Effect of Cycling Loaded Rare Earths on Stripping Process in P507 Extraction System

P507 （HEH [EHP]） is an important extractant for the separation of rare earth and is widely used in industry. Since the complexes of heavy rare earth ions with saponified P507 are so stable that the rare earth ions are difficult to be exchanged and stripped by H^＋ ions. Thus, the cycled extractant loads certain amount of heavy rare earth ion after stripped by acid. This amount of rare earth ions loaded in blank organic phase is named as the ＂cycling loaded rare earth ions （CLREs）＂. In the separation process of Tm^3＋, Yb^3 ＋, and Lu^3 ＋ , the amount of CLREs carl be more than 10% of the normal capacity of saponifiedorganic phase. In fact, CLREs affect the separation efficiency and decrease the purity of the products. Based on the extracting-stripping equilibrium and mass balance, the influence of different process parameters on the amount of CLREs was studied by computer simulation. The results indicate that higher acid consumption and more stripping stages are required to eliminate CLREs. For an industrial practice, however, the acid consumption and the number of stripping stage can be designed by choosing an economic process and controlling CLREs at a reasonable level.

Surface Analysis of Chemical Stripping Titanium Alloy Oxide Films

The chemical stripping method of titanium alloy oxide films was studied. An environment friendly solution hydrogen peroxide and sodium hydroxide without hydrofluoric acid or fluoride were used to strip the oxide films. The morphologies of the surface and cross-section of the oxide films before and after the films stripping were characterized by using scanning electron microscopy （SEM）. The microstructure and chemical compositions of the oxide films before and after the films stripping were investigated by using Raman spectroscopy （Raman） and X-ray photoelectron spectroscopy （XPS）. It was shown that the thickness of the oxide film was in the range of 5-6 μm. The oxide films were stripped for 2 to 8 min in the solution. Moreover, the effect of the stripping time on the efficiency of the film stripping was investigated, and the optimum stripping time was between 6-8 min. When the stripping solution completely dissolved the whole film, the α/β microstructure of the titanium alloy Ti-10V-2Fe-3Al was partly revealed. The stripping mechanism was discussed in terms of the dissolution of film delamination. The hydrogen peroxide had a significant effect on the dissolution of the titanium alloy anodic oxide film. The feasibility of the dissolution reaction also was evaluated.

Porous polymer electrolytes for long-cycle stable quasi-solid-state magnesium batteries

The development of applicable electrolytes is the key point for high-performance rechargeable magnesium batteries(RMBs).The use of liquid electrolyte is prone to safety problems caused by liquid electrolyte leakage.Polymer-based gel electrolytes with high ionic conductivity,great flexibility,easy processing,and high safety have been studied by many scholars in recent years.In this work,a novel porous poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)membrane is prepared by a phase inversion method.By immersing porous PVDF-HFP membranes in MgCl2-AlCl3/TEGDME(Tetraethylene glycol dimethyl ether)electrolytes,porous PVDF-HFP based electrolytes(PPEs)are formed.The PPE exhibits a high ionic conductivity(4.72×10^(-4) S cm-1,25℃),a high liquid electrolyte uptake of 162%,as well as a wide voltage window(3.1 V).The galvanostatic cycling test of Mg//Mg symmetric cell with PPE reveals that the reversible magnesium ion(Mg^(2+))plating/stripping occurs at low overpotentials(~0.13 V).Excellent long cycle stability(65.5 mAh g^(-1) over 1700 cycles)is achieved for the quasisolid-state RMB assembled with MoS2/C cathode and Mg anode.Compared with the liquid electrolyte,the PPE could effectively reduce the side reactions and make Mg^(2+)plating/stripping more uniformly on the Mg electrode side.This strategy herein provides a new route to fabricate high-performance RMB through suitable cathode material and polymer electrolyte with excellent performance.

HEAT TRANSFER ANALYSIS DURING ROLLING OF THIN SLAB IN CSP

A mathematical model has been built to numerically predict the thermal history of thin slab during CSP （compact strip process） rolling. To estimate the temperature distribution in the slab mare accurately, the mathematical model combines heat transfer in the slab, in the roll, and at the roll-slab interface during bite. The numerical results agree with on-site running data, which proves the reliabili~, of the mathematical model. The results show that roll chilling has a significant effect on the temperature distribution in the slab.

In-situ observation and analysis of solidified structure evolution of S50C steel in soaking furnace

The evolution of solidified structure of S50C steel during heat treatment in compact strip production process was studied through an ultra-high-temperature confocal scanning laser microscope.It was found that the solidified structure consisted of dendritic crystals with secondary dendrite arm spacing ranging in 32-120μm,where carbon segregation was evident,and the dendrite arms wereα-Fe.The insignificant change was observed at a soaking temperature of 1180℃,whereas at 1300℃,the finer structure firstly disappeared,and then,the coarsening decreased,indicating that carbon tended to be homogenized.Therefore,the microsegregation was improved at 1300℃for 15 min.The phase transformation ofα-Fe→γ-Fe enhanced the carbon diffusion,and the evolution of the equivalent radius req was controlled by carbon diffusion.The diffusion coefficient of carbon(D=15μm2/s)was determined by using the inverse problem method.

Effects of design parameters and tension on behavior of a coil using finite element analysis

During the thin strip coiling process, it is necessary to use a sleeve with a mandrel to prevent excessive deformation of the strip. Stress distribution in the sleeve and in the strip is an important factor that determines the quality of the coil. However, owing to the accumulation of high pressure, it is difficult to determine the stress distribution through experimentation. Thus, stress analysis of the strip coiling process was conducted. Finite element analysis was used to investigate the effects of the weight of the strip and the mandrel on the stress distribution and stress concentration near the starting point of the coil. The radial stress was predicted for a coil with a stacked thickness of 384 mm, which corresponds to a strip length of 1486 m, using the stress analysis model developed in a preceding research. A method was presented to reduce the weight and radial stress of a strip coil. It was found that the deformation of the sleeve can be reduced by decreasing the gap between the mandrel segments. The thickness of the sleeve can be reduced from 120 to 106 mm using the stress analysis results. Furthermore, coiling tension can be reduced by 44% compared to the existing value considering the interlayer slip of the strip coil.