Real-time analysis of metallic mineral grade and slurry concentration is significant for improving flotation efficiency and product quality. This study proposes an online detection method of ore slurry combining the P...
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Real-time analysis of metallic mineral grade and slurry concentration is significant for improving flotation efficiency and product quality. This study proposes an online detection method of ore slurry combining the Prompt Gamma Neutron Activation Analysis (PGNAA) technology and artificial neural network (ANN), which can provide mineral information rapidly and accurately. Firstly, a PGNAA analyzer based on a D-T neutron generator and a BGO detector was used to obtain a gamma-ray spectrum dataset of ore slurry samples, which was used to construct and optimize the ANN model for adaptive analysis. The evaluation metrics calculated by leave-one-out cross-validation indicated that, compared with the weighted library least squares (WLLS) approach, ANN obtained more precise and stable results, with mean absolute percentage errors of 4.66% and 2.80% for Fe grade and slurry concentration, respectively, and the highest average standard deviation of only 0.0119. Meanwhile, the analytical errors of the samples most affected by matrix effects was reduced to 0.61 times and 0.56 times of the WLLS method, respectively.
Catalysts with high catalytic performance are crucial for the catalytic ozonation of organic wastewater. This study synthesized an efficient, stable, and practical Fe-Mn/Al2O3 ozone catalyst for wastewater treatment u...
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Catalysts with high catalytic performance are crucial for the catalytic ozonation of organic wastewater. This study synthesized an efficient, stable, and practical Fe-Mn/Al2O3 ozone catalyst for wastewater treatment using an impregnation calcination method, and applied it in the catalytic ozonation of wastewater. When the concentration of manganese nitrate was 0.15 mol/L, the Mn/Fe ratio was 3:1, the immersion time was 24 h, the calcination temperature was 500 degrees C, and the calcination time was 4 h, the prepared Fe-Mn/Al2O3 had the best catalytic effect on simulated wastewater, with a chemical oxygen demand (COD) removal efficiency of 73.6 %. At the same time, the physicochemical properties of the catalyst were investigated, and the catalytic effect of the catalyst on actual coking wastewater was investigated on a laboratory scale. When the ozone concentration was 20 mg/L, the gas flow rate was 0.5 L/min, the catalyst concentration was 400 g/L, and the pH was 7.02, the actual COD removal efficiency of coking wastewater was 71.6 %. The pilot test results showed that the COD of the treated coking wastewater could stably meet the standard (COD<80 mg/L), with an average COD removal rate of about 58.3 %, indicating that the Fe-Mn/Al2O3 had high catalytic activity and good stability. Kinetic analysis showed that the degradation process of organic pollutants followed the pseudo-second-order kinetic equation. The results of water quality analysis such as conventional water quality indicators, fluorescence spectroscopy, and molecular weight classification indicated that the large molecular organic pollutants were efficiently degraded. Mechanism analysis indicated that the active components of the catalyst reacted with ozone through electron transfer to enhance the ozone utilization efficiency and efficiently remove organic pollutants. This study can provide theoretical support and technical reference for the standardized discharge of coking wastewater in the future.
In this study, a series of aluminum borate ceramics (ABCs) with needle-like whiskers were obtained using a low-cost, solid-state, pressureless sintering ceramic route, without any additives during the preparation proc...
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In this study, a series of aluminum borate ceramics (ABCs) with needle-like whiskers were obtained using a low-cost, solid-state, pressureless sintering ceramic route, without any additives during the preparation process. The effects of different alumina/boric acid molar ratios and sintering temperatures on the phase composition, microstructure, mechanical properties, specific surface area, pore size distribution, and sub-cadmium neutron shielding properties of ABCs were studied using orthogonal experiments. It was observed that pure phase aluminum borate (Al18B4O33) ceramics could be obtained at 1100 degree celsius, forming a mass of needle-like whiskers. The whiskers' aspect ratio, fracture work, specific surface area, and pore size distribution of ABCs are maximized when ABCs are sintered at 1100 degree celsius with 9:6 alumina/boric acid molar ratio. In this condition, ABCs (0.5 cm) can shield 70% of sub-cadmium neutrons (E<0.4 eV). These findings demonstrate the great potential of aluminum borate ceramics for neutron shielding applications.
In this work, a novel electromagnetic wave absorption geopolymer was created with efficient utilization of two solid wastes iron tailings and blast furnace slag, meanwhile the mechanism and impacts of iron tailings co...
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In this work, a novel electromagnetic wave absorption geopolymer was created with efficient utilization of two solid wastes iron tailings and blast furnace slag, meanwhile the mechanism and impacts of iron tailings content, water-solid ratio and specimen thickness on their electromagnetic wave absorption and mechanical property were systematically investigated. It was found the pores, micro-cracks and unreacted particles in the specimens are benefitial for electromagnetic wave absorption but against to compressive strength, even though the compressive strength reaches 69.7 MPa with the iron tailings content 50% and water-solid ratio 0.4. The addition of iron tailings significantly enhances the electromagnetic wave absorption properties of the geopolymers, and increasing iron tailings content improves the number of pores, micro-cracks and the permeability of geopolymers. The electromagnetic wave absorption properties of the geopolymer initially increase and then decrease with the increase of specimen thickness and water-solid ratio. With an iron tailings content 70%, water-solid ratio 0.4 and thickness 30 mm, the effective absorption bandwidth (< -5 dB) was optimized to 10.44 GHz with a minimum reflection loss of -13.34 dB. A new mechanism for electromagnetic absorption in iron tailings has been proposed, in which the electromagnetic wave absorption of geopolymers is mainly dominated by magnetic loss and spatial propagation loss. This study provides higher competitiveness and comprehensive utilisation of iron tailings in the field of electromagnetic wave absorbing building materials, and has great potential for applications in military and other fields affected by high electromagnetic wave frequencies.
In order to understand the enhancement mechanism of the interaction between functionalised carbon nanotubes and polymer matrix, and to investigate the effects of different functionalised carbon nanotubes on the proper...
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In order to understand the enhancement mechanism of the interaction between functionalised carbon nanotubes and polymer matrix, and to investigate the effects of different functionalised carbon nanotubes on the properties of composites at the microscopic level, the models of pure polyurethane (PUR), carbon nanotubes/polyurethane (CNTs/PUR), hydroxyl-functionalised carbon nanotubes/polyurethane (CNTOH/PUR), and carboxyl-functionalised carbon nanotubes/polyurethane (CNTCOOH/PUR) systems were constructed, and molecular dynamics methods were used to simulate the effects of different functionalised carbon nanotubes on the mechanical properties of polyurethane composite systems. The effects of different functionalised carbon nanotubes on the properties of PUR composite systems were compared by analysing the properties of PUR and its composite systems in terms of free volume fraction (FFV), radial distribution function (RDF), binding energy, and density distribution of PUR around different functionalised carbon nanotubes. The effects of intermolecular interactions on the properties of the composite systems were elucidated at the microscopic level. The final simulation results show that the CNTCOOH/PUR composite system with added carboxylated CNTs has the highest tensile yield strength, compressive properties and modulus;the smallest free volume fraction;the strongest bonding energy between CNTCOOH and PUR matrix, the largest density distribution of PUR matrix around CNTCOOH, and the best interfacial interaction. [GRAPHICS] .
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