Qing Jun Zhang

Study of Metallurgical Properties in the Sintered Ore with Variable SiO2

The low silicon sintered ores are prepared, where SiO2 content is 4.4%, 4.6%, 4.8%, 5.0% and 5.2%, respectively. Their metallurgical properties are also measured. The results state that the low temperature reduction degradation of low silicon sinter is improved with the SiO2 content increase. With the SiO2 content increasing in low silicon sinter, the reducing index sharply decline, and reduction gradually deteriorate. In the meantime, softening initial temperature gradually reduced, softening interval gradually widened, so exceeded SiO2 content does harm to softening property.

The Pore Structure Multifractal Research of Low Silicon Sinter

With the combination of fractal theory and metallurgical properties of low silicon sinter, the influence of metallurgical properties in different content of R, MgO, SiO2 and C is analyzed on the condition of existing experiment and fuel, and by using the mercury intrusion machine it measured the volume of micro-pore structure after broken of low silicon sinter; and it combined with the multifractal theory measured multifractal spectrum for the pore structure, which is established the relationship between with the metallurgical properties and fractal theory.

Study of Metallurgical Properties in the Sintered Ore with Variable Carbon

The low silicon sintered ores are prepared, where C content is 3.3%, 3.5%, 3.7%, 3.9% and 4.1%, respectively. Their metallurgical properties are also measured. The results state that the low temperature reduction degradation property in low silicon sintered ore is to achieve the best when the carbon content was 3.7%. With increasing carbon content, it has a trend that the low silicon sintered reducing gradually become variation. In this range of carbon content, softening initial temperature exceed 1230 oC, the softening interval is less than 120 oC, so suitable C content are helpful to improve metallurgical properties for low silicon sintered ore.

Fractal of Grain Distribution in Sintered Ore with Variable Brazil Iron Ore

The low silicon sintered ores are prepared, where C content is 3.3%, 3.5%, 3.7%, 3.9% and 4.1%, respectively. Their metallurgical properties are also measured. The results state that the low temperature reduction degradation property in low silicon sintered ore is to achieve the best when the carbon content was 3.7%. With increasing carbon content, it has a trend that the low silicon sintered reducing gradually become variation. In this range of carbon content, softening initial temperature exceed 1230 oC, the softening interval is less than 120 oC, so suitable C content are helpful to improve metallurgical properties for low silicon sintered ore.

Calculation and Analysis of Multifractal Spectrum of Sinter Surface

Multifractal spectrums of sinter with different alkalinity were analyzed by multifractal software. The results show that sinter pore structure change from uniform to non-uniform with the improvement of alkalinity, Δα increases from 0.53 to 0.55. The structure of sinter pore is mainly microscopic by competition between macropores and micropores, Δf changes from 0.14 to-0.44. The distribution of sinter pores is quantitatively characterized by multi-fractal spectrum, which is consistent with transmission electron microscopy image.

Multi-Fractional Research on Pore Distribution in the Sinter Ore with Different Basicity

The pore distribution of low silica sinter ore samples with different alkalinity was measured by pressure mercury, and the fractal characteristic of pore distribution was calculated with multifractal theory, then metallurgical properties were also obtained, finally, their connection among them was discussed. The results showed that the pore distribution has experienced a process from non-uniform to uniform with increasing alkalinity. When the alkalinity was 2.0, the spectral width Δα was minimum, multifractal structure was more uniform, fractal characteristics was better, in the meantime, the pore distribution was more uniform, and the pores were larger, which improved metallurgical properties. The results also showed that when the alkalinity was 2.0, its metallurgical properties was optimal.

Multi-Fractal Behaviors in Grain Size Distribution of Low Silica Sinter

Multi-fractal theory is used to detect fractal behaviors embedded in grain size distribution ofsinter with low SiO2. Impacts of SiO2, basicity, and MgO on structures of sinter ore are measured quantitatively by means of fractal dimension dm, d(1) and multi-fractal strength Δd. Increase of SiO2 induces decrease of fractal dimension and multi-fractal strength. While proper levels of carbon, basicity, and MgO lead to minimum values of fractal dimension and multi-fractal strength. This kind of quantitative measurement of structures in sinter ore can help us to investigate the relation of mechanical properties and structures in a quantitative way.

Influence of La2O3-Doping on Dielectric Properties of Ba(Ti, Sn)O3 Ceramics

Ba(Ti0.95Sn0.05)O3 ceramics were prepared using BaCO3, SnO2 and TiO2 et al as crude materials, La2O3 as dopant, and their dielectric properties are investigated. The morphology analysis of sintered samples was conducted by SEM. It is found that for 0.1 wt% La2O3 doped BTS5 ceramics sintered at 1290oC has the highest dielectric constant. It can also be seen that the samples sintered at 1260oC have higher dielectric loss, which can result from the existence of the pore. Meanwhile, in the terms of dielectric loss, 0.1 wt% La2O3 doped BTS5 ceramics has lower value and the dielectric loss is more stable with temperature varying.

Fractal of Grain Distribution in Mini-Sintering Sinter

The sinter ore samples with different content of silica were prepared by the mini-sintering method so as to study the micro-mechanism of sinter. The fractal theory was also applied to analyze quantitatively the grain distribution in the samples’ two-dimensional microstructure. The study found that the grain distribution of the sinter shows the fractal characteristic, its fractal dimension is about 1.95, and the fractal dimension can be used to characterize uniformity of the grain distribution. With the increase of silica content, the fractal dimension of the samples shows a linear decreasing trend and it is the same trend in the comparing sintering-cup experiment when the fractal dimension of particle size distribution reduces, the silica content increases. In addition, the compressive strength of mini-sintering sinter sample was also measured. It shows that the compressive strength is the highest when the silica content is 3.8 wt%, which is correlative with the porosity, the content of calcium ferrite and glassiness in the sinter ore besides the fractal dimension.

Fractal Characters of Micro-Pores in the Sinter

The pore in the sinter is an important character. Because of multiphase and asymmetry in the sinter, the structure of the pore is very complex. To study the character of the pore effectively, the method of mercury intrusion porosimetry is applied to measure the pore in the sinter, and the results are dealt with by the fractal theory. The results prove that the pores in the sinter are actually fractal structure when the size of the pores is more than 204.5 nm because their curves in the log-log plot are linear, and some curves qualified with the linearity obviously possess of the segment linearity character. According to the calculation of the fractal D, the relationship of the strength and fractal D will be established.