Coal-based reduction followed by magnetic separation is an effective way to recover iron from high phosphorus-containing oolitic hematite ore. Given that high quantities of dephosphorization agent are needed to obtain low phosphorus reduced iron, a novel approach is proposed by the authors. Without prior phosphorus removal, the phosphorus was enriched in the reduced iron during a reduction process, then high-phosphorus reduced iron was refined to low phosphorus molten iron and high phosphorus dephosphorization slag to be used as a phosphate fertilizer. The influences of various parameters, including the reduction temperature, the reduction time, and the C/O molar ratio, on the reaction behavior of phosphorus during reduction process were studied. Experimental results indicate that a higher reduction temperature, a longer reduction time, or a higher C/O molar ratio was favorable for the reduction of apatite to phosphorus and the enrichment of phosphorus in reduced iron. X-ray diffraction (XRD) analysis demonstrated that the apatite was reduced to phosphorus and Ca₂SiO₄ (or Ca(Al₂Si₂O₈)) in the presence of SiO₂ and Al₂O₃, whilst the phosphorus enriched in reduced iron formed Fe₃P. The migration behavior of phosphorus was investigated using line scanning analysis of reduction products at different reduction times. The results show that the phosphorus primarily existed in the slag phase 10 min before reduction, and a large amount of phosphorus migrated into iron phase from slag phase with a reduction time of 40 min. The phosphorus content in the iron phase only slightly changed after 50 min. The pre-dephosphorization of reduced iron was performed at 1873 K, indicating a higher basicity or Fe_tO content of CaO-based slag was beneficial to dephosphorization of the reduced iron.

Suspension magnetization roasting followed by magnetic separation is an innovative and effective way to recover iron from refractory iron ores, and the particle size of the ore greatly affects the roasting index. To identify the effect of particle size on the reduction kinetics for the...

Reduced iron (1.74% P) is produced from oolitic hematite ore by coal-based reduction and magnetic separation. To realize the comprehensive utilization of Fe and P, the dephosphorization behavior of the reduced iron is investigated in the presence of CaO–SiO ₂ –FeO–Al ₂ O ₃ slag. The P content of the final iron and the P ₂ O ₅ content of the high-P-containing slag are determined, and the phase composition and P ₂ O ₅ solubility of the slag are analyzed. The P content can be decreased to 0.2% when the initial slag has a basicity of 3.5 and contains 55% FeO and 6% Al ₂ O ₃ . The phases of the high-P-containing slag are mainly Ca ₂ Al ₂ SiO ₇ , Ca ₂ SiO ₄ , Ca ₅ (PO ₄ ) ₂ SiO ₄ , and FeO, and P exists in the form of Ca ₅ (PO ₄ ) ₂ SiO ₄ . Excessively high basicity or low content of FeO and Al ₂ O ₃ results in free CaO, which affects the dephosphorization results. The change rule of the intensity of the Ca ₅ (PO ₄ ) ₂ SiO ₄ diffraction peak agrees well with the dephosphorization indexes, which further verify the accuracy of the dephosphorization experiments. Moreover, the P ₂ O ₅ content and P ₂ O ₅ solubility of the high-P-containing slag reached as high as 14.41 and 94.54%, respectively, indicating that it can be used as a phosphate fertilizer.

Through the brief introduction of the working principle of the brake motor, combined with the theoretical analysis of the brake motor dynamic brake torque test method (directtest method and indirect test method), it is concluded that the selection of the test method is closely related. According to the sensor type, installation position, test range and accuracy requirements. The differences between direct measurement method and indirect measurement method are compared, their respective measurement methods are introduced, and their advantages and disadvantages are summarized. According to the test requirements, the appropriate test method can be selected, and the direct test method and indirect test method can be selected at the same time, to ensure the safety and stability of product