Mechanism and structure-activity relationship of a new composite binder to improve the quality of green pellets
-
摘要: 降低膨潤土用量是提高球團品位、實現節能減排的有效途徑之一。基于新型高效復合粘結劑，通過生球制備、線性擬合分析、生球力學特征分析等手段研究了復合粘結劑對生球質量的影響規律及與重要指標的構效關系，闡明了復合粘結劑提高生球質量的作用機理。結果表明：配比（質量分數）為1.2%膨潤土+0.028%有機粘結劑的復合粘結劑球團，落下強度（0.5 m高度落下次數）達到6.2、平均抗壓強度達到14.5 N、爆裂溫度達到542 ℃，與2.0%膨潤土球團相比，生球質量相近，但膨潤土消耗減少40%；基于構效關系分析，有機粘結劑對生球落下強度、爆裂溫度作用顯著，膨潤土對干球強度影響更大；有機粘結劑通過增強顆粒的親水性、毛細力和黏性力強化了生球落下強度，干燥時在表層形成少量孔隙，有利于球團內水分的排出，提高了生球爆裂溫度，干燥后以固態連接橋的形式強化干球強度，但是孔隙的位點和尺寸可能會降低干球強度，因此，對干球強度起決定性作用的是膨潤土，有機粘結劑對干球強度的影響呈現多面性。Abstract: Reducing bentonite consumption is one of the effective ways to improve the grade of pellets and realize energy saving and emission reduction. Based on the new high-efficiency composite binder, the effect of the composite binder on the quality of green pellets and structure-activity relationship with important indexes were studied by means of green pellet preparation, linear fitting analysis, and green pellet mechanical characteristics analysis. Moreover, the mechanism of the composite binder to improve the quality of the green pellets was expounded. Results show that the composite binder pellet, with a ratio of 1.2% bentonite and 0.028% organic binder, has a drop number (dropped from 0.5 m height) of 6.2, a average crushing strength of 14.5 N, and a shock temperature of 542 ℃. Compared with the pellet with 2.0% bentonite, the mass of the green pellets is similar; however, the bentonite consumption is reduced by 40%. Based on the analysis of the structure-activity relationship, the organic binder has a considerable effect on the drop number and the shock temperature of the green pellets, and the bentonite has a greater effect on the dry-crushing strength. The organic binder strengthens the drop number of the pellets by enhancing the hydrophilicity, capillary force, and viscosity, and it forms small amounts of pores on the surface layer during drying, which is beneficial for discharging water in the pellets and improving the shock temperature of the pellets. After drying, the organic binder strengthens the pellets in the form of a solid connection bridge; however, the site and the size of the pores may reduce the dry-crushing strength. Therefore, bentonite plays a decisive role in the strength of the dry pellets, and the influence of the organic binder on the strength of the dry pellets is multifaceted.
-
圖 1 膨潤土用量對生球質量的影響
Figure 1. Influence of bentonite dosage on the quality of green pellets
圖 4 有機粘結劑P比例對復合粘結劑黏度的影響
Figure 4. Influence of organic binder P ratio on the viscosity of composite additive
圖 7 有機粘結劑P的熱重分析和差熱分析
Figure 7. Thermogravimetric analysis and differential thermal analysis of organic binder P
表 1 鐵精礦的主要化學成分及靜態成球指數
Table 1. Main chemical compositions and static pelletization index of iron-containing raw materials
Iron ore Chemical composition（mass fraction）/% LOI Mass fraction of iron ore with ?74 μm/% Mass fraction of iron ore with ?45 μm/% Specific surface area/（cm2·g?1） Static pelletization TFe FeO SiO2 Al2O3 CaO MgO S P A 65.15 24.89 4.95 1.66 0.40 0.54 0.077 0.012 ?0.74 94.0 78.8 1408 Medium B 65.46 25.83 3.76 0.63 1.02 1.62 0.200 0.100 ?1.91 99.5 94.8 1466 Excellent Z 65.75 26.50 6.57 0.84 0.30 0.48 0.054 0.014 ?0.47 93.6 80.3 1568 Good Note: LOI is burning loss. 
下載: 導出CSV
表 2 膨潤土的物化性能
Table 2. Physical and chemical properties of bentonite
Methylene blue adsorbed/
(per 100 g)/gWater absorption
(2 h)/ %Swelling coefficient/
(mL·g?1)Colloid index
(per 15 g)/mL21.69 496 25 580
下載: 導出CSV
表 3 有機粘結劑P灰分化學成分（質量分數）
Table 3. Chemical composition of the organic binder P ash
% Na2O SOx CaO SiO2 Cl MgO Al2O3 K2O 88.4 10.06 0.382 0.366 0.277 0.214 0.168 0.024
下載: 導出CSV
表 4 復合粘結劑用量對生球質量的影響
Table 4. Influence of compound binder dosage on the quality of green pellets
Mass fraction of bentonite/% Mass fraction
of P / %Drop number Average crushing strength
of green pellet / NShock temperature/ ℃ Average crushing strength
of dry pellet / NMoisture content of
green pellet/ %1.1 0.020 3.9 11.0 535 82.3 8.4 0.030 4.7 11.3 550 81.8 8.4 0.040 5.1 11.9 560 90.7 8.8 0.050 5.8 11.6 540 89.5 8.6 1.2 0.020 4.8 14.6 535 59.0 8.1 0.024 5.8 13.8 530 57.1 8.5 0.028 6.2 14.5 542 66.0 8.3 0.032 6.6 13.9 554 73.9 8.6 1.3 0.016 4.1 13.3 540 65.2 8.7 0.020 5.9 12.2 546 72.3 8.6 0.024 6.4 11.7 549 63.3 8.7 0.028 7.0 13.6 555 73.1 8.5 1.4 0.008 4.1 12.1 520 88.4 8.6 0.012 5.2 11.2 535 107.3 8.8 0.016 6.9 12.8 528 98.3 8.7 0.020 7.8 13.8 530 108.1 9.0
下載: 導出CSV
表 5 回歸方程顯著性和擬合度
Table 5. Significance and fitness of regression equation
Factor Significance of variance P Significant correlation R2 Drop number 0.0004 Very significant 0.882 Green crushing strength 0.551 Not relevant 0.433 Shock temperature 0.006 Significant 0.713 Dry crushing strength 0.008 Significant 0.588
下載: 導出CSV
表 6 有機粘結劑P和膨潤土標準化回歸系數
Table 6. Standardized regression coefficient of organic binder P and bentonite
Factor P Bentonite Drop number 0.905 0.734 Shock temperature 0.851 0.206 Dry crushing strength 0.190 0.843
下載: 導出CSV
中文字幕在线观看表 7 膨潤土和有機粘結劑P的黏度
Table 7. Viscosity of bentonite and organic binder P
Binder Viscosity / (mPa·s) Bentonite 3 P 90–120
下載: 導出CSV
-
參考文獻
[1] Xing Y, Zhang W B, Su W, et al. Research of ultra-low emission technologies of the iron and steel industry in China. Chin J Eng, 2021, 43(1): 1邢奕, 張文伯, 蘇偉, 等. 中國鋼鐵行業超低排放之路. 工程科學學報, 2021, 43(1):1 [2] Wang X D, Jin Y L. Strategy analysis and study of high ratio of pellet utilized in blast furnace. Iron Steel, 2021, 56(5): 7王新東, 金永龍. 高爐使用高比例球團的戰略思考與球團生產的試驗研究. 鋼鐵, 2021, 56(5):7 [3] Xing Y, Cui Y K, Su W, et al. Study of the mechanism of removing ultrafine particles using SBA-15. Chin J Eng, 2020, 42(3): 313邢奕, 崔永康, 蘇偉, 等. SBA-15脫除超細顆粒的機制研究. 工程科學學報, 2020, 42(3):313 [4] Wu S L, Zhang Y Z, Su B, et al. Analysis of main factors affecting NOx emissions in sintering process. Chin J Eng, 2017, 39(5): 693吳勝利, 張永忠, 蘇博, 等. 影響燒結工藝過程NOx排放質量濃度的主要因素解析. 工程科學學報, 2017, 39(5):693 [5] Yan B J, Xing Y, Lu P, et al. A critical review on the research progress of multi-pollutant collaborative control technologies of sintering flue gas in the iron and steel industry. Chin J Eng, 2018, 40(7): 767閆伯駿, 邢奕, 路培, 等. 鋼鐵行業燒結煙氣多污染物協同凈化技術研究進展. 工程科學學報, 2018, 40(7):767 [6] Zhang X B, Zhu M W. Effect of bentonite additive on pelletizing operation of our country. Sinter Pelletizing, 2003, 28(6): 3 doi: 10.3969/j.issn.1000-8764.2003.06.002張新兵, 朱夢偉. 膨潤土對我國球團生產的影響. 燒結球團, 2003, 28(6):3 doi: 10.3969/j.issn.1000-8764.2003.06.002 [7] Kawatra S K, Ripke S J. Developing and understanding the bentonite fiber bonding mechanism. Miner Eng, 2001, 14(6): 647 doi: 10.1016/S0892-6875(01)00056-5 [8] Kawatra S K, Ripke S J. Laboratory studies for improving green ball strength in bentonite-bonded magnetite concentrate pellets. Int J Miner Process, 2003, 72(1-4): 429 doi: 10.1016/S0301-7516(03)00117-0 [9] Pei Y H, Gan X F, Chen Y Y. Experimental research on new type of organic binder as pellet additive. Sinter Pelletizing, 2012, 37(1): 39 doi: 10.3969/j.issn.1000-8764.2012.01.010裴業虎, 甘學鋒, 陳義勇. 新型有機粘接劑作球團添加劑試驗研究. 燒結球團, 2012, 37(1):39 doi: 10.3969/j.issn.1000-8764.2012.01.010 [10] Fan X H, Wang Y, Gan M, et al. Strength enhancement of oxide pellet with organic binder. J Iron Steel Res, 2008, 20(5): 5范曉慧, 王祎, 甘敏, 等. 提高有機粘結劑氧化球團礦強度的措施. 鋼鐵研究學報, 2008, 20(5):5 [11] Huang G X. Study on Preparation of Oxidized Pellet by New-Style Organic Binder [Dissertation]. Changsha: Central South University, 2007黃桂香. 應用新型有機粘結劑制備氧化球團的研究[學位論文]. 長沙: 中南大學, 2007 [12] Li H X, Jiang T, Qiu G Z, et al. Molecular structure mould and selecting criterion of organic binder for iron ore pellet. J Central South Univ Technol Nat Sci, 2000, 31(1): 17李宏煦, 姜濤, 邱冠周, 等. 鐵礦球團有機粘結劑的分子構型及選擇判據. 中南工業大學學報(自然科學版), 2000, 31(1):17 [13] Li H X, Wang D Z, Hu Y H, et al. The mechanism of improving pellet strength by carboxyl methlated amylum. J Central South Univ Technol Nat Sci, 2001, 32(4): 351李宏煦, 王淀佐, 胡岳華, 等. 羧甲基淀粉鈉提高球團強度的機理. 中南工業大學學報(自然科學版), 2001, 32(4):351 [14] Yang Y B, Huang G X, Jiang T, et al. Application of organic binder as substitutes for bentonite in pellet preparation. J Central South Univ Sci Technol, 2007, 38(5): 850楊永斌, 黃桂香, 姜濤, 等. 有機粘結劑替代膨潤土制備氧化球團. 中南大學學報(自然科學版), 2007, 38(5):850 [15] Huang Z C, Wang Y M, Chai B, et al. Preparation of oxide pellets with fibrosis bentonite and its mechanism. J Central South Univ Sci Technol, 2014, 45(7): 2145黃柱成, 王雨蒙, 柴斌, 等. 纖維化膨潤土強化氧化球團制備及其機理. 中南大學學報(自然科學版), 2014, 45(7):2145 [16] Huang Z C, Li T H, Yi L Y, et al. Preparation of fibrosis bentonite and its application in iron ore concentrate pellet. J Central South Univ Sci Technol, 2014, 45(2): 341黃柱成, 李鐵輝, 易凌云, 等. 纖維化膨潤土制備及其在鐵精礦球團中的應用. 中南大學學報(自然科學版), 2014, 45(2):341 [17] Zhang Y B, Ouyang X Z, Lu M M, et al. Application effect of humic acid modified bentonite binder in iron ore pellets. Sinter Pelletizing, 2018, 43(4): 27張元波, 歐陽學臻, 路漫漫, 等. 腐植酸改性膨潤土在鐵礦球團中的應用效果. 燒結球團, 2018, 43(4):27 [18] Xie X L, Duan T, Zheng F Q, et al. Study of magnetite oxidized pellet prepared by modified composite binder. Met Mine, 2018(1): 79謝小林, 段婷, 鄭富強, 等. 改性復合黏結劑制備磁鐵礦氧化球團研究. 金屬礦山, 2018(1):79 [19] Pan S X, Sun W J, Zhang R D, et al. Data analysis and SPSS software application. J Jilin Mil Med Coll Fourth Mil Med Univ, 2005, 26(3): 145 doi: 10.3969/j.issn.1673-2995.2005.03.010潘淑霞, 孫王杰, 張若東, 等. 數據分析與SPSS軟件應用. 吉林醫藥學院學報, 2005, 26(3):145 doi: 10.3969/j.issn.1673-2995.2005.03.010 [20] Xu K C, Bi L P, Chen M C. Prediction model of compressive strength of lithium slag concrete based on SPSS regression analysis. J Archit Civ Eng, 2017, 34(1): 15 doi: 10.3969/j.issn.1673-2049.2017.01.003許開成, 畢麗蘋, 陳夢成. 基于SPSS回歸分析的鋰渣混凝土抗壓強度預測模型. 建筑科學與工程學報, 2017, 34(1):15 doi: 10.3969/j.issn.1673-2049.2017.01.003 [21] Liu L F. Micromechanics study on agglomerate impact breakage. Adv Mech, 2006, 36(4): 599 doi: 10.3321/j.issn:1000-0992.2006.04.011劉連峰. 顆粒聚合體碰撞破損的細觀力學仿真研究. 力學進展, 2006, 36(4):599 doi: 10.3321/j.issn:1000-0992.2006.04.011 [22] Orr F M, Scriven L E, Rivas A P. Pendular rings between solids: Meniscus properties and capillary force. J Fluid Mech, 1975, 67(4): 723 doi: 10.1017/S0022112075000572 [23] Wei R F, Li J X, Tang G W, et al. Strength and consolidation mechanism of iron ore and coal pellets. Ironmak Steelmak, 2014, 41(7): 514 doi: 10.1179/1743281213Y.0000000147 [24] Pan J, Tian H Y, Zhu D Q, et al. Particle size and wettability effect of ultrafine magnetite concentrate on ballability. Chin J Eng, 2017, 39(6): 830潘建, 田宏宇, 朱德慶, 等. 超微細鐵精礦的粒度特性和潤濕性對其成球性能的交互影響. 工程科學學報, 2017, 39(6):830 [25] Hotta K, Takeda K, Iinoya K. The capillary binding force of a liquid bridge. Powder Technol, 1974, 10(4-5): 231 doi: 10.1016/0032-5910(74)85047-3 [26] Davis R H, Serayssol J M, Hinch E J. The elastohydrodynamic collision of two spheres. J Fluid Mech, 1986, 163: 479 doi: 10.1017/S0022112086002392 [27] Lian G, Adams M J, Thornton C. Elastohydrodynamic collisions of solid spheres. J Fluid Mech, 1996, 311: 141 doi: 10.1017/S0022112096002534 [28] Adams M J, Perchard V. The cohesive forces between particles with interstitial liquid. Inst Chem Eng Symp, 1985, 91: 147 [29] Goldman A J, Cox R G, Brenner H. Slow viscous motion of a sphere parallel to a plane wall—II Couette flow. Chem Eng Sci, 1967, 22(4): 653 doi: 10.1016/0009-2509(67)80048-4 [30] Liu L F, Wang Z Y, Wang C. Simulations of impact attrition of cuboidal and spherical wet agglomerate of fine particles. Chin J Appl Mech, 2020, 37(5): 1929劉連峰, 王振陽, 王超. 球形和方形濕顆粒團的碰撞模擬研究. 應用力學學報, 2020, 37(5):1929 -
點擊查看大圖
圖(7) / 表(7)
計量
- 文章訪問數: 633
- HTML全文瀏覽量: 281
- PDF下載量: 62
- 被引次數: 0
