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Curcuma wenyujin , a perennial herb of the ginger family, is renowned for its significant medicinal properties. Phosphorus (P), a vital nutrient for plant growth and development, has seen its levels, particularly organic P, increase in the soils of agricultural regions in southern China, presenting new challenges for nutrient management. This study aimed to uncover the molecular responses of C. wenyujin seedlings to both normal and high phosphorus (HP) conditions, shedding light on their adaptation strategies to P stress. Through transcriptome and metabolome analyses of the seedlings under normal and HP conditions, we identified 1,793 metabolites, with 195 showing differential expression. Notably, KEGG enrichment analysis highlighted 35 significantly differential accumulation metabolites (DAMs). Comparing the control group (CK) and HP treated groups (T) revealed 840 differentially expressed genes (DEGs), pinpointing the molecular divergences in response to varying P levels. Importantly, we found a potential gene, purple acid phosphatase 17 ( pap17 ) that may cofer HP stress conditions in C. wenyujin . That elucidated the response variations of C. wenyujin seedlings to diverse P concentrations. The research suggested that C. wenyujin may adjust to varying P levels by modulating metabolites and genes linked to amino acid and phenylpropane metabolism. It highlighted the sophisticated mechanisms plants utilize to manage P stress, offering insights into their survival tactics in settings where P availability changes.

A high-phosphorus-content polyphosphonate (PBDA), containing two phosphorus-based structures: phosphaphenanthrene (DOPO) and phenyl phosphonate groups, was synthesized and used in flame retardant polyethylene terephthalate (PET). Good self-extinguishing property (high UL 94 grade and LOI value), superior flame retardancy (lower heat/smoke release), and high quality retention (high carbon residue) were endowed to PET by PBDA. When 10 wt% PDBA was added, the peak heat release rate (pHRR), total heat release (THR), and total smoke rate (TSR) of PDBA/PET were found to be significantly reduced by 80%, 60.5%, and 21%, respectively, compared to the pure PET, and the LOI value jumped from 20.5% for pure PET to 28.7% with a UL-94 V-0 rating. The flame-retardant mode of action in PET was verified by thermogravimetric analysis-Fourier transform infrared (TGA-FTIR), pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), real-time FTIR, and scanning electron microscopy (SEM). Phosphaphenanthrene and phosphonate moieties in PDBA decomposed in sequence during heating, continuously releasing and keeping high-content PO· and PO2· radicals with a quenching effect and simultaneously promoting the formation of viscous crosslinked char layers causing a high barrier effect. PDBA mainly acted in the gas phase but the condensed-phase flame retardant function was also considerable.

Reduction of iron in high-phosphorus oolitic ore from the Lisakovsk deposit using solid carbon, carbon monoxide, and hydrogen. An X-ray phase analysis was used to determine the phase composition of the samples after reduction roasting. When reduced with carbon monoxide or hydrogen, α-iron appears in the samples, while phosphorus remains in the form of iron, calcium, and aluminum phosphates. After roasting with solid carbon, phosphorus is reduced from iron and calcium phosphates and migrates into the metal but remains in aluminum phosphate. A micro X-ray spectral analysis showed that at a temperature of 1000 °C and a holding time of 5 h, during reduction with solid carbon, the phosphorus content in the metallic phase reaches up to 7.1 at. %. When reduced with carbon monoxide under the same conditions, the metallic phase contains only iron, and phosphorus is found only in the oxide phase. When reduced with hydrogen at 800 °C, phosphorus is almost absent in the metallic phase, but at 900 °C, phosphorus is reduced and its content in the metallic phase reaches 2.1 at. %.

Conventional separation methods often prove ineffective for complex, refractory high-phosphorus iron ores. Recent advances propose a coal-based direct reduction dephosphorization-magnetic separation process, achieving significant dephosphorization efficiency. This review systematically analyzes phosphorus occurrence states in high-phosphorus oolitic iron ores across global deposits, particularly within iron minerals. We categorize contemporary research and elucidate dephosphorization mechanisms during coal-based direct reduction. Key factors influencing iron mineral phase transformation, iron enrichment, and phosphorus removal are comprehensively evaluated. Phosphorus primarily exists as apatite and collophane gangue m horization agents function by: (1) inhibiting phosphorus-bearing mineral reactions or binding phosphorus into soluble salts to prevent incorporation into metallic iron; (2) enhancing iron oxide reduction and coal gasification; (3) disrupting oolitic structures, promoting metallic iron particle growth, and improving the intergrowth relationship between metallic iron and gangue. Iron mineral phase transformations follow the sequence: Fe2O3 → Fe3O4 → FeO (FeAl2O4, Fe2SiO4) → Fe. Critical parameters for effective dephosphorization under non-reductive phosphorus conditions include reduction temperature, duration, reductant/dephosphorization agent types/dosages. Future research should focus on: (1) investigating phosphorus forms in iron minerals for targeted ore utilization; (2) reducing dephosphorization agent consumption and developing sustainable alternatives; (3) refining models for metallic iron growth and improving energy efficiency; (4) optimizing reduction atmosphere control; (5) implementing low-carbon emission strategies.

Excessive phosphorus (P) levels can disrupt nutrient balance in plants, adversely affecting growth. The molecular responses of Pennisetum species to high phosphorus stress remain poorly understood. This study examined two Pennisetum species, Pennisetum americanum × Pennisetum purpureum and Pennisetum americanum , under varying P concentrations (200, 600 and 1000 µmol·L − 1 KH 2 PO 4 ) to elucidate transcriptomic alterations under high-P conditions. Our findings revealed that P. americanum exhibited stronger adaption to high-P stress compared to P. americanum × P. purpureum . Both species showed an increase in plant height and leaf P content under elevated P levels, with P. americanum demonstrating greater height and higher P content than P. americanum × P. purpureum . Transcriptomic analysis identified significant up- and down-regulation of key genes (e.g. SAUR , GH3 , AHP , PIF4 , PYL , GST , GPX , GSR , CAT , SOD1 , CHS , ANR , P5CS and PsbO ) involved in plant hormone signal transduction, glutathione metabolism, peroxisomes, flavonoid biosynthesis, amino acid biosynthesis and photosynthesis pathways. Compared with P. americanum × P. purpureum , P. americanum has more key genes in the KEGG pathway, and some genes have higher expression levels. These results contribute valuable insights into the molecular mechanisms governing high-P stress in Pennisetum species and offer implications for broader plant stress research.

With the use of high phosphorus iron ore, there is a large amount of high phosphorus steel slag formed, which is difficult to handle. How to separate the elemental phosphorus has become a key issue in the secondary utilization of steel slag. Experiments found that there were distinct phosphorus-rich phases, iron-rich phases and matrix phases in the high-phosphorus steel slag cooled with the furnace. In this study, the effects of heat treatment conditions and slag basicity on the P2O5 content, as well as the size of the phosphorus-rich phase were investigated. Taking all factors into consideration, the optimal experimental conditions were determined as the holding temperature and time of 1350 °C and 60 min, respectively, and the slag basicity of 1.8. At this time, the P2O5 content in the phosphorus-rich phase reached 24.2%, and the average size of the phosphorus-rich phase was 63.51 μm. The phosphorus-rich phase is separated by crushing and magnetic separation for making phosphate fertilizer, and the residual steel slag is used again for steelmaking, which enables the realization of the resource utilization of high phosphorus steel slag.

Diverging from conventional dephosphorization approaches, this study employs a novel pre-reduction and smelting separation (PR-SS) to efficiently co-recover iron and phosphorus from high-phosphorus oolitic iron ore, directly yielding Fe–P alloy, and the Fe–P alloy shows potential as feedstock for high-phosphorus weathering steel or wear-resistant cast iron, indicating promising application prospects. Using oolitic magnetite concentrate (52.06% Fe, 0.37% P) as feedstock, optimized conditions including pre-reduction at 1050 °C for 2 h with C/Fe mass ratio of 2, followed by smelting separation at 1550 °C for 20 min with 5% coke, produced a metallic phase containing 99.24% Fe and 0.73% P. Iron and phosphorus recoveries reached 99.73% and 99.15%, respectively. EPMA microanalysis confirmed spatial correlation between iron and phosphorus in the metallic phase, with undetectable phosphorus signals in vitreous slag. This evidence suggests preferential phosphorus enrichment through interfacial mass transfer along the pathway of the slag phase to the metal interface and finally the iron matrix, forming homogeneous Fe–P solid solutions. The phosphorus migration mechanism involves sequential stages: apatite lattice decomposition liberates reactive P2O5 under SiO2/Al2O3 influence; slag–iron interfacial co-reduction generates Fe3P intermediates; Fe3P incorporation into the iron matrix establishes stable solid solutions.

High-phosphorus oolitic iron ores (HPOIOs) possess abundant reserves but are incompatible with conventional blast furnace ironmaking, as phosphorus migrates into hot metals during carbothermic reduction, preventing the production of low-phosphorus clean steel. To overcome this limitation, an innovative approach integrating alkaline briquette direct reduction and smelting separation was proposed. Briquettes were prepared from oolitic magnetite concentrate (52.01 wt% Fe, 0.29 wt% P, 0.11 wt% S) with a basicity (R) of 2.0 and 5 wt% MgO added as a desulfurizer. After direct reduction and smelting separation, the resulting metallic iron exhibited a content of 98.56 wt% Fe, with 0.036 wt% P and 0.046 wt% S, achieving an Fe recovery of 87.63%. The dephosphorization and desulfurization efficiencies reached 94.67% and 90.56%, respectively, meeting the clean steel requirements. Phosphorus was effectively stabilized within the gehlenite and merwinite phases as a solid solution of Ca3(PO4)2, inhibiting its transfer to iron. Thermodynamic analyses confirmed that high basicity (R ≥ 2.0) significantly suppressed P2O5 activity, preventing phosphate reduction. The formation of a Ca3(PO4)2–Ca2SiO4 solid solution further obstructed phosphorus migration. This dual mechanism of “chemical fixation and thermodynamic stabilization” enables efficient dephosphorization, offering a sustainable pathway for utilizing HPOIOs.

Phosphorous is an undesired element present in iron ore used in the steel making process. It leads to an increase in overall production cost as well as deteriorated steel quality. The desired phosphorus content in iron ores used in steel making is < 0.1%. Numerous beneficiation studies are mentioned in the literature; however, there is no commercial scale technology established to beneficiate high phosphorous iron. The major phosphorous bearing minerals are apatite (Ca 5 (PO 4 )(Cl/F/OH), wavellite (Al 3 (PO 4 ) 2 (OH) 3 ·5(H 2 O)), senegalite (Al 2 (PO 4 )(OH) 3 (H 2 O), barrandite ((Fe,Al)PO 4 ·2H 2 O), etc. Ultrafine grinding is required to liberate phosphorous minerals from iron ore minerals and subsequently subject it to flotation, acid leaching, and bioprocessing. The selective flotation of iron ore could successfully reduce the phosphorous content from 0.82% to < 0.20% with the combination of grinding, magnetic separation, and carbothermic reduction. Acid leaching processes are also able to remove ~80% (0.85%→0.16%) of phosphorus; however, these are relatively costly and complex processes. The mechanism of bio-extraction for phosphorous removal is reported as one of the most successful processes. This process is capable of removing more than 80% of the total phosphorous and significantly reducing the phosphorous content from 1.06% to 0.16%. The main disadvantage of this process is that it occurs at a much slower pace. In today’s scenario, ultrafine grinding followed by froth flotation seems to be the most feasible solution for the beneficiation of high phosphorous iron ore in which the concentrate obtained can be utilized for pellet making and ultimately used for steel making processes. Development of additives for leaching, roasting, and bioprocessing can be explored further to make these processes more effective and economically viable.

The paper proposes the innovative technology of hydrogen mineral phase transformation–magnetic separation–acid leaching for iron enrichment and dephosphorization, based on the mineralogical characteristics of high phosphorus oolitic hematite and difficulties that make it difficult to utilize traditional beneficiation for separation. The influences of the reduction temperature, reduction time, and reductant concentration during hydrogen mineral phase transformation on the separation index of high phosphorus oolitic hematite were investigated. The optimal conditions were determined to be a reduction time of 25 min with a reductant concentration of 30% and a reduction temperature of 540 °C, under which an iron grade of 65.05%, iron total recovery of 81.86%, and phosphorus content of 0.081% were obtained for the iron concentrate. The evolution of mineral phases, magnetic properties, and mineral microstructures was investigated by XRD, VSM, XPS, SEM, and BET. The results provide new references of technology and theoretical support for the efficient utilization of refractory iron ores.