Mud Waste Research Articles

UTILIZATION OF BAUXITE RESIDUE IN SELF-COMPACTING CONCRETE AND EVALUATE RHEOLOGICAL BEHAVIOR AND MECHANICAL CHARACTERISTICS

This thesis aims to investigate the potential utilization of bauxite residue, by-product of aluminum production, in self-compacting concrete (SCC) and evaluate its impact on the rheological behavior and hardened state characteristics of the resulting concrete. Bauxite residue is a red mud waste generated during the extraction of alumina from bauxite ore. Finding sustainable solutions for its disposal or reuse is crucial for environmental and economic reasons. The research methodology involves laboratory experiments to determine the optimal proportion of bauxite residue in SCC mixtures. The rheological properties of fresh concrete, such as slump flow, flow time, and passing ability, will be assessed using standard tests. Additionally, the effects of bauxite residue on key mechanical properties of hardened concrete, including compressive strength, flexural strength, and durability, will be examined. It is reveled from the result that as the red mud percentage increases workability also increases but mechanical properties increases upto 30 percentage of red mud above 30% it get decreases. Key word – Red Mud, Workability, Self-Compacting Concrete, Mechanical Properties

Waste to wealth: Facile activation of red mud waste and insights into industrial reactive dye removal from wastewater

Reactive dyes, widely applied in the textile industry for their vibrant colors, excellent fastness, and ease of application. Their presence poses multifaceted threats to aquatic ecosystems and health risks, including skin irritation, allergic reactions, respiratory problems, and increased cancer risk. In response to these challenges, this study explores the potential of acid-activated red mud, an industrial solid waste by-product from the aluminum industry, as an economical adsorbent for the removal of commercial reactive dyes from industrial wastewater. The robustness of the employed Box-Behnken design is evidenced by the high determination coefficient (0.997) and correlation coefficient (0.994) values. The optimum acid activation condition was determined to be 385 K activation temperature, 91 min activation time, and 2.5 N HCl acid concentration, resulting in a 99.24 ± 0.04 % removal efficiency for reactive dyes. Analysis of X-ray Diffraction and X-ray Fluorescence data revealed that the activation process significantly increased the composition of Al and Fe compounds. This enhancement was achieved by eliminating compounds that block active sites and improves the overall surface area from 37.35 m2/g to 173.81 m2/g. Detailed morphological analysis, conducted through high-resolution transmission electron microscopy and scanning electron microscopy, reveals profound transformation in the surface structure. The study primarily focuses on removing four commercial reactive dyes: Reactive Blue 2 (RBL-2), Reactive Black 5 (RBK-5), Reactive Red 24 (RR-24), and Reactive Yellow 15 (RY-15). These dyes demonstrate maximum adsorption capacities of 118.24 mg/g, 121.02 mg/g, 129.19 mg/g, and 142.64 mg/g, respectively. In order to comprehend the interactions between dye molecules and the adsorbent, a first principle based model was employed to simulate the adsorption kinetics.

A review on sustainable utilization of bauxite residue (red mud) for the production of mortar and concrete

The establishment of many industries produces a large amount of by-products in solid, semi-solid, and liquid form because industrial waste can be toxic or non-toxic in nature, causing serious damage to the environment. India has a vast network of existing industries, and in the future, many more will produce millions of tons of various by-product materials. Pollution and disposal problems can be reduced by using these materials effectively in civil engineering projects. This paper examined the evaluation of red mud produced in the alumina processing industry to determine its suitability as a construction material based on physical, chemical, and other civil engineering properties. Red mud is the fine-grained residue that remains after alumina has been extracted from bauxite ore. About 10 million metric tons of red mud waste is generated every year in India, causing very serious and alarming environmental problems. Neutralizing this red mud would be very beneficial, as it would reduce pollution. In addition, the neutralized red mud could be reused in construction mixes and as a raw material. The physical, chemical, and geotechnical characteristics of these waste materials were critically evaluated for this purpose. It was found that red mud can be used as building material.

APLICAÇÃO DA LAMA DE BENEFICIAMENTO DE ROCHAS ORNAMENTAIS COMO CATALISADOR NO PROCESSO FOTO FENTON PARA A DESCOLORAÇÃO DE CORANTE EM SOLUÇÃO AQUOSO

APPLICATION OF ABRASIVE MUD FROM THE PROCESSING OF ORNAMENTAL ROCKS AS A CATALYST IN THE PHOTO FENTON PROCESS FOR THE DECOLORIZATION OF DYE IN AQUEOUS SOLUTION. The extraction and processing of ornamental rocks generate a very significant amount of waste, representing an environmental and public health problem. The residue is a fine-grained compound by rock powder and inputs used in the processing process have a potential economic value. The present study was carried out to evaluate the efficiency of the waste generated in the discoloration of an aqueous solution containing methylene blue dye, such as alternative for treating textile effluents. The samples were characterized by X-ray diffraction, inductively coupled plasma optical emission spectroscopy, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The catalytic properties of the samples were evaluated in the Fenton and photo Fenton reactions at pH 3 and natural pH. The best decolorization efficiency (≈ 95%) was achieved using the GRM catalyst at pH 3, after 5 min of photo Fenton reaction. Importantly, owing to its excellent structural and chemical stability, the samples showed a decolorization efficiency above 95% after 5 consecutive cycles of 30 min of reaction. This innovative strategy not only offers a new prospect for the rational disposal of abrasive mud waste, but also contributes to minimizing environmental impacts, promoting sustainable development in the stone industry.

The role of red mud and cow manure for sustainable post-gold mining land rehabilitation

The detrimental ecological impact of unauthorized gold mining in Indonesia is significantly profound, notably apparent in the nutrient-deficient, sandy soils with low pH resulting from the process. These conditions contribute to considerable land productivity decline, especially in West Kalimantan. In response to this challenge, the current study proposes an inventive approach for soil reclamation using red mud residue, derived from bauxite ore extraction, and cow manure as restorative elements. This research delves into a novel soil restoration technique that employs red mud waste (a residual from ore refinement) in conjunction with cow manure as ameliorative agents. A distinct amalgamation of 0.2 kg of red mud and 3 kg of cow manure (T2R3) showcased superior results. The incorporation of this blend resulted in a significant increase in soil pH by 0.93 units, an increase in macronutrient content ranging from 82.84%-503.07%, and plant growth (plant height and stem diameter) increased between 32.85%-54.31% in the treatment with 0.2 kg of red mud and 3 kg of cow manure (T2R3) compared to the lower treatment of 0.1 kg of red mud and 1 kg of cow manure (T1R1). These changes were evident, indicating improved soil fertility and the potential for increased crop yield

Red mud and foundry sand industry wastes for reducing NOx in plasma activated diesel exhaust

Solid waste in association with plasma was explored as an alternate to commercial catalyst/adsorbents. We have demonstrated reuse of foundry sand and red mud wastes for adsorption of gaseous pollutant from plasma treated diesel exhaust. A novel dielectric barrier discharge reactor with dual metal film is designed to explore the oxidation potential of surface discharge plasma effect onto the exhaust. The metal film was subjected to high voltage pulse/AC energization to assess the effect of plasma in oxidising NO to NO2. A separate reactor filled with industry wastes was cascaded with plasma reactor to test its efficacy in NO2 adsorption. It was observed that some amount of NO was also reduced owing to some visible light-enabled photocatalytic activity. About 85 % NOx (oxides of nitrogen) reduction was observed with red mud waste compared to half of that with foundry sand.

Study on mechanical properties and microstructure of fly-ash-based geopolymer for solidifying waste mud

The chemical solidification of construction waste mud presents a strategy for mitigating environmental concerns as well as addressing problematic geotechnical engineering properties. The present study explores the efficacy of utilizing fly ash (FA)-based geopolymer, activated by calcium carbide residue (CCR) and sodium silicate solution (NS), for waste mud solidification. An unconfined compressive strength (UCS) test was conducted to ascertain the optimal CCR/NS ratio. Supplementary tests were executed to examine factors such as water content, pH level, X-ray diffractometry (XRD), scanning electron microscopy (SEM), and natural dehydration. According to the UCS results, an optimal 28-day strength of 2.2 MPa was observed when employing a CCR/NS ratio of 6:4. A notable reduction in the water content of the mud was achieved in the short term, with the most effective results observed at a pH level of 12. Microstructural analyses indicated that calcium silicate hydrate (CSH) and aluminosilicate-Na hydrate (NASH) acted as the primary cementitious products, filling pores and creating bonds with particles to facilitate strength development. Variations in crack morphology and water content during the natural dehydration process were also analyzed for both solidified and untreated mud. The findings suggest that solidified mud holds promise for application in subgrade engineering projects, potentially diverting significant volumes of waste mud and industrial by-products such as CCR and FA away from landfills.

Influence of Some Key Parameters on the Efficiency of Flocculation–Solidification–Filter Press Combined Method for Sustainable Treatment of Waste Mud Slurry

The flocculation–solidification–filter-press combined method is a new type of method for treating waste slurry that combines flocculation and chemical curing with a mechanical filter press. Among these processes, the mechanical filter-press process is key to the efficient disposal of waste engineering slurries by the flocculation–solidification–filter-press combined method. In the mechanical filter-press process, parameters including the initial thickness of filtration mud, the magnitude of filtration pressure, and the duration of press filtration have important impacts on the dewatering and strength after subsequent curing. In this work, a series of laboratory tests were conducted to study the influence of filter-press parameters on flocculated–solidified mud by measuring the properties of treated and cured mud. The test results showed that the initial mud bag thickness is an important factor in the mud treatment effect. As the initial mud bag thickness increases, the greater the water content of the mud at the end of the filter-press process after applying the same amount of time and the same amount of pressure, the lower the post-conservation strength will be. The increase in filtration pressure and filtration time within a certain range can reduce the water content of the mud brick after filtration and significantly improve its shear strength. In the actual process of filtering in the project, the thickness of the initial mud bag should be no more than 140 mm, the filtration pressure is about 0.35 MPa, and the filtration time is suitable for 2 min.

Biomass-derived carbon/iron composite (FexOy-BC (RM)) with excellent Cd(II) adsorption from wastewater – Red mud resource utilization

Red mud is an industrial by-product produced in the process of alumina refining. It contains many iron elements, and the traditional resource utilization method is to extract it. This study took an alternative approach by using red mud's iron content as the substrate to synthesize a novel iron-biochar adsorbent for removing heavy metals from wastewater. Walnut shell biochar was reacted with the iron in red mud via an in-situ reduction–oxidation process to produce an iron-carbon composite adsorbent (FexOy-BC). A series of characterization analyses (e.g., SEM, FTIR, XPS, etc.) and batch adsorption experiments were conducted to investigate the properties and Cd(II) removal performance of the adsorbent, respectively. Response surface methodology was further employed to optimize the adsorption conditions, identifying the ideal 6 g/L adsorbent dose, 10 mg/L initial Cd(II) concentration (C0), and pH 6. The optimized quadratic model demonstrated excellent fit, with an average Cd(II) removal efficiency of 92.59 % under optimal conditions. The adsorption mechanism, renewability, and preliminary cost-benefit analysis indicate that FexOy-BC has the potential to be a highly efficient and sustainable adsorbent. In summary, the new method can recover resources from red mud waste and synthesize heavy metal adsorbents, which comprehensively solves two long-standing problems of industrial waste.

Influence of mud waste and straw grass addition in fired bricks production: technical properties evaluation

Influence of mud waste and straw grass addition in fired bricks production: technical properties evaluation

Study on the removal of iron (II) and manganese (II) in acidic mine drainage by red mud: Performance and mechanism.

Red mud is an environmental burden during the alumina production process. To mitigate the hazards associated with red mud storage, this study investigated the utilization of alkaline red mud as a treatment agent for acidic mine drainage (AMD) with high concentrations of Fe(II) and Mn(II). This study explored the influence of reaction times, addition amounts of red mud, and pH values on the removal efficiency of Fe (II) and Mn(II) from high-concentration AMD. Various parameters such as suspended solids levels, effluent pH, and zeta potentials were measured to meet discharge standards. The adsorption mechanism of red mud was examined using SEM, XRD, EDX, XPS, and 3D-EEM analysis. Optimal conditions were determined as a reaction time of 2 h, pH value of 5.01 and the addition of 100 g/L red mud, achieving effective removal of Fe(II) (reduced from 1000 to 0.224 mg/L) and Mn (II) (reduced from 20 to 1.03 mg/L). The treated AMD meets discharge standards with reduced suspended matter content of 37.4 mg/L. These findings provided valuable insights for the utilization of red mud waste in engineering applications.

Study on the Factors Affecting the Performance of a Pressure Filtration–Flocculation–Solidification Combined Method for Mud Slurry Treatment

A pressure filtration–flocculation–solidification combined treatment possesses great potential for the reutilization of the waste mud slurry generated from diverse construction projects as filling material due to its versatility and high efficiency. However, very limited existing studies have focused on the factors affecting pressure filtration’s efficiency. In this paper, a calculation model for compression filtration is established based on laboratory pressure filtration model tests and one-dimensional large-strain consolidation theory. The influence of various parameters on pressure filtration’s efficiency is analyzed, and favorable values for these parameters are recommended. The results show that an increased initial mud cake thickness significantly increases the dewatering time and reduces the treatment’s efficiency. A lower dewatering time and higher efficiency can be achieved by increasing the filtration pressure, but the efficiency improvements become limited after reaching the critical pressure threshold. For the mud slurry used in this study, the optimal values for the initial mud slurry bag thickness, filtration pressure, and dewatering time are 240 mm, 1.0 MPa, and 30 min, respectively, yielding a final mud cake water content of 58.7% after filtration.

Research on closed-loop utilization of engineering waste mud in engineering sites

Abstract The large amount of waste mud generated during construction projects makes it difficult to implement closed-loop on-site treatment, resulting in the inability to achieve zero emissions, which not only wastes land resources but also pollutes the environment. This article first studied the flocculation effect and mechanism of two flocculants. Then, the treated sediment was used to prepare fluidized solidified soil, and the effect of flocculants in the sediment on the performance of fluidized solidified soil was studied. Finally, this technology of flocculation and re-solidification was applied in engineering. The results showed that the composite effect of adding PAC flocculant first and then APAM flocculant in the mud had the best mud-water separation effect. The soil was combined with the flocculants to prepare fluidized solidified soil that can effectively improve the strength and water stability of the solidified soil. Through engineering applications, it has been proven that closed-loop utilization of engineering waste mud can be achieved on-site. Therefore, this work provides a new method for achieving zero emissions through closed-loop utilization of engineering waste mud on-site and innovative experience for the construction of “waste-free cities”.

Efficient synthesis of forsterite via high-temperature thermochemical reactions from boron mud waste without briquetting

Forsterite is a highly demanded material in high-temperature industries due to its superior performance in elevated temperatures. This study proposes synthesizing high-quality forsterite via high-temperature thermochemical reactions using abundant boron mud waste. The new synthesis method capitalizes on the high reactivity of fine raw powder materials, enabling the reaction to reach completion at low temperatures rapidly. The chemical characteristics, microscopic morphology, and structure of synthesized samples are systematically studied using XRD and SEM. The results confirm that boron mud can be efficiently transformed into forsterite after 10 min of reactions at 1500 °C. The synthesized products attain over 98.7% densification and contain more than 85.0% forsterite with well-developed grains. The activation energy of forsterite grain growth in the 1100–1500 °C temperature range is 165.5 kJ/mol. This study provides a low-cost method for producing forsterite and an efficient and environmentally friendly solution for treating solid waste.

Preparation of Mesoporous γ-Alumina from Red Mud Waste

In this paper, a novel green and cost-effective synthesis method in this field is presented. Mesoporous γ-alumina was obtained by inorganic in situ crystallization, and sodium aluminate as an aluminum origin was abstracted from red mud. The influence mechanism of the reactant ratio of NaHCO3 to NaAlO2, the reaction temperature and the concentration of the template was systematically investigated. As indicated by the results, the obtained mesoporous γ-alumina possesses extensive specific surface areas, narrow pore size distribution, nearly spherical particle morphology and wormlike structure pores. This green and economical synthesis method can be used for the preparation of alternative mesoporous or various porous materials as well.

INFLUENCE OF CEMENT CONTENT AND MOISTURE CONTENT ON THE PULLOUT-INTERFACE PROPERTIES OF GEOGRID-SOLIDIFIED WASTE MUD

In engineering, waste mud is often used as a filling material after a solidification treatment. Geogrids, being excellent geotechnical engineering materials, are often used for soil reinforcement. In this work, a pullout test that considered the influence of different waste-mud moisture contents and cement contents was conducted to investigate the interface characteristics of geogrid-solidified waste-mud-reinforced soil. Then, the relationship between the pullout force and displacement, and the variations in the cohesion, friction angle and quasifriction coefficient were analysed. The results showed that the pullout force-displacement curve represented a strain-softening pattern. With the increasing moisture content, the peak pullout force, interfacial cohesion and quasifriction coefficient decreased gradually, but the internal friction angle did not change substantially. With the increasing cement content, the peak pullout force, interfacial cohesion, internal friction angle and quasifriction coefficient increased gradually. The peak pullout force was linearly correlated with the change in the moisture content and logarithmically correlated with the change in the cement content. Compared with the moisture content, the reinforcement-soil interface was more affected by the cement content. This study provides guidelines for the mixture design of reinforced solidified waste mud.

Highly efficient catalytic ozonation degradation of levofloxacin by facile hydrogenation-modified red mud wastes

Iron-rich red mud (RM) is a potential catalyst. However, as industrial waste, is strongly alkaline, low effectiveness, and safety concerns are problems that cannot be ignored, it is urgent to mine out a reasonable disposal and utilization technology for the waste. In this study, an effective catalyst (H-RM) was obtained by facile hydrogenation heating modification of red mud. Then above-prepared H-RM was applied in the catalytic ozonation degradation of levofloxacin (LEV). The H-RM exhibited more remarkable catalytic activities than the RM in terms of LEV degradation, and the optimal efficiency can reach over 90% within 50 min. The mechanism experiment proved that the concentration of dissolved ozone and hydroxyl radical (•OH) significantly increased, which enhanced the oxidation effect. Hydroxyl radical played a dominant role in the degradation of LEV. In the safety test, it is concluded that the concentration of total hexavalent chromium (total Cr(Ⅵ)) in the H-RM catalyst decreases and the leaching concentration of water-soluble Cr(Ⅵ) in aqueous solution is low. The results indicated that the hydrogenation technique is an available Cr (Ⅵ) detoxification method for RM. Moreover, the H-RM has excellent catalytic stability, which is beneficial to recycling and maintains high activity. This research provides an effective means to fulfill the reuse of industrial waste as an alternative to standard raw materials, and comprehensive utilization of the waste to attain the purpose of treating pollution with wastes.

Mode of innovative green production for concrete engineering: life cycle assessment of accelerators prepared from aluminum mud wastes.

In this study, two types of liquid alkali-free accelerators were prepared by aluminum sulfate (AF1) and aluminum mud wastes (AF2), and the life cycle assessment (LCA) in the preparation of AF1 and AF2 was compared. The LCA was considered from cradle to gate including raw materials used, transportation, and accelerator preparation based on the method ReCiPe2016. The results indicated that AF1 had a higher environmental impact in all midpoint impact categories and endpoint indicators than that of AF2, and AF2 reduced 43.59% emission of CO2, 59.09% emission of SO2, 71% consumption of mineral resources, and 46.67% consumption of fossil resources than that of AF1 respectively. As an environment-friendly accelerator, AF2 had a better application performance than traditional accelerator AF1. When the dosage of accelerators was 7%, the initial setting times of cement pastes containing AF1 and AF2 were 4 min 57 s and 4 min 04 s respectively, the final setting times of cement pastes containing AF1 and AF2 were 11 min 49 s and 9 min 53 s respectively, and the compressive strengths at 1 d of mortars containing AF1 and AF2 were 7.35 MPa and 8.33 MPa respectively. This study aims to provide technical feasibility and environmental impact assessment for exploring new avenues of preparing environment-friendly liquid alkali-free accelerators with aluminum mud solid wastes. It has great potential in reducing carbon and pollution emissions and has a greater competitive advantage due to great application performance.

Efficient utilization of red mud waste via stepwise leaching to obtain α-hematite and mesoporous γ-alumina

Utilizing the red mud sustainably is now a challenging issue. Red mud due to its wide production, presence of some radioactive elements, high alkalinity, and salinity, has a dramatic potential to contaminate soil and groundwater. Notwithstanding its drawbacks, Red mud consists several elements, including Ca, Al, Ti, Si, and Fe, in various mineral forms. In this study, stepwise leaching was applied as a proper method to separate and purify the main valuable elements using available and affordable HCl. The pre-leaching step under optimized conditions using HCl (0.2 M) at room temperature for 2 h removed 89% of the calcium content from red mud. To selectively remove the solid silica, the residue was treated with concentrated HCl (3.0 M, L/S of 20 mL/g) at 95 °C, resulting in the dissolution of iron and aluminum content with up to 90% efficiency. After precipitation of the Fe3+ and Al3+, they were characterized using FT-IR, BET, EDS, XRD, SEM and TEM monographs, confirming the formation of nanosized hematite (α-Fe2O3) and mesoporous gamma alumina (γ-Al2O3). Consequently, inexpensive red mud was converted into highly valuable nano-sized metal oxides using simple, sustainable techniques and cheap reagents. Moreover, this technique generates the lowest amounts of waste during the leaching process and all reagents can be recycled for further uses, making this method a sustainable utilization.

Red mud waste/nanoclay/polystyrene‐modified epoxy hybrid composites: Mechanical, thermal, and flammability properties

AbstractIn this study, bisphenol A‐type epoxy (ER) and epoxy phenol novolac resins (EPN) with two amine‐type curing agents (KH 816 and IPOX EH 2041) having different total amine values were selected. The mechanical properties and density of the EPN resin were found higher in the case of both curing agents. EPN was modified with polystyrene (EPN‐PS) and used as a matrix using an IPOX hardener. Nano‐ and hybrid composites were prepared with pristine and modified with tetramethylammonium chloride nano montmorillonite (NC and MNC), and red mud waste (RMW). The chemical structure was elucidated by the Fourier transform infrared (FT‐IR). The composites were characterized by scanning electron microscopy and x‐ray diffraction. Appropriate PS and NC ratio was accepted as 4% and 2% by weight, respectively. Curing degrees calculated from the FT‐IR spectra of ER, EPN, and EPN‐PS were 99.3%, 99.9%, and 86.5%, respectively. A comparative study of the two binary systems; (i) 2 wt% NC‐(15–35) wt% RMW; and (ii) 2 wt% of MNC‐(15–35) wt% of RMW on the mechanical, thermal, and flammability properties of EPN‐PS matrix was carried out. The appropriate RMW ratio was 30 wt%. Hybrid composites with 25–30 wt% RMW can be considered self‐extinguishing materials.