Bauxite washing for the removal of clay

Clay impurities associated with bauxite negatively affect the Bayer process for alumina production. These impurities should be removed as far as possible by a beneficiation technique before the ore is used as feed for the Bayer process. In this current investigation, bauxite washing was conducted in the laboratory. Bauxite washing is a physical process that causes the disintegration and deagglomeration of the clay matrix, and bauxite is liberated from the clay（mainly rich in silica）. Subsequently, separation occurs with the assistance of wet screening at a predetermined cut size. Three techniques were investigated in the laboratory： drum washing, water-jet washing, and ultrasonic washing. Various operating parameters were investigated for drum washing and water-jet washing, including materials retention time, drum rotation speed, solid concentration, water-jet spray duration, pressure, and height. We concluded that the retention time of bauxite inside the drum at a solid concentration of 55wt% and a drum rotation speed of 31 r/min is the dominant parameter for the removal of clay from the bauxite surface.

A facile process to optimize performance of regenerated Nd-Fe-B sintered magnets:Chemo-selective dissolution washing

In this work,the recycled Nd-Fe-B powders and regenerated Nd-Fe-B sintered magnets with low impurity content were successfully prepared from Nd-Fe-B magnet sludge via reduction diffusion(RD)method followed by a chemo-selective dissolution washing proc ess.The chemo-selective dissolution effect of various solution(deionized water,dilute acetic acid solution,NH_(4)Cl-methanol solution) was evaluated by impurity content and magnetic properties of the recycled Nd-Fe-B powder.The NH_(4)Cl-methanol solution can selectively remove impurities with minimal damage to the magnetic phase.Besides,the optimal NH_(4)Cl concentration and liquid-to-solid ratio were investigated.As a consequence,the contents of Ca,O,and H after optimal washing process are reduced to 0.07 wt%,0.31 wt% and 0.22 wt%,respectively.Hence,M_(3) Tis increased to 146.72 emu/g,which is 33% higher than that of the initial sludge.Then,the regenerated Nd-Fe-B sintered magnets with properties of B_(r)=11.66 kG,H_(cj)=16.49 kOe,and(BH)_(m)=31.78 MGOe were successfully prepared by mixing with 40 wt% Nd4Fe14B alloy powders.Compared with the corresponding regenerated magnets washed with deionized water,the remanence and coercivity are increased by 18% and 59%,respectively.

High-efficiency organic solar cells enabled by an alcohol-washable solid additive

The solvent additive strategy has been widely utilized to boost the power conversion efficiency(PCE)of organic solar cells(OSCs).However,the residual solvent additive in the active layer tends to induce a gradual morphology degradation and further influences the long-term stability of OSCs.Here,a solid additive,1,4-diiodobenzene(DIB),was introduced to fabricate efficient OSCs.We found that the treatment of DIB can lead to optimized morphology to form a bicontinuous network with intensified intermolecular packing in the donor and acceptor phases.Notably,DIB can be easily removed from the active layer via a simple alcohol washing process and no further post-thermal annealing is needed,which is desirable for large-scale manufacturing of OSCs.As a result,high efficiencies of 17.47%for PM6:Y6 and 18.13%(certified as 17.7%)for PM6:BTP-eC9 binary OSCs are achieved,which are among the highest efficiencies reported for binary OSCs thus far.Moreover,OSCs fabricated with DIB also exhibit superior stability compared with the as-cast and traditional solvent additive processed devices.Additionally,DIB was successfully applied in different active layers,manifesting its general applicability.This work provides a feasible approach to enhance both the efficiency and stability of OSCs.