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Gyrokinetic simulation of the toroidal rotation of plasma with a stochastic magnetic field perturbation is carried out. The simulation results suggest that the stochastic magnetic perturbation drives the plasma to toroidally rotate through the ambipolar radial electric field E r established on the timescale of electron transit time. It is found that this spontaneous flow driven on the timescale less than an ion–ion collision time is the parallel return flow of the E r × B drift. The ion–ion collisional effect further changes the parallel return flow to the toroidal rigid-body flow after a few ion–ion collision times. This simulation result is consistent with the toroidal rigid-body rotation observed in tokamak experiments with a stochastic layer induced by the externally applied resonant magnetic perturbation. [ABSTRACT FROM AUTHOR]

Dephosphorization is essential for utilizing high-phosphorus iron ore (HPIO), and this work prepared reduced iron powder via reductive roasting in a semi-industrial rotary kiln follower by magnetic separation. Under the conditions, reductive temperature of 1150°C, duration time of 60 min, mass ratio of briquettes to pea coal of 1:1, the reduced iron powder with an iron grade of 93.21% and phosphorus content of 0.13% was obtained, of which the corresponding iron recovery is 82.68% and dephosphorization ratio is 89.87%. The limestone reacted with gangue to form calcium aluminum silicate, preventing the reduction of phosphorate and in turn the formation of ferrophosphorus. [ABSTRACT FROM AUTHOR]

To realize the comprehensive utilization of ludwigite ore, an integrated and efficient route for the boron and iron separation was proposed in this work, which via soda-ash roasting under CO–CO2–N2 atmosphere followed by grind-leaching, magnetic separation, and CO2 carbonation. The effects of roasting temperature, roasting time, CO/(CO+CO2) composition, and Na2CO3 dosage on the boron and iron separation indices were primarily investigated. Under the optimized conditions of the roasting temperature of 850°C, roasting time of 60 min, soda ash dosage of 20wt%, and CO/(CO+CO2) of 10vol%, 92% of boron was leached during wet grinding, and 88.6% of iron was recovered during the magnetic separation and magnetic concentrate with a total iron content of 61.51wt%. Raman spectra and 11B NMR results indicated that boron exists as B(OH)4− in the leachate, from which high-purity borax pentahydrate could be prepared by CO2 carbonation. [ABSTRACT FROM AUTHOR]

A radially propagating electrostatic shear Alfvén wave (ωH mode) is found during the formation of ambipolar radial electric field in a magnetic stochastic layer through gyrokinetic simulation. It is found that the times scale of the ambipolar radial electric field formation is the damping time of the ωH mode. The frequency and damping rate of the ωH mode are theoretical derived, which are in good agreement with the simulation results. [ABSTRACT FROM AUTHOR]