Alkaline Fusion Method Research Articles

Synthesis of kaliophilite by alkaline fusion and ultrasonic treatment method from kaolin raw material

Mexico has important kaolin deposits, which must be assessed to obtain products with a high commercial value, such as kaliophilite as raw material for biodiesel production. Two kaolins, A and B, with approximate SiO2:Al2O3 ratios of 1 and 1.2, respectively, were used as raw materials to produce kaliophilite. Both kaolins were obtained from the municipality of Agua Blanca in the State of Hidalgo, Mexico. Kaolins are a source of Al and Si for the synthesis of kaliophilite through an alkali fusion process at 700 °C followed by ultrasonic treatment at 28 kHz to different times and for Kaolin-KOH ratios of 1:1 and 1:1.2 (mass: mass). The kaolins as received and the alkaline mixtures heat and ultrasonically treated were analyzed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). The most suitable kaolin for synthesizing kaliophilite was kaolin A with the Si/Al mass ratio of approximately 1, which exhibited a higher crystallinity index range from 54 to 79.6%. Higher KOH concentrations promote the amorphous material formation decreasing the kaliophilite amount. The crystallinity index was increased when the time of ultrasonic treatment was increased.

Recovery of Silica from Sidoarjo Mud by Alkali Fusion

Sidoarjo mud contains potentially valuable minerals, the largest content of which is silica. Silica decomposition from Sidoarjo mud can be done by using alkaline fusion method. The purpose of this study is the recovery of silica from the Sidoarjo mud against variations in Na2CO3 alkaline fusion time. Stages Sidoarjo mud mass ratio Na2CO3 1:3 is inserted into the furnace at a temperature of 700°C with a long alkaline fusion time of 1:1.5;2;2.5; and 3 hours. Based on the calculation results, the best % recovery occurred for 3 hours, which was 48.3%. It can be concluded that the alkaline fusion time can affect the silica decomposition of the Sidoarjo mud

High adsorption capacity of ammonia nitrogen on hexagonal porous aluminosilicate derived from solid-waste bagasse bottom ash

This study investigates the use of a hexagonal-porous aluminosilicate (HAS) adsorbent derived from bagasse bottom ash (BBA), an agricultural solid waste, for the adsorption of ammonia nitrogen (NH3–N)—a key water pollutant from agricultural and farming activities. Sodium silicate derived from BBA via the alkaline fusion method was employed, resulting in energy savings due to a synthesis temperature 1.53 times lower than that of commercial sodium silicate synthesis. The sol-gel method was utilized to successfully synthesize HAS featuring a high surface area and porosity using the sodium silicate prepared from BBA. However, an increase in aluminum content resulted in a decrease in surface area and hexagonal porosity. In performance tests, the HAS(5) adsorbent exhibited the most efficient NH3–N removal, outperforming other adsorbents by 4.54–25.19 times across all initial concentrations. This enhanced efficiency can be attributed to its numerous acidic surface sites, enabling the bonding of NH3–N molecules through monolayer adsorption on the HAS surface.

Synthesis of NaP Zeolite Based on Bauxite Red Mud Using Hydrothermal Method on Mole Ratio of SiO2/Al2O3 Variations

Red mud is a bauxite industrial waste of reddish-brown mud with high alkalinity. Red mud has relatively high silica and alumina content, so it can be utilized as a raw material in the synthesis of zeolite. This study aims to synthesize high-purity NaP zeolite from red mud at various SiO2/Al2O3 mole ratios. The synthesis begins with neutralizing the red mud, followed by decomposition using the alkaline fusion method at a ratio of red mud:NaOH = 1:1 (w/w). The filtrate produced by the alkaline fusion was adjusted to the mole ratio of SiO2/Al2O3 = 2.0; 2.5; 3.0; and 4.0, respectively, by adding sodium silicate, followed by a hydrothermal process using an autoclave at 120oC for 16 hours. The synthesized zeolites were characterized using XRD and FTIR spectrophotometry. The XRD results showed that the zeolite produced in all variations of the SiO2/Al2O3 mole ratio studied was a type of high-purity NaP with no other zeolite crystalline phases found as impurities. The structure formed is tetragonal with a degree of crystallinity of 74.54%; 76.47%; 78.94%; 75.64%, and crystal size 80.2286; 54.3437; 37.7099 and 40.1226 nm for zeolite with SiO2/Al2O3 mole ratio 2.0; 2.5; 3.0; and 4.0, respectively. Based on the results of the study, pure NaP zeolite can be synthesized from red mud material using the hydrothermal method at the ratio of moles SiO2/Al2O3 = 2.0 – 4.0.

Comparison of the fluctuations of the signals measured by ICP-MS after laser ablation of powdered geological materials prepared by four methods.

Sample preparation is a crucial point for quantitative multi-elemental analses by LA-ICP-MS of powdered geological materials. Four different methods are compared in this study with respect to signal stability and intensity as follows: the preparation of glass beads (GlassB) by alkaline fusion method and three grinding and pelletizing methods relying on the use of an organic binder (VanBind, vanillic acid), an adhesive binder (MixGlue, methyl methacrylate) and a sol-gel process for glass formation (SolGel, chemical reaction of tetraethoxysilane), respectively. Sixty elements were analyzed by means of a ns-UV (213nm) laser ablation system coupled to a single collector sector field ICP-MS with a low or medium mass resolution. Signal stability was found to strongly depend on the sample homogeneity provided by the preparation method. These methods were applied to three geological standard materials (CRM). The following criteria were used to evaluate and compare the methods: (1) proportion of the measurement cycles which are above a given signal intensity threshold (defined here as signal average ± 3 times the standard deviation), (2) signal stability of the analyzed nuclides (internal precision estimated by the relative standard deviations on raw count rates), (3) signal stability of the internal standards added to the samples, (4) external precision estimated by the relative standard deviation over five preparations for each geological CRM. For the majority of the analyzed elements, signals measured for samples prepared with the four methods are reproducible. Specific contamination in one or several elements (Cr, Fe, Co, Ni, Cu, Mo, W, Au and Bi) was observed depending on the sample preparation method. In addition, compared to grinding made with PTFE material, grinding performed with tungsten carbide material was found to produce better homogeneity, especially for the sol-gel and mixing with glue protocols, although some metallic contamination (W and Co) was observed. Thanks to the suppression of grain effects by alkaline melting, the glass bead method systematically provided signal stability and percentage of "over the threshold" close to those of the NIST glasses. This may be explained by the preparation of more homogeneous samples by alkaline melting. Finally, the described methods were found to be reproducible for the majority of the analyzed elements.

Effect of sintering temperature on physical, mechanical, and electrical properties of nano silica particles synthesized from Indonesia local sand for piezoelectric application

ABSTRACT This study aims to determine the effect of the sintering temperature of nanosilica on physical, mechanical, dielectric, and output voltage properties. The nanosilica particles used in this experiment were produced using the alkaline fusion method from natural sand. The green bodies were uniaxially formed with a pressure of 75 MPa and then were pressureless sintered at various temperatures of 1330, 1360, 1390, 1420, and 1450°C for 2 hours in an air atmosphere. The results of sintering showed that the highest bulk density and the relative density of 2.49 ± 0.03 g/cm3 and 94.03 ± 0.01% respectively were achieved at a sintering temperature of 1390°C. The XRD patterns of the sintered silica indicated phases of quartz, tridymite, and cristobalite, with the strongest peak corresponding to the cristobalite phase. The highest compressive strength and diametral tensile strength values of 17.23 ± 0.27 MPa and 6.06 ± 0.71 MPa respectively were obtained on specimens sintered at 1390°C. However, the highest values of the dielectric constant of 544.28, dielectric loss of 195.94, and output voltage of 1.58 mV were obtained at a sintering temperature of 1330°C. Various sintering temperatures do not significantly influence the characteristic of dielectric and output voltage of the sintered specimens.

Improved alkaline fusion method for B isotope and concentration measurements of silicate materials

Boron (B) is one of the most powerful tracers of fluid-mediated processes. This improved method permits safe, precise, and accurate measurement of B isotope and B concentration through a single dissolution.

Synthesis of Silica Nanoparticles from Silica Sand via Vibration Assisted Alkaline Solution Method

The effect of frequency of speaker membrane vibration on the grain size of the silica nanoparticles (SNP) was investigated. SNP was synthesized using the alkaline fusion method under the vibration of the membrane speaker. Variations of membrane vibration used in this research were 0, 50, 100, and 200 Hz. The material compositions, crystal structure, and morphology of the synthesized SNP were characterized using X-ray fluorescence (XRF), X-ray diffraction (XRD), and transmission electron microscopy (TEM), respectively. Meanwhile, its dielectric property was determined using impedance spectroscopy. The results showed that the SNP consisted of 99.35% silica and corresponded to the crystalline structure of quartz silica. The SNP size was decreased with increasing vibration frequencies. The smallest size of SNP (9.04±1.9 nm) was obtained at a frequency of 200 Hz. Moreover, the dielectric constant and dielectric losses were increased with an increase in membrane vibration frequency due to the decrease of SNP size.

SYNTHESIS AND CHARACTERIZATION OF ZEOLITE Y FROM KANKARA CLAY USING ALKALINE FUSION METHOD.

Zeolite Y was synthesized from Kankara clay, following alkaline fusion method which compared favourably with other conventional method of synthesis to obtain a high yield of zeolite Y. The raw material was hydrothermally activated with NaOH to synthesized zeolite Y. The starting materials for zeolite Y synthesis were prepared in two stages; The first stage was colloidal seed with a composition (5% of Al): 10.67 Na2O: Al2O3:10SiO2:180H2O and the second phase was the preparation of feedstock gel which was done few hours before the ageing time of the colloidal gel elapsed. The method used eliminated a lot of challenges, cost and energy of production using conditions crystallization temperature of 100oC and time of 5 h. This produced zeolite Y with a specific surface area of 686 m2/g, the SEM images demonstrated that the produced zeolites Y possessed agglomerated tetrahedral euhedral morphology. The transformation of the starting material into zeolite Y was evaluated using X-ray diffraction, scanning electron microscopy and fourier transform infra-red spectroscopy to elucidate the crystallization process of zeolites

Synthesis and toxicity assessment of environment friendly high yield ceria nanoparticles for biosafety

Different compounds at nanoscale level show more efficient behavior because of increased surface area and optical properties. CeO2 nanoparticles are of great importance for their unique properties. However, the extensive release of CeO2 nanoparticles in the environment is also a serious problem that must be addressed as available data related to ceria toxicity is currently not comprehensive. The present study was aimed to evaluate the potential of CeO2 nanoparticles in biomedical applications and assessment of their toxicity by using mutagenic and acute in-vivo approaches. High yield CeO2 nanoparticles with spherical morphology and with an average size of 40 nm were synthesized by adopting the alkaline fusion method under mild conditions. The synthesized CeO2 nanoparticles showed antibacterial activity at different concentrations (50–500 µg/mL) against E. coli. The antioxidant properties of CeO2 nanoparticles were determined, and CeO2 nanoparticles show antioxidant behavior that may be helpful for anti-cancer and anti-inflammatory drug preparation. Ames test confirms no mutagenicity at different concentrations of CeO2 nanoparticles. Moreover, in the current study CeO2 nanoparticles showed no toxicity for aquatic life even at a concentration of 100 mg/L in the same way the in-vivo toxicology was not evident even at the highest concentration (≥5000 mg/kg BW for rats), no significant change was observed in hematological and biochemical parameters of control and CeO2nanoparticles exposed rats. In-vivo dermal toxicity was not observed in rabbits at the application of 0.5 g CeO2 nanoparticles. These results indicate the nontoxic nature of these nanomaterials. However, further experimentation is recommended to completely define the toxic potential of the nanomaterials.

Removal of Pb(II) in Aqueous Solutions Using Synthesized Zeolite X from Ecuadorian Clay

Zeolite X was synthesized from clay using the alkaline fusion method and hydrothermal treatment to remove Pb(II) in aqueous solutions. Clay and zeolite were characterized through X-ray diffraction and fluorescence (XRD, FRX), as well as through specific surface area (SSA). The adsorbents were prepared as cylindrical extrudates using clay and a clay-zeolite combination (60-40%, respectively). The effects of pH, isotherm, and adsorption kinetics on the removal of Pb(II) in solutions of 80 mg Pb(II)/L were studied. It was possible to obtain a zeolite X from clay, with an SSA of 376 m2/g, 30 times greater than that of clay (12 m2/g). In the combined extrudate was present the zeolitic structure, with an SSA 12 times higher compared to the clay extrudate. The adsorption capacity, at 30 °C and V/m ratio of 1 g/L, is almost double compared to the clay extrudate (24 mg Pb(II)/g vs. 13 mg Pb(II)/g). Adsorption follows second order kinetics, and the Langmuir isotherm equation showed a good fit with the experimental equilibrium data for the two extrudates. The Webber-Morris and Bangham-Burt’s models suggest that pore and film diffusion influence the kinetic mechanism.

Economic evaluation of thorium oxide production from monazite using alkaline fusion method

Monazite is a phosphate mineral that contains thorium (Th) and rare earth elements. The Th concentration in monazite can be as high as 500 ppm, and it has the potential to be used as fuel in the nuclear power system. Therefore, this study aimed to conduct the techno-economic analysis (TEA) of Th extraction in the form of thorium oxide (ThO2) from monazite. Th can be extracted from monazite through an alkaline fusion method. The TEA of ThO2 production studied parameters, including raw materials, equipment costs, total plant direct and indirect costs, and direct fixed capital cost. These parameters were calculated for the production of 0.5, 1, and 10 ton ThO2 per batch. The TEA study revealed that the highest production cost was ascribed to installed equipment. Furthermore, the highest return on investment (ROI) of 21.92% was achieved for extraction of 1 ton/batch of ThO2, with a payback time of 4.56 years. With further increase in ThO2 production to 10 ton/batch, the ROI was decreased to 5.37%. This is mainly due to a significant increase in the total capital investment with increasing ThO2 production scale. The minimum unit production cost was achieved for 1 ton ThO2/batch equal to 335.79 $/Kg ThO2.

Ekstraksi dan Identifikasi Komponen Utama Pasir Putih dari Desa Marinsow Kabupaten Minahasa Utara dengan Pengujian XRF dan XRD

North Sulawesi is one of the regions in Indonesia which has a wealth of natural resources which is quite abundant, one of the natural potential that can be utilized is White sand. White sand has a composition that is SiO2, CaO, Fe2O3, TiO2, MgO. This study aims to identify the composition of the main components of white sand through XRF testing and the results of extraction of white sand from Marinsow village using the alkaline fusion method, NaOH solution for extracting and crystallizing the formation of silica crystals and tested using XRD testing to determine the crystal characteristics. Extraction and testing processes have been carried out using XRF and XRD on white sand samples taken in Marinsow Village, North Minahasa Regency. The results of the identification of the components of the white sand constituents through XRF testing namely CaO is the largest main component of the white sand compilers in the village of Marinsow which is as much as 89.97%. The content of SiO2 compounds in white sand (Marinsow) is as much as 1.41%. Other components found in white sand from Marinsow village, North Minahasa Regency include MgO as much as 5.85%, SrO as much as 2.31%, Fe2O3 as much as 0.277 %, TiO2 is 0.079%, Cr2O3 is 0.032%, Nb2O5 is 0.0238%, MoO3 is 0.0159%, SnO2 is 0.0082%, Sb2O3 is 0.0079% and RuO4 is 0.0074%. The results of XRD testing on white sand taken in the village of Marinsow give results that white sand has a calcite crystal structure (CaO) and for the SiO2 silica component is quartz.

A study of cerium extraction from Bangka tin slag using hydrochloric acid

Bangka Tin Slag (BTS) was a tin-smelting waste containing high silica and other elements that have high economic value, including cerium, which is a rare earth element. Silica and Ce 2 O 3 contents in BTS were 32.86 % and 1.35 % respectively. Other elements that have high concentrations in BTS include 15.46 % of CaO, 10.88 % of Al 2 O 3 , and 9.20% of Fe 2 O 3 . The objective of this study was to determine the optimum conditions for cerium extraction using HCl, which includes HCl concentration, temperature, particle size, stirring speed, and dissolution time. In addition, the effect of these parameters on Ce extraction was also studied. The one-factor-at-time method was used to determine the optimum conditions. Pretreatment of BTS with the alkaline fusion method and water leaching was done to reduce both the silica content and increasing its porosity. Alkaline fusion carried out at 700 ℃ using NaOH converts the silica into water-soluble sodium silicate. Characterization of the slag structure before and after the pretreatment process was completely carried out by using X-ray diffraction (XRD), X-ray fluorescence (XRF), Scanning electron microscope (SEM), and optical microscope. Furthermore, measurement of Ce content in the filtrate of the dissolution process was performed with inductively coupled plasma – optical emission spectrometry (ICP-OES). The results showed that the optimum of 75.16 % Ce was extracted by using some parameter conditions, namely by 2.5 M of HCl concentration, at the temperature of 40 ℃, with the particle size of –325 mesh, stirring speed of 150 rpm, and dissolution time of 180 minutes. Each parameter gives a significant effect on Ce extraction, wherein the initial stage, the increase in the value of each parameter gives an increase in Ce extraction and begins to decrease when equilibrium occurs

Low threshold Q-switched fiber laser incorporating titanium dioxide saturable absorber from waste material

We experimentally demonstrate a passively Q-switched erbium-doped fiber laser incorporating microfiber-based titanium dioxide (TiO2) polymer composite saturable absorber. The anatase TiO2 is derived from natural ilmenite waste via alkaline fusion method. The TiO2 polymer composite is prepared using solvent exchange method and deposited onto tapered microfiber via dip coating technique. The passive Q-switching at 1558.3 nm with low threshold pump power of 16.4 mW, average output power of 1.0 mW and pulse energy of 47.6 nJ are realized. The shortest pulse width of 7 μs with 22.56 kHz repetition rate is recorded. This work opens up a new window for the generation of microsecond pulses using waste material.

Synthesis of Zeolite Na-LSX from Iraqi Natural Kaolin using Alkaline Fusion Prior to Hydrothermal Synthesis Technique

The synthesis of zeolite materials by hydrothermal transformation of kaolin using an alkaline fusion prior to hydrothermal synthesis method was investigated. The kaolin clay used in the present investigation was supplied from Iraq. The physical and chemical characterization of the starting kaolin and produced zeolite Na-LSX samples were carried out using different analytical techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X – Ray Diffraction (XRD), X – Ray Fluorescence (XRF), Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR) Spectroscopy and Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES). An alkaline fusion method was introduced prior to the hydrothermal treatment while kaolin clay powder was mixed manually with NaOH powder (ratio = 1/1.2 in weight). The metakaolinisation phase was achieved by calcining the mixture in air at 600 oC for 1hr. The result from this route shows that zeolite Na-LSX with cubic rounded edge crystal habit have been successfully synthesised. Finally, The kinetic study indicated the suitability of the zeolite Na-LSX for the removal of Cu2+, Fe3+, Pb2+ and Zn2+ ions from synthetic wastewater.

Alkaline fused phosphate mine tailings for geopolymer mortar synthesis: Thermal stability, mechanical and microstructural properties

The present study investigates the efficiency of alkaline fusion method to enhance the geopolymeric reactivity of phosphate mine tailings. The effect of sodium hydroxide content and fusion temperature on the mineralogical composition of the fused phosphate sludge was assessed by XRD measurement. The microstructure as well as the mechanical behavior of the prepared geopolymer mortars were investigated using compressive strength test and EDS/SEM analysis. Furthermore, the thermal stability of samples was studied by measuring the mechanical properties after exposure to several cycles of heat treatment at different elevated temperatures (350, 500, 650 and 800 °C). The obtained results showed that the structure of phosphate sludge underwent a significant variation after fusion. Alkali thermal treatment led mainly to the decomposition of illite, palygorskite and dolomite, and the formation of Na-rich crystalline phases. NaOH content as well as temperature of fusion has been proved to be essential factors controlling the transformations of the material structure and hence the development of the geopolymer strength. The optimum conditions of fusion were set at 10 wt% of NaOH and a temperature of 550 °C, providing geopolymer mortars with high compressive strength (40 MPa).

Synthesis, characterization and investigation of photocatalytic activity of nano-titania from natural ilmenite with graphite for cigarette smoke degradation

Abstract Titanium dioxide (TiO2) nanoparticles and TiO2 with recycled graphite (TiO2/G) nanocomposite have been successfully synthesized by alkaline fusion method using synthetic rutile for measuring the degradation time of the cigarette smoke under the visible light irradiation. In this work, the synthetic rutile was derived from natural Malaysian Ilmenite’s waste to produce a low cost of TiO2 nanoparticles via environmental friendly process. The prepared samples were then analyzed using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Energy Dispersive X-Ray Fluorescence (EDXRF) to study their structural phase composition, functional group, and elemental composition respectively. The surface morphology and the size of the particles were studied using Field Emission Scanning Electron Microscopy (FESEM) and Particle Size Analyzer (PSA), respectively. The functionality of the prepared nanoparticles in terms of photocatalyst activity was analyzed by degradation of cigarette smoke under the exposure to the visible light. The UV–Vis Spectroscopy (UV–VIS) results revealed that the energy band gap of modified TiO2/G nanocomposite decreases to 2.90 eV compared with the commercial TiO2, 3.06 eV. This is capable enough to TiO2/G nanocomposite degrade the smoke under the visible light irradiation for 2 min faster compared to others types of TiO2 nanoparticles. This indicated the material has the ability to purify the toxins in the air.

Development of a novel recycling system for waste cathode ray tube funnel glass based on the integration of nanoscale Fe0 with ball milling

A novel and effective system was developed for recycling cathode ray tube (CRT) funnel glass wastes. Initially, the combination of nanoscale Fe0 with ball milling promoted lead transfer that was strongly encapsulated in the glass inner structure to the surface of funnel glass and/or adhere to iron substance due to the collapse of SiO bonds. This condition enhanced the dissolution of lead in the acid solution. A high lead extraction rate of 97.8% from funnel glass was achieved through nitric acid leaching by optimizing the operational parameters (Fe0/funnel glass mass ratio, 0.5:1; ball milling time; 72 h). Subsequently, lead sulfate, iron hydroxides, and sodium nitrate were gradually recovered from the acid leachate by using three simple operations, namely, sulfation, alkali neutralization, and salt evaporation. Meanwhile, the leaching results of short-term toxicity characteristic leaching (TCLP) and long-term multiple extraction procedures (MEP) clearly demonstrated that the residual high silica products (after acid leaching) had no impact on the environment and could be used to synthesize high value-added zeolites as raw materials. With the addition of Al sources, the complete conversion of high silica residues into high crystalline zeolites with high cation exchange capacity value was realized by applying an alkaline fusion method during the hydrothermal treatment. Furthermore, lead, NO−3, and SO2−4 concentrations of the resulting drainage were considerably lower than the relevant standard for surface water quality. Therefore, the proposed recycling system provided an eco-friendly and feasible technique for complete reutilization of obsolete CRT funnel glass.

A Novel Synthesis Method of Zeolite X From Coal Fly Ash: Alkaline Fusion Followed by Ultrasonic-Assisted Synthesis Method

This study was focused on synthesis of zeolite X from coal fly ash using the alkaline fusion method coupled with a novel method which uses ultrasonic energy for aging step. Optimum conditions were investigated using the Taguchi experimental design method. Synthesized zeolitic products were characterized by X-ray diffractometry, scanning electron microscopy, surface area, and cation exchange capacity analysis. Aging time was reduced from 24 to 2 h with usage of ultrasonic energy. Due to high surface area and similar crystal and morphological properties of the final products, we propose that the synthesized zeolitic products can serve as commercially competitive available material.