Mud Powder Research Articles

CO2 mineralization into waste-valorized lightweight artificial aggregate

The construction industry faces a notable scarcity in the supply of aggregates. This study investigated the upcycling of red mud (also known as bauxite residue), a hazardous waste from alumina production, into porous and lightweight (lighter than water) red mud artificial aggregates (RMAA) for CO2 sequestration. Calcite is identified as the main carbonation product, with two hydration modes at low and high water to solid (w/s) ratios. A low w/s ratio inhibited formation of calcium carbonate, implying water is indispensable in CO2 sequestration. A high w/s ratio increased carbonate crystallinity and boosted the amount of carbonation products and calcium conversion. The highest CO2 sequestration ability (16.4 %) and calcium conversion degree (59.3 %) for red mud powder, as well as the highest strength (∼8 MPa) of carbonated RMAA, occur to the highest investigated w/s ratio. The CO2 sequestration effectively stabilized the heavy metals in RMAA. The CO2 sequestration mechanism and strength gain of RMAA are explored considering the key factors of CO2 diffusion rate and the quantity and crystallinity of carbonation products. This study advances carbon capture, utilization, and storage by transforming solid waste to energy to combat climate change.

Effect of Mud Powder on the Performance of Bridge Deck Leveling Concrete in a Seasonally Frozen Region.

Mud powders in aggregates are often found to cause deterioration of concrete properties. Based on a study of the mechanical properties of bridge deck leveling concrete (BDLC) containing different mud powders at various ages, the effects of mud powders on concrete durability were evaluated through rapid chloride permeability testing, freeze-thaw testing, and the coupling of salt solution and a freeze-thaw test. The properties of the interfacial transition zone (ITZ) were also investigated via microhardness testing. The test results showed that mud powder reduced the compressive strength, static compressive elastic modulus, and bond strength at early stages of curing. Moreover, mud powder was found to reduce the tensile properties and durability of concrete, with clay powder causing a greater reduction than mud powder in river sands and coarse aggregate. In addition, the width of the ITZ of concrete containing mud powder was found to increase by 23.1-48.3%. A significant correlation between the ITZ and the tensile properties, as well as the durability of concrete, was also observed. Therefore, in order to improve the tensile properties and durability of BDLC in seasonally frozen regions, the content of mud powder in the aggregates should be minimized according to the different compositions of mud powders. The coupling effect of salt solution and a freeze-thaw cycle should also be taken into consideration.

A green phosphate-based geopolymer adsorbent or binder with high specific surface area for environmental applications

High water content mud has complex chemical composition and high water content, making it difficult to be directly utilized in engineering. However, its high clay content, small particle size, and large specific surface area may make it possible to prepare a adsorbent or binder with high specific surface area for environmental applications. This study attempts to prepare a phosphate-based geopolymer (PGEOs) adsorbent or binder with high specific surface area using aluminum dihydrogen phosphate as the activator, high water content mud powder and fly ash as raw materials. The microstructure of PGEO was invsetigated using X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and N2 adsorption/desorption experiments. The results showed that the PGEOs belong to mesoporous materials, and has the maximum strength (9.06 MPa) at 28 days when the mud powder content was 10 %. Moreover, the specific surface area of the PGEO increased significantly with an increase in mud powder content, at 7 days of curing, when the mud powder content increases to 50 %, and the specific surface area increased from 42.074 m 2/g to 311.660 m2/g. which are significantly higher than many existing adsorbents. Therefore, the PGEOs prepared with mud powder and fly ash has great potential in pollutant adsorption and solidification/stabilization treatment in future.

Study on performance and fractal characteristics of high-strength manufactured sand concrete with different MB values

The mud powder in the manufactured sand will have an influence on the indicators of the manufactured sand concrete (MSC), and the methylene blue value can quantitatively indicate the mud powder content. To demonstrate the impact of MB values on the performance and microstructural characteristics of the manufactured sand concrete, the paper designed five high-strength MSC proportions at five MB values by controlling the clay powder content. On this basis, the workability, chloride migration coefficient, relative dynamic modulus of elasticity (P), mass loss rate (η), and dry shrinkage rate of MSC concrete were tested under five mix ratios, and the relationship between concrete microstructure, fractal characteristics, and compressive strength (fcc) was analyzed by combining SEM technology and fractal theory. The experiment showed that: the higher the MB, the lower the fluidity of the MSC, and the cohesiveness gradually increases, while the water retention remains basically unchanged. In addition, the chloride migration coefficient gradually increases, the P after 300 freeze-thaw cycles first increases and then gradually decreases, while the η and drying shrinkage first decreases and then gradually increases, and the MB value corresponding to the turning point of these three changes are all 1.10. With MB values of 0.85 and 1.10, the degree of hydration of MSC is higher and the overall structural compactness is better. The higher the MB value, the more inadequate the hydration of concrete, and the mineral components such as fly ash that have not been hydrated inside gradually increase, which leads to the gradual decrease of the overall structure compactness. In addition, when the MB value is small, the SEM image texture of concrete is relatively simple, the fractal dimension value is small, and the corresponding fcc is large. When the MB value is large, the texture of the SEM image is complex, the fractal dimension is large, and the corresponding fcc is small.

Diagenetic Evolution of Marine Carbonate Reservoirs: A Case Study from M51-2 Submember of Middle Ordovician Majiagou Formation in SE Ordos Basin, China

In the Yan’an gas field, southeast of Ordos Basin, the discovered natural gas reserves are 114 billion cubic meters. Highly productive gas reservoirs were formed in paleokarst. By using 164 samples from 27cores, the geochemical study of diagenetic evolution was carried out, and the relationship between different diagenesis environments was discussed by using scanning electron microscopy, carbon and oxygen isotope, and isotopic and fluid inclusion microthermometric observations. Results show that the lithology of reservoir is anhydrite-bearing mud powder crystal dolomite, powder crystal dolomite, and karst breccia dolomite; the filling includes dolomite, calcite, anhydrite, quartz, fluorite, and clay minerals; δ13C (‰ PDB) value is between −6.31‰ and 1.01‰, δ18O (‰ PDB) value ranges from −11.36‰ to −6.54‰, and the 87Sr/86Sr value ranges from 0.7077 to 0.7081. The overall carbon isotope of Majiagou Formation decreases first and then increases, and the strontium isotope evolution curve generally increases first and then decreases, indicating that the water environment of Majiagou Formation experienced a relatively high salinity concentration period and a relative desalinization period during deposition. The stratigraphic development shows a cyclical trend, responding to the multistage transgression and regression process. The homogenization temperature of fluid inclusions is 70–100°C, salinity is 0–3.5%, homogenization temperature of fluid inclusions is 70–100°C, salinity is >3.5%, homogenization temperature of fluid inclusions is 100–160°C, salinity is 0–3.5%, homogenization temperature of fluid inclusions is 100–160°C, salinity is >3.5%, homogenization temperature of fluid inclusion temperature is 160–200°C, and salinity is >3.5%, indicating that the fluid source in the sedimentation and diagenesis process is seawater, atmospheric freshwater, hydrocarbon fluid, and deep thermal fluid. The diagenetic environments are divided into marine diagenetic environments, metric freshwater diagenetic environments, and burial diagenetic environments.

Analysis of composition and microstructure of diatom frustules in mud on the coast of Boryeong- city, South Korea

The microstructure of diatom frustules found in mud sediments along the coast of Boryeong- city, South Korea, was observed using a scanning electron microscopy (SEM), and the constituent elements of diatoms were analyzed using energy-dispersive X-ray spectroscopy (EDS). Diatom frustules and clay minerals were present in the SEM images of the mud powder. High-magnification SEM images revealed that the surface of the frustules contained identically shaped circular pores, measuring 1 μm in diameter, arranged at regular intervals. This study revealed that the diatom shell fragments in the mud powder ranged in size from 3 to 30 μm, with an average thickness of approximately 2.5 μm. The elements Si, Al, Fe, K, Na, Mg, and Ti were detected while analyzing the frustule constituents, with Si being the primary component with the highest content.

Methane decomposition to produce hydrogen and carbon nanomaterials over costless, iron-containing catalysts

In this work, a series of iron-containing materials (not laboratory-synthesized but from natural, industrial raw materials, by-products or wastes), such as iron concentrate powder, fine/coarse ash and steel slag from steel plants and volcanic mud powder, were investigated as catalysts for methane decomposition. These catalysts exhibited relatively good methane conversion under the following conditions: 2.0 g of catalyst, 50 mL/min CH4, 900 °C for 5 h, even without hydrogen pre-reduction. Fe2O3 species on these samples were found to be gradually reduced by methane to Fe3O4, FeO and then finally into Fe0 active species. When methane decomposed onto the Fe0 active sites, Fe3C species would form to deposit graphite around themselves to finally form carbon nanomaterials, showing possible application in the oxygen evolution reaction and in Li-ion batteries as anode electrodes. Furthermore, using the best catalyst, iron concentrate powder, the effect of temperature and gas hourly space velocity was studied, where 900 °C and 3 L/gcat·h were determined as the optimized reaction conditions to reach the highest carbon/hydrogen yield.

Binary blended cement pastes and concrete using gravel wash mud (GWM) powders

An alternative supplementary cementitious material (SCM) based on quarry waste sludge, namely gravel wash mud (GWM) powder, is investigated for its performance in blended cement pastes and concretes. Varying mix designs of blended cement pastes and concrete mixtures at Ordinary Portland cement (OPC) substitution degrees from 10 wt% up to 30 wt% by uncalcined and calcined GWM powders were examined at different curing ages using isothermal calorimetry, strength-based examinations, shrinkage test, carbonation test and scanning electron microscopy. The pozzolanic nature of the calcined GWM powder was confirmed, however, minor to no significant physiochemical contributions to the early hydration reactions were observed. The incorporation of calcined GWM powders up to OPC replacement levels of 20 wt% showed an enhancement of the long-term properties of the hardened specimens, namely less drying shrinkage and reduced progression of carbonation compared to the control mixtures. Beneficial strength-enhancing effects were observed for binary blended concrete mixes using calcined GWM powders at OPC replacement levels of 10 wt% and 20 wt% and classified them as viable proportions for alternative SCM-based concretes. The revalorisation of the GWM, a quarry waste product, as a novel and competitive raw material resource for cement production, would provide an environmental-friendly and alternative solution to the expensive and inefficient end-of-life scenario of GWM at the landfills.

Creep Fracture Characteristics of Fractured Rock Mass Strengthened with Toughened Epoxy Resin

For improving the toughness and long‐term strength of the fractured rock mass reinforced with epoxy resin and reducing the opening displacement of the crack tip, three types of converging cracks are established according to the deformation and failure characteristics of the rock mass, structural planes, and epoxy resin composite structure. The stress intensity factor of the type II compound crack and the analytical formula of the crack surface tip opening displacement are obtained. An improved Kelvin nonlinear creep model is proposed. Through the creep isochronous curve, the time and long‐term strength of accelerated creep failure are obtained, as well as creep rupture coupling characteristics. The ductile plastic deformation is used to characterize the toughness, and the toughness of epoxy resin is enhanced by adding mud powder, and the relationship between toughness and long‐term strength is established. Combined with experimental verification, when the drying mud powder content is 20%, the toughness of the epoxy resin has a good correlation with the long‐term strength; when the mud powder content exceeds 30%, its ductility and long‐term strength decrease, and at the same time the toughness effect is significantly weakened. The research results can provide a useful reference for toughened epoxy resin to strengthen fractured rock mass engineering.

Properties Analysis of Asphalt Binders Containing Bayer Red Mud

In this work, related performances of asphalt binders with Bayer red mud powder (RMP) were studied. RMP replaced the traditional limestone powder (LSP) as a filler in asphalt binder. The replacement rates were 0%, 25%, 50%, 75%, and 100%, respectively. In this study, seven F/A (filler-to-asphalt, weight/weight) ratios for each of the fillers were selected: 0.3, 0.6, 0.9, 1.2, 1.5, 1.8, and 2.1. Penetration, softening point, rotational viscosity (RV), dynamic shear rheometry (DSR), and bending beam rheometry (BBR) tests were used to evaluate the properties of the asphalt binder. Penetration into the asphalt binder decreases linearly with increasing F/A ratio. Moreover, penetration of binder with RMP is lower than that of asphalt binder with LSP (RMP0), and among the five fillers tested, RMP100 showed most significant influence on penetration of the asphalt binder. The addition of RMP increases the softening point of the binder. DSR results show that the improvement in the high temperature performance is most significant after replacing 75% of the LSP with Bayer RMP. BBR results show that with increasing substitution of RMP for LSP, the creep stiffness (S) increased while the rate of change of S (m-value) declined. The low temperature performance of every asphalt binder was not enough to meet the Superpave requirements. In order to meet the Superpave requirements for S and m-values, the maximum F/A ratios of the five replacements corresponding to the fillers with 0%, 25%, 50%, 75%, and 100% RMP, were 1.3, 1.2, 1.1, 1.0 and 0.9, respectively. At 135 °C, rotational viscosity showed that RMP75 and RMP100 with a maximum F/A ratio of 1.1 are the best choices for asphalt binders, considering economic and construction requirements.

Development of green concrete using waste marble dust

The use of industrial waste locks as a raw material to reduce their adverse effects on the environment and to enhance its environmental efficiency. Marble mud powder can be used as a filling assist and leads to can complete voids of concrete construction. This paper shows how to use a 100 percent alternative to natural sand in concrete with the marble mud dust. This research examined the strength of compression and the microstructure of mixed cement. Cement hydration products have been detected by electron microscopy scanning. The strength is described by various parameters: curing time, composition of the binder and (vadium/aggregate) ratio. Composite cements were found at 28 days and higher intensity than 7 days. The greater the strength, the more dust the marble contains. The concrete is thus made of marble dust that contributes to natural resource consumption and to reducing pollution and environmental pollution.

Abrasion Resistance of Manufactured Sand (MS) Concrete and Its Influence Factors

The feasibility of using MS to replace river sand (RS) in concrete pavement has been widely concerned by scholars, however the abrasion resistance of MS concrete pavement serves as a major factor restricting application. Published literature shows huge potential of MS as a replacement of natural fine aggregate. A detailed overview of published literature on property of MS and influencing factors on abrasion resistance of MS concrete is being presented. Regarding the characteristics of MS, the granular shape is characterized by irregular shape, multi-angle and large aspect ratio, the gradation shows a phenomenon of less in the middle and more on both ends, and MS contains high content of stone powder and little mud powder. The influencing factors include mix ratio, lithology, stone powder, admixture, polymer, etc. Among them, stone powder has attracted the attention of many scholars. Nevertheless, few related studies exist at present, source selection and in-depth research merit consideration.

Red Mud and Its Applicability in Fluoride Abatement

In the current study red mud is used as a medium to adsorb the hazardous exhaust gas containing gaseous fluorides coming out of aluminum industries as a measure to control environmental pollution. A high temperature fluidized bed reactor is used in this case which can be operated at around 300°C using a ceramic heater connected to the fluidized bed column. Optimally sized red mud powder having good fluidization quality is used to check the adsorbing properties of the gaseous fluorides on the metallic components present in red mud. Various characterization techniques like PSA, TGA-DTA, FT-IR, ICP-MS, FESEM, EDX and XRD are used. These characterization techniques proves the reaction between the metallic components present in red mud with the gaseous fluorides due to the presence of AlF3, FeF2, FeF3 and NaF observed in the products. This report thus proves the applicability of fluidized bed reactor in treating the gaseous exhaust containing fluorides using red mud which otherwise is considered as a waste in the aluminum industry itself.

Dry Sliding Wear behaviour of Aluminium-Red mud- Tungsten Carbide Hybrid metal matrix composites

Red mud is an industrial waste obtained during the processing of alumina by Bayer's process. An attempt has been made to utilize the solid waste by using it as the reinforcement material in metal matrix composites. Red mud received from NALCO has been subjected for sieve analysis and milled to 42 nanometers using high energy ball mill. Red mud is used as a reinforcement material in Pure Aluminium matrix composite at 2%, 4%, and 6% weight at 100 microns level as well as 42 nano meters along with 4%Tungsten carbide by weight. Micro and Nano structured red mud powders, Tungsten carbide powder and Aluminium is mixed in a V-Blender, compacted at a pressure of 40 bar and samples are prepared by conventional sintering with vacuum as medium. In this current work, dry sliding wear characteristics at normal and heat treatment conditions are investigated with optimal combination of Aluminium, Tungsten carbide and different weight fractions of micro and nano structured red mud powder.

Study of Red Mud as Compound Sulfur-Fixing Agent

The research has revealed the problem of sulfur dioxide emissions during the coal combustion. Combustion experiments were made for Shanxi coal at 1000oC. Red mud, carbide and shell powder were chosen as the primary sulfur-fixing agent. Through the experiment, the best ratio of Ca/S is 2.0 at 1000oC. When the ratio of red mud, carbide and shell powder were 50%, 15% and 35%, the maximum sulfur-fixing efficiency was 76.05%. Orthogonal experimental results showed that the best additive formula was 9% of Fe2O3, 5% of Na2CO3, 5% of ZnO. The maximum sulfur-fixing efficiency reached 89.23%. In addition, it was made thermogravimetric analysis of coal with different additives. By contrast, samples with sulfur-fixing agent generated two-stage combustion significantly, ignition point increased. The amount of coal residues with sulfur-fixing agent and sulfur-fixing additives showed an increase in the quantitative analysis.

Red Mud Powders Applied on Filling Rubber Composite Material

Red mud is a kind of fine particles which with a strong alkalin value. The paper used red mud powder to prepare red mud-rubber composite for the feasibility of recycling about red mud. XK-160 open-mixing machine, QLB Series vulcanizing machine, multifunction electronic tensile machine, JC-1086 rotary roller, fluorescence spectroscopy analyzer, BT-9300 laser particle size distribution analyzer etc were used for test. The results showed that red mud in rubber composites played as beneficiations added in rubber significantly.

The influence of citrate anion on Ni(II) removal by raw red mud from aluminum industry

The removal of Ni(II) from aqueous solutions by raw red mud powder was studied in the absence and in the presence of citrate ligand, as a function of process parameters. Using lower initial Ni(II) concentration (10−3mol/L) detectable amounts were found only at initial pH 3, whereas for higher concentration (2×10−3mol/L) removal increased simultaneously with pH in the range 3–4 and at pH>8. Process efficiency was suppressed in the presence of citrate. However, at Ni/Citrate molar ratios 1:0.25 and 1:0.5, 10–20% decrease was noticed in acidic media, while the negative influence diminished with the rise of pH. At higher ligand rates, formation of stable aqueous complex between Ni(II) and citrate significantly reduced metal removal in the whole tested initial pH range (3–10). Due to instantaneous pH rise above 8, removal of Ni(II) from 10−3mol/L solution was completed in 5min. Kinetic data demonstrated slower Ni(II) uptake using both solutions of higher initial Ni(II) concentrations and Ni/Citrate solutions. At initial pH 5, estimated capacity towards Ni(II) was found to be 27.4mg/g, without citrate. For Ni/Citrate molar ratios 1:0.25 and 1:0.5, capacities decreased slightly to 25mg/g and 21mg/g, whereas at equimolar and higher concentrations, citrate significantly inhibited Ni(II) immobilization (7.6mg/g and 2.5mg/g, respectively for Ni/Citrate ratios 1:1 and 1:2). The results demonstrated beneficial effect of red mud high alkalinity on Ni(II) removal. The sorbent satisfactorily immobilize nickel from solutions having initial Ni/Citrate molar ratios lower than 1:1, and neutral to alkaline initial pH. FTIR analysis confirmed that red mud can act as a removal agent for Ni(II), Ni/Citrate complex and free citrate ligand.

IMPROVEMENT IN HARDNESS AND CORROSION RESISTANCE OF STEEL THROUGH RED MUD COATING

Red mud is a waste product produced during alumina extraction from bauxite by the Bayer’s process and has become a major issue in connection with its disposal. As the aluminum demand in the world is increasing, the disposal of red mud waste into the environment also increases, bringing with its environmental issues coupled, however, a potential for the waste to generate a huge amount of unutilized resources still contained in the red mud, such as Fe2O3, Al2O3, SiO2, and others. As a possible useful utilization of the disposable waste, red mud can be used as a fine ceramic coating material onto metal substrates. For a fine ceramic coating, fine red mud powder was mixed with other substances to form a non-aqueous coating slurry with toluene as the solvent, PEG 6000 as the binder and plasticizer, and sesame oil as the dispersant. The coating process was performed by a dip-coating method onto ST-37 steel with a withdrawal speed of 0.23 mm/sec. The densification of coating material took place after calcinations at 900 °C, 1100 °C, and 1300 °C for 2 hours in nitrogen atmosphere. This treatment evinced an improvement of the surface hardness from 146.2 HV to 1738.8 HV for the sample calcined at 1100°C and the corrosion resistance by 4.14 times, for the sample calcined at 1300°C.

Corrosion protection performance of sol–gel coatings doped with red mud applied on AA2024-T3

This paper studies the effect of 5wt% red mud particles addition to sol–gel films applied on AA2024-T3 aluminium alloy. The red mud powder was dried or calcined, previously to added to the sol–gel film, in order to analyzed the effect of the thermal activation. The RM particles were characterized using several techniques; x-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results confirm that the thermal treatment leads to several phase transformations which affect to gibbsite, Al(OH)3, boehmite, AlO(OH), and goethite, FeO(OH), species.The anti-corrosion properties were evaluated by salt pray test and electrochemical impedance spectroscopy (EIS) techniques. Both types of studies indicate increased protecting properties of the sol–gel films doped with calcined red mud particles. Although the inhibition mechanism is not well-established, it must be related to the formation of reactive species during the heat treatment, which can evolve to mixed aluminium oxides in contact with the electrolyte.

Effect of Nucleation Agents on the Freezing Probability of Supercooled Water inside Capsules

The effect of nucleation agents on the freezing probability of supercooled water inside cylindrical capsules during a cold storage process was investigated. Different types of nucleation agents (including silver iodide (AgI), lead iodide (PbI2), river sand, and mud powder were used to achieve)water nucleation under different coolant temperatures. The effect of the amount of nucleation agents on the freezing probability of cylindrical capsules was studied. The results indicate that the nucleation probability and nucleation temperature of supercooled water inside capsules adding nucleation agents are higher than those of capsules containing pure water only, which suggests that nucleation agents are effective in reducing supercooling of water. Of the nucleation agents used, silver iodide showed the best results in facilitating the nucleation. However, river sand is recommended as the nucleation agent because it is the most inexpensive and effective for the type of encapsulated storage tank used in a cold storage air-conditioning system.