Fe Removal Research Articles

Effects of Mn addittion, cooling rate and holding temperature on the modification and purification of iron-rich compounds in AlSi10MnMg(Fe) alloy

The use of secondary aluminum alloys in industry is still limited by the high Fe contents in recycled alloys. In general, the Fe-rich intermetallic compounds deteriorate the performance of secondary Al–Si alloys, specially the β-Fe phase. To mitigate the detrimental effects of iron, the influence of diferent cooling rates and holding temperatures on the modification and purification of iron-rich compounds in commercial AlSi10MnMg alloy with 1.1 wt % Fe was studied. According to the results obtained by CALPHAD calculations, the alloy was modified by adding a 0.7 wt%, 1.2 wt%. and 2.0 wt% of Mn. The phase formation and morphology of iron-rich compounds was systematically studied and correlated by different microstructural characterization techniques. The experimental results showed that the detrimental β-Fe phase can be avoided by adding at least 1.2 wt % of Mn at the studied cooling rates. Finally, the effect of different holding temperatures in the sedimentation of Fe-rich compounds also was studied. Hence, the gravitational sedimentation experiments at different holding times and temperatures were conducted to validate the feasibility of the methodology in different processing conditions. The experimental results showed a high Fe removal efficiency up to 64% and 61%, after a holding time of 30 min at 600 °C and 670 °C, respectively. The addition of Mn improved the Fe removal efficiency but not gradually, as the best results were obtained in the alloy containing 1.2 wt % Mn.

The batch tests on new catalytic filtration masses creation by natural materials modification with MnO2 supporting by electrolysis with the view of Fe and Mn removal

The batch tests on new catalytic filtration masses creation by natural materials modification with MnO2 supporting by electrolysis with the view of Fe and Mn removal

A study on Fe removal in aluminum scrap to make A356 aluminum alloy

The domestic demand for A356 raw material is increasing, so the price is often very high. The goal of this study is to sort the scrap, then reduce Fe from about 1 % to less than 0.15 %. The reducing Fe by Na2B4O7 to refine aluminum scrap has been conducted under laboratory conditions. The results showed that the iron reduction rate increased with the addition of Na2B4O7 and the heat retention time and obeyed the first-order exponential law. The addition of flux containing Na2B4O7 can reduce the iron content from 1% to less than 0.1% and reach an optimal rate of 77 %. The XRD, SEM and EDS analyzes of aluminum samples described the microstructure and morphology of the obtained aluminum products. This product is a good raw material for making Al alloy group A356.

Potensi Bacillus cereus dan Bacillus subtilis Menurunkan Kandungan Logam Fe dan Mn pada Air Asam Tambang

Acid mine drainage (AMD) with pH 2,56, also high concentration of Fe and Mn respectively 35 mg/L and 8,83 mg/L should be treated to prevent the pollution. AMD treatment can be done by adding bacteria. Bacillus cereus and Bacillus subtilis isolated from AMD sample using selective media agar. Each bacteria was added 5% and 10% to the 200 mL AMD sample separately. The result shows that the highest removal of Fe and Mn in AMD was 62.03% and 18.02% with 10% B. cereus. Meanwhile, with addition 5% B.subtilis shows the highest Fe and Mn removal respectively 41.91% and 16.79%. Therefore, these bacteria have potential to decrease Fe and Mn concentrations in AMD.

Adsorptive removal of aqueous pollutants on waste biomass-derived activated carbon: A mechanistic evaluation

The mismanagement of waste biomass is known to have environmental repercussions. Accordingly, valorisation of waste biomass holds significance. The present study evaluates valorisation of waste rice straw as waste biomass-derived activated carbon (WB-AC) as potential adsorbent for different aqueous pollutants. The WB-AC was characterized to have a distributed porous structure along with various surface functionalities. The WB-AC was utilized for adsorption of two different representative aqueous pollutants, namely iron (Fe) as metal and methylene blue (MB) as organic pollutants in the batch process. The effect of initial pollutants concentration, adsorbent dose, and adsorption temperature was studied under natural pH conditions. The adsorption of both pollutants (Fe and MB) was found to follow pseudo-second-order kinetics and was best described by the Langmuir isotherm model. The adsorption was noted as endothermic, spontaneous, and thermodynamically feasible. The physical interaction may be the dominant mechanism for both the pollutants; however ionic interaction seems predominant for Fe adsorption whereas chemical interaction might have also occurred alongside physical adsorption for MB. The maximum adsorption capacity of 172.41 mg g−1 and 95.24 mg g−1 were recorded for Fe and MB adsorption on WB-AC, respectively. A maximum of 99.56 % Fe removal and around 90.90 % MB removal were recorded in this study. Thus, WB-AC has been demonstrated as a universal adsorbent for different aqueous pollutants which include metals and organics.

Blended nylon 6,6 and choline glycinate-ionic liquid for adsorptive nanofiber membrane on the removal of Fe(III) from synthetic wastewater

The concentration of heavy metals in the environment has increased tremendously with the rapid growth in the human population and urbanization. This is potentially hazardous to humans and the environment in high concentrations. Recently, membrane filtration has received considerable attention for heavy metals removal. In this study, amino acid-based ionic liquid (AAIL) was used as an addictive for electrospun nylon 6,6 nanofiber membrane (NFM) for removal of Fe(III) from synthetic wastewater. The characterizations of NFM/AAIL and its performances on Fe(III) removal were studied and compared with the pure NFM. Based on the results, the NFM/AAIL has a comparably smaller membrane diameter than the NFM, thus resulting in larger pore sizes. Moreover, no distinctive changes in the chemical properties between NFM/AAIL and pure NFM based on the FTIR results. In addition, only 0.16 % of AAIL leached out from the membrane when 500 mL of permeate ran through the membrane. Furthermore, due to the membrane larger pore size and hydrophilicity of AAIL, the pure water and iron permeability of NFM/AAIL was reportedly higher than the pure NFM by 99 % and 98 %, respectively. For adsorption analysis, the interactions of carboxylate groups and amine groups from AAIL with Fe (III) has enhanced the adsorption capacity of NFM/AAIL by 97 % as compared to pure NFM.

Recovery of copper-dominated resources from copper mine drainage by chemical oxidation and sulfur biocycling: A pilot-scale study

The copper mine drainage (CMD) formed during copper mining and smelting has the characteristics of being low pH, with a high sulfate concentration and large amounts of metal ions such as Fe, Cu, and Mn. In order to recover copper-dominated many resources from CMD, realize effective control of environmental pollution and avoid the loss of precious resources. The combined process of Fe pretreatment recovery, Cu treatment recovery, and S treatment recovery was established based on H2O2 oxidation, sulfate-reducing bacteria (SRB) reduction, and sulfur-oxidizing bacteria oxidation. A pilot-scale study was carried out with a CMD inlet flow rate of 12 m³/d. Results show that the average Cu2+ removal rate was 99.66%, and the recovered dry matter precipitated (mainly was CuS) copper content was 35.6%. In addition, the average total Fe, Mn and Mg removal rate was 99.46%, 99.10% and 84.08%. And the S2− oxidation rate was above 90% (mainly converted to sulfur). 27.52% Fe precipitated dry matter and 42.9% S, 32.2% Mg, and 13.8% Mn precipitated dry matter were also recovered as by-products. Through high-throughput analysis of the functional and structural changes in the SRB community, showed that indigenous SRB from the copper mine exhibit good adaptability to CMD conditions, with the enrichment and acclimation of SRBs achieving a high level of expression of bioactive. The bottleneck of SRB applied to CMD treatment was solved. Finally, the economic feasibility analysis shows that the combined process treatment CMD can save 58.6% of the cost compared with traditional lime neutralization method, and avoid the sludge treatment cost of 29.03 million USD per year. The above provides engineering practical reference for CMD treatment and resource recovery.

Effect of in-situ oxidation on the phase composition and magnetic properties of Fe3O4: Implications for zinc hydrometallurgy

• Iron precipitates at different oxidation degrees are obtained by H 2 O 2 . • Ms value of Fe 3 O 4 shows a decrease and then recovery with oxidation. • Magnetic properties are affected via a Fe-O bond length-related mechanism. • The “magnetic iron oxides” method is promoted for industrial iron precipitation. Large quantities of hazardous waste are generated in the removal process of iron in zinc hydrometallurgy, which poses a severely permanent threat to the environment. Recently, an innovative magnetite (Fe 3 O 4 ) method for iron precipitation has been proposed. Whereas, the magnetic separation performance and phase composition of Fe 3 O 4 are sensitively disturbed by the oxidizing conditions in the pregnant leach solution from zinc hydrometallurgy. In this work, a series of Fe 3 O 4 samples with different oxidation degrees were in-situ formed. We found that oxidation did not worsen the Fe removal and that all samples have a relatively high iron content (>42.3%). Meanwhile, although the magnetic properties of the samples showed a decrease (from 32.31 to 6.56 emu/g), it could be recovered (10.60 emu/g) by controlling the oxidation to a certain degree. This is correlated with the phase transition of iron oxides as the oxidation degree increase. Furthermore, it is clarified that the mechanism by which the oxidation affects the magnetic properties was the change of Fe-O bond length, as revealed by Raman and Fourier transform infrared spectrometer measurement. This work provides a new strategy for the practical implication of the “magnetic iron” instead of the magnetite precipitation method in zinc hydrometallurgy.

Stepwise recycling of Fe, Cu, Zn and Ni from real electroplating sludge via coupled acidic leaching and hydrothermal and extraction routes

Fe/S-bearing erdite flocculant has been proven to be effective in the precipitation of heavy metals from real electroplating wastewater, with the only drawback being the huge production of sludge. This sludge was rich in Fe/S/Zn/Cu/Ni and refractory to be recycled due to the extractant pollution by free Fe and the dissolution of sulphide. Herein, a multistep separation method was developed to dissolve sulphide and separate Fe prior to Zn/Cu/Ni. Results showed that more than 92% sludge was dissolved as Fe/Zn/Cu/Ni-rich leachate after the sludge was leached by nitric acid, with the rest of the remaining undissolved elemental sulphurs. When the leachate was directly extracted by using commercially extractant Acorga M5640 and Di-(2-ethylhexyl) phosphoric acid (P204), Fe was complexed by the phosphate group of the extractant. The Fe was effectively removed prior to Zn/Cu/Ni to avoid the extractant pollution. The Fe removal efficiency was only 38.34% without sucrose, but it rose to 99.94% with the addition of 0.5 g sucrose. The added sucrose reacted with nitrate to consume H+, which showed a similar rate to the H+ release from Fe hydrolysis. Thereafter, the Fe hydrolysis was continued to remove, the Fe at a high level. The removed Fe was in the form of high-purified hematite nanorod with a diameter and length of 300–600 nm and 0.5–2.5 μm, respectively. After Fe removal, Cu/Zn/Ni was extracted by using Acorga M5640 and P204 to form three halite, including a mixture of copper sulphate hydrate and bonattite (96.8% CuSO4·H2O/CuSO4·3H2O), gunningite (97.5% ZnSO4·H2O) and dwornikite (97.9% NiSO4·H2O). The rest of the solution was neutralised by lime water to remove sulphate as gypsum (95.9% CaSO4) to meet the discharge standard of the electroplating industry. In summary, the recycling efficiency of Fe/Cu/Zn/Ni from the sludge reached 94.4%, 92.6%, 94.7% and 95.3%, which provided an alternative strategy to resource utilise Fe/S-bearing solid waste.

Iron Removal from Metallurgical Grade Silicon Melts Using Synthetic Slags and Oxygen Injection.

Novel SiO2-CaO-CaF2-R2O-MgO based synthetic slags (R2O represents alkali metal oxides) with varied binary basicity values were used with oxygen injection to refine silicon melts and remove Fe from metallurgical-grade silicon. Silicon samples and slags at the silicon-slag interfaces were obtained during refinement. The compositions of the silicon samples were analyzed, and the quenched slag samples and mild cooling slags from the final crucible were inspected using scanning electron microscopy and energy dispersive X-ray spectroscopy. After 15 min of refinement, the Fe removal rate ranged from 52.3 to 60.1 wt%. During the refining process, the Fe-concentrated phase formed within the silicon droplets and was then transferred to the silicon-slag interfaces and wetted with slags. The Fe-concentrated phase at the silicon-slag interface can dissolve directly in the slags. It can also be transferred into the slag phase in the form of droplets, which can be affected by the binary basicity of the slags. Ti removal demonstrated a similar mechanism. Fe-bearing crystals were not detected in the quenched slag samples obtained during refinement, while complex Fe-bearing phases were detected in the final slag. This study demonstrates Fe removal from metallurgical-grade Si using slag refining methods and reveals the removal mechanism during the refinement.

Experimental Study on the Removal of Fe2+ and Mn2+ from Zinc Sulfate Water by Micro-nano Ozonation

Experimental Study on the Removal of Fe2+ and Mn2+ from Zinc Sulfate Water by Micro-nano Ozonation

Adsorption test using ultra-fine materials on heavy metals removal

Acid mine drainage (AMD) contains numerous heavy metals, which need appropriate treatment before releasing to the environment. This study reports Fe and Mn removal from AMD by adsorption using ultra-fine biochar derived from coal, peat, and coconut shell. Clamshell waste was used and compared with pure CaO as a conventional precipitant. All adsorption materials were tested in an artificial solution at different pH conditions and contact time at room temperature. The adsorption process reached equilibrium at 100 min. Neutral pH was the best condition to achieve a higher removal efficiency. Results showed that biochar could successfully remove >90 % Fe and 80 % Mn. The isotherm model of each sorption fit with the Langmuir model. Metals can be precipitated in 10 min using clamshell waste, which is comparable with pure CaO. biochar, pure CaO, and clamshell are potential materials to solve heavy metal pollution and increase pH in wastewater.

Purification of Residual Ni and Co Hydroxides from Fe‐Free Alkaline Electrolyte for Electrocatalysis Studies

AbstractIt is critical to control Fe impurity concentrations in oxygen‐evolution‐reaction electrocatalysis experiments so that unambiguous assignments of activity and mechanistic details can be made. An established method to prepare Fe‐free KOH electrolyte is by using particulate Ni(OH)2 or Co(OH)2 as absorbents to remove the Fe from KOH or other neutral‐to‐alkaline electrolytes. However, this method yields residual Ni or Co species in the electrolyte which can be redeposited on the working electrode. Thus, current methods of Fe removal could convolute studies of OER. In this work, we compared two different methods, continuous electrolysis and nano‐filtration, to remove the Ni and/or Co species from Fe‐free alkaline electrolyte. We found the best approach is to pass the Fe‐free electrolyte through a hydrophilic 0.1 μm polyethersulfone filter which decreases the Ni species concentration in 1 M KOH to single ppb levels. This result suggests the remaining Ni or Co species are primarily particulate in nature, consistent with their small solubility as ions. In comparison, extended pre‐electrolysis of the electrolyte removed only a portion of the Ni/Co.

Treatment of Acid Drainage from Coal Mines Produced in the Boyacá Region, Colombia, using an Anaerobic Wetland with an Upward Flow

Coal mining represents one of the primary economic incomes in the department of Boyacá, Colombia. However, the acid mine drainage (AMD) generated has a tremendous environmental impact in the area due to the presence of sulfate ions (SO4-2), heavy metals, and low pH This article studies the behavior in the content of Fe and sulfates in AMD samples when treated within an artificial anaerobic vertical flow wetland, analyzing the concentration of these elementsand the content of dissolved oxygen (DO) and pH at different time intervals. The treatment of a MAD from the department of Boyacá was carried out using a bioreactor prototype with an organic substrate to provide the necessary conditions for the development of sulfate-reducing bacteria. Measurements were made with hydraulic retention times between 24 to 120 hours, monitoring the changes in the content of total Fe, SO4-2, pH, and DO. The data obtained show a reduction for total Fe of 88.3%, established at 5.61g∙m-2∙day-1, and for SO4-2 of 34.3% with 9.35g∙m-2∙day-1; reaching a maximum removal degree of 52.32% at 120h for sulfates and 92% for Fe, where the maximum removal peak is achieved, reducing the Fe removal rate for longer times. The reduction in the concentration of Fe is related to the reduction of DO and regulation of the pH, in addition to favoring the reduction of sulfate ions through the formation of the mineralogical phases pyrite and siderite. These data show that the anoxic conditions of the organic environment are maintained, for which a subsequent aeration stage is suggested.

Performance of Semi-passive Systems for the Biological Treatment of High-As Acid Mine Drainage: Results from a Year of Monitoring at the Carnoulès Mine (Southern France)

Two semi-passive treatment systems for iron (Fe) and arsenic (As) removal in AMD were installed and monitored in-situ for more than a year. These technologies were designed to treat the As-enriched AMD (≈ 1 g/L Fe(II) and 100 mg/L As(III)) of the ancient Carnoulès mine. The treatment was based on biological Fe and As oxidation by indigenous bacteria, and subsequent immobilization of As by ferric hydroxysulfates. Forced aeration and wood/pozzolana or plastic support were used for biofilm attachment. The system performance ranged from 86 to 98% for Fe oxidation, 30 to 60% for Fe removal, and 50 to 80% for As removal at a hydraulic retention time of 9 h. No significant difference were measured between the two biofilm supports. The wood/pozzolana support had a shorter delay for performance recovery after interruptions. Iron oxidation rates were similar to those obtained in the Carnoulès AMD stream and laboratory bioreactor, while As oxidation seemed to be enhanced. The sludge accumulated between 39 and 91 mg/g of As, mainly in the As(V) oxidation state; jarosite and amorphous ferric hydroxysulfate phases were the main Fe and As scavengers. Challenging environmental conditions during the long monitoring period confirm the robustness of the treatment units. The data will be useful in designing future full-scale treatment systems adapted to As-rich AMD.

Dynamic Adsorption Properties of Insoluble Humic Acid/Tourmaline Composite Particles for Iron and Manganese in Mine Wastewater.

Iron- and manganese-contaminated mine water is widespread around the world, and economical and efficient remediation has become a priority. Insoluble humic acid/tourmaline composite particles (IHA/TM) were prepared by combining inorganic tourmaline (TM) with the natural organic polymer humic acid (HA), and the effects of different calcination temperatures and calcination times of TM and IHA on the adsorption of Fe2+ and Mn2+ were analyzed. Based on the microscopic characterization of Scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Brunnauer–Emmet–Teller (BET), X-ray diffractometer (XRD) and Fourier transform infrared (FTIR), the simultaneous adsorption performance of IHA/TM on Fe2+ and Mn2+ was studied through dynamic adsorption tests, and a dynamic adsorption model was established. Adsorption regeneration experiments were carried out to further investigate the effectiveness of the composite particles in practical applications. The results show that, when the calcination temperature was 330 °C and the calcination time was 90 min, the removal rates of iron and manganese by the IHA/TM composite particles reached 99.85% and 99.51%, respectively. The curves for penetration of Fe2+ and Mn2+ ions into the IHA/TM composite particles were affected by the bed height, flow rate and influent concentration. Decreasing the flow rate, decreasing the influent concentration, or increasing the bed height prolonged the operation time of the dynamic column. If the bed height was too low, the penetration point was reached before the expected treatment was achieved, and when the bed height was too high, the removal of Fe2+ and Mn2+ was slow, and the utilization rate of the adsorbent was also reduced. If the flow rate was too low, longitudinal remixing easily occurred in the column. However, when the flow rate was too high, the speed of Fe2+ and Mn2+ ions passing through the adsorption layer increased, which reduced the total amount of adsorption. The increase in influent concentration not only reduces the removal rate, but also greatly shortens the total operation time of the dynamic column and reduces the treatment water. The dynamic process for the adsorption of Fe2+ and Mn2+ by IHA/TM was fitted best by the Thomas model. The adsorption column was continuously regenerated five times, and the results show that the IHA/TM composite particles were suitable for iron and manganese removal from mine wastewater. The research results will provide a reference for the effectiveness of the IHA/TM composite particles in practical applications.

Metal (Fe, Mn, and Cu) Removal from Synthetic Wastewater Using Modified Rice Husk in Fixed-Bed Columns

Metal (Fe, Mn, and Cu) Removal from Synthetic Wastewater Using Modified Rice Husk in Fixed-Bed Columns

A sustainable process to recycle aluminum from coal fly ash for simultaneous removal of iron: Solid waste management and evaluation

Coal fly ash (CFA) is one of the largest forms of global industrial waste, and continuous accumulation of CFA puts great pressure and poses potential risks to the natural environment. The objective of this study was to evaluate a sustainable process to recycle valuable elements in high-alumina coal fly ash (HACFA). In this study, an efficient and applicable approach was developed to recover Al selectively from HACFA, while most Fe recovery and removal were realized simultaneously in the leaching process. First, the thermodynamic stability of HACFA and the feasibility of Al leaching in HACFA were calculated. Then, HACFA was subjected to nitric acid pressure leaching to selectively extract Al. Under the optimal conditions (temperature of 220 °C, nitric acid concentration of 300 g/L, liquid-to- solid ratio of 4 mL/g, and duration of 2 h), 84.24% of the Al was extracted, and the leaching rate of Fe was 6.67%. The concentrations of Al and Fe in the leachate were 46.34 g/L and 0.52 g/L, respectively. The separation of Al and Fe was completed in the leaching process. The leach liquor was purified to further remove impurities, and Al2O3 was obtained after crystallization and pyrolysis of the aluminum-rich leachate. Leach residue was mainly composed of silica and Fe2O3. This process provides a feasible method for the recovery and utilization of valuable components in HACFA.

Spinel Ferrite Transformation for an Efficient Fe Removal from Circulating Fluidized Bed Fly Ash by Carbothermal Reduction at a Low Temperature.

Alumina (Al2O3) extraction from circulating fluidized bed (CFB) fly ash (CFBFA) is one of the most important pathways for value-added utilization. However, in CFBFA, impurity iron (Fe) normally coexists, resulting in complicated separation processes, low Al2O3 extraction efficiency, and substandard Al2O3-based products. How to remove Fe impurity effectively from CFBFA has become an important issue. For an effective Fe removal from CFBFA, spinel ferrite transformation by carbothermal reduction at a low temperature was discussed in the paper. The effects of the reduction temperature and reduction time on the removal efficiency of Fe and the recovery of aluminum (Al) as well as the removal of other metals were systematically investigated, and the transformation mechanisms of Fe-containing phases were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and a scanning electron microscope–energy dispersive spectrometer. The results showed that Fe in CFBFA was present in the form of weakly magnetic α-Fe2O3, leading to a Fe removal of about 17.1% after magnetic separation; however, the recovery efficiency of Al reached 97.4%. Weakly magnetic hematite (α-Fe2O3) could be converted to strongly magnetic spinel-type ferrite (MFe2O4) after carbothermal reduction at 700 °C for 60 min, and the Fe removal efficiency could reach 62.8% after magnetic separation; however, the recovery of Al was 81.2%, which was decreased compared to the recovery of Al under the condition without carbothermal reduction treatment. However, the carbothermal reduction–magnetic separation process did not have a major effect on the existing form and leaching behavior of Al, Li, and Ga. Simultaneously, it could be observed that some transition metal elements such as Mn, Cr, and so forth could be enriched in spinel-type MFe2O4 and removed after magnetic separation, which also provided a way for transition metal enrichment and extraction of transition metals from other tailings.

Energy-efficient leaching process for preparation of aluminum sulfate and synergistic extraction of Li and Ga from circulating fluidized bed fly ash

ABSTRACT Sequential leaching and extraction of precious metals from high aluminum (Al) circulating fluidized bed (CFB) fly ash in China, which associated with lithium (Li) and gallium (Ga), is one of the most significant ways for value-added utilization. However, industrial application has been limited due to serious corrosion of equipment, significant energy consumption, and complex purification processes. To sufficiently leach valuable metals from CFB fly ash, a novel energy-efficient sulfuric acid (H2SO4) leaching process using dilution heat was developed, and the effects of iron (Fe) amount in the raw materials on the extraction process of Al, Li, and Ga as well as the as-prepared Al-based products were studied to efficiently obtain the qualified aluminum sulfate (Al2(SO4)3) products. The leaching behavior of each target element was systematically investigated by the laboratory and pilot-scale experiments. The extraction efficiencies for Al, Li, and Ga were 95.2%, 94.2%, and 87.7%, respectively, when the acid leaching process was conducted at the temperature of 140°C for 2 h, with the H2SO4 concentration of 40% and the solid-to-liquid ratio of 1/3, In the Pilot-scale experiment, the temperature of the reaction system can reach 120°C, 140°C, and 160°C by regulating the amount of H2SO4 added to release different heat, and efficient leaching of the target elements was achieved by the energy-efficient sulfuric acid leaching process. To obtain qualified Al2(SO4)3 products from fly ash, carbothermal reduction magnetic separation, and acid leaching were used for Fe removal from raw fly ash, and the Fe content in the as-prepared Al2(SO4)3 products was only 0.45% and 0.29%, which reached the standards of Class II qualified products and Class II first-grade products, respectively. This paper might provide an energy-efficient process for efficient and high-value utilization of solid waste fly ash.