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Study of recycling blast furnace dust by magnetization roasting with straw charcoal as reductant

Ju Jinrong, Feng Yali, Li Haoran, Zhang Qian

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 3

art. no. 149265

EN

Blast furnace dust generated in the iron-making process not only contains a large amount of iron but also the widely used non-ferrous metal zinc, which is classified as hazardous waste. In this study, the process of recycling blast furnace dust by magnetization roasting with straw charcoal as the reductant is proposed, and the mechanism of magnetization roasting was explored through thermodynamic analysis, X-ray diffraction analysis, and thermogravimetric analysis. The results for the thermodynamic analysis showed that the reduction of blast furnace dust by the straw charcoal was feasible theoretically. The increase in the roasting temperature not only promoted the reduction of hematite (Fe2O3) but also reduced zinc ferrite (ZnFe2O4) to Fe3O4 and ZnO. The results showed that almost all Fe2O3 and ZnFe2O4 in the blast furnace dust were reduced to Fe3O4 and ZnO under the conditions of straw charcoal amount of 6%, the roasting temperature of 750℃, and the roasting time of 60 min. Then, the iron concentrate with the iron recovery of 85.61% and an iron grade of 63.50% was obtained by the magnetic separation. Meanwhile, the grade of zinc in the iron concentrate was 0.19%. Finally, the flowsheet of simultaneously recovering iron and zinc from the blast furnace dust was put forward, which could realize that 85.61% of iron was recovered and 92.57% of zinc was extracted into the solution.

2

Three-dimensional poroelasticity solution of sandwich, cylindrical, open, functionally graded composite panels under multi-directional initial stress: semi-numerical modeling

Liu Rongzheng, Li Haoran, Khadimallah Mohamed Amine, Safarpour Mehran

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e13, 2022

EN

Up to now, no studies have been yet reported to study the mechanical behaviors of three-dimensional functionally graded graphene platelets reinforced composite (FG-GPLRC) open-type panel. In this paper, the free vibration of FG-GPLRC open-type panel under multi-directional initially stressed using three-dimensional poroelasticity theory is investigated for the first time. Weight fraction of graphene open-type panel is assumed to be distributed either uniformly or functionally graded (FG) along the radial direction. Modified Halpin–Tsai model is used to compute effective Young’s modulus, whereas effective Poisson’s ratio and mass density are computed using the rule of mixture. State-space differential equations are derived from the governing equation of motion and constitutive relations in cylindrical co-ordinates. The accuracy of the obtained formulation is validated by comparing the numerical results with those reported in the available literature as well as with the finite-element modeling. The influences of several importance parameters, such as various directional initial stress, compressibility coefficient, porosity, and various type of sandwich open-type cylindrical panel, are investigated on the frequency of the structures. The results of the present study can be served as benchmarks for future mechanical analysis of cylindrical FG-GPLRC structures.

3

Acoustic Matching Characteristics of Annular Piezoelectric Ultrasonic Sensor

Li Haoran, Hu Yan, Li Laibo, Xu Dongyu

Archives of Acoustics

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2022

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Vol. 47, No. 2

275--284

EN

Using intelligent materials and sensors to monitor the safety of concrete structures is a hot topic in the field of civil engineering. In order to realize the omni-directional monitoring of concrete structural damage, the authors of this paper designed and fabricated an embedded annular piezoelectric ultrasonic sensor using the annular piezoelectric lead zirconate titanate (PZT) ceramic as a sensing element and epoxy resin as the matching and the backing layers. The influence of different matching and backing layers thickness on the acoustic characteristic parameters of the sensor were studied. The results show that the resonant frequency corresponding to the axial mode of annular piezoelectric ceramics moves toward the high frequency direction with the decrease of the height of piezoelectric ceramics, and the radial vibration mode increases as well as the impedance peak. With the thickness of the backing layer increases from 1 mm to 2 mm, the radial resolution of the annular piezoelectric ultrasonic sensor is enhanced, the pulse width is reduced by 39% comparing with the sensors which backing layer is 1 mm, and the head wave amplitude and −3 dB bandwidth are increased by 61% and 66%, respectively. When the matching layer thickness is 3 mm, the sensor has the highest amplitude response of 269 mV and higher sensitivity.

4

Basic theory and optimization of gold containing antimony concentrate leaching by alkaline sulfide

Wu Hao, Feng Yali, Li Haoran, Liao Shengde, Wang Hongjun

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 1

248--257

EN

As sodium sulfide is easily oxidized to polysulfide and thiosulfate which have a gold leaching effect, gold would dissolve in leaching solution when extracting stibium from gold containing antimony concentrate by alkaline sulfide. Through leaching test and kinetics analysis, the decomposition regularity of sodium sulfide and leaching rate were studied under different leaching conditions. The results indicated that the gold content in antimony concentrate was 28.41g/Mg, and the content of antimony and sulfur was 36.01% and 14.04%, respectively. The main metallic minerals were native gold, arsenopyrite, stibnite, and the gangue minerals were mainly quartz. Anodic polarization curve shows reduced iron powder can increase the peak potential of the oxidation of the leaching solution and it can effectively prevent the decomposition of sodium sulfide and the dissolution of gold. Optimized stibium-extraction efficiency was achieved under the following conditions: a concentration of sodium sulfide and sodium hydroxide at 110g/dm³ and 20g/dm³, respectively; a ratio of iron powder to concentrate of 1:30; a ratio of liquid to solid of 5:1; agitation speed of 600rad/min; reaction temperature of 353.15K; and a reaction time of 3 h. Under the optimized conditions, high antimony recovery (97.35%) and low gold dissolution (1.32%) were achieved.