Orthogonal Array Method Research Articles

Tensile strength of friction stir additive manufactured laminated AA 6061/TiC/GS composites

Abstract With the fast progress of industrial manufacturing, friction stir additive manufacturing has fascinated wide-ranging consideration in the industry due to high material consumption rate. Friction stir additive manufacturing (FSAM), a newly developed solid-phase additive manufacturing technique was employed to fabricate AA6061/TiC/GS composite. The process parameters like tool rotational speed, transverse speed, tool tilt angle and type of tools used in friction stir additive manufacturing were analyzed. Taguchi’s L16 orthogonal array and ANOVA method was used to find the optimum process parameters for the tensile strength. Development characteristics of stirred zone, recrystallization and mixing of reinforced particles will significantly improve the mechanical properties of the fabricated composites. Microstructural investigation and fractography was done by using optical microscopy and scanning electron microscopy (SEM). Corrosion, wear behavior and elemental analysis through EDS was also performed for the fabricated material. The maximum tensile strength of 385.74 MPa was attained under optimal parameters of the tool rotational speed 1,200 rpm, transverse speed 55 mm min−1, and tool tilt angle of 1° for scrolled tapered octagonal tool pin. The findings of the linear regression model showed a minor variance between model and experimental values. Prominent results of the experiment were compared by few other researcher’s findings working in similar area.

The Versatility of the Taguchi Method: Optimizing Experiments Across Diverse Disciplines

AbstractThe Taguchi method, a robust experimental design technique, establishes a strong connection between input and output variables. Known for its capacity to yield precise results with fewer trials and minimized errors, this method has gained widespread application in various fields such as engineering, physics, chemistry, economics, finance, and more. In this paper, the authors examine the importance of the Taguchi orthogonal array method, its step-by-step optimization procedure, and its potential for future applications. Through a thorough literature review, the authors investigate how the Taguchi method has been effectively employed to identify key factors influencing response variables. The versatility of the Taguchi method becomes apparent when considering its applications across diverse disciplines. Researchers in engineering have successfully utilized this technique to optimize processes and enhance product quality. Furthermore, in scientific fields like physics and chemistry, the Taguchi method has proven invaluable for conducting experiments efficiently, resulting in more accurate and reproducible outcomes. Researchers gain critical insights into the effects of factors on the response variable by employing statistical tools such as mean analysis, variance analysis, and signal-to-noise ratio. The Taguchi method remains a valuable and broadly applicable tool for optimizing experiments and identifying influential factors across multiple disciplines. This paper’s extensive literature review emphasizes its significance in various fields and outlines the step-by-step procedure to leverage its potential for optimization.

Optimization Of Process Parameters For Incremental Forming Of Aluminium 1060

In the past two decades, extensive research was done on incremental sheet forming (ISF). It has resulted in significant advances in fundamental understanding and the development of new processing and tooling solutions. However, ISF is yet to be fully implemented in mainstream high-value manufacturing industries due to a number of technical challenges, all of which are directly related to ISF process parameters. Now a days, the demand for new materials for sheet plate has become high in the number of applications because of various attributes in the material such as high tensile strength, good flexibility and durability. The present work gives the effect of several process parameters such as tool rotating speed, step size(z-axis), and feed (x-y axis) on forming force of incremental forming. Particular attention is given to the deformation rate and stress developed in the material during incremental forming. The tool path for incremental forming is generated using MATLAB software. Simulations are done using Taguchi’s L9 orthogonal array method. All the simulations are done in Abaqus software. Stress developed in the material during incremental forming is determined in the simulations. The effect of each process parameter on the stress developed is investigated. Finally, Optimization of the Process parameters is done for Incremental forming process. ANOVA technique is used to find the influence of each process parameter on the stress developed in the material

Experimental Investigation of Optimal Welding Parameters and Mechanical Properties of Shielded Metal Arc Welded Mild Steel Plates

This study focuses on achieving enhanced mechanical properties of the welded joints, which is critical for the applications of mild steel (MS) plates in various industries. In this regard, a systematic approach is used to adjust welding parameters such as welding current and workpiece thickness in shielded metal arc welding (SMAW), with the objective of identifying the optimal combination that maximizes weld quality. The experiments were planned with the help of Taguchi’s L9 orthogonal array method in order to reduce experimental cost and time. The weld quality is optimized by determining the signal-to-noise ratios of weld penetration, tensile strength, impact strength, and microhardness for each experimental sample. As a result, 110 A welding current is obtained as the optimal SMAW parameter for a 5 mm thick MS IS 2062 Grade B plate. This optimized result has also achieved 394.78 N/mm2 tensile strength and 53 J of impact resistance for the respective specimen. Besides, research not only enhances understanding of the SMAW process but also offers practical implications for industries requiring high-performance welded joints in MS structures. Additionally, this study can assist upcoming researchers in optimizing any existing welding procedures.

Analysis of variance and grey relational analysis application methods for the selection and optimization problem in 6061-T6 flange friction stir welding process parameters

A study was carried out to investigate and enhance the effects of friction stir welding on the mechanical characteristics of a flange composed of 6061-T3 aluminum alloy. The pipes possess an outer diameter and wall thickness of 6 mm, while the plates are sized at 100 x 100 × 6 mm. Nine unique experiments were planned using the Taguchi orthogonal array method, with the welding tool remaining constant. Three independent variables (travel speed, rotation speed, and shoulder diameter) were altered at three different levels for each variable. The research analyzed the influence of various FSW factors on the weld flange joint. Analysis of variance (ANOVA) and grey relational analysis (GRA) were employed to determine the impact of each FSW underwater parameter. Moreover, the statistical Taguchi technique (TM) was used to predict the optimal combination of welding parameters to improve tensile properties, including tensile strength (UTS), yield strength (YS), elongation (EI%), and bending load (BL) of welded joints. Additionally, the actual tests demonstrated a high level of agreement with the results obtained from the proposed mathematical model. The validation results obtained indicate that the optimization method is a dependable tool for enhancing the quality responses of friction stir welding.

Effect of Cutting Speed and Feed per Tooth on the Trimmed Surface Roughness and Tool Wear During Milling of CFRP: Aerostructural Part

The machining quality plays a pivotal role in determining the service life of components. In this context, the primary focus of the experimental investigation is centered on the impact of cutting conditions during edge trimming of carbon fiber reinforced plastics (CFRP) material. The ultimate objective of this experiment is to pinpoint the most effective machining parameters, specifically the cutting speed, Vc and the feed per tooth, fz, to minimize damages during the edge trimming process using actual aerostructural sample components composed of CFRP material. Furthermore, the study took into account the issue of tool wear on cutting tools. The Design of Experiment (DoE) technique, specifically the Taguchi L9 orthogonal arrays method, was used to conduct this research. It was shown that the feed per tooth, fz, and the cutting speed, Vc, had the biggest effects on the trimmed surface quality as the longitudinal surface roughness increased. It was demonstrated that the fracture of the pyramidal tooltips in router-type tools happened more frequently at higher cutting speeds, Vc. The optimal machining parameters for minimizing damages during CFRP edge trimming were the combination of the feed per tooth, fz at 0.05 mm and cutting speed, Vc at 50 m/min. The most significant element influencing the tool’s wear was the cutting speed, Vc.

Experimental investigation of 3D printed polylactic acid and polylactic acid – hydroxyapatite composite through material extrusion technique for biomedical application

In biomedical industries, composite additive manufacturing are employed for customization, quicker production, efficient use and capital reduction. This experimental work focuses on the development of poly lactic acid (PLA) and novel extruded hydroxyapatite (HA) reinforced poly lactic acid (HPLA) by material extrusion (ME) technique and their properties were compared with that of standard 3D printed PLA. The extruded composite filaments were subjected to thermal characterization (DSC, TGA) and chemical characterization (FTIR) to ensure filament quality and its implementation in ME technique for 3D printing process. In addition, the melt compounded composite filaments were subjected to annealing to observe the influence of heat treatment upon their mechanical properties and thereby to validate their potential to resist breakage during ME process. Taguchi orthogonal array method using MiniTab software is employed to execute the parameter optimization for the 3D printing process. The 3D printed tensile, flexural and impact specimens, using pure PLA and extruded composite filaments, as per American Society for Testing and Materials (ASTM) standards were subjected to a comparative experimental study which showed that 3D printed specimens using PLA and HPLA performed better than that of standard PLA specimens due to the improvement in their crystalline nature. The ruptured specimens were subjected to microstructural characterization (optical microscopy, SEM) to observe failure modes and ash content test was conducted to validate the homogenous distribution HA filler particles in PLA matrix. In addition, mechanical characterization was also performed on 3D printed bone plate/bone scaffold application using extruded filaments of PLA and HPLA, as per ASTM F543 standards, to validate incorporation of the composite filaments in real-time application in biomedical industry.

Machining Performance Analysis of Ti6-Al-4V in Powder-Mixed EDM Using Green Dielectric Oil

In this investigation, the factors were oil type ([Formula: see text]), powder type ([Formula: see text]), and powder concentration ([Formula: see text]) level, and the machining parameters were the voltage (V), capacitance (pf), pulse-on time ([Formula: see text]), and pulse-off time ([Formula: see text]). The output parameters were the material removal rate (MRR), and tool wear rate (TWR). Three types of oils and powders, along with their respective particle concentrations, were selected for this experiment. Neem, Karanja, and sesame oils were mixed with aluminum oxide (Al2O3), chromium (Cr), and nickel (Ni) powder at 4, 6, and 8[Formula: see text]gm/l, respectively, using an overhead stirrer to investigate the conditions under which the green oil powder mixed mixture yielded a higher MRR and lower TWR during the micro-EDM process of titanium alloy (Ti-6Al-4V) using a 0.8[Formula: see text]mm tungsten carbide (WC) tool with fixed machining parameters (240[Formula: see text]V, 100[Formula: see text]pf, 20[Formula: see text][Formula: see text]s [Formula: see text], and 5[Formula: see text][Formula: see text]s [Formula: see text]). All the powders used in this experiment had a 32-micron (450 mesh) size. The Taguchi L[Formula: see text] orthogonal array and grey relational analysis methods were used to design and optimize the input process parameters for both responses. SEM, optical microscopic analysis, and EDS analysis were performed to examine the surface morphology, characteristics of the WC tool, and elemental composition of both the tool and the workpiece material. The optimum conditions for Karanja oil with a Cr powder mixture concentration of 4[Formula: see text]g/l resulted in higher MRR and lower TWR. However, machining with neem and sesame oils resulted in higher TWR and lower MRR.

Determining key factors affecting coconut sap quality after harvesting

The production of coconut sap beverages faces a challenge with the quality of the incoming coconut sap sourced from farmers. The clarification of pivotal factors influencing the quality of coconut sap after harvesting is of paramount importance for fostering mutual benefit between the involved parties. This research focuses on assessing the quality and degradation of coconut sap during the post-harvest stage. It addresses the shortcomings in evaluating coconut sap quality and improper pick-up conditions. To improve these processes, various experiments were designed, including 1) preliminary experiments that explored microbial count, pH, and soluble solids in harvested coconut sap at varying intervals, and 2) the L9 Taguchi Orthogonal Array method. These approaches identify the optimal levels of factors such as cleaning method, storage temperature, and preservative type. By reducing the number of experiments, costs and time were minimized, 3) the 23 factorial design was implemented, reducing the levels of each factor while measuring coconut sap quality based on pH and total soluble solids (representing sweetness) at different post-harvest intervals. The results from the Taguchi method were then used to design the factorial method experiment. The analysis revealed crucial factors influencing coconut sap quality at the 10-h mark. Storage and transportation temperatures, along with the type of preservative, significantly impacted the pH value. However, the washing method and preservative type showed no statistically significant effect on Total Soluble Solids (TSS) value (p > 0.05). Recommendations include using tap water for container cleaning, opting for Payom wood as a preservative, and adhering to cold chain practices for transportation exceeding 4 h, with temperatures maintained below or equal to 10 °C. Swift sap collection within 4 h post-harvest, coupled with stringent temperature control during transportation (not exceeding 10 °C), is advised to ensure optimal quality. Integrating pH with TSS values enhances comprehensive quality assessment, aligning with established best practices in coconut sap handling.

Optimizing SKD-61 steel machining for marine component manufacture: A grey-Taguchi study on nanofluid minimum quantity lubrication

SKD-61 steel finds extensive application in various sectors, including the marine industry where materials must withstand harsh aquatic conditions. In this study, we employ the Grey-Taguchi approach to optimize surface roughness (Ra), cutting force (Fc), and material removal rate (MRR) when hard-milling SKD-61 steel in pure minimum quantity lubrication (MQL) and nanofluid MQL environments, aligning with the demands of marine engineering. The orthogonal array method generates a set of experiments based on four input parameters: cutting speed, depth of cut, feed per tooth, and cutting condition, which are essential factors in marine component manufacturing. Our approach combines Grey relational analysis (GRA) with the Taguchi method to enhance multi-objective outcomes in machining. The results of this marine-focused study reveal that the lowest surface roughness, cutting force, and highest material removal rates are attained when the cutting conditions align with the principles of nanofluid MQL at a cutting velocity of 80 m/min, a depth of cut of 0.2 mm, and a feed per tooth of 0.01 mm/tooth. Keywords: hard milling, nanofluid MQL, optimization machining parameters; Grey relational analysis; Taguchi

Experimental Investigation of the Surface Roughness for Aluminum Alloy AA6061 in Milling Operation by Taguchi Method with the ANOVA Technique

The surface roughness of the machined parts is the most important parameter to predict the performance of mechanical components. Moreover, predicting the optimal machining parameters conditions is the preferable method for cost reduction and achieving the desired surface quality of the product. This study investigates three cutting parameters, such as depth of cut, spindle speed, and feed for the milling aluminium alloy AA6061, to predict the surface roughness quality. The experimental work utilized a manual milling machine with a coated carbide cutter. Furthermore, the experiments were arranged using the Taguchi L9 orthogonal array (OA) method. The average surface roughness (Ra) was measured and converted to signal-to-noise (S/N) ratio and then analyzed in the statistical method of analysis of variance (ANOVA). Finally, the optimal combination set speed, feed, and depth of cut was 2400 rpm, 30 mm/min, and 0.5 mm, respectively. Also, according to the ANOVA test, the most influential parameter was the spindle speed among the selected parameters, with the highest P value of (66.42%). In comparison, the lowest P value is a depth of cut (5.34%). Furthermore, spindle speed was the only significant factor statistically. By selecting a high spindle speed (2400 rpm), surface quality was enhanced, but the preferable level was low for depth of cut and feed.

Systematic determination of the optimized Zr content of Ba(ZrxTi1-x)O3 with high dielectric constant at room temperature for high-voltage system application

In this study, by replacing the B-site element in BaTiO3, a ferroelectric material, with an element with a larger ionic radius, a ferroelectric material with high permittivity at room temperature was synthesized. The powders were prepared by solid-state reaction to perform lattice substitution with Zr4+ (0.72 Å), which has a larger ionic radius than Ti4+ (0.605 Å). To perform effective solid-state reaction and better understand the correlation between variables, this study introduced a design of experiment (DOE) based on the orthogonal array (OA) method included in the PIAno software. By substituting 0.222 mol of Zr, which has a large ionic radius, the crystal structure was deformed through an effective diffuse phase transition (DPT), and this resulted in the largest improvement in permittivity at room temperature. In addition, the powder, which underwent solid-state reaction at 1300 °C, formed the densest structure during sintering, which established the conditions for realizing the best dielectric properties. These results can be utilized as a key material for improving the properties of passive devices used in high-voltage industrial systems in societies undergoing the fourth industrial revolution.

Biodegradable containers from rice husk as substitutes for single-use plastic products

Vietnam ranks among the top four nations for single-use plastic (SUP) waste, trailing only China, Indonesia, and Philippines. The abundant rice husk (RH) by-product of rice cultivation presents an opportunity to fabricate biodegradable containers, potentially supplanting single-use disposables. This study focuses on creating biodegradable containers from RH via thermo-pressing. Utilising the Taguchi orthogonal array method, we examined the impact of the RH to modified starch (MS) ratio (w/w %), pressing temperature (°C), and time (minutes) on the trays’ hardness, colour variation, and density, aiming to refine the manufacturing process. Additionally, variations in adhesive concentrations and glycerol were assessed for their influence on the aforementioned properties. The identified optimal conditions for fabricating viable biodegradable containers were a RH and MS composition of 80% (w/w), with a pressing duration of 3 minutes at 150°C. The resulting product exhibited a hardness of 5.26±0.22 kgF. Moreover, the thickness, density, and colour on the front and back sides were measured at 2.05±0.01 mm, 0.97±0.004 g/cm³, 50.87±0.96, and 48.05±0.87, respectively. Consequently, RH-based materials have emerged as promising candidates for crafting consumer-safe, environmentally benign biodegradable containers.

Performance Analysis of Agricultural Waste Using Gray Relational Analysis (GRA) Method

Agricultural waste, which is produced in large Sizes in India, for biogas production is A promising ingredient. A circular economy based on agro-waste biogas requires the Integration of agricultural waste management, biogas production and utilization and policy support. This article is from agricultural waste and Discusses in detail the feasibility of biogas production, its development and governance initiatives and policy regulations. For predicting the biogas content of agricultural wastes a simple theoretical study of anaerobic digestion is proposed. There are many different models, but most of them are instead of biochemical equations Relies on algebraic equations, and many more input parameters and Computational time is required. This work provides a simplified model that predicts the amount of biogas produced and can be used for agricultural energy feasibility studies, for example, bioreactors. That digests animal waste slurry. The objective of this thesis finding the best cleaning location for Agricultural waste or the Gray Relational Analysis (GRA) method showing. Based on grey correlation analysis for improving with many performance characteristics. This paper presents a useful approach. Based on the Taguchi method of orthogonal arrays sixteen test runs was performed. Such as laser power and cutting speed the laser cutting parameters are optimized considering multi-functional characteristics, that is Work piece surface roughness, Top kerf width and heat affected zone (HAZ) width. By analyzing the corresponding grayscale, Laser power is in the answers rather than slowing down and can be seen to have a greater effect. Ultimate analysis C, Ultimate analysis H, Ultimate analysis O, Ultimate analysis N, Ultimate analysis S there are alternatives parameter and Poultry Litter (Dry), Pig Solids (Dry), Fodder Manure (Dry), and Beef feedlot manure (dried) there are evaluation parameters. Ultimate analysis S is got the first rank whereas the Ultimate analysis O is having the lowest rank in this paper Agricultural waste Ultimate analysis S is got the first rank whereas the Ultimate analysis O is having the lowest rank.

An investigation into enhancing energy storage capacity of solar ponds integrated with nanoparticles through PCM coupling and RSM optimization

Solar energy is a promising renewable resource for meeting energy demands, with solar pond systems offering efficient thermal energy storage. Integrating Phase Change Materials (PCMs) and nanoparticles into solar ponds has shown potential to enhance energy storage capacity and thermal performance. This study focuses on optimizing the energy storage capacity of a solar pond system by employing Response Surface Methodology (RSM) to analyze the combined effects of PCM and nanoparticles integration. As input parameters for the optimization process, variables such as pond depth, salinity gradient, insulating materials, and solar radiation were taken into account. To maximize energy collecting and storage efficiency, the goal was to determine the ideal combination of these characteristics. To optimize the temperature distribution, Taguchi's L13 orthogonal array method and ANOVA were used. The results of the study indicate that the solar pond configurations with AgTiO2/Paraffin wax and CNT/Paraffin wax exhibited significantly higher energy storage capacities compared to the plain paraffin wax solar pond. Specifically, the AgTiO2/Paraffin wax solar pond showed an energy storage capacity increase of 7.48⁒, while the CNT/Paraffin wax solar pond exhibited an increase of 3.82⁒, in comparison to the plain paraffin wax solar pond. These findings highlight the substantial improvements in energy storage achieved by incorporating nanoparticles (AgTiO2 and CNT) into the paraffin wax as phase change materials within the solar pond system. The optimization study's findings showed that solar pond system performance has significantly improved.

Optimizing thermal comfort in physical exercise spaces: A study of spatial and thermal factors

Fitness centers have become famous for maintaining a healthy lifestyle. They require different thermal comfort conditions and higher fresh air supply rates than other indoor spaces. However, even well-designed centers may cause discomfort due to factors such as design decisions, ventilation, overheating, and overcrowding. The standards for fitness centers do not consider these specific requirements sufficiently, so this study focuses on understanding the thermal comfort requirements during physical exercise and evaluating spatial and thermal factors affecting the thermal environment around the body. The study investigated the ceiling height, lateral and frontal distances between machines, and vent locations as spatial factors and inlet temperature and air velocity as thermal factors. A thirty-minute moderate-intensity constant work rate exercise test was conducted in a controlled climatic chamber using a cycle ergometer with six healthy male participants. The experiment conditions were simulated in CFD software using the collected data. Once a validated simulation model was provided, computational models for different environmental and spatial scenarios for the five-person cycling class were generated. Using Taguchi L9 (34) orthogonal arrays method, nine spatial scenarios were simulated with three different thermal operations each. Optimal factor levels were determined by using thermal comfort conditions (based on predicted mean vote) around the body’s thermal plume. The results showed that a ceiling height of 5 m, lateral and frontal distances of 1 m and 0.5 m between machines, and Type 2 (two inlets mounted on the ceiling) ventilation strategy were optimal for achieving better thermal comfort values in a thermal condition of 18 °C and 0.2 m·s−1. The study found that increasing the ceiling height and using cross-positioned vents that project air vertically from the ceiling improved the comfort conditions significantly. It is expected that these criteria, which were determined, compared with the standards and detailed, will contribute to the production processes of comfortable exercise spaces.

Strength and manufacturability enhancement of a composite automotive component via an integrated finite element/artificial neural network multi-objective optimization approach

This study addresses the enhancement of an injection-molded fiber-reinforced plastic / metal hybrid automotive structure and its plastic injection molding process through the integration of the finite element method, artificial intelligence and evolutionary search methods. Experiments are conducted to validate the finite element models. The orthogonal array and Latin hypercube methods are employed to generate a database via finite element analysis. The database is then used to train artificial neural networks that accurately evaluate component distortion, manufacturing time, and structural strength. A genetic optimization algorithm is applied to identify optimal process parameters. The procedure was demonstrated to simultaneously reduce product warpage and manufacturing time by 10 and 62 %, respectively, when compared with the reference manufacturing process while strength is kept above the required levels with a reduced number of required data points. A more in-depth investigation into the causes of strength variation and deformation is also provided. The results contribute to the advance of robust composite automotive structures with superior quality, manufactured through efficient processes.

Optimization and ANFIS-based modeling of two step FSSW process parameters on tensile strength for triple-sheet joining of aluminum alloy

In this paper, a potential technique is used to weld three sheets of AA 6082 through a two-step friction stir spot welding (TSFSSW). The optimal settings of the process parameters, namely, the rotational speed of the tool, dwell time, and plunge depth during welding have been analyzed. Taguchi’s L9 orthogonal array and ANOVA method is used to get proper material flow, appropriate heat conduction and the stir zone expansion, which helps in preparing sound joint. Microstructural tool analysis and fractography are performed by employing optical microscopy and Scanning Electron Microscopy (SEM). The tool was analyzed before and after use for heat effect along with the observation of the fracture behavior of the joint. To analyze the residual stresses developed in the joint, the XRD analysis is also carried out. The maximum tensile strength of 94.51 MPa was obtained under optimal parameters of the rotational speed of 1200 rpm, dwell time of 10 s, and plunge depth of 2.9 mm. The results of the ANFIS model revealed that a minor difference between experimental and model values (95.62) confirms the validation of the experiment. The resulting experimental findings of the ANFIS model were compared with other similar work done by researchers previously.

Occurrence state of fluoride in barite ore and the complexation leaching process

Barite ore is typically associated with difficult-to-remove vein minerals, but commercial barite products require a high BaSO4 content. We investigated the occurrence state of fluoride in barite ore using various analytical techniques, which indicated that elemental fluorine in barite predominantly exists as fluorite. Fluoride was then leached from barite ore via complexation. The effects of HCl and AlCl3 concentrations, temperature, time, and liquid-solid ratio on the leaching rate were examined, and the leaching conditions were optimized using an orthogonal array method. The fluorine leaching rate approached 93.11% after stirring for 30 min at 90 °C and 300 rpm with 3 mol/L HCl, 0.4 mol/L AlCl3, a liquid-solid ratio of 10:1 mL/g, and an ore sample size of −75 μm + 48 μm. According to the leaching kinetics, the process conformed to the solid membrane diffusion control model at a high temperature and the joint chemical reaction-diffusion control model at a low temperature. The apparent activation energy was 56.88 kJ/mol. Furthermore, aluminum and fluorine coordination numbers increased with increasing Al3+/F− molar concentration ratios. Competing complexation reactions of Al3+, H+, and F− occurred at three levels. This complexation approach effectively leaches fluoride from barite, improves barite product quality, and reduces environmental pollution.

Application of Cold Sintering Process for Stabilizing Heavy Metals in Municipal Solid Waste Incineration Fly Ash

Municipal solid waste incineration fly ash (MSWI FA) consists predominantly of compounds comprising elements such as calcium, aluminum, silicon, sodium, and others. Additionally, it encompasses a complex mixture of heavy metals, chlorides, sulfates, organic pollutants, and other constituents. The effective and economically viable treatment of MSWI FA poses a formidable challenge for resource cycling at the current stage. In this research report, we adopt a novel low-temperature sintering method called the “Cold Sintering Process” (CSP) as a means to immobilize heavy metals within the fly ash. By utilizing a Taguchi orthogonal array method, we will adjust five control factors in the CSP, including sintering temperature, uniaxial pressure, sintering time, initial water addition, and sodium carbonate dosage. The leaching of cadmium from the fly ash, as measured by the Toxicity Characteristic Leaching Procedure (TCLP), will serve as the quality indicator of products. Through the application of CSP, MSWI FA was transformed into structurally stable ceramic blocks, and the heavy metals within the blocks were effectively immobilized. The results of the experiments showed that MSWI FA under the conditions of a temperature of 300 °C, uniaxial pressure of 312 MPa, sintering time in 60 min, 25 wt% water addition, and 9 wt% Na2CO3 addition could effectively reduce the leaching of cadmium by 77.71%, lead by 21.14%, zinc by 42.37%, and chromium by 99.99%, as compared to the original MSWI FA TCLP results. The X-ray Diffraction (XRD) results indicate that during the CSP, fly ash forms phases such as calcium silicate, rankinite, hydrogrossular, anorthite, and marilite. These phase transformations are considered beneficial for preventing the leaching of internal heavy metals. Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS) results reveal that CSP is advantageous for compacting the overall structure, and EDS results further demonstrate that some of the Pb and Zn are carried out from the interior of the blocks, with uneven distribution on the surface of fly ash particles. The aforementioned experimental results serve as preliminary indications of CSP’s capability to stabilize detrimental components within high-purity fly ash. Future research endeavors may entail the refinement of material proportions, modification of experimental parameters, and other methodologies, thus facilitating potential scalability to industrial applications. Such developments align with the overarching goal of resource utilization.