Search

Abstract: This study reported a facile synthetic method for MCM-41 mesoporous material at room temperature using iron ore tailing and cetyltrimethylammonium bromide (CTAB) as a silicon source and a structure-directing agent, respectively. The obtained product was systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and nitrogen absorption–desorption measurement. It was confirmed that the as-synthesized material exhibited a well-ordered mesostructure with high surface area of ca. 634m2/g, large pore volume of 0.61cm3/g, and average pore diameter of 3.8nm. The removal efficiency towards model pollutant methylene blue (MB) was performed through produced MCM-41 and 111mg/g of MB could be eliminated under an optimal condition. Therefore, the material could be potentially used as a low-cost and efficient adsorbent candidate to treat organic contaminates in wastewater or other fields. [Copyright &y& Elsevier]

Abstract: Iron ore tailing—a waste material of mineral beneficiation plants, is used as a source of iron for synthesizing magnetite powder. Iron ore tailings containing 15.98% Fe2O3, 83.36% SiO2 and 0.44% Al2O3 have been subjected to HCl digestion on a hot plate to extract the entire amount of Fe2O3 as FeCl3. A portion of extracted FeCl3 solution has been used to convert it to FeCl2 via metallic iron formation by using NaBH4 as a reducing reagent. Then, the left out FeCl3 solution and derived FeCl2 solutions (from FeCl3) are mixed in an appropriate molar ratio (2:1) for synthesizing magnetite powder by the addition of alkali solution. The magnetite powder samples have been characterized by means of powder XRD, SEM, vibrating sample magnetometer and laser particle size analyzer. XRD study confirms the formation of magnetite phase. The magnetite particles synthesized in different ways show varying degrees of magnetization behavior which is attributed to the change in their particle size induced by the use of different precipitating reagents. [Copyright &y& Elsevier]

The aim of this study is to understand the relationship between the polymerization degree and cementitious activity of iron ore tailings. In light of the poor usage of iron ore tailings, stockpile samples from Tangshan were studied in terms of their ability to become cementitious materials. Compound thermal activation was used to improve the cementitious properties of the tailings, while analyzing methods, such as X-ray diffraction (XRD), infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and X-ray photoelectron spectrometer (XPS), were employed to study the changes in phase and structure under different activation conditions. The results reveal clear relationships between the binding energies of Si2p and O1s, polymerization degree, and cementitious activity of iron ore tailings. [ABSTRACT FROM AUTHOR]

Excessive and unregulated stacking of iron ore tailing (IOT) has created numerous environmental issues, which has drawn considerable attention to focus on the resource utilization of IOT. The present study attempts to investigate the feasibility of IOT as a filler alternative compared to limestone filler, from the perspective of asphalt mastic. To achieve that, the physical and chemical properties for two types of fillers (IOT and limestone) were tested by the laser particle size analyzer, X-ray fluorescence as well as scanning electron microscopy. Four filler/asphalt weight ratios (0.6, 0.8, 1.0, 1.2) were then selected to prepare asphalt mastics. The rotational viscosity test, temperature sweep test as well as multiple stress creep recovery test were conducted to assess the high-temperature performance for asphalt mastics. Furthermore, environmental and economical aspects were evaluated by the leaching toxicity and cost-benefit analysis. Results show that the IOT possesses a smaller particle size and larger specific surface area than the limestone, which contributes to the adsorption of asphalt on the particle surface. As for asphalt mastics, the replacement of filler by IOT can greatly enhance the viscosity, rutting factor as well as percentage of elastic recovery, and significantly reduce the non-recoverable creep compliance. Further, IOT has no risk of large-scale use as building material based on the leaching results, and considerable economic benefits (benefit-cost ratio >1) can be obtained from the utilization process. Consequently, IOT has a promising potential as an environment-friendly filler to replace the mineral filler in asphalt mixture in view of the pavement performance and environmental aspects. [Display omitted] [ABSTRACT FROM AUTHOR]

• Dry and sludge iron-rich mining tailing (IOT) were studied as cement replacement. • Hydration, rheology and compressive strength were investigated. • The iron ore tailing favored hydration of the aluminate phases. • Rheological properties were affected by the morphology and content of the IOT. The present work aims at evaluating the technical feasibility of reusing iron ore tailing (IOT) rich in iron in natura (sludge and dry), partially replacing cement in pastes by up to 15%. Fluid, hydration and hardened state properties were investigated. IOT favored hydration of the aluminate phases due to the nucleation effect and the rheological behavior was affected by the morphology of the particles. The early age compressive strength of the cement paste is maintained when using 10% or less of sludge in the mixture. The use of higher contents or 10% of dry IOT reduced slightly the late age strength of the material. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the influence of the incorporation of iron ore tailings (IOTs) on the mechanical, thermal, and morphological properties of polypropylene, IOT, and maleic anhydride grafted polypropylene (MAPP) composites. IOTs come in the form of coarse particulates (sand) and fine particulates (iron sludge). Composites were processed using a twin-screw extruder, and specimens for tensile and impact tests were fabricated through injection molding. Results showed that coarse IOTs were predominantly composed of quartz (SiO 2) and hematite (Fe 2 O 3), while fine IOTs mainly contained hematite and quartz. Results of the tensile tests showed that, for both types of IOTs, when the IOT content was increased, the modulus of elasticity increased, while the ultimate tensile strength, elongation at break, and impact strength of the composite decreased. Thermal analysis showed that the incorporation of IOTs increased the crystallinity of the composite relative to pure PP; however, the increase in the amount of both coarse and fine IOTs did not significantly change the crystallinity. The melting temperature was influenced by the IOT content for both types of IOTs. The interaction between PP and IOT was not favorable, because PP only partially wetted the IOTs without encapsulating the entirety of the particles. There was a good dispersion of IOT particles into PP; however, there were some formation of agglomerates. In general, both types of IOTs can be used as filler in PP matrix. Therefore, it is necessary to develop a method to improve the interaction between IOTs and PP to successfully manufacture PP-IOT composites. [ABSTRACT FROM AUTHOR]