Addition Of NaOH Research Articles

Study on the Compressive Strength of Alkali Activated Fly Ash and Slag under the Different Silicate Structure.

Due to its high activation efficiency, waterglass has been widely used for alkali activations in geopolymer. In this study, the n(SiO2)/n(Na2O) (Ms) of waterglass was selected as the variable to investigate the role of the silicate structure on the mechanical properties of harden pastes. Ms was changed by the addition of NaOH to obtain the different silicate group, structure and experiments were performed by employing the liquid-sate 29Si nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and gel permeation chromatography (GPC) techniques. Furthermore, selected dissolution, scanning electron microscope (SEM-EDX), X-ray photoelectron spectroscopy (XPS) and FTIR experiments were used to measure the development of the amorphous gel and other materials with different curing condition. Results show that silicate structure of the waterglass was changed via the Si-ONa+ formation and the electric charge effect of Na+. Under the lower Ms waterglass, the Q0, Q1 and QC2 structure reverted to the main structure of the silicate group, which was kind of lower seize, molecule weight, linear or circular chain lower geopolymerization degree silicon structure. It would accelerate the geopolymerization speed of prepolymer formation. In addition, higher activity degree of Q0 and Q1 were useful to increase the formation amount of the gel structure with a low Si/Al ratio and size. Thus, silicate structure of waterglass controls the amorphous gel properties to adjust the compressive strength of alkali-activated materials.

Remediation of real soil polluted with hexachlorocyclohexanes (α-HCH and β-HCH) using combined thermal and alkaline activation of persulfate: Optimization of the operating conditions

Contamination of organic pollutants such as hexachlorocyclohexane (HCH) isomers poses a significant threat to human health and the environment. The alkaline activation of persulfate (PS) intensified by temperature to remediate surface sediments contaminated with HCH-wastes dumped by a lindane producing company (mainly α-HCH = 254 mg kg−1 and β-HCH = 99 mg kg−1) has been optimized. The treatment leads to promising results at 40 °C. Batch experiments were carried out to evaluate the influence of reagent addition order (simultaneous or sequential), reaction temperature (40–60 °C), liquid/soil ratio (VL/WS = 1 and 2), PS concentration (20–60 g L−1) and stirring rate (10–100 rpm) on chlorinated compound abatement. The reagent addition order did not affect the efficiency of the process. Raising either temperature or PS concentration significantly accelerates the hydrolysis rate of β-HCH and the generated trichlorobenzenes (TCBs) oxidation rate. Increasing the VL/WS ratio also accelerated the pollutant oxidation rate. At the selected operating conditions (pH > 12, simultaneous addition of PS and NaOH, 50 °C, PS = 40 g L−1, VL/WS = 2, NaOH/PS = 2 and 100 rpm), a conversion of α-HCH and β-HCH of 100% and 81%, and a dechlorination degree of 94% were achieved in 3 days. PS consumption was 29%; thus, the aqueous solution could be reused in a new batch of soil remediation, the separation of the aqueous and the soil phases being a rapid sedimentation step.

Adsorption of Horseradish Peroxidase on Metallic Nanoparticles: Effects on Reactive Oxygen Species Detection Using 2',7'-Dichlorofluorescin Diacetate.

The fluorescent probe 2′,7′-dichlorofluorescein diacetate (DCFH-DA) together with the enzyme horseradish peroxidase (HRP) is widely used in nanotoxicology to study acellular reactive oxygen species (ROS) production from nanoparticles (NPs). This study examined whether HRP adsorbs onto NPs of Mn, Ni, and Cu and if this surface process influences the extent of metal release and hence the ROS production measurements using the DCFH assay in phosphate buffered saline (PBS), saline, or Dulbecco’s modified Eagle’s medium (DMEM). Adsorption of HRP was evident onto all NPs and conditions, except for Mn NPs in PBS. The presence of HRP resulted in an increased release of copper from the Cu NPs in PBS and reduced levels of nickel from the Ni NPs in saline. Both metal ions in solution and the adsorption of HRP onto the NPs can change the activity of HRP and thus influence the ROS results. The effect of HRP on the NP reactivity was shown to be solution chemistry dependent. Most notable was the evident affinity/adsorption of phosphate toward the metal NPs, followed by a reduced adsorption of HRP, the concomitant reduction in released manganese from the Mn NPs, and increased levels of released metals from the Cu NPs in PBS. Minor effects were observed for the Ni NPs. The solution pH should be monitored since the release of metals can change the solution pH and the activity of HRP is known to be pH-dependent. It is furthermore essential that solution pH adjustments are made following the addition of NaOH during diacetyl removal of DCFH-DA. Even though not observed for the given exposure conditions of this study, released metal ions could possibly induce agglomeration or partial denaturation of HRP, which in turn could result in steric hindrance for H2O2 to reach the active site of HRP. This study further emphasizes the influence of HRP on the background kinetics, its solution dependence, and effects on measured ROS signals. Different ways of correcting for the background are highlighted, as this can result in different interpretations of generated results. The results show that adsorption of HRP onto the metal NPs influenced the extent of metal release and may, depending on the investigated system, result in either under- or overestimated ROS signals if used together with the DCFH assay. HRP should hence be used with caution when measuring ROS in the presence of reactive metallic NPs.

Positive Influence of Liquid Sodium Silicate on the Setting Time, Polymerization, and Strength Development Mechanism of MSWI Bottom Ash Alkali-Activated Mortars.

Setting time and mechanical properties are key metrics needed to assess the properties of municipal solid waste incineration (MSWI) bottom ash alkali-activated samples. This study investigated the solidification law, polymerization, and strength development mechanism in response to NaOH and liquid sodium silicate addition. Scanning electron microscopy and X-ray diffraction were used to identify the formation rules of polymerization products and the mechanism of the underlying polymerization reaction under different excitation conditions. The results identify a strongly alkaline environment as the key factor for the dissolution of active substances as well as for the formation of polymerization products. The self-condensation reaction of liquid sodium silicate in the supersaturated state (caused by the loss of free water) is the major reason for the rapid coagulation of alkali-activated samples. The combination of both NaOH and liquid sodium silicate achieves the optimal effect, because they play a compatible coupling role.

Performance and stability of biogas recirculation-driven anaerobic digestion system coupling with alkali addition strategy for sewage sludge treatment

Wastewater treatment plants are particularly challenging with the treatment and disposal of sewage sludge produced from the treatment units due to its high costs and environmental hazards. In this study, a biogas recirculation-driven anaerobic digestion (AD) system was developed with upward shear force being provided by biogas recirculation coupled with the alkali addition strategy, targeting biogas upgrading, sludge stabilization, and sludge flocculation simultaneously, thus reducing the sludge management costs. Compared to the conventional AD system, the novel biogas recirculation-driven AD system could achieve biogas upgrading with 10% higher CH4 content. Besides, the combination of NaOH and Ca(OH)2 addition strategy obviously improved sludge settleability and dewaterability compared to the single NaOH addition strategy. Owing to the attraction between negatively charged sludge particles and Ca2+ ions, the available Ca2+ in the former AD system may facilitate the re-flocculation and P immobilization in solid digestate, fix partial CO2 with less CO2 emission, and bridge with some sludge flocs. Moreover, 12.6% lower net cost for sludge management was achieved by this biogas recirculation-driven AD system together with the combination alkali addition strategy, which is regarded as a promising integrated multi-purpose system for sludge treatment.

Partial oxidation of phenolic wastewater using NaOH and Ni addition for hydrogen production and phenolics degradation in supercritical water

Phenolic wastewater is a challenge for traditional microbial treatment because of complex pollutant constituents and high concentration of aromatic hydrocarbons. Using H2O2 as oxidant, partial oxidation of phenolic wastewater using NaOH and Ni addition for hydrogen production and phenolics degradation in supercritical water was explored. It was found that higher oxygen ratio was advantageous for phenolics and other organic pollutants converting to gaseous products from supercritical water partial oxidation without any catalyst addition, but hydrogen production peaked at 0.5 oxygen ratio. Hydrogen gasification efficiency were raised to 75.68% within 0.5 oxygen ratio and 3.0% NaOH addition. Although separate Ni catalyst effectively enhanced the production of the gasifiable intermediate, hydrogen gasification efficiency appeared to a balance due to the enhancement of hydrogenation and methanation reactions. Both organic pollutants removal and hydrogen production enhancement were significantly improved under the combined NaOH-Ni catalyst, 85.24% TOC removal and 86.39% hydrogen gasification efficiency achieved within 1.0 NaOH + 2.0 Ni catalyst. There was very little cyclic compounds detected in liquid phase from combined NaOH-Ni catalytic partial oxidation, compared with individual addition. S, O and Si elements deposited in the surface of Ni catalyst, which have some negative effect on reuse. The positive effect of combined NaOH-Ni catalyst on organic pollutants removal and hydrogen production enhancement was demonstrated, which provided novel results and information that help to solve the problems in the process of toxic and high concentration organic wastewater treatment and facilitate the engineering application of supercritical water partial oxidation technology in the future.

Characterization of used oil distillate at various distillation temperatures as diesel fuel

Used oil is a hazardous and toxic waste. When this waste is disposed off into the environment, it harms the environmental. The conversion of used oil to diesel fuel candidates has been studied utilizing a simple distillation method. The distillation is carried out on used oil with a zeolite catalyst placed on a distillation tower. Distillation temperature variations of 360 °C, 380 °C, 400 °C are applied to used oil to produce fuel distillates. Tests were carried out on distillates in flashpoints using ASTM D93, Kinematic Viscosity using ASTM D445 and Cetane Index using ASTM D4737. The results of the calculated cetane index test showed the respective values of 48.44, 48.46 and 48.84. The viscosity at 40°C (mm 2sec) resulted in 1.57, 1.64, and 2.00. While the flashpoint value shows the number 27°C, the temperature variation does not affect the flashpoint value. The results of this test, when compared with Dirjen Migas Specification, the flashpoint value has not been fulfilled although with the addition of NaOH. A distillation temperature of 400°C only fulfils the minimum kinetic viscosity. In contrast, the Calculated cetane index has been fulfilled, with the largest value generated at a distillation temperature of 400°C.

Effect of NaOH concentration on microstructure and corrosion resistance of MAO coating on cast Al−Li alloy

Ceramic coating was prepared on cast Al−Cu−Li alloy by micro-arc oxidation (MAO) in a silicate electrolyte solution with additives including NaWO and NaOH. The effect of NaOH addition varying from 1 to 9 g/L on the microstructure and corrosion behavior of the coatings was investigated. The coating was characterized by XRD, XPS and SEM with respect to the composition and microstructures. The results show that NaOH promoted the formation of oxides in the reaction of MAO and contributed to the increase of layer thickness. Electrochemical tests (polarization curve and EIS) and mass loss test indicate that the corrosion resistance of the coated Al−Cu−Li alloy was improved with the increased addition of NaOH. Moreover, the results prove that the alumina coating formed in the electrolyte with 7 g/L NaOH showed the best corrosion resistance. The examination of the full immersion corrosion test presents the same result of corrosion resistance.

Optimization of NaOH concentration and cooking time in delignification of mature coconut (Cocus nucifera L.) coir

The main product of mature coconuts is coconut meat, while its by-products consisting of coconut water, shell fiber and coir. Coconut coir contains 75% fiber and 25% cork. The high value of fiber in coconut coir provides an opportunity to be utilized in making paper. Coconut fiber has a cellulose content of 26.6%-43.44% and lignin of 29.4%-45.84%. Due to the high lignin content, delignification process should be carried out which can be done using sodium hydroxide (NaOH). This study aims to obtain the optimal point of addition of NaOH and cooking time to produce optimal cellulose and lignin levels in the delignification of the mature coconut fiber pulping process. The research method uses the Response Surface Methodology (RSM) with two factors and two optimized responses. The experimental design was performed with a central composite design. The variables involved were NaOH concentration (5-15%) and cooking time (90-150 minutes). Two responses studied were lignin and cellulose content. The combination of these treatments produces the optimum point of NaOH concentration of 5% and cooking time of 150 minutes, resulting in 15.56% lignin content and 37.29 % cellulose content.

The Production of Zeolite Y Catalyst From Palm Kernel Shell for Fluid Catalytic Cracking Unit

Exorbitant costs of fluid catalytic cracking unit (FCCU) catalysts coupled with their ever-increasing demand have led researchers to develop alternative materials from indigenous sources. In this study, the zeolite Y component of the FCCU catalyst was synthesized from palm kernel shells. Leaching was carried out with the aid of citric acid to remove impurities. The synthesis process was done using alkaline hydrothermal treatment while varying reagent concentration and reaction time. The resultant products were characterized using XRF, XRD, FTIR, BET, and SEM analysis. The XRD and XRF showed a high silicate content level, while an 85% reduction in iron oxide impurities was observed after leaching. The process carried out at a duration of 9 hours, a temperature of 80°C with a NaOH molarity strength of 2 mol/L, had the highest SiO2 and Si/Al ratio value. A spongy, porous zeolite crystal was formed with the presence of hydroxyls in its sodalite cage. All samples had a combination of types II & I adsorption isotherms, Si/Al ratio of 2–5, and specific surface area within 80–260 m2/g, which indicates the presence of intermediate mesostructured Zeolite Y catalyst. Synthesized zeolite Y showed a more significant gap in its structural formation as the addition of NaOH decreased the grain size by 14.3%. FTIR highlighted the significant functional groups present in the novel compound, which, when compared to previous works, proves its suitability.

Duality of foam stabilization

Can a foam reversibly switch between particle and surfactant stabilization? Sure it can. Foams are usually stabilized either by surfactant or hydrophobic nanoparticles. Their combination often worsens the stability of the foam, with surfactant adsorption on the particles causing complex behavior. A system that shifts between both types of mechanisms is desirable both for fundamental studies and practical applications. We developed a system consisting of aqueous solution of 0.1 mM sodium dodecyl sulfate (SDS) + 1.23 mM ZnSO4 + 1.23 mM ethylenediaminetetraacetic acid (EDTA). The foam was produced by the shaking method. The pH value was varied by small additions of HCl or NaOH. We tuned the foam lifetime from 15 to 20 s (at pH = 3 – 6), to ~ 180 s near pH = 1, and increase it in the pH range of 6–12, reaching 15 min at pH = 12. This is due to emerging of nanoparticles of Zn(OH)2 at pH > 8, smoothly switching between the stabilization mechanisms. The nano-suspension of Zn(OH)2 is transparent due to the low aggregation. The low cost (<$1 per metric ton) and the large timescales makes our system desirable for industrial applications.

Combined effect of NaAlO2 and NaOH on the early age hydration of Portland cement with a high concentration of borate solution

The early age hydration of ordinary Portland cement in 5 M borate solution, with or without the addition of NaAlO2 and/or NaOH, was investigated. Hydration was measured using calorimetry, X-ray diffraction, thermogravimetric analysis, 11B and 27Al magic angle spinning NMR analysis, and scanning transmission electron microscopy. The purpose of this study was to reveal the mechanisms behind the retardation caused by a high concentration borate solution and the restoration of hydration through the combined addition of NaOH and NaAlO2. Amorphous ulexite, which formed on the surface of the cement particles and prevented the further dissolution of anhydrous phases, was identified as the retardation product. The mechanism of the combined addition of NaAlO2 and NaOH in overcoming retardation was to transform amorphous ulexite into B-AFt and gowerite (CaB6O10·5H2O). Formation of gowerite is favorable because of the much higher boron immobilization capacity in weight percentage, comparing to usual boron-containing phases reported previously.

Optimasi Sintesis Methyl Cellulose (MC) dari Biji Salak (Salacca edulis Reinw) Pondoh Super

Snake fruit (Salacca zalacca) is one of the typical fruits from Indonesia. Pondoh is one of the snake fruit species largely found in Yogyakarta. The kernels of snake fruit are wastes, but contains a lot of cellulose. Cellulose can be processed into methyl cellulose And be used as food additive. This study aimed to understand the optimized the optimizing synthesis of methyl cellulose through the concentration of NaOH, dimethyl sulfate and reaction temperature. The study was conducted by extracting cellulose using 4 % NaOH concentrations. Dehemicellulose and bleaching were done to dilute hemicellulose and lignin. The optimization of methyl cellulose was done using Response Surface Methodology with various concentrations of NaOH (10, 15, 20, 25, 30%), dimethyl sulfate (2, 3, 4, 5, 6 ml), and temperature (45, 50, 55, 60, 65°C). NaOH could change cellulose crystalline region and formed Na-cellulose. Dimethyl sulfate can be acted as substitution agent, while temperature controlling plays role to obtain appropriate conditions for reaction. The results showed that the use of NaOH concentration, dimethyl sulfate and temperature affected the degree of substitution, OHC and lightness. The addition of NaOH and dimethyl sulfate in producing methyl cellulose had more effect on the increasing of degree of substitution than temperature treatment. The optimum condition of methyl cellulose were 0.91% NaOH; 3.52 ml of dimethyl sulfate, at 46.51°C temperature.

Efficient aramid fiber monomerization using alkaline subcritical water

To establish the chemical recycling of copoly(p-phenylene-3,4′-oxydiphenylene terephthalamide) fibers (i.e., Technora®), their hydrolysis in pure supercritical, pure subcritical, and alkaline subcritical water was investigated, and an efficient purification method to recover the constituent monomers in high yields and > 99% purity was developed. Technora® hydrolysis in pure supercritical water required high temperatures, thus leading to monomer degradation and hence low monomer yields. Similarly, Technora® hydrolysis to monomers was incomplete in pure subcritical water, which also resulted in low monomer yields. In contrast, the addition of NaOH to subcritical water promoted fiber decomposition, rendered hydrolysis irreversible, and prevented degradation of the produced monomers by allowing the reaction to proceed at lower temperature. Thus, when subcritical water containing 10 equivalents of NaOH per Technora® unit was used at 250°C and 4 MPa for 3 h, the fibers decomposed with 100% efficiency, and the monomers were recovered in 88–99% yields. The rate of Technora® hydrolysis in a neutral medium of either pure supercritical or subcritical water was represented well using the cylindrical-surface reaction model. This model was adjusted to describe the reaction in an alkaline medium, i.e., subcritical water containing NaOH, by considering the decrease in both NaOH concentration and Technora® surface area.

Effect of Alkali Concentration on Strength Development in Jointly Activated Pond Ash-GGBFS Mixtures through Geopolymeric Reactions

This paper presents research findings of the effect of mutual activation of pond ash and ground granulated blast furnace slag (GGBFS) in the development of unconfined compressive strength (UCS) with the addition of NaOH as an alkali activator at concentrations of 2, 4, 6, 8, and 10M. Compressive strength tests were carried out on alkali-activated samples of pond ash-GGBFS mixtures compacted at their respective optimum moisture content (OMC), maximum dry density (MDD) and were kept cured in polythene at ambient temperature. The strength of un-mixed pond ash activated with NaOH at molarity of 6 and above shows significant UCS when curing time increases up to 56 days. However, a great increase in strength of geopolymer mixtures was observed with increase in GGBFS content. The majority of samples of pond ash-GGBFS mixtures activated at 4M NaOH showed the highest strength in comparison to higher concentrations of 6, 8, and 10M NaOH with increasing GGBFS content and curing time. To confirm the occurrence of geopolymeric reactions during alkali interaction with pond ash-GGBFS mixtures, the samples were also characterized by the Fourier Transform Infrared Spectroscopy (FTIR), X-ray Powder Diffraction (XRD) and Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis (SEM/EDX) data. In the present study the alkali activated pond ash-GGBFS mixtures have also been tried to evaluate their utilization as construction materials in civil engineering applications.

Recycling Technology for Waste Glass Fiber Reinforced Plastics (GFRP) Using Pyrolysis with NaOH

Glass fiber reinforced plastics (GFRP) are composite materials with high strength and flame retardancy, and the disposal process is expensive to cause illegal dumping. Therefore, new recycling technology of waste GFRP are desired. In this study, recycling of waste GFRP using pyrolysis with sodium hydroxide (NaOH) under an inert atmosphere was attempted by gasification of resin and conversion of glass fiber into soluble sodium silicate. The pyrolysis behavior of GFRP, the characteristics of the obtained residue, the composition and the yield of generated gas, and the silica extraction into the solution were investigated. As a result, the gasification of the resin and the conversion of the glass fiber into soluble sodium silicate were promoted by pyrolysis with NaOH. It was confirmed that the gas yield, especially flammable gases (H2 and CH4), and the silica extraction increased and the residual ratio decreased as the increase of the heating temperature, NaOH addition and heating time.

Continuous Thermal Stripping Process for Ammonium Removal from Digestate and Centrate

The state of California has passed legislation to divert organic materials from landfills to reduce the emission of methane to the atmosphere. A large amount of this source separated organic (SSO) material is expected to be used as a feedstock for anaerobic digestion processes. Based on a review of properties for likely SSO feedstocks, it is clear that while SSO are high in volatile solids, they are also concentrated sources of nutrients (principally, ammonium). When SSO feedstocks are digested, these nutrients are released into the digestate, where ammonium can cause problems both within the digester and in downstream treatment processes. The focus of this paper is on the performance of two pilot studies designed to remove ammonia from a digester effluent. The process used in the study is a thermal stripping column with tray configuration, operating under a vacuum. In the first study, food waste digestate was treated as a slurry in the stripping column with and without NaOH addition. At process temperatures near 90 °C, the performance with and without caustic was similar. In the second study, centrate from a co-digestion facility, that blends food processing waste with wastewater process solids, was treated in the same thermal stripping column under the same conditions and without chemical addition. The results from both studies, which can be described using the same performance curves, are presented and discussed in this paper.

Influences of cation valence on water absorbency of crosslinked carboxymethyl cellulose

Anti-drought is a global challenge. The addition of superabsorbent polymers (SAPs) in soil can lower down the water percolation and evaporation. However, the salt-tolerance and repeating water absorbency (RWA) of prepared SAPs have not satisfied the requirements for implementation. This research investigated the influence of cation valence (Na+, Ca2+ and Al3+) on the structural variations of a crosslinked carboxymethyl cellulose (CCMC) using carboxymethyl cellulose (CMC) cross linked by epichlorohydrin (ECH). The results showed that higher addition of NaOH resulted in higher water absorbency (WA) due to the existence of more carboxyl group. The prepared CCMC sample with 5% CMC and 3% NaOH (CCMC53) was a qualified SAP with WA of 969.0 g/g in deionized water. The salt resistance and the hydrophilicity of sample CCMC53 decreased with the increase of cation valence in the solution. The introduction of Na+ resulted in the replacement of H+ from carboxyl group in sample CCMC53-Na. The coordination of carboxyl group and Ca2+ was bidentate chelating and tridentate bridging for carboxyl group and Al3+. The introduction polyvalent cations benefited the stabilization of carboxyl group, however, retarded the swelling ability of sample CCMC53 and hence resulted in lower WACS. The RWA of sample CCMC53 in deionized water and salt solution dropped the most in the first absorption cycle and then reached constant after a few more cycles. It was necessary to control the first swelling degree of SAP in order to keep the RWA at a higher level.

A New Protocol Using Acidification for Preserving DMSP in Macroalgae and Comparison with Existing Protocols.

Dimethylsulfoniopropionate (DMSP) plays many important physiological and ecological roles in macroalgae. The most common method to measure DMSP is by gas chromatography analysis of the dimethylsulfide (DMS) produced after NaOH hydrolysis (pH>12). Storage of DMS, however, is not recommended for more than a week. We investigated if acidification can be a suitable method to preserve DMSP in macroalgal samples over three months of storage, compared to widely used protocols such as drying and freezing at -20°C. The DMSP content of green (Ulva sp. and Ulva compressa), red (Chondrus crispus), and brown (Bifurcaria bifurcata) macroalgae were analyzed: 24h after NaOH addition (control values); and after acidification (0.2mol · L HCl-1 ) for 24h of fresh material, followed by NaOH addition for 24h. These values were compared to measurements after 3-month storage of samples that had been either dried in a heater (60°C for a night, and storage at room temperature), or frozen at -20°C, or kept in 0.2mol · L HCl-1 . There was no significant difference between DMSP measurements on freshly collected material and after acidification of the samples, whether 24h later or after 3months of storage. This was in contrast to 3-month storage protocols involving overnight drying at 60°C (75-98% DMSP loss), and to a lesser degree freezing at -20°C (37-80% DMSP loss). We thus advise to acidify macroalgal samples for preservation over long periods of time rather than drying or freezing, when assaying DMSP content.

Investigation of mechanical and thermal activation on metal extraction from red mud

Red mud is an inevitable and under-utilized byproduct of the aluminium industry. The current study evaluates the effect of mechanical and thermal activation on the acid leaching of red mud. The acid leaching of the pretreated product is followed by acid-base treatment to precipitate the dissolved aluminium values from solution and enrich the residue with Fe and Ti values. Mild acid leaching yielded ~76% aluminium dissolution with 81% silicon removal. The direct acid leaching resulted in dissociation of sodium aluminosilicate; meanwhile, gibbsite phase remains in the residue. The mechanical milling for 1 h enhanced the aluminium dissolution to 89.5% with silicon and iron dissolution of 98.5 and 9.6%, respectively. The silica and iron oxide values were separated before HCl leaching by thermal pretreatment step using microwave heating with NaOH and carbon additives respectively. The sodium silicate and sodium aluminate phases formed during alkali thermal treatment resulted in ~33% silicon and ~ 27% aluminium removal by water washing. Meanwhile, HCl leaching of the water wash residue resulted in 82% aluminium dissolution with 70% recovery and residue containing ~52% Fe2O3, and 28% TiO2 is obtained. The carbothermal reduction yielded iron-rich magnetic concentrate having 48% iron grade with 20% metallic iron, and ~ 83% iron recovery. Leaching of the non-magnetic fraction containing hercynite and fayalite as the major aluminium and silicon bearing phases resulted in 81% aluminium dissolution with overall aluminium recovery of only 37%. Mullite formation is also observed in the precipitate with a high Al/Si molar ratio. The carbothermal route was found as an energy-efficient route, whereas the mechanical milling route yielded maximum Al extraction of ~90% with Fe and Ti content of 41.1% and 16.8% in the residue.