Frontiers of Materials, Chemical and Metallurgical Technologies

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Authors: Xuan Ming He, Ye Pan, Wei Li, Jia Qi Fang, Xiao Juan Wang
Abstract: Co-carbonization characteristics of long flame coal mixed with algae in different proportions were studied in a dry distillation equipment, and focusing on the coal tar of the product with GC-MS and FT-IR in order to investigate the changes in coal tar, The results show that the tar yield increases with the increasing of algae added, the light oil components of co-carbonized coal tar (with the optimal proportion 20:10 ) compared with conventional coal tar increased 29.55% while naphthalene content increased 9.15% and phenol content increased 23.93%. The algae sample played a role in hydrogen donating and the reactions involved opening-ring reaction, alkyl aromatic side chain reaction and condensation reaction, etc.
Authors: Lian Chen
Abstract: Based on the composition and characteristics of steelmaking precipitator dust, cold briquetting ores were processed with scale and applied to converter vanadium recover. The research results show that the use of cold briquetting ores, molten iron carbon oxidation rate increased from 15.01% to 17.68%, vanadium oxidation rate increased from 79.47% to 82.07%, the TFe content of vanadium slag reduced, the consumption of iron and steel materials decreased. In the process of converter vanadium recover, the amount of coolant could cut down.
Authors: Xiang Dong Huo, Lin Guo, Kuang Nian He, Rui Huang
Abstract: In order to shorten the spheroidizing annealing time, the effects of annealing time on microstructure and hardness of GCr15 have been researched by using OM, SEM and Vickers hardness tester. The original microstructural constituent of bearing steel is pearlite and cementite. Prolonged time at 805°Cwill decrease the number and increase size of cementite particles. After incomplete austenization at 805°C, prolonged time at 720°C induces increase of particle size, and uniform distribution of divorced pearlite. The hardness of specimens treated with different spheroidization process fluctuates around 200HV, and is equivalent to that with conventional spheroidization process. It is realizable to shorten the annealing time on the premise of good quality of bearing steel.
Authors: Wei Chen, Yong Ping Feng, Na Zheng, Ying Chen
Abstract: For understanding the surface and internal defects of Q195 steel of 150mm×220mm rectangular bloom, a solidification heat transfer mathematics model based on temperature measuring is established. Meanwhile, the secondary cooling water is optimized according to the metallurgical criteria by means of subproblem approximation method. The results showed that: after the optimizing result is applied in actual production, the water consumption is reduced 8.2~11.5%, the quality of bloom improved obviously, and the defects such as central pipe, center porosity and internal cracks are reduced respectively.
Authors: Jun Chen, Yong Chen, Xin Teng Liang, Jian Hua Zeng
Abstract: According to the test of reducing tapping temperature of BOF, factors affect the tapping temperature are studied and measures to reduce temperature drop during tapping are raised. Results show that the average tapping temperature during test is 1672°C, which is 13°C lower than mass production; and the tapping temperature more than 1690°C only account for 14.28%, which is twenty percentage points lower than before; temperature drops during tapping is decreased from 99.0°C to 93.64°C, which 5.36°C lower than before.
Authors: Wen Tang Xia, Xue Jiao Zhou, Jian Guo Yin, Yi Feng Gao, Wen Qiang Yang, Juan An
Abstract: Removing phosphorus from high phosphorus converter steel slag by hydrometallurgical method was studied in this paper. The influence of different dephosphorizting agents on the effect of phosphorus slag was investigated, and high efficient dephosphorizating agent was found. The effects of reaction time, liquid to solid ratio, stirring speed, reaction temperature and dephosphorizing agent concentration on the impact of dephosphorization were studied. The results showed that on the conditions of the reaction time 40 min, slag particle size <0.147 mm, liquid to solid ratio of 4:1, stirring speed 400 rpm, the reaction temperature 25 °C, and dephosphorizing agent concentration 5 mol/L, the optimum dephosphorization results were achieved. The dephosphorization ratio can reach 70%, and the phosphorus content in steel slag decreased from 1.03% to 0.46%, the total iron content increase from 30.676% to above 44%.
Authors: Lian Chen, Jian Wang, Wen Sun Ge, Shi Chuan Jiang, Liang Gang Yi
Abstract: In order to solve the environmental problems produced by vanadium extraction tailings of calcium roasting, the technology of vanadium extraction tailings used for converter steelmaking is investigated. The research results show that for common steel production, the technology of BOF slagging with vanadium extraction tailings is feasible. Compared with the original complex slagging flux, slag formation times is shortened, rate of dephosphorization, oxygen blowing time, iron loss and so on are slightly better after addition of vanadium extraction tailings. And only the sulfur content of molten steel increased 0.004% and the temperature reduced 10°C. In addition, there is no significant adverse impact on the quality of molten steel.
Authors: Ting Hu, Quan Jun Liu, Rong Dong Deng, Feng Hong Ye
Abstract: The paper recovered the tin from a refractory tin ore in Kazakhstan. The grade of tin in raw ore is 1.19%. Through technological mineralogy study, we found the tin was mainly in the forms of cassiterite and stannite. Considering the gravity process would make the stannite lost in tailings because of its small specific gravity, we explored the flotation to recover the tin. In fact, the grade and recovery of tin were bad by collectors contrast test. Finally, we adopted gravity flowsheet to recover cassiterite. The recovery of tin is not high because the tin in the form of stannite lost in tailings. As a result, the tin concentrate with a grade of 21.56% and the recovery of 52.90% were obtained.
Authors: Wen Jiang, Kun Yu Zhao, Dong Ye, Jun Li, Zhi Dong Li, Shao Hong Li, Jie Su, Qi Long Yong, Xiao Chen Han
Abstract: The microstructure and mechanical properties of Cr15 super martensitic stainless steel after different heat treatment were studied by SEM and XRD. The results show that the microstructure of steel A and B are lath martensite and retained austenite after quenching. The original austenite grain size increases with the increasing quenching temperature. The microstructure is composed by tempered martensite and reversed austenite after tempering. The amount of reversed austenite in both steels increases first and then decreases with the increasing tempering temperature. Both of the tested steels have the best mechanical properties at 650°C tempering temperature.
Authors: Qi Chun Peng, Wei Xiong, Xue Sen Yu, Jian Zou, Sheng Peng, Xi Song Sheng
Abstract: Through studying the inclusions of low carbon steel slabs produced in different casting stages, the results are dawn as follow. The reoxidation of liquid steel is very serious in casting starting,but the casting ending is not. Most of large-inclusions containe K or Na are found in the first and final slabs, which may relate to serious slag entrapment in the mould in the casting starting and ending. Many MgO-Al2O3 and Al2O3-CaO-SiO2-MgO inclusions suggest the serious entrapment of the tundish in the casting ending.

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