Effect of magnesium oxide and its occurrence on the roasting and metallurgical performance of magnetite pellets
-
摘要: 分別以5種不同的含鎂添加劑（高鎂磁鐵礦、鎂橄欖石、白云石、菱鎂石和氧化鎂粉）制備鎂質球團，闡述MgO含量和來源對磁鐵礦球團焙燒特性及冶金性能的影響。研究結果表明：不同的含鎂添加劑對于生球的落下強度有著一定影響，其中氧化鎂粉與高鎂磁鐵礦均能夠提高球團的落下強度。相同的預熱焙燒制度下，提高MgO含量會增加球團孔隙率，降低預熱和焙燒球團的抗壓強度，其中白云石對焙燒球團強度的不利影響最小。增加預熱球團的氧化度有利于促進鎂質焙燒球團固結，提高其抗壓強度。在MgO來源相同的情況下，MgO含量的增加會導致球團孔隙的增減，降低了球團強度，而配加不同種類的含鎂添加劑，均能不同程度改善球團的還原膨脹性、低溫還原粉化性和還原性，其中配加高鎂磁鐵礦的球團的還原膨脹性和低溫還原粉化性均優于于其他含鎂球團。Abstract: Increased Al2O3 content in blast furnace slag in China presents adverse effects in blast furnace smelting. In response to this problem and to improve fluidity of blast furnace slag, MgO pellets are added. Blast furnace can be operated smoothly, but on the other hand, higher MgO content is unfavorable to the pelletizing property and pellet roasting performance of raw materials. Five kinds of pellets containing high-magnesium magnetite, forsterite, dolomite, magnesite, and magnesia powder, respectively, were made to investigate the effect of MgO content and its occurrence on induration behavior and metallurgical performance of pellets. Results show that various magnesium-containing fluxes have different influences on the quality of green balls. Both magnesia powder and high-magnesium magnetite can improve the drop numbers of green balls, which is due to their chemical properties and specific surface areas. With fixed firing temperature and time, increasing MgO content leads to lowered compressive strength of the preheated and fired pellets, with the lowest impact from dolomite observed. With the oxidation degree elevation of preheated pellets, compressive strength of roasted pellets improves, which indicates that we can increase the preheating time in actual production to improve the roasting performance of magnesium magnetite pellets. Under the same source of MgO, increasing MgO content will lead to an increase in porosity of pellets, which presents a negative effect on the strength of pellets. For five kinds of fired pellets, increased MgO content improves the reduction swelling index, low temperature degradation indices, and reduction degree. The reduction swelling index and low temperature degradation indices of pellets with high-magnesium magnetite are observed to be better than those of other magnesium-containing pellets.
-
Key words:
- magnetite pellets /
- MgO content /
- MgO sources /
- roasting behaviour /
- metallurgical performance
-
圖 1 MgO質量分數及來源對高品位磁鐵礦球團生球落下強度的影響
Figure 1. Effect of MgO mass fraction and source on the drop numbers of green balls
圖 2 MgO質量分數及來源對磁鐵礦預熱球團抗壓強度的影響（預熱溫度950 ℃，預熱時間12 min）
Figure 2. MgO mass fraction and source on compressive strength of preheated pellets (preheating at 950 ℃ for 12 min)
圖 3 MgO質量分數及來源對磁鐵礦焙燒球團抗壓強度的影響（預熱溫度950 ℃，預熱時間12 min，焙燒溫度1240 ℃，焙燒時間15 min）
Figure 3. MgO mass fraction and source on compressive strength of fired pellets (preheating at 950 ℃ for 12 min, roasting at 1240 ℃ for 15 min)
圖 4 配加不同含鎂熔劑的焙燒球團微觀結構圖（預熱溫度950 ℃，預熱時間12 min，焙燒溫度1240 ℃，焙燒時間15 min，w(MgO)=2.45%）。（a）氧化鎂粉；（b）菱鎂石；（c）白云石；（d）高鎂磁鐵礦；（e）鎂橄欖石（H—赤鐵礦；S—(Fe，Mg)Fe2O4；P—孔洞；MgO—氧化鎂；T—鐵酸鈣；F—鎂橄欖石）
Figure 4. Mineral phases of roasted pellets with different MgO source under optical microscope (preheating at 950 ℃ for 12 min, roasting at 1240 ℃ for 15 min, w(MgO)=2.45%): (a) magnesia powder; (b) magnesite; (c) dolomite; d) high magnesium magnetite; (e) forsterite (H—Hematite; S—(Fe2O4) spinel; P—hole; T—calcium ferrite; F—forsterite)
圖 5 具有不同MgO來源的預熱球團氧化度對焙燒球團抗壓強度的影響（預熱溫度950 ℃，焙燒溫度1240 ℃，焙燒時間15 min，w(MgO)=2.45%）
Figure 5. Relationship between compressive strength of fired pellets and different degree of preheated pellets (preheating at 950 ℃, roasting at 1240 ℃ for 15 min, w(MgO)=2.45%)
圖 6 MgO質量分數（a）與不同含鎂添加劑（b）對成品球團孔隙率的影響
Figure 6. Effect of MgO mass fraction (a) and different magnesium-containing flux (b) on porosity of pellets
圖 7 MgO質量分數（a）與不同含鎂添加劑（b）對球團低溫還原粉化率RDI?3.15 mm的影響
Figure 7. Effect of MgO mass fraction (a) and different magnesium-containing flux (b) on RDI?3.15 mm of pellets
圖 8 MgO質量分數（a）與不同含鎂添加劑（b）對球團還原膨脹率的影響
Figure 8. Effect of MgO mass fraction (a) and different magnesium-containing flux (b) on swelling index of pellets
圖 9 MgO質量分數(a)與不同含鎂添加劑(b)對球團還原度的影響
Figure 9. Effect of MgO mass fraction (a) and different magnesium-containing flux (b) on reducing degree index of pellets
表 1 原料的主要化學成分（質量分數）
Table 1. Chemical composition of raw materials
% Raw materials TFe FeO MgO Al2O3 SiO2 CaO K2O Na2O P S LOI* Ordinary magnetite 69.660 15.710 0.340 0.010 1.660 0.180 0.010 0.010 <0.010 0.020 ?1.010 High magnesium magnetite 67.730 24.660 2.480 1.250 0.970 0.270 <0.010 0.010 0.020 0.520 ?1.240 Forsterite — — 35.670 — 52.290 2.350 0.049 0.130 <0.010 0.054 9.560 Dolomite — — 20.930 — 1.230 30.520 0.022 0.040 <0.010 0.018 45.990 Magnesite — — 45.780 — 1.480 0.820 0.020 0.029 0.027 <0.010 50.640 Bentonite 2.820 — — 13.430 69.990 2.090 0.440 2.310 0.030 0.050 9.240 Note：* is burning loss. 
下載: 導出CSV
表 2 原料的物理性能
Table 2. Physical properties of raw materials
Raw materials Specific surface area/ (cm2·g?1) Ratio for different particle sizes/% ?0.074 mm ?0.043 mm Ordinary magnetite 1061 89.94 69.13 High magnesium magnetite 669 69.92 64.29 Forsterite 2836 88 74.9 Dolomite 2282 94.8 81.8 Magnesite 3068 86.5 67.8 Magnesia powder 4826 99.5 97.2
下載: 導出CSV
表 3 膨潤土物理性能
Table 3. Physical properties of bentonite
Colloid index/
(mL·g?1)Swelling coefficient/
(mL·g?1)Water absorption
(2 h)/%Ethylene blue
adsorbed/gMontmorillonite
content/%Size
(<0.074 mm)/
%10.45 25.25 605.33 39.09 80.42 99.73
下載: 導出CSV
表 4 成品球團礦化學成分（質量分數）
Table 4. Chemical analysis of fired pellets
% MgO source TFe FeO SiO2 CaO MgO K2O Na2O P S — 68.35 — 1.82 0.18 0.35 0.010 0.010 <0.010 <0.010 Magnesia powder 68.18 0.25 1.62 0.18 0.60 0.010 0.010 <0.010 <0.010 Magnesia powder 66.33 0.33 1.58 0.17 1.19 0.010 0.010 <0.010 <0.010 Magnesia powder 64.13 0.38 1.53 0.17 1.78 0.010 0.010 <0.010 <0.010 Magnesia powder 61.59 0.48 1.47 0.16 2.45 0.010 0.010 <0.010 <0.010 Magnesite 67.39 0.41 1.66 0.21 2.42 0.010 0.010 <0.010 <0.010 Dolomite 65.84 0.42 2.32 3.27 2.43 0.020 0.030 <0.010 <0.010 Forsterite 64.49 0.39 4.64 0.31 2.45 0.010 0.020 <0.010 <0.010 High magnesium magnetite 66.70 2.33 1.37 0.31 2.44 <0.010 <0.010 <0.010 <0.010
下載: 導出CSV
www.77susu.com<span id="fpn9h"><noframes id="fpn9h"><span id="fpn9h"></span> <span id="fpn9h"><noframes id="fpn9h"> <th id="fpn9h"></th> <strike id="fpn9h"><noframes id="fpn9h"><strike id="fpn9h"></strike> <th id="fpn9h"><noframes id="fpn9h"> <span id="fpn9h"><video id="fpn9h"></video></span> <ruby id="fpn9h"></ruby> <strike id="fpn9h"><noframes id="fpn9h"><span id="fpn9h"></span> -
參考文獻
[1] Sahoo S K, Tiwari J N, Mishra B, et al. Prediction of flow characteristics of Al2O3–CaO–MgO–SiO2–TiO2-type blast furnace slag and its evaluation. Arab J Sci Eng, 2019, 44(7): 6393 doi: 10.1007/s13369-019-03878-8 [2] Lü X W, Yan Z M, Pang Z D, et al. Effect of Al2O3 on physicochemical properties and structure of blast furnace slag: review. Iron Steel, 2020, 55(2): 1呂學偉, 嚴志明, 龐正德, 等. A2O3對高爐渣物化性能和結構影響研究綜述. 鋼鐵, 2020, 55(2):1 [3] Liu X J, Li J P, Liu S, et al. Research and development for the effect of MgO on the blast furnace production. Multipurpose Util Miner Resour, 2019(2): 16 doi: 10.3969/j.issn.1000-6532.2019.02.003劉小杰, 李建鵬, 劉頌, 等. MgO對高爐生產影響的研究現狀及其展望. 礦產綜合利用, 2019(2):16 doi: 10.3969/j.issn.1000-6532.2019.02.003 [4] Jiang X, Shen F M, Han H S, et al. Analysis and application of sectional control of w(MgO)/w(Al2O3) in blast furnace slag. Iron Steel, 2019, 54(10): 12姜鑫, 沈峰滿, 韓宏松, 等. 高爐渣適宜鎂鋁比分段管控的分析與應用. 鋼鐵, 2019, 54(10):12 [5] Yang F, Wu Z Q, Cheng J W. Effects of w(MgO) on high temperature properties of high alumina blast furnace slag. Res Iron Steel, 2011, 39(1): 4楊福, 吳志清, 程建文. w(MgO)對高爐高鋁渣高溫性能的影響. 鋼鐵研究, 2011, 39(1):4 [6] Wu Y, Liu Z M, Li X J, et al. Study on suitable MgO content in sinter. Res Iron Steel, 2016, 44(3): 6武軼, 劉自民, 李小靜, 等. 燒結礦中適宜MgO含量的研究. 鋼鐵研究, 2016, 44(3):6 [7] Pan X Y, Long Y, Li S Z, et al. Effect of MgO/Al2O3 on metallurgical properties of sinter. Iron Steel Van Tit, 2019, 40(4): 100 doi: 10.7513/j.issn.1004-7638.2019.04.019潘向陽, 龍躍, 李神子, 等. MgO/Al2O3對燒結礦冶金性能的影響. 鋼鐵釩鈦, 2019, 40(4):100 doi: 10.7513/j.issn.1004-7638.2019.04.019 [8] Liu C, Zhan Y Z, Kang Y, et al. Effect of MgO content on properties of low silicon sintering ore. Foundry Technol, 2017, 38(4): 885劉超, 張玉柱, 康月, 等. MgO含量對低硅燒結成礦性能的影響. 鑄造技術, 2017, 38(4):885 [9] Zheng A Y, Liu Z J, Cang D Q, et al. Effects of MgO on the mineral structure and softening-melting property of Ti-containing sinter. Chin J Eng, 2018, 40(02): 184鄭安陽, 劉征建, 蒼大強, 等. MgO對含鈦燒結礦礦相結構及軟熔滴落性能的影響. 工程科學學報, 2018, 40(02):184 [10] Chen Q C, Han X L, Liu L. Distribution patterns and formation mechanisms of the mineralogical structure of high basicity sinter. Chin J Eng, 2019, 41(02): 181(陳前沖, 韓秀麗, 劉磊. 高堿度燒結礦礦相結構分布模式及形成機理. 工程科學學報, 2019, 41(02):181 [11] Yan Z Z, Lu J G, Lü Q, et al. Impact of magnesium oxide on the green ball quality and cruslring strength of pellets. Iron Steel Van Tit, 2017, 38(6): 98 doi: 10.7513/j.issn.1004-7638.2017.06.018嚴照照, 盧建光, 呂慶, 等. MgO對生球質量和球團礦抗壓強度的影響. 鋼鐵釩鈦, 2017, 38(6):98 doi: 10.7513/j.issn.1004-7638.2017.06.018 [12] Xie L B. Investigation on Strengthening Concretion of Magnesium Pellets and its Mechanism [Dissertation]. Changsha: Central South University, 2012謝路奔. 含鎂球團焙燒固結強化及其機理研究[學位論文]. 長沙: 中南大學, 2012 [13] Liu H, Xiang X P, Gan M Y, et al. Experimental study on preparation of pellets using high MgO-bearing iron ore concentrate. Sinter Pelletiz, 2019, 44(2): 33劉華, 向小平, 甘牧原, 等. 高鎂鐵精礦制備球團試驗研究. 燒結球團, 2019, 44(2):33 [14] Qing G L, Wang C D, Hou E J, et al. Compressive strength and metallurgical property of low silicon magnesium pellet. J Iron Steel Res, 2014, 26(4): 7青格勒, 王朝東, 侯恩儉, 等. 低硅含鎂球團礦抗壓強度及冶金性能. 鋼鐵研究學報, 2014, 26(4):7 [15] Xu C G, Long Y, Tian T L, et al. Experimental study on metallurgical properties of high magnesia alkaline pellets. Sinter Pelletiz, 2016, 41(1): 36徐晨光, 龍躍, 田鐵磊, 等. 高鎂堿性球團礦冶金性能試驗研究. 燒結球團, 2016, 41(1):36 [16] Fan X H, Xie L B, Gan M, et al. Roasting characteristics of magnesium pellets and mechanism of strengthening concretion. J Cent South Univ Sci Technol, 2013, 44(2): 449范曉慧, 謝路奔, 甘敏, 等. 高鎂球團焙燒特性及其固結強化機理. 中南大學學報(自然科學版), 2013, 44(2):449 [17] Zhu D Q, Gao Z F, Pan J, et al. Influence of pellet basicity and MgO content on roasting and metallurgical properties of pellets. J Cent South Univ Sci Technol, 2013, 44(10): 3963朱德慶, 高子富, 潘建, 等. 堿度及MgO質量分數對球團焙燒及冶金性能的影響. 中南大學學報(自然科學版), 2013, 44(10):3963 [18] State Administration for Market Regulation, Standardization Administration. GB/T 13240—2018 Iron Ore Pellets for Blast Furnace Feedstocks-Determination of the Free-Swelling Index. Beijing: Standards Press of China, 2018國家市場監督管理總局, 中國國家標準化管理委員會. GB/T 13240—2018高爐用鐵球團礦自由膨脹指數的測定. 北京: 中國標準出版社, 2018 [19] General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China, Standardization Administration. GB/T 24189—2009 Iron Ores for Blast Furnace Feedstocks-Determination of the Reducibility by the Final Degree of Reduction Index. Beijing: Standards Press of China, 2009中華人民共和國國家質量監督檢驗檢疫總局, 中國國家標準化管理委員會. GB/T 24189—2009高爐用鐵礦石用最終還原度指數表示的還原性的測定. 北京: 中國標準出版社, 2009 [20] General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China, Standardization Administration. GB/T 24204—2009 Iron Ores for Blast Furnace Feedstocks - Determination of Low-Temperature Reduction-Disintegration Indices by Dynamic Method. Beijing: Standards Press of China, 2009中華人民共和國國家質量監督檢驗檢疫總局, 中國國家標準化管理委員會. GB/T 24204—2009高爐爐料用鐵礦石低溫還原粉化率的測定--動態試驗法. 北京: 中國標準出版社, 2009 [21] Gao Q J. Preparation of MgO Bearing Additive for Pellet and Mechanism Investigation of It on the Effect to Quality of Pellets [Dissertation]. Shenyang: Northeastern University, 2014高強健. MgO基球團添加劑制備及對球團礦質量影響的機理研究[學位論文]. 沈陽: 東北大學, 2014 [22] Wu D, Zhang W Y, Lu S Q, et al. Study on hydration of MgO in different systems. J Salt Chem Ind, 2020, 49(3): 31 doi: 10.3969/j.issn.2096-3408.2020.03.010吳丹, 張文燕, 路紹琰, 等. 氧化鎂在不同體系中的水化研究. 鹽科學與化工, 2020, 49(3):31 doi: 10.3969/j.issn.2096-3408.2020.03.010 [23] Yang Y B, Zhang J, Zhong Q, et al. Effect of pretreatment on the ballability of hematite in preparation of a fluxed pellet. Min Metall Eng, 2019, 39(4): 83 doi: 10.3969/j.issn.0253-6099.2019.04.020楊永斌, 張健, 鐘強, 等. 預處理強化赤鐵礦熔劑性球團制備性能的研究. 礦冶工程, 2019, 39(4):83 doi: 10.3969/j.issn.0253-6099.2019.04.020 [24] Pan J, Yu H B, Zhu D Q, et al. Influence of MgO sources on behavior of preheated pellets of magnetite concentrate. J Cent South Univ Sci Technol, 2016, 47(6): 1823 doi: 10.11817/j.issn.1672-7207.2016.06.001潘建, 于鴻賓, 朱德慶, 等. MgO來源對磁鐵精礦球團預熱行為的影響. 中南大學學報(自然科學版), 2016, 47(6):1823 doi: 10.11817/j.issn.1672-7207.2016.06.001 [25] Gao Z F. Preparation of Magnesium Flux Pellets and Its Reduction Behaviors in CORER Process [Dissertation]. Changsha: Central South University, 2013高子富. 用于COREX的含鎂熔劑性球團制備及其還原行為研究[學位論文]. 長沙: 中南大學, 2013 [26] Zhao Z L, Tang H Q, Guo Z C. Effects of CaO on precipitation morphology of metallic iron in reduction of iron oxides under CO atmosphere. J Iron Steel Res Int, 2013, 20(7): 16 doi: 10.1016/S1006-706X(13)60120-X [27] Cheng G J, Xue X X, Gao Z X, et al. Effect of Cr2O3 on the reduction and smelting mechanism of high-chromium vanadium-titanium magnetite pellets. ISIJ Int, 2016, 56(11): 1938 doi: 10.2355/isijinternational.ISIJINT-2016-234 -
點擊查看大圖
計量
- 文章訪問數: 1207
- HTML全文瀏覽量: 505
- PDF下載量: 79
- 被引次數: 0
