Hai Chuan Wang

Desulfurization and Structural Transformation Behavior of Lead Sulfate in Sodium Hydroxide Molten Salt

This paper is devoted to studying the desulfurization and structural transformation behavior of lead sulfate in alkaline medium. The effects of roasting temperature, roasting time, and raw material ratio on the desulfurization and phase transition behavior of lead sulfate in sodium hydroxide molten salt was systematically investigated through a series of experiments and analyses. The results show that lead sulfate is gradually transformed to Pb5O4SO4, α-PbO, β-PbO, and finally to Pb3O4 during roasting in sodium hydroxide molten salt at temperatures of 250°C to 550°C. At the conditions of roasting temperature 450°C, roasting time 40 minutes, molar ratio of lead sulfate to sodium hydroxide 1 : 2.6, lead sulfate can be completely converted to near-pure phase β-PbO powder. This paper provides a simple and efficient method for the recycling of waste lead acid battery, which consists mainly of lead sulfate.

Kinetics of Microwave-Assisted Reduction of Manganese Oxide

The reduction rates of manganese oxide by carbon and SiC was examined by heating MnO2-carbon and MnO2-SiC mixtures in a 7-kW industrial microwave oven. The results show that the rate of the reduction increased with the amount of carbon in MnO2-carbon mixture and with SiC in MnO2-SiC mixture. The rate of the MnO2 reduction by carbon was proportional to the reaction time, and that by SiC was proportional to 2/3 power of the reaction time. The reduction was found to be controlled by chemical reaction. The reaction rate constant of the reduction of MnO2kC increased with increasing the amount of carbon in the mixtures but kSiC decreased with increasing the amount of SiC in the mixtures.

Effect on Inclusion and Microstructure of Ultra-Low S and Low P Steels with Vacuum Treatment

The simultaneous desulphurization and dephosphorization of molten steel with CaO-based slag containing BaO for vacuum treatment, and inclusion in steel and microstructure of steel are carried out separately. These results show that desulfurization rate exceed 92% and dephosphorization rate exceed 50% , final [S] content and [P] content in molten steel are less than 0.0024% and 0.020% respectively for all heats, and the lowest final [S] content and [P] content are 0.0012% and 0.010% respectively, they satisfy the demand of ultra-low S steels and low P steels; Comparing a grade 1.5 of inclusion level of the compared sample without vacuum treatment, inclusion level of these treated samples with vacuum is all less than grade 1.0 and that is less than grade 0.5 for 78% of treated samples; And micro-structure of the compared sample is ferrite + pearlite in steel base, but micro-structure of these treated samples is all needle-like ferrite + pearlite + netted ferrite in steel base and netted ferrite + pearlite in local area. This kind of fiber structure which comes from netted ferrite + needle-like ferrite and grade 0.5 of inclusion level can make steel possess better mechanical properties.

Performance of Anti-Erosion and Anti-Oxidation of High Al Steels at 1373K

The effect of Al content on the anti-erosion and anti-oxidation performance of high Al steels at 1373K is studied in this paper. By 168-hour heat treating at 1373 K and at oxidation atmosphere, These results show that for comparing non-Al steel and low-Al (w[Al]=1.14%) steel sample there are a more obvious and easily-dropping oxidation layer in surface in 24 h , the average oxidation rate is up to 0.406 mg/(cm2.h), but for high Al steel, there is a thinner gray oxidation layer in surface and a more fast oxidation rate for w[Al]<5% sample , and there is a thin, close and yellow gloss film and the average oxidation rate is only 0.016 mg/(cm2.h) for w[Al]=8.46% sample. The average erosion rate is 0.096 mg/cm2.h in initial 24 h and thereafter the erosion is very slow. But there is a higher erosion rate and the average erosion rate is 0.594 mg/(cm2.h) in 6 % HCl solution for high Al steel sample and comparing non-Al steel. Accordingly high Al steel possesses a good performance of high temperature anti-oxidation and anti-erosion in NaCl solution.

Effect of Static Magnetic Field on Distribution of Elements in the Fe-S, Fe-Si, and Fe-Mn Alloys

Three binary Fe-based alloys Fe-S, Fe-Si, and Fe-Mn has been designed and melted in order to investigate the effect of static magnetic field on the migration behavior and distribution of the three elements during the solidification process in this study, and microstructure and chemical composition on the samples have been inspected by optical microscopy and Original Position Analysis technologies. It has been found that the magnetic field can effectively change the distribution of S, Si and Mn, and the migration behaviors of the three elements are different.

A Study on Smelting Cold Heading Steel SWRCH6A Using Double-Slag Process

The paper carries out a study on the composition control of smelting low-carbon low-silicon and high-aluminum cold heading steel SWRCH6A using double-slag process for converter at No.3 General Plant of Steelmaking & Rolling of Masteel, analyzes carbon increasing and silicon increasing status in each smelting process, and studies the mechanical properties, microstructure and inclusion ratings of test steel samples. These results indicate that in smelting process the average carbon increasing △w[C]=0.014%, the average silicon increasing △w[Si]=0.030%, the average content w[Al]s is 0.030% and w[Al]s fluctuates from 0.015% to 0.041%,, but all targets of test steel samples meet the requirements of cold heading steel SWRCH6A.

Effects of electric pulse on solidification process of Fe-C-S alloy treated with RE

The experiment has studied the effect of solidification process of Fe-C-S alloy treated RE on the distribution of elements and inclusions on the distribution of elements and inclusions after the electric pulse field is applied. The results show that Rare Earth in the molten steel has played a purification role and change the strip MnS inclusions into spherical sulfide inclusions. Meanwhile, the co-action of electric pulse field and Rare Earth can reduce and refine inclusions and improve the distribution of elements in solidification microstructure.

Effect of Pulsed Electric Field on the Distribution and Migration of P, S, and Si Elements of Fe-based Alloys

Pulsed electric field has been effectively used to control and modify the solidification process in castings. In this study, a pulsed electric field at 8 volts and 19 kHz has been applied to Fe-P, Fe-S, and Fe-Si binary alloys, and microstructure and elements distribution of the three alloy samples have been inspected. The results indicated that P migrated from cathode to anode while S and Si migrated from both electrodes to the center under the pulsed electric field during the solidification process.

Effect of ultrasonic power on the microstructure and hardness of commercially pure aluminum

Molten, commercially pure aluminum has been treated ultrasonically with differing input power. The results show that the ultrasonic power can significantly refine the microstructure of the aluminium and increase the hardness of the samples. A mathematical model developed in this paper can predict the effect of the ultrasonic power on the grain size of the pure aluminium well.

Study on Effect of Pulse Electric Field on Solidification Process of Fe-C-S Alloy Melt

It can reduce the grain boundary segregation effectively, and improve the solidification microstructure, as well as cause the migration and redistribution of elements by adding the pulse electric field during the solidification process of the Fe-C-S alloy melt. Where, the element S migrates from the positive polarity to the negative polarity, while the migration law of the element C is reverse to that of the element S. The principal ingredient of the inclusion in solidification microstructure after treatment is FeS and a small amount of MnS, while FeS is distributed at the edge and in the centre area of the whole sample spherically.