High Aluminum Content Research Articles

Physical, thermal, and mechanical properties of calcium aluminate cement-based refractory conerete at elevated temperature

In the past decade, calcium aluminate cement is widely used to manufacture refractory concrete for infrastructure works which frequently were subjected to elevated temperature thanks to the thermal stability by the high content of aluminum. This paper presents experimental results of the physical, thermal, and mechanical properties of calcium aluminate cement-based refractory concrete specimens. As experimental results, with a calcium aluminate content of about 50%, the refractory concrete provides remarkable physical, thermal, and mechanical properties. The high density and low water content were characterized for this concrete. The thermal diffusivity coefficient of refractory concrete is lower from 3 to 4 times than that of normal concrete while the conductivity is around of 1.05 (W/m.K). Furthermore, from the thermomechanical tests, the direct tensile strength and Young’s modulus of refractory concrete were identified at different temperature levels. The effect of elevated temperature on the performance of this refractory concrete was analyzed and highlighted

Effects of combined application of nitrogen, phosphorus, and potassium fertilizers on tea (Camellia sinensis) growth and fungal community

Fertilization is an effective strategy for enhancing tea yield and quality. In practice, fertilizer application in tea plantations is often characterized by N, P, or K deficiencies, which suppress tea growth. Fertilization also exerts indirect effects on tea yield and quality by affecting the microbial community in the soil which is critical for regulating nutrient cycling and soil multiplication. Due to their tolerance to adverse environments in tea plantations including low pH and high aluminum and fluorine content, fungi are strongly associated with tea growth and are involved in the decomposition of pruning residues. To elucidate the poorly understood effects of different fertilizer combinations on soil fungi and tea, soil and plant samples were collected from a five-year (2016–2020) field experiment involving combined application of N, P, and K fertilizers (NF: no fertilizer; PK, NK, and NP: fertilization under conditions of N, P, and K deficiency, respectively; and NPK: fertilization with N, P, and K). Yield and quality differences between NPK and PK were more significant than those between NPK and NK, and NPK and NP. Of these three nutrients, N was the primary limiting factor for tea growth and N deficiency had more significant effects on fungal diversity than P or K deficiencies. N addition accelerated soil acidification and promoted native soil organic carbon decomposition, thereby decreasing the fungal diversity and modifying fungal community composition and structure. Moreover, in the PK (N deficiency) treatment, the fungal network had the lowest modularity, indicating that N deficiency reduced the resistance of fungal communities to external disturbances. The relationship between tea and fungi at different soil depths revealed that yield and amino acid content of tea were more strongly correlated with fungi in the topsoil than in the subsoil. This indicates that soil samples collected from the top layer are more informative for investigating the relationship between tea and soil. Overall, these findings deepen our understanding of how combined fertilization affects tea growth and soil quality, thereby guiding optimal fertilization strategies toward maximization of tea yield and quality and minimization of environmental risks.

Mineralogical, Geochemical Characterization and Physicochemical Properties of Kaolinitic Clays of the Eastern Part of the Douala Sub-Basin, Cameroon, Central Africa

The sedimentary clays of the Douala sub-basin (Cameroon) were studied to determine their mineralogical composition and physicochemical properties to boost their potential suitability as materials for traditional ceramics and eventually modern ceramics. These clayey materials are not widely used locally as building materials and little data are available on these materials in the field of ceramics and they are relatively unknown. Three profiles from 3.9 to 7.4 m thickness were studied on the field in order to determine their mineralogical (X-ray diffraction, infrared), chemical (X-ray fluorescence) and physicochemical (particle size, Atterberg limits, organic matter, cation exchange capacity and hydrogen potential) properties. Globally, ten (10) clay samples were analyzed to highlight the nature and technological properties of these clays. Mineralogically, kaolinite (48.3–69.2 wt.%) and quartz (20.5–41.2 wt.%) were the most abundant minerals in these raw clay materials. They were associated with a very small or moderate quantity of illite, hematite, goethite, feldspar, gibbsite and micas. Geochemically, the clayey materials had high silica (SiO2, 22.21–58.03%) and alumina (Al2O3, 12.84–22.94%) contents, with a significant amount of iron oxides (Fe2O3, 1.07–17.92%). Other oxides (K2O, MgO, TiO2, Na2O, MnO, CaO and P2O5) were in a relatively lower proportion. A high level of alumina content explains the kaolinitic nature of these clayey materials. The results of the granulometric analysis of the clayey materials showed the following distribution: clay (26–99%) followed by silt (1–70%) and sand (0–4%). This corresponds to silty clay soils according to the Belgian textural classification diagram, with high plastic index (63.9%) characteristics. The studied clay materials are good candidates for the production of ceramics and terracotta building. This study is therefore important for any application of this type of clay in various industrial fields.

Selenium as a new decopperization approach for steel scrap

• Copper selenide was formed and located on the oxides after the addition of selenium into the liquid Fe-Cu alloy. • Copper selenide was massively detected in the slag along with the alumina or (Mg, Fe)Al 2 O 4 -spinel. • The detected copper selenide indicate that selenium may be considered as a sufficient approach for the decopperization. Selenium was added into the molten Fe-Cu alloy at 1600 °C to test its decopperization possibility. After the addition of selenium into the liquid Fe-Cu alloy, copper selenide was found to deposit on the particle with a complex composition that located on the solidified alloy sample. Furthermore, a secondary metallurgical ladle slag with a high content of alumina was added into the liquid Fe-Cu alloy after the addition of selenium. Thereby the decopperization efficiency was found to be enhanced by the addition of slag. The copper selenide was massively observed in the slag along with the oxides (alumina or (Mg, Fe)Al 2 O 4 -spinel). The formation of the spinel was predicted by the FactSage software.

Causes of poor dregs settling in a green liquor clarifier

A study was conducted to examine the most likely parameters responsible for poor dregs settling at a kraft mill over a 2.5-year period, using multivariate data analysis (MVDA) and machine learning (ML) techniques. The dregs settling behavior seems to be seasonally influenced, implying that wood quality variation can be a factor. The results from the MVDA/ML analysis show that poor dregs settling is correlated to incomplete combustion and/or low load conditions in the recovery boiler, low sulfidity in the causticizing plant, and high flow in the green liquor–weak wash cycle. Compositions of dregs and black liquor were also examined to identify correlations with impaired dregs settling. The results show that poor dregs settling strongly correlates with high silicon (Si) content in dregs and moderately correlates with high iron (Fe) and high aluminum (Al) contents, and with low bulk density in dregs. For mills that experience dregs settling or green liquor filtering issues, regular compositional analyses of dregs, green liquor, weak wash, and black liquor are recommended in order to monitor the dynamics of silicon and other constituents in the recovery cycle.

CREATING SURFACE LAYERS OF PARTS WITH INCREASED TRIBOLOGICAL CHARACTERISTICS USING COLD GAS-DYNAMIC SPRAYING

One of the transitions to the path of intensification of the production processes is the perceptibly low stability of the details of the nodes in the possession of these production processes. The stamina of the details is small, vindictive, nasampered, rubbing in pairs, especially quiet, which works out of significant tensions in aggressive middles. The wear of the upper balls of parts can ruin the possession, which leads to the waste of energy and material resources. One of the ways to solve the problem is the creation of functional coatings on the surfaces that are resistant to aggressive environments. The results of the analysis of antifriction properties of materials containing copper, tin, lead, aluminum, and polymers are presented. The advantages and disadvantages of antifriction properties of the materials in question are shown and the possibility of their application on the surface of parts using cold gas dynamic spraying. The use of liquid and solid antifriction materials as lubricants is analyzed. Attention is paid to materials with a crystalline structure similar to the structure of graphite, known as 2D structures (two-dimensional materials)." The most studied 2D materials are MoS2 and carbon-based compounds, including graphene and graphite. The diagram of the interaction of sliding surfaces, including molecular deformation, wear, bonding, the thermal effect, and environmental influence is shown. It is noted that the application of antifriction materials to the surface of parts can be carried out using cold gas-dynamic spraying. Found that compared to the material of the substrate AA7075, the coefficient of friction of sliding of the spray coating with the crystal of copper-graphite powder was reduced by 47% - 62%. Rubber composite coatings are made of a mechanical mixture of aluminum powder A30-01 and copper C01-00. The dependence of the coefficients of spraying aluminum and copper on the content of aluminum in the composite mixture that is sprayed is obtained. until it reaches 61%. At higher concentrations of aluminum (more than 66%) the coefficients of spraying aluminum, copper, and their mixtures coincide.

Zeolite greenly synthesized from fly ash and its resource utilization: A review

Fly ash is an incineration byproduct of thermal power plants. Due to the complex composition of fly ash, improper disposal will seriously harm the ecological environment. Therefore, how to effectively use fly ash to safely and environmentally replace landfills is a worldwide concern. Considering the high silicon and aluminum contents in fly ash, it has the potential to synthesize zeolite, which has a wide range of applications in sewage treatment, gas adsorption, etc. Therefore, the synthesis of zeolites from fly ash is consistent with the theme of sustainable development. The synthesis mechanism of zeolite, various synthetic methods of zeolite from fly ash and their advantages and disadvantages was introduced in detail. In addition, combined with the current research hotspots, the application of synthetic zeolite from fly ash in the fields of sewage treatment and gas adsorption was introduced. Finally, the future development prospects and research directions of synthetic zeolite from fly ash to improve the utilization rate of fly ash were considered.

Insight into leaching of rare earth and aluminum from ion adsorption type rare earth ore: Adsorption and desorption

Clay minerals are inferred to be the primary host materials for ion-exchangeable rare earth in ion adsorption type rare earth ore (IAREO). During the rare earth leaching process, the adsorption and desorption reactions of the cations controlling the leaching process continue to occur at the clay minerals-leaching agent solution interface. In order to understand the leaching mechanism and behavior of rare earth and co-leached aluminum, adsorption, competitive adsorption, and desorption experiments were carried out using kaolin as a typical clay mineral. The powerful electrostatic attraction and concentration driving forces facilitate the adsorption of cations. The adsorption ability and competitive adsorption ability of cations depend on their charge, hydration radius, and hydrolysis properties, and decrease in the order of La3+, Y3+, Al3+, Mg2+, and NH4+. The desorption of rare earth and aluminum is positively affected by the concentration-driving force exerted by high concentrations of Mg2+ and NH4+, with the order of the desorption ability being opposite to the adsorption ability. However, unspecified interactions between clay mineral particles enhanced by high-concentration desorbents, especially by Mg2+ than NH4+, will adversely affect desorption reactions, which result in lower desorption efficiencies of rare earth and aluminum obtained with magnesium sulfate compared to those obtained with ammonium sulfate at high concentrations. Solid-phase Al(OH)3 generated at a high peak aluminum concentration leads to a considerably delayed aluminum efflux, thereby partially separating the rare earth from aluminum during the actual column leaching process. To advance the mining technology of IAREO by selectively improving the rare earth leaching efficiency with minimal leaching agent consumption, higher charged cations with concentrations limited to suitable levels should be preferred as leaching agents.

Adsorption of Organic Dye onto Mesoporous Aluminosilica Monoliths: Equilibrium, Kinetic and Thermodynamic Studies

AbstractIn the present study, high order aluminosilica monolith (HOASM) composite with high alumina content (Si/Al=1.5) was fabricated through a reproducible, simple, and one‐pot synthesis strategy. Achieved was a realistic control over the cubic Ia3d geometry of aluminosilica monoliths using microemulsion phases of copolymer P123 as soft templates. The geometrical and textural pore structures of the HOASM composite were characterized with various tools of EDX, FESEM, HRTEM, XRD and N2 isotherms. The quantity of aluminum species present in the walls of the silica pore structure has a substantial impact on the acidity of nanoadsorbent. The HOASM nanoadsorbent was used as a removal of Crystal violet (CV) from wastewater. A major contributing factor to the improvement of the coverage of the HOASM composite adsorbent surfaces were the multi‐directional pores (3D) and the mesostructural geometries of the aluminosilica adsorbent. The performance factors like temperature, adsorbent dose, concentration, pH, and contact period, were all examined to evaluate the CV dye adsorption. It was found that, at a pH of 8, the greatest CV dye adsorption on HOASM composite was achieved. The optimal concentration for CV adsorption was 1.5 mmol/g, and the adsorption isotherm matched the Langmuir model, though the adsorption kinetics were matched to a pseudo‐second‐order model. Thermodynamic experiments have shown that the CV dye adsorption on the HOASM composite is endothermic and spontaneous.

Study on physical properties of Al2O3-based slags used for the self-propagating high-temperature synthesis (SHS) – metallurgy method

Abstract The Al2O3-based slags are playing important roles in the preparation of Cu–Cr alloy through self-propagating high-temperature synthesis (SHS) – Metallurgy method. However, the current research on Al2O3-based slag is mainly concentrated on steel metallurgical slag and electroslag remelting slag, and the research on aluminum thermal reduction slag with high content of Al2O3 is still insufficient. Therefore, systematic studies of the physical properties of slag with high aluminum content were carried out in the present work, and the influence of CaF2, CaO, MgO, SiO2, and Na3AlF6 on viscosities, liquidus temperatures, densities, and surface tensions of high Al2O3 content slags was measured and analyzed. The results indicated that CaO and CaF2 have positive effects on the physical properties of Al2O3-based slags, MgO has positive effects when its content is not over 3%, and SiO2 and Na3AlF6 have negative impacts. CaO, CaF2, and MgO (not over 3%) could be used as additives to improve the metallurgical performance of Al2O3-based slags in aluminothermic reduction–slag refining method.

Microstructure and Continuous Cooling Transformation of an Fe-7.1Al-0.7Mn-0.4C-0.3Nb Alloy

Reducing pollutant emissions and improving safety standards are primary targets for modern mobility improvement. To meet these needs, the development of low-density steels containing aluminum is a new frontier of research for automotive applications. Low-density Fe-Mn-Al-C alloys are promising. In this regard, an alloy with high aluminum content and niobium addition belonging to the Fe-Mn-Al-C system was evaluated to understand the possible phase transformations and thus obtain a transformation diagram by continuous cooling to help future processing. Dilatometry tests were performed in a Gleeble thermomechanical simulator with different cooling rates (1, 3, 5, 10, 15, 20, 30, and 50 °C/s). Chemical analyses carried out simultaneously with dilatometry tests showed the presence of proeutectoid ferrite (αp), δ-ferrite, retained austenite, and niobium carbide (NbC). In the case of low cooling rates (1 and 3 °C/s), lamellar colonies of the eutectoid microconstituents were observed with a combination of α-ferrite and k-carbide. For higher cooling rates (5 to 50 °C/s), martensite was observed with body-centered cubic (BCC) and body-centered tetragonal (BCT) structures.

Sustainable process for valuable-metal recovery from circulating fluidized bed fly ash through nitric acid pressure leaching

Circulating fluidized bed fly ash ( CFBFA ) is receiving widespread attention due to its threat to the environment and its high content of alumina (30–50%), gallium (30–100 g/t), etc. In this research, nitric acid pressure leaching technology was proposed to selectively extract aluminum and gallium from CFBFA. The E-pH diagram of the Al–Fe–H 2 O system and experiments proved that the leachate ranged within pH −0.5 to 1, which was not favorable for the generation of Al(OH) 3 colloids. Moreover, Al entered the leachate as Al 3+ , and the divalent iron was initially oxidized by NO 3 − and then hydrolyzed to form hematite . The lg c Fe3+ at equilibrium of Fe 3+ hydrolysis had a certain relationship with pH. Thus, at high acidity with increased temperature, more Al entered the solution and more Fe entered the residue. Based on experiments, the optimum conditions were found to be as follows: leaching temperature of 220 °C, liquid-to-solid ratio of 4:1 mL/g, HNO 3 concentration of 340 g/L, and leaching duration of 2 h. The leaching rate of Al, Fe, and Ga were approximately 80%, 6%, and 78% respectively. The basic separation of aluminum and iron could be realized during leaching. In the evaporation, concentration and crystallization process of the leachate, aluminum nitrate precipitated out at room temperature when leachate density exceeded 1.38 g/cm 3 . A greater density of the leachate was concentrated, and crystallization benefited the formation of aluminum nitrate crystals with less crystal water. • A feasible process for recovering aluminum from solid waste (CFBFA) was developed. • The E-pH diagram of Al–Fe–H 2 O system at high temperature was analyzed. • Aluminum and iron were basically separated during the leaching process. • The leaching agent could be regenerated and the process was sustainable.

Water sludge reuse as a geotechnical component in road construction: Experimental study

In Brazil, the process of surface water potabilization for public supply generates sludge, but information on this waste is scarce, and its disposal in landfills and waterways, without prior treatment, generates pollution. This experimental study evaluated the incorporation of aluminum and ferric sludge, commonly generated in Brazil, into different soils for road pavement infrastructure. Sludge generated in two water treatment plants in the state of São Paulo was characterized regarding risks to human health and the environment and individually incorporated into clayey sand soil and sandy soil in proportions of 25 and 50%. Evaluation of the mechanical tests of the soil sludge mixtures and their suitability for road construction found that i) all percentages of aluminum and ferric sludge incorporated into clayey sand soils and sandy soil met the mechanical standards for use in embankment; ii) aluminum sludge incorporated into sandy soils proved to be suitable for use in pavement subbase; iii) the percentual incorporation is higher than previous research; iv) the use of sludge as a partial replacement for virgin soil makes road construction cleaner. Analyses of variance on the mechanical properties of the soil-sludge mixtures showed that soil type is the only factor influencing this variable. Only the interaction of water treatment sludge (WTS) type with the other factors is significant for the CBR and Swell data. • In Brazil, WTS can be used in road pavement as embankment and subbase. • The factors influencing the mechanical properties were evaluated using ANOVA. • WTP produces different sludge according to the coagulant and quality of the treated water. • The sludge contains high concentrations of iron, aluminum, and manganese. • Sludge can substitute for natural material in road construction until 50%.

Facile and fast synthesis of cancrinite-type zeolite from coal fly ash by a novel hot stuffy route

Coal fly ash (CFA) is an industrial solid waste discharged from coal-fired power plants. Due to the high contents of aluminum and silicon, it can be direct used for synthesis of zeolites. In this study, cancrinite (CAN) type zeolite was prepared from CFA by a novel hot stuffy method. The effects of various parameters such as alkaline dosage, crystallization temperature and holding time on the formation of zeolite were studied systematically. A well-crystallized CAN type zeolite was synthesized after mixing CFA with NaOH in a mortar followed by hot stuffy at 140 °C for 4 h. The characterized results revealed that the CAN zeolite showed a solo mineral phase with typical porous surface and internal ring structure. The synthesized zeolite was used as an adsorbent to remove anionic acid from aqueous solution, exhibiting great adsorption performance with 98 % removal efficiency within 40 min. This study provided a facile alternative for efficient utilization of solid waste to produce high value-added zeolite, exhibiting great potential for industrial application.

Sinterability and microstructure evolution of powder metallurgy processed titanium aluminides

The objective of this study was to assess the effect of different aluminium additions in microstructure evolution and hardness of powder metallurgy processed titanium aluminides. Alloys with aluminium contents of 10, 20, 30, 40 and 45 at.-% were prepared using mixtures of elemental powders that were cold uniaxially pressed. Sintering was conducted at 1300 and 1400°C for 2 h under argon atmosphere. The results indicated a sharp decrease in sinterability for larger elemental aluminium additions. Furthermore, the hardness values decreased with the aluminium content due to the higher porosity. However, in alloys with higher aluminium content, despite the higher porosity, microstructural homogeneity was improved and equilibrium phases α2-Ti3Al and γ-TiAl could be achieved in fully lamellar Ti-40Al and Ti-45Al.

Synthesis of Well-Ordered Mesoporous Aluminosilicates with High Aluminum Contents: The Challenge and the Promise.

SBA-15 has recently emerged as a potential material for the catalytic conversion of large molecules. Usually, SBA-15 has a low content of aluminum due to the conventional acidic synthesis medium. Although a few approaches have been adopted to prepare Al-SBA-15 with a high alumina content, it is still challenging to prepare well-ordered Al-SBA-15 with a high alumina content. Here, we demonstrate a facile synthesis process in neutral mediums for the grafting of Al into the framework of SBA-15. This approach relies mainly on the dissociation of Si-O-Si bonds and the polymerization of Si-O-Si/Al bonds promoted by sodium persulfate (SPS) in neutral mediums. In this way, well-ordered Al-SBA-15 with a high aluminum content and enhanced acidity was obtained. Results of X-ray fluorescence spectroscopy (XRF) showed an n(SiO2)/n(Al2O3) ratio of 13.7, much lower than that of the conventional sample (21.7) obtained in acidic medium. The characterization results indicated the presence of a well-ordered Al-containing mesophase with high hydrothermal stability. Notably, the Al content and the acidity of Al-SBA-15 can be tuned by changing the SPS amount.

Material extrusion for ceramic additive manufacturing with polymer-free ceramic precursor binder

Additive manufacturing of dense ceramic products has been challenging because of the high polymeric content of the ceramic feedstock materials. Several studies have been conducted to increase the ceramic content in the feedstock, but the binder and additives in it have remained in the polymeric content. A novel strategy for highly dense additive manufacturing using a sol-gel-based ceramic slurry without polymeric additives is presented. Alumina, which is the most widely used fine ceramic, was chosen as a representative ceramic material. The proposed sol-gel solution enabled a high solid loading of approximately 50 vol% without any polymeric dispersant while satisfying the requirements for material extrusion process, such as extrudable viscosity (<100 Pa.s) and self-sustainable yield stress. This novel sol-gel binder system evolves into aluminum oxide nanoparticles during the sintering process, eventually fusing to the alumina particles. The as-printed green body possessed high alumina content and 66% of theoretical density, which was higher than that obtained via the conventional molding methods. A reduced linear shrinkage of less than 16% and a high density of 99.5% of the theoretical value were also achieved. This research would present a practical strategy for ceramic additive manufacturing as an emerging fabrication process.

A newly defined, long-lived Paleozoic intra-oceanic arc in the South Tianshan (NW China): Implications for multiple accretionary tectonics in the southern Altaids

AbstractThe South Tianshan Orogenic Belt marks the final assembly of the southern Altaids and the Karakum-Tarim Cratons. Integrated petrological, geochemical, and geochronological studies were carried out on the Akeyazi high-alumina basaltic lavas (HABs) and their host sandstones from the southern margin of the Central Tianshan Block. Given their relative high alumina contents (Al2O3 &amp;gt; 16 wt%) and geochemical similarity to basalts from modern arcs (e.g., Aleutian, Kamchatka, Izu, and Honshu arc), the Akeyazi basaltic lavas are classified as HABs. The Akeyazi HABs are distinguished by strong enrichment in large ion lithophile elements (LILE) and negative Nb-Ta anomalies. Furthermore, their mid-oceanic ridge basalt (MORB)-like Sr-Nd-Hf (87Sr/86Sr(i) ~0.705766, εNd(t) ~+2.5, εHf(t) ~+9.5), along with arc-like trace element patterns, indicate a petrogenesis derived from a mantle wedge metasomatized by pelagic, sediment-derived melts (2%–5% melts mixed, as confirmed by melt modeling). Zircon U-Pb ages of Akeyazi HABs and associated arc-related gabbros suggest that they were mainly erupted during ca. 415 Ma. Moreover, host sandstones of Akeyazi HABs exhibit a unimodal distribution with a peak at 480–410 Ma in the detrital zircon spectrum, which is notably distinct from those of the Central Tianshan Block, South Tianshan Accretionary Complex, and North Tarim Craton, each of which is multimodal. The maximum depositional age (MDA) of the meta-sandstones is 351.0 ± 4.3 Ma, with the weighted average of three oldest Paleozoic grains at 502 ± 26 Ma. Collectively, our data, for the first time, discloses an intra-oceanic arc setting from ca. 502–351 Ma during the northward subduction of the South Tianshan Ocean, which further reveals the history of multiple episodes of accretion in the southern Altaids.

Mechanically stimulated reactions in metal–oxide (carbide) systems

The processes of mechanochemical reduction of oxides of iron, nickel, and copper with aluminum with a stoichio metric ratio of components and in mixtures with a two-, three-, and four-fold excess of the aluminum content over the stoichiometric, as well as in the presence of an excess of oxide-forming metal and solid solutions of aluminum in iron and copper, were studied by the Mössbauer and IR spectroscopy, X-ray diffraction analysis, including the use of synchrotron radiation, and electron microscopy. The conditions for formation of metals modified with aluminum oxide (iron, nickel, copper) and their monoaluminides are determined. High aluminum content aluminides are formed at a three-fold excess of aluminum, and at a four-fold excess, a mechanochemical reduction of oxides does not occur. The preferred method for modifying metals with alumina is the mechanochemical reduction of oxides with a solid solution of aluminum in the oxideforming metal. Mechanochemical interaction in the high-energy Hf–C system in the presence of 20, 30, and 50 wt. % copper leads to the formation of hafnium carbide; and with an increase in the copper content, the crystallite size decreases.

Phytoremediation of bauxite wastewater potentiality by Jatropa curcas.

Bauxite wastewater creates soil contamination and produces toxic effects on human health such as respiratory and skin rash problems. In this study, we investigated the phytoremediation ability of Jatropha curcas to remove bauxite wastewater from soil. Pot experiments were conducted to investigate the bauxite wastewater on the phytoremediation potential of J. curcas grown in contaminated soils. J. curcas exhibited a significant increase in plant growth leaf, root activity, plant height, and plant shoot when grown in bauxite contaminated soils compared with J. curcas grown in uncontaminated soils after 30 d treatment. Under bauxite exposure, a higher aluminium removal (88.5%) was observed in soils planted with J. curcas than unplanted soils (39.6%). The bioconcentration factor was also found to be 5.62, indicating that J. curcas have great tolerance and hyperaccumulator of aluminium under high aluminium concentrations and are capable of phytoextraction of soil contaminated with bauxite wastewater.