conduction channel. In-situ surface oxygen deficiency induced by NaOH and the bridge function of carbonate enable rapid ion migration along the interface of the composite electrolyte. The fuel cell with the prepared electrolyte can deliver an excellent maximum power density (MPD) of 1039 mW cm-2 at 550 °C. At 350 °C, the cells are also able to show a very impressive power density of 365 mW cm-2. The concise design, convenient preparation process, and outstanding performance of the fuel cell collectively offer an effective strategy for advancing the manufacture of electrolyte materials for low-temperature operation.

Conduction/Densification Enhancement of Na1+X Zr2Si x P3-X O12 Nasicon Solid Electrolyte for Solid-State Na Batteries

Due to the better safety feature, replacing organic liquid electrolyte with ceramic solid electrolytes (SE) may effectively suppress the fire incidents caused by conventional rechargeable batteries. Recently, solid-state batteries using Na+ ion conductors tend to receive much attention because the abundance of Na in earth’s crust. However, solid-state batteries (SSBs) have been suffered by the relatively high interface polarization between electrode and SE. For higher Na+ conductivity, Na1+x Zr2Si x P3-x O12 with NASICON (Na Super Ionic Conductor) structure is selected for this study. Although solid state reaction is adopted, it is believed the selection of precursors may be critical for better crystallization and densification of Na1+x Zr2Si x P3-x O12. For instance, adequate amount of Na2CO3 may be used as the Na source as well as flux for densification. Thus, the objectives of this study is to (1) to identify the role of precursors such as Na2CO3 for conduction/densification of NASICON, (2) to search the appropriate temperature for synthesis/crystallization of NASICON, (3) to investigate the factors, such as crystallinity/density, affecting the ionic conductivity. During the different stages of processing, the structural, microstructural and electrical properties of decomposed precursors and resultant NASICON will be examined using XRD, SEM and DC/AC impedance measurements.

Effects of Na2CO3 on the carbothermic reduction and magnetic separation of ilmenite concentrate

Ilmenite concentrates are the raw material used for the production of titania pigment and metallic titanium. This work studies the effect of the addition of Na2CO3 in direct carbothermic reduction of ilmenite concentrate to enhance the separation of metallic iron from titanium components. The effects of temperature, Na2CO3 content and C/O molar ratio on the mineral phases, metallization degree of iron, and iron grain size of the reduced product are evaluated. The optimal conditions for the direct reduction of ilmenite concentrate are 1300 °C, a C/O molar ratio of 1.1, and 5 wt% Na2CO3. Under these optimal reduction conditions, the metallization of iron reaches the maximum of 96.8%, and the average iron grain size is 20.1 μm. After grinding and magnetic separation, the direct reduced iron product (magnetic component) contains 93.9 wt% of iron and 4.66 wt% of TiO2, with an iron recovery of 93.9%, while the non-magnetic product contains 69.9 wt% of TiO2 and 7.61 wt% of iron, with a TiO2 recovery of 93.5%. The results show that an appropriate amount of Na2CO3 effectively promotes the reduction of ilmenite. However, excessive Na2CO3 adversely affects ilmenite reduction. The phase transition patterns of Na2CO3 in the direct reduction of ilmenite is investigated.

Effective disproportionation of SiO induced by Na2CO3 and improved cycling stability via PDA-based carbon coating as anode materials for Li-ion batteries.

In order to improve the initial coulombic efficiency (ICE) and cycle performance of SiO, in this study, the disproportionation reaction of commercial SiO is performed with the assistance of Na2CO3 under high temperatures. A polydopamine-based carbon is then in situ formed on the surface of the mixture (d-SiO-G) of disproportionated-SiO and graphite. It is found that an appropriate amount of Na2CO3 can effectively enhance the ICE of the commercial SiO due to the formation of Si, SiO2, and silicate; the mass ratio of d-SiO-G to the dopamine monomer is the important factor in influencing the cycling stability of the d-SiO-G@C composite. Due to the synergistic effect of graphite and the polydopamine-based carbon layer, the ICE for the d-SiO-G@C composite is 72.6%, and its capacity retention reaches 86.2% after 300 cycles, which is 11% higher than that of d-SiO-G. The modification method is an effective strategy for SiO materials in commercial applications.

Probing the Electrochemical Role of Na2CO3 as Surface Residual on LiNi0.6Co0.2Mn0.2O2

Lithium bearing compounds like LiOH and Li2CO3 are important raw materials for manufacturing of lithium-ion batteries. The chemical tolerance level of battery grade raw materials towards impurities will eventually determine the complexity and cost of the manufacturing process for raw materials. Sodium bearing compounds are a class of major impurities for lithium compounds extracted from the brine. In this work, the electrochemical role of surface residual Na2CO3 was systematically investigated using LiNi0.6Co0.2Mn0.2O2 as the model cathode material. As a demonstration, different amount of Na2CO3 was deposited on the surface of LiNi0.6Co0.2Mn0.2O2 for determination of the tolerance level towards Na2CO3. It was found that excessive amount of Na2CO3 (>10,000 ppm of Na+) substantially accelerated the parasitic reactions between the delithiated cathode and the electrolyte, leading to accelerated capacity fading of the cathode material. It was also found that low concentration Na2CO3 (≤1,000 ppm of Na+) had marginal impact on the electrochemical performance of the cathode primarily due to the existing background Li2CO3 impurity inherited from the synthesis and storage of the cathode material.

Corrosion behavior of Q235 steel by synergistic action of high concentration Cl− and complex scale in mixed salt flooding

The corrosion mechanism of Q235 steel by the synergistic effect of high concentration Cl− and complex scale in the preparation process of a mixed salt oil displacement method was investigated using measurements of weight loss, electrochemical impedance spectroscopy, linear polarization curve and open circuit potential. Scanning electron microscope and energy dispersive spectroscopy results indicated that the amount of Na2CO3 in the preparation process had an influence on the composition of the complex scale. This study investigated the corrosion process on Q235 steel using solutions with three different CO32−/Cl− molar ratios R: 0.11, 0.27, and 0.37. At a low concentration of CO32−, serious pitting corrosion occurred and the composition of corrosion product was diverse. When the R was 0.27, a discontinuous passive film was formed on the metal surface, and crevice corrosion took place between the adsorbed Si scale and substrate. With a further increased in CO32− concentration, the steel surface was covered with a passive film that was mainly composed of FeCO3 and Fe2O3. The initial growth process of calcium carbonate was restricted. At the R = 0.37 solution, corrosion was successfully inhibited, making this a good candidate for use in the oil recovery process.

Investigation on the Inhibition of Aluminum Dust Explosion by Sodium Bicarbonate and Its Solid Product Sodium Carbonate.

To characterize the inhibiting effects of sodium bicarbonate (NaHCO3) on aluminum dust, the inhibiting capacities of NaHCO3 and its solid product sodium carbonate (Na2CO3) on the explosions of 10 and 20 μm aluminum dusts were studied using a standard 20 L spherical chamber. Explosion parameters were analyzed based on the induction period and explosion stage to evaluate the inhibiting effects. The results show that the induction period of 10 μm aluminum dust explosion is 18.2 ms, which is shorter than that of 20 μm aluminum dust. Two aluminum dust explosions can be completely inhibited during the induction period when inert ratios of NaHCO3 are 350 and 150%, respectively, but that is not observed after adding the corresponding amount of Na2CO3. When the inert ratio ranges from 0 to 150%, the physical effect of NaHCO3 on 10 μm aluminum is poor and the chemical effect is the essential process. But as the inert ratio increased from 200% to 350%, the physical effect of NaHCO3 is higher than the chemical effect, suggesting that the physical effect is the key factor. With the increase of NaHCO3, the physical effect increases gradually. However, the chemical effect changes little. The physical effects of NaHCO3 including heat absorption and isolation play an essential role in the inhibiting process, which has a significant impact on the pyrolysis process and explosion parameters. The results of the present work provide guidance for the prevention and control of aluminum dust explosions.

Passivating oxygen atoms in SiO through pre-treatment with Na2CO3 to increase its first cycle efficiency for lithium-ion batteries

Silicon monoxide (SiO) is a promising anode material for Li-ion batteries because of its high capacity. Though, its low first Coulombic efficiency (FCE) due to the formation of inactive Li–Si–O compounds during lithiation hinders its practical application. Herein, we report a facile pre-sodiation technique by annealing SiO with a small amount of Na2CO3 (≤ 5 wt%) under 850 °C, which improves FCE of pristine SiO from 61.4% to 86.0% without the use of lithium metal, solvent and disassembling and re-assembling of cells. Transmission electron microscopy, X-ray photoelectron spectroscopy, and nuclear magnetic resonance demonstrate that the incorporation of Na facilitates the disproportionation of SiO into crystalline Si and SiO2 through nucleophilic substitution, and reduces the reactivity of the oxygen atoms with lithium and thereby suppresses the irreversible capacity during initial lithiation. The pre-sodiation process also improves thermal stability of SiO. Since the Na-containing SiO material is not sensitive to moisture in ambient condition, special handling of the material is not necessary. Combining with a LiFePO4 cathode, the full cell shows a FCE of 85.8% with good cycle stability. The energy density of lithium-ion battery can even reach 900 Wh L−1 based on a theoretical calculation with high-capacity Ni-based metal-oxide cathode.

Mechanochemical-Assisted Extraction and Hepatoprotective Activity Research of Flavonoids from Sea Buckthorn (Hippophaë rhamnoides L.) Pomaces.

Pomaces of sea buckthorn berry were usually side-products during the processing of juice. Due to a lack of an economical and effective extraction method, it was typically recognized as waste. For the purpose of resource utilization, the mechanochemical-assisted extraction (MCAE) method was applied to develop an ecofriendly extraction method and product with better pharmacology activity. The parameters were investigated through response surface methodology (RSM) design experiments. The processing conditions were optimized as follows: amount of Na2CO3 40%, ball-to-material rate 29:1 g/g, milling speed 410 rpm, milling time 24 min, extraction temperature 25 °C, extraction time 20 min and the solid-to-solution ratio 1:10 g/mL. Under these conditions, the yields of flavonoids from sea buckthorn pomaces were 26.82 ± 0.53 mg/g, which corresponds to an increase of 2 times in comparison with that extracted by the heat reflux extraction method. Meanwhile, the hepatoprotective activity of sea buckthorn pomaces extracts was studied by the liver injury induced by ip injection of tetracycline. Biochemical and histopathological studies showed that biomarkers in serum and liver of nonalcoholic fatty liver disease (NAFLD) mice were significantly ameliorated when sea buckthorn flavonoids extracted by MCAE were used. Altogether, these results demonstrate that, as a green and efficient extraction, MCAE treatment could increase the extraction yield of sea buckthorn flavonoids, meanwhile it could exhibit significant activity of improving liver function. This research provided a new way to use pomaces of sea buckthorn as a functional food. It also has great value on the comprehensive utilization of nature’s resources.

Inorganic salts as effective additive for adjusting the curing of natural oriental lacquer

Oriental lacquer, a milk-white sap collected from lacquer trees, can be cured automatically to bright and dense films in the presence of air, thus is worthy of being regarded as a type of natural green coating, as it does not emit any volatile organic compounds. It has been used in Asia for more than 8000 years attributing to its excellent characteristics. However, during harvesting and storage process, the lacquer sap surface can automatically polymerize into lacquer blocks under the catalysis of laccase present in the sap, wasting a significant amount of resources. It is an arduous task how to slow down the curing of oriental lacquer in storage without affecting the normal curing process in operation. Herein, the curing of oriental lacquer was adjusted using Na2CO3 and NaCl as additives. The results indicated that the addition of Na2CO3 quenched the semiquinone radical during the polymerization of urushiol, the main component of oriental lacquer, without affecting the laccase activity. Under the appropriate condition (25 °C and 80% relative humidity), the touch-free dryness time of the oriental lacquer mixed with Na2CO3 increased from 3 h to 15 days. Moreover, the addition of same amount of Na2CO3 and NaCl to oriental lacquer improved the curing time to 6 h, which was similar to that of pristine lacquer without the addition of any salts. The polymerization rate of the lacquer sap returned to the normal again, that may be due to the blocking of the reaction between urushiol and CO32‐ after the introduction of NaCl. Thereby, this study provided a novel and green method for oriental lacquer to achieve storage for a long time and relatively normal curing during application. This provides a guarantee for the wide use of oriental lacquer as a green natural coating.

Antibacterial bioglass in dental implants: a canine clinical study

Abstract Background Peri-implantitis is considered the most challenging biological complication in implantology, as untreated disease can progress and result in implant loss. Therefore, disease prevention is crucial in daily clinical practice. It has been reported that the use of bioactive glass, as an implant coating, can stimulate tissue integration and accelerate tissue regeneration. Besides these properties, it is possible to promote bacterial activity by inserting silver into the bioglass Methods Bioglass with composition 45S5 was synthesised by the fusion method, replacing the amount of Na2CO3 by AgNO3 (BG 2% wt). The implants were resealed by the CoBlast® technique. Clinical cases with pathology of the mandible/maxilla were selected and implants dimensioned for the canine bone structure were applied. Results Three months after implantation, imaging exams, namely CT scans, showed no signs of early rejection by septic or cytotoxic loss. No decrease or loss of peri-implant bone was observed. In all cases the implants remained without signs of instability, and with sufficient support for the application of the exo-prosthesis or dental crown. The results of histological analysis showed no signs of infection or osteolysis. The zone of peri-implant fibrosis was not observable in the samples, showing a good evolution in implant osteointegration. Conclusions The results show promising evidences for the use of this biomaterial as a coating, since aseptic rejection, later on, and that related to the shape and biomaterials used in the implant's design, usually begins during the first 3 months.

Carbon xerogel from 5-methylresorcinol-formaldehyde gel: The controllability of structural properties

Sol-gel-derived porous carbon is an attractive electrode material for various applications because its structure, along with its physical properties, can be tailored to the specified task by selecting suitable precursors and synthesis conditions. To complement oil shale-based sol-gel materials, in the current study, the tunability of the properties of 5-methylresorcinol-formaldehyde (5MR-FA) carbon xerogel is examined. As expected, the porosity of the 5MR-FA carbon xerogel is lower than those of the corresponding carbon aerogels, but the specific surface area in the range of 2–417 m2/g and the electrical conductivity of 0.8 S/cm demonstrate the potential of this xerogel in electrochemical applications as an electrode material. Furthermore, the synthesis conditions and final structure of the resulting carbon were in satisfactory correlation, including with the results of spectroscopy analysis. Na2CO3, which is used as a catalyst in this sol-gel reaction, affects the structure of the resulting carbon. In this study, it was established that the oxidation level of carbon and the short-range structural order and disorder are also influenced by the amount of Na2CO3, which is supported by the trends in the electrical conductivity results.

The Effect of Deprotonation on the Reaction Kinetics of an Oxygen Scavenger Based on Gallic Acid

Oxygen scavengers based on gallic acid (GA) usually contain a base that establishes the alkaline conditions necessary for the humidity-induced scavenger reaction. Here we measured the effect of sodium carbonate (Na2CO3) and sodium hydroxide (NaOH) on the reaction kinetics of such scavengers. The time-dependent oxygen absorption of aqueous GA solutions (pH 2.9–13.8) was determined and the results were described using a second-order kinetic model. We calculated the degree of deprotonation (DoD) of GA in the solutions from the species distribution curves, and assessed the effect of the DoD on the reaction kinetics. This revealed that both the reaction rate coefficient k and the scavenger capacity n were significantly affected by the DoD. If the DoD fell below 0.25, there was no significant reaction. Although k increased with the DoD, n reached a maximum at DoD = 0.6–0.7. In principle, target DoD values can be achieved using any base, but a strong base is more efficient because lower quantities are required. In our experiments, the amount of Na2CO3 required to reach the maximum DoD was more than twice that of NaOH. Our results provide the basis for the functional design of active packaging systems incorporating optimized GA-based oxygen scavengers.

The strategy of entire recovery: From spent cathode material with high nickel content to new LiNi0.5Co0.2Mn0.3O2 and Li2CO3 powders

As the cathode ternary activated materials with high content of nickel have been widely used in lithium-ion batteries, the recycling of the spent cathode materials has been paid worthy attention. In this work, the sulfate solution with Li, Ni, Co and Mn elements was formed by dissolving the spent LiNi0.5Co0.2Mn0.3O2 cathode materials in 20% sulfuric acid and 30% H2O2, assisted with reflux at 90 °C for 1 h. Based on the above solution, the precursor (Ni0.5Co0.2Mn0.3(OH)2), along with the lithium and sodium sulfates mixture solutions were prepared by co-precipitation at 55 °C. Then Li2CO3 powders and sodium sulfate solution were obtained through evaporating filtered solution separated from the preparation of the precursor and added an amount of Na2CO3, with the removal of 30% water and separation at about 70 °C. The purity of recovered Li2CO3 is about 99.5%. The residual concentrations of Ni, Co and Mn in the filtered solution separated from the preparation of precursor are only 0.041, 0.025, 0.038 ppm left, respectively. The prepared cathode material LiNi0.5Co0.2Mn0.3O2 from the precursor exhibits good cycle performance and shows a stable discharge capacity of 140 mAh g−1 at a current rate of 100 mA g−1 between 2.8 and 4.2 V.

Effects of the type of activator on the self-healing ability of fiber-reinforced alkali-activated slag-based composites at an early age

This paper presents an experimental investigation of the self-healing ability of fiber-reinforced slag-based composites activated by a single type of alkali activator at an early age. In order to investigate the effects of the type of alkali activator on the self-healing ability of fiber-reinforced slag-based composites, three mixtures reinforced by polyethylene fibers and with different alkali activators, in this case calcium hydroxide, sodium hydroxide, and sodium silicate, were designed and prepared. Compressive strength and uniaxial tension tests were conducted to measure the mechanical properties of each mixture. The self-healing ability in each case was evaluated by observing the crack width and by measuring the resonance frequency. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were also utilized to analyze the morphology and chemical compositions of the healing materials. The results of these tests showed that autogenous healing of alkali-activated slag-based composites is accomplishable through structural restoration, specifically by reducing the crack opening and through mechanical recovery. The dominant healing materials of the calcium activator-based alkali-activated slag composite was CaCO3, in contract to the C-(N)-A-S-H, CaCO3, and some amount of Na2CO3 which formed in the sodium activator-based alkali-activated slag composites.

Cellulose-supported Pd nanoparticles: effective for the selective oxidation of glucose into gluconic acid

Cellulose-supported on Pd nanoparticles (Pd/cellulose) were successfully prepared by chemical reduction technique and characterized by various experimental tools. The Pd/cellulose catalyst was found to effectively promote the oxidation of glucose into gluconic acid under mild conditions. The base played a crucial role in the oxidation of glucose into gluconic acid. Glucose was fully converted at room temperature after 3 h by the use of stoichiometric amount of Na2CO3 to neutralize gluconic acid, and gluconic acid was obtained in a high yield of 91.2%. The catalyst was recovered from product and reused up to five times without significant loss in its catalytic activity.