scholarly journals Confined Bed Breakage of Fine Iron Ore Concentrates

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 666
Author(s):  
Túlio M. Campos ◽  
Gilvandro Bueno ◽  
Luís Marcelo Tavares
Keyword(s):  
High Pressure ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Iron Ore ◽  
Mining Industry ◽  
Additional Increase ◽  
Material Response ◽  
Fine Iron

High-pressure grinding rolls (HPGR) have gained great popularity in the mining industry in the last 25 years or so. One of the first successful applications of the technology has been in iron ore pressing prior to pelletization. Piston-and-die tests can provide good insights on the material response in an HPGR. This work analyzed confined bed breakage of four iron ore concentrates under different conditions. Saturation in breakage of particles contained in the top size in the tests was observed to occur at specific energies of about 2 kWh/t, whereas full saturation in breakage, with no additional increase in specific surface area of the material, occurred at energies above about 6 kWh/t. An expression was proposed to characterize the propensity of a material to break under confined bed conditions. The phenomenology involved in confined bed breakage of such materials was then analyzed in light of the results.

The whole-aperture pore-structure characteristics of marine-continental transitional shale facies of the Taiyuan and Shanxi Formations in the Qinshui Basin, North China

2019 ◽  
Vol 7 (2) ◽  
pp. T547-T563 ◽  
Author(s):  
Jiyuan Wang ◽  
Shaobin Guo
Keyword(s):  
High Pressure ◽  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Gas Adsorption ◽  
Pore Morphology ◽  
Qinshui Basin ◽  
Mercury Intrusion ◽  
Structure Characteristics

To systematically study the whole-aperture pore-structure characteristics of the marine-continental transitional shale facies in the Upper Palaeozoic Taiyuan and Shanxi Formations of the Qinshui Basin, we have collected a total of 11 samples for high-pressure mercury intrusion, low-pressure gas adsorption ([Formula: see text] and [Formula: see text]), nuclear magnetic resonance (NMR), and field-emission scanning electron microscopy with argon-ion polishing experiments to determine the pore morphology and distribution characteristics of shale samples in detail and to perform quantitative analyses. Then compared the pore-development characteristics of the Taiyuan Formation samples with those of the Shanxi Formation to determine which is preferable. The experimental results indicate that the shale samples of the Qinshui Basin mainly develop three types of pores: organic pores, intergranular pores, and microfractures. High-pressure mercury intrusion and gas-adsorption experiments indicate that the pore-size distributions exhibit multiple peaks. The samples contained varying proportions of macropores, mesopores, and micropores, among which the former two are dominant, accounting for approximately 85% of the total pore volume, whereas micropores account for only 15%. However, mesopores and micropores dominate the specific surface area; between them, the micropores are much more prevalent, accounting for more than 99% of the total specific surface area. Macropores contribute less than 1% of the specific surface area and therefore can be neglected. The pore morphology resembles the slit type parallel platy pores with a ballpoint pen structure. The NMR [Formula: see text] spectra have multiple-peak values. In addition, the large difference between the curved areas before and after centrifugation indicates that the samples contain a large proportion of mesopores and macropores, which is consistent with the results presented above. The results demonstrate that the development of pores in the Taiyuan Formation is better than that in the Shanxi Formation.

The Carbon Deposition during Iron Ore Reduction in Carbon Monoxide

2012 ◽  
Vol 625 ◽  
pp. 243-246
Author(s):  
Shu Hua Geng ◽  
Wei Zhong Ding ◽  
Shu Qiang Guo ◽  
Xiong Gang Lu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Iron Ore ◽  
Iron Reduction ◽  
Carbon Deposition ◽  
Reduction Process ◽  
Ore Reduction ◽  
X Ray ◽  
Iron Ore Reduction

Iron ore reduction and carbon deposition in pure CO was investigated by using thermogravimetric (TG) method over the temperature range of 0-1200°C. The results of the work may be summarized as follows: in CO stream, carbon deposition occurred below 900°C, no carbon deposition was found above 1000°C. X-Ray analysis of the reacted sample indicated that the carbon deposition occurred with the iron was reduced. The iron reduction process and carbon deposition occurred simultaneously. The rate of carbon deposition changed with the transformation of iron oxides. The specific surface area and pore structure of reduced samples were analyzed. The specific surface area changed with the amount of carbon deposition.

scholarly journals The Effect of 200 MPa Pressure on Specific Surface Area of Clay

2015 ◽  
Vol 36 (4) ◽  
pp. 3-6 ◽  
Author(s):  
Ewa Koszela-Marek
Keyword(s):  
High Pressure ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pressure Effect ◽  
Laboratory Studies ◽  
Adsorption Method ◽  
Pressure Tests ◽  
Soil Skeleton

Abstract The paper presents the results of laboratory studies of the 200 MPa pressure effect on specific surface area of clay. The original high-pressure investigation stand was used for the pressure tests. Determination of the specific surface area was performed by the methylene blue adsorption method. The results of the specific surface area test were compared for non-pressurized clays and for clays pressured in a high-pressure chamber. It was found that the specific surface area of pressurized soil clearly increased. This shows that some microstructural changes take place in the soil skeleton of clays.

Preparation of UHPC with Fly Ash Replaced by Rich-Silicon Iron Ore Tailing Powder

2017 ◽  
Vol 872 ◽  
pp. 119-124
Author(s):  
Ke Xin Liu ◽  
Zhi Gang Zhu ◽  
Shun Kai Li ◽  
Si Zhang
Keyword(s):  
Fly Ash ◽  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Performance ◽  
Iron Ore ◽  
High Performance Concrete ◽  
Silicon Iron ◽  
Iron Ore Tailing

In order to raise up the the rate of multipurpose utilization of rich-silicon iron ore tailing (IOTP for short) and the preparation of ultra-high performance concrete(UHPC for short), the influence rules and mechanism of rich-silicon iron ore tailing powder replacing fly ash in UHPC were studied, the influences of different specific surface area and dosage of IOTP replacing fly ash on its strength and liquidity were tested. Moreover, the pore structure and hydration products morphology of UHPC were tested by MIP and SEM methods, respectively. The results show that when fly ash replaced by IOTP, the liquidity of UHPC will be increased. When alternative content of IOTP is less than 10%, proper specific surface area of IOTP can improve the strength and pore structure, it can get the best result when the alternative content is 5% and the specific surface area is 588m2/kg. However, when alternative content of IOTP is 15% or more, all of these properties of UHPC become worse. It proves that IOTP can be used in the preparation of UHPC and improve the properties of UHPC.

scholarly journals Synthesis of fibre reinforced Al2O3−SiO2 aerogel composite with high density uniformity via a facile high-pressure impregnation approach

2017 ◽  
Vol 11 (3) ◽  
pp. 185-190 ◽  
Author(s):  
Gang Yang ◽  
Yonggang Jiang ◽  
Junzong Feng ◽  
Sizhao Zhang ◽  
Jian Feng
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Aerogel Composite ◽  
Sio2 Aerogel ◽  
The Mean

Alumina-silica (Al2O3?SiO2) aerogel composite, with low density, low thermal conductivity and hightemperature stability, is attracting increased interest in the field of thermal insulation application. In this paper, a novel way to fabricate fibre reinforced Al2O3?SiO2 aerogel composite via a facile high-pressure impregnation approach was reported. Two Al2O3?SiO2 aerogel composites, HPe and LPe, were synthesized via high-pressure and low-pressure impregnation approach, respectively. The effects of the impregnation approach on the aerogel composites performance were studied, and the impregnation model was established. The results showed that the as-prepared HPe exhibited higher density uniformity, better high-temperature stability, higher specific surface area and lower thermal conductivity. It was also shown that the effect of impregnation approach on the mean density and morphology of the aerogel composites is negligible. However, the standard deviation of density (0.00857) and mean thickness shrinkage (9.98%) of HPe were 37.8% and 15.4% lower than that of LPe, respectively. The specific surface area (884.1m2/g) of HPe was 43.5% higher than that of LPe. The thermal conductivity of HPe at 1100?C was 2.74% lower than that of LPe. The impregnation model of the aerogel composites presented that the density uniformity and thermal conductivity of HPe were improved obviously, because there were less large pores in HPe than in the LPe.

Sign in / Sign up

Export Citation Format

Share Document