Review on coal-based reduction and magnetic separation for refractory iron-bearing resources

Zhang, Qiang; Sun, Yongsheng; Han, Yuexin; Li, Yanjun; Gao, Peng

doi:10.1007/s12613-021-2408-x

Cited by 18 publications

(4 citation statements)

References 124 publications

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“…Previous works have demonstrated that iron oxides reduce to a cementite phase (Fe-C) during CVD of polymers [12] or even to Fe 0 [52]. In fact, the reduction of iron at high temperatures (>230 • C) in the presence of carbon is a well-known process [53], so iron can be reduced during the process under study in this work. Upon TGA in air, a mass increase of up to 143% can be expected for the oxidation of Fe 0 to Fe 2 O 3 [54] for temperatures above 600 • C or up to 128% for the oxidation of Fe 0 to FeO.…”

Section: Carbon Nanotubesmentioning

confidence: 83%

Carbon Nanomaterials from Polyolefin Waste: Effective Catalysts for Quinoline Degradation through Catalytic Wet Peroxide Oxidation

Roman,

De Grande Piccinin,

Santos Silva

et al. 2023

Catalysts

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Quinoline (QN) is highly toxic and carcinogenic and has been detected in soil, groundwater, and biological tissues. Advanced oxidation processes (AOPs) have shown promise to address its degradation in wastewater treatment, with catalytic wet peroxide oxidation (CWPO) being highlighted due to its cost-effectiveness and mild operation. However, developing active and inexpensive catalysts is crucial for CWPO’s effectiveness. Another pressing issue is the accumulation of mixed, dirty plastic solid waste (PSW), particularly polyolefins used in packaging. Although recycling rates have increased, much plastic packaging remains in landfills. However, polyolefins can be converted into carbon-based nanostructured materials (CNMs), such as carbon nanotubes (CNTs), through chemical vapor deposition (CVD) using PSW as a carbon precursor. While many studies focus on CNT preparation, their application is often overlooked. In this context, this work proposes the preparation of CNMs, particularly CNTs, through CVD using a single-stage pyrolysis reactor. Polyolefins (LDPE, HDPE, and PP), both individually and in a mixture simulating PSW, were used as carbon sources. Given a sufficiently high temperature, the desired CNT architecture was successfully synthesized regardless of the starting polymer. These CNMs were then tested as catalysts for CWPO in simulated wastewater containing QN. The results showed a rapid degradation of QN (30–120 min) and high removals of total organic carbon (TOC) and aromatic compounds (75% and >90%, respectively), demonstrating the applicability of PSW-derived CNTs in the CWPO process for QN abatement.

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Section: Carbon Nanotubesmentioning

confidence: 83%

Carbon Nanomaterials from Polyolefin Waste: Effective Catalysts for Quinoline Degradation through Catalytic Wet Peroxide Oxidation

Roman,

De Grande Piccinin,

Santos Silva

et al. 2023

Catalysts

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“…As the main raw material of the steel industry, iron ore is an important strategic resource for a country [1][2][3][4]. With the rapid development of iron and steel metallurgy technology, the demand for iron ore is increasing [5].…”

Section: Introductionmentioning

confidence: 99%

Study on Efficient Dephosphorization in Converter Based on Thermodynamic Calculation

et al. 2023

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Given the accelerating depletion of iron ore resources, there is growing concern within the steel industry regarding the availability of high-phosphorus iron ore. However, it is important to note that the utilization of high-phosphorus iron ore may result in elevated phosphorus content and notable fluctuations in molten iron, thereby imposing additional challenges on the dephosphorization process in steelmaking. The most urgent issue in the process of converter steelmaking is how to achieve efficient dephosphorization. In this study, the influence of various factors on the logarithm of the phosphorus balance distribution ratio (lgLp), the logarithm of the P2O5 activity coefficient (lgγP2O5), and the logarithm of the phosphorus capacity (lgCp) were examined through thermodynamic calculations. The impact of each factor on dephosphorization was analyzed, and the optimal conditions for the dephosphorization stage of the converter were determined. Furthermore, the influence of basicity and FetO content on the form of phosphorus in the slag was analyzed using FactSage 7.2 software, and the precipitation rules of the slag phases were explored. The thermodynamic calculation results indicated that increasing the basicity of the dephosphorization slag was beneficial for dephosphorization, but it should be maintained below 3. The best dephosphorization effect was achieved when the FetO content was around 20%. The reaction temperature during the dephosphorization stage should be kept low, as the dephosphorization efficiency decreased sharply with the increasing temperature. In dephosphorization slag, Ca3(PO4)2 usually formed a solid solution with Ca2SiO4, so the form of phosphorus in the slag was mainly determined by the precipitation form and content of Ca2SiO4. The phases in the dephosphorization slag mainly consisted of a phosphorus-rich phase, an iron-rich phase, and a matrix phase. The results of scanning electron microscopy and X-ray diffraction analyses were consistent with the thermodynamic calculation results.

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“…Iron ore, as the basic raw material in steelmaking, plays an indispensable role in the iron and steel industry [1]. With the explosive growth of steel demand worldwide, especially the rapidly expanding steel production in China, the supply of high-quality iron ore has been severely limited while the exploration and exploitation of refractory iron ore has become urgent [2]. However, traditional beneficiation techniques based on density, magnetic properties, and surface hydrophobicity pose difficulties to processing low-grade iron ores with more complex mineralogical assemblage, especially iron ores in China [3].…”

Section: Introductionmentioning

confidence: 99%

“…For many years, considerable research has investigated the reduction roasting of iron ore, including: thermodynamic possibilities [2,4], kinetic mechanisms which control the process [5][6][7], and optimization of process parameters [6,8,9], etc. Practice shows that reduction roasting-magnetic separation can achieve excellent process indexes and obtain high-quality ironmaking raw materials from refractory iron ore resources [10,11].…”

Section: Introductionmentioning

confidence: 99%

Waste Corn Straw as a Green Reductant for Hematite Reduction Roasting: Phase Transformation, Microstructure Evolution and Process Mechanism

Zhang,

Sun,

Jin

et al. 2023

Minerals

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Mineral phase transformation (MPT) of hematite to magnetite by reduction roasting is a viable means of developing refractory iron ore resources. However, conventional coal-based reductants are prone to high carbon emissions and environmental pollution. Biomass, as a renewable green reductant, can make the MPT process more environmentally friendly while reducing the environmental impact associated with processing agricultural waste. This study systematically explored the feasibility of waste corn straw as a green reductant for hematite. Under the conditions of 8 min, 700 °C, a mass ratio of corn straw to hematite of 1:4, and a N2 flow rate of 300 mL/min, the best beneficiation indexes were achieved, with an iron grade of 69.82% and an iron recovery of 93.95%. During the MPT process, hematite was reduced under the action of corn straw, and the new magnetite particles were loose and porous, showing an acicular crystal structure. Meanwhile, the corn straw was converted into porous biochar.

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Review on coal-based reduction and magnetic separation for refractory iron-bearing resources

Cited by 18 publications

References 124 publications

Carbon Nanomaterials from Polyolefin Waste: Effective Catalysts for Quinoline Degradation through Catalytic Wet Peroxide Oxidation

Carbon Nanomaterials from Polyolefin Waste: Effective Catalysts for Quinoline Degradation through Catalytic Wet Peroxide Oxidation

Study on Efficient Dephosphorization in Converter Based on Thermodynamic Calculation

Waste Corn Straw as a Green Reductant for Hematite Reduction Roasting: Phase Transformation, Microstructure Evolution and Process Mechanism

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