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Experimental investigation on magnetic-gravity combined beneficiation of low-grade iron ore

Ye Fangping, Duan Yaojie, Guo Zhiqiang

Physicochemical Problems of Mineral Processing

2024

Vol. 60, iss. 5

atr. no. 192832

Iron ore is an important raw material for manufacturing steel, while the grade of domestic iron ore is relatively low in China, thus it is difficult to concentrate. The low-grade iron ore with a total iron content of only 33.51% is innovatively upgraded by the magnetic-gravity combined beneficiation method. The effects of three key operating parameters of magnetic induction, grinding concentration, and centrifuge speed on magnetic-gravity combined beneficiation are investigated. These results show that the magnetic-gravity combined beneficiation method significantly improves the iron grade of the concentrates at high recovery. The feasibility is further confirmed through continuous expansion semi-industrial tests with the optimized parameters. The grade of the iron ore concentrate is increased from 33.51% to 63.58% with an iron recovery of 71.01% and a productivity of 37.43%. It is thus concluded that the magnetic-gravity combined beneficiation method has provided a technical reference for the recovery of iron resources from low-grade ores.

Influence of initial casting temperature on the properties and microstructure of ultra-light cement-based foam composites for energy-saving buildings

Zhang Yangkai, Sang Guochen, Zhao Caiyun, Guo Teng, Cui Xiaoling, Guo Zhiqiang, Zou Saisai

Archives of Civil and Mechanical Engineering

2023

Vol. 23, no. 3

art. no. e190, 2023

The application of ultra-light cement-based foam composites (ULCF) in buildings has been verified as an effective way to achieve energy conservation in the building sector. However, the production process of ULCF is difficult to complete at the ideal constant temperature during practical industrial production due to cost control and other factors. The sun exposure and residual heat from the machines will cause the initial casting temperature of ULCF to be raised in the preparation process, which will inevitably have an impact on the macroscopic properties of ULCF. In this study, a series of tests were conducted to explore the effect of initial casting temperature (30–55 °C) on the macroscopic properties and microstructure of ULCF for the first time. The results indicated that the 28-day compressive strength of ULCF exhibited a tendency to first increase and then decrease with the increase of initial casting temperature, which was attributed to the variation of its internal pore structure. The thermal conductivity test shows that the thermal conductivity of ULCF existed a minimum value of 0.0651 Wm−1 K−1 when the initial casting temperature reached 40 °C. Meanwhile, SEM and XRD were employed to examine the microstructure and hydration products of ULCF with different initial casting temperatures. Furthermore, the internal pore structure parameters of ULCF were quantitatively analyzed through Image-Pro Plus software, and the results demonstrated that there is a critical value for the initial casting temperature of ULCF, which allows the internal pore structure of ULCF to have characteristics of small size and approximate spherical shape.