Effect of flocculation sedimentation on the yield stress of thickened ultrafine tailings slurry
-
摘要: 深錐濃密機內底部料漿的屈服應力過高容易導致壓耙，為此通過對不同絮凝沉降條件下獲得的濃縮超細尾砂料漿的屈服應力進行原位測量，并通過對絮凝前后料漿總有機碳的測試來分析超細尾砂顆粒表面的絮凝劑吸附量，進而分析了絮凝沉降對濃縮超細尾砂料漿屈服應力的影響規律。研究發現，絮凝沉降對濃縮超細尾砂料漿的屈服應力有顯著影響，pH和絮凝劑單耗通過影響尾砂顆粒表面的絮凝劑吸附量進而影響濃縮超細尾砂料漿的屈服應力，屈服應力隨著pH和絮凝劑單耗的增大均不斷增大。綜合考慮尾砂料漿的絮凝沉降效果和所得濃縮超細尾砂料漿的屈服應力，最佳絮凝條件是pH值為11和絮凝劑單耗為15 g·t?1，在此最優條件下料漿固液界面的初始沉降速率為0.4565 mm·s?1，沉降后上清液濁度為143 NTU，底部沉積尾砂料漿的固相質量分數為51.56%、屈服應力為243.18 Pa。初步建立了適用于超細人造尾砂的基于絮凝劑吸附量的屈服應力模型，屈服應力隨尾砂顆粒表面單位面積的絮凝劑吸附量的增大而增大，為實際生產中控制全尾砂絮凝沉降參數提供參考。Abstract: With the advantages of efficiency and economy, deep-cone thickener (DCT) has been increasingly applied in tailings management. The rake in the DCT is essential for obtaining high-concentration underflow slurry; thus, more emphasis was placed on the effects of rakes on the underflow concentration. However, high concentration means high yield stress, which may lead to rake blockage. Therefore, this study investigated the effects of flocculation and sedimentation on the yield stress of thickened ultrafine tailings slurry. First, flocculation and sedimentation experiments were conducted under a pH range of 8 to 11 and flocculant dosage of 0 to 45 g·t?1 to obtain different thickened ultrafine tailings slurries. Then, the yield stress was measured through an in situ test. Finally, the amount of flocculant adsorbed on the tailings particle surface was analyzed by total organic carbon analysis. The amount of flocculant adsorbed on the tailings particles surface increased with the pH and flocculant dosage over the entire experiment range. Then, the yield stress increased with the increase in the amount of adsorbed flocculant, indicating that flocculation sedimentation has a significant influence on the yield stress. Based on the flocculation sedimentation behavior and yield stress, the optimal conditions were a pH of 8 and flocculant dosage of 15 g·t?1. Under these conditions, the initial settling rate of the solid–liquid interface was 0.4565 mm·s?1, supernate turbidity was 143 NTU, solid mass fraction of sediment was 51.56%, and yield stress was 243.18 Pa. The relationship between yield stress and the amount of flocculant adsorbed and yield stress was investigated, and an empirical model for yield stress based on flocculant adsorption was established. It was found that the yield stress increased with the amount of flocculant adsorbed, providing a reference for the control of flocculation sedimentation parameters in actual production.
-
Key words:
- tailings /
- flocculation sedimentation /
- total organic carbon /
- flocculant adsorption /
- yield stress
-
圖 2 絮凝條件對絮凝沉降的影響。（a）pH；（b）絮凝劑單耗
Figure 2. Effects of conditions on flocculation and settling: (a) pH; (b) flocculant dosage
圖 3 絮凝條件對絮凝劑吸附效率的影響。（a）pH；（b）絮凝劑單耗
Figure 3. Effects of conditions on efficiency of flocc adsorption: (a) pH; (b) flocculant dosage
圖 4 絮凝條件對屈服應力的影響。（a）pH；（b）絮凝劑單耗
Figure 4. Effects of conditions on yield stress: (a) pH; (b) flocculant dosage
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] Wu A X, Yang Y, Cheng H Y, et al. Status and prospects of paste technology in China. Chin J Eng, 2018, 40(5): 517吳愛祥, 楊瑩, 程海勇, 等. 中國膏體技術發展現狀與趨勢. 工程科學學報, 2018, 40(5):517 [2] Qi C C, Fourie A. Cemented paste backfill for mineral tailings management: Review and future perspectives. Miner Eng, 2019, 144: 106025 [3] Fawell P D, Nguyen T V, Solnordal C B, et al. Enhancing gravity thickener feedwell design and operation for optimal flocculation through the application of computational fluid dynamics. Miner Process Extract Metall Rev, 2019(2): 1 [4] Jiao H Z, Wang S F, Yang Y X, et al. Water recovery improvement by shearing of gravity-thickened tailings for cemented paste backfill. J Clean Prod, 2020, 245: 118882 [5] Wu A X, Ruan Z E, Bürger R, et al. Optimization of flocculation and settling parameters of tailings slurry by response surface methodology. Miner Eng, 2020, 156: 106488 [6] Chen X M, Jin X F, Jiao H Z, et al. Pore connectivity and dewatering mechanism of tailings bed in raking deep-cone thickener process. Minerals, 2020, 10(4): 375 [7] Du J H, Pushkarova R A, Smart R S C. A cryo-SEM study of aggregate and floc structure changes during clay settling and raking processes. Int J Miner Process, 2009, 93(1): 66 [8] Wu A X, Wang Y, Wang H J. Effect of rake rod number and arrangement on tailings thickening performance. J Cent South Univ Sci Technol, 2014, 45(1): 244吳愛祥, 王勇, 王洪江. 導水桿數量和排列對尾礦濃密的影響機理. 中南大學學報(自然科學版), 2014, 45(1):244 [9] Rudman M, Paterson D A, Simic K. Efficiency of raking in gravity thickeners. Int J Miner Process, 2010, 95(1-4): 30 [10] Wang S Y, Wu A X, Ruan Z E, et al. Rheological properties of paste slurry and influence factors based on pipe loop test. J Cent South Univ Sci Technol, 2018, 49(10): 2519 doi: 10.11817/j.issn.1672-7207.2018.10.019王少勇, 吳愛祥, 阮竹恩, 等. 基于環管實驗的膏體流變特性及影響因素. 中南大學學報(自然科學版), 2018, 49(10):2519 doi: 10.11817/j.issn.1672-7207.2018.10.019 [11] Wu A X, Wang Y, Wang H J. Estimation model for yield stress of fresh uncemented thickened tailings: Coupled effects of true solid density, bulk density, and solid concentration. Int J Miner Process, 2015, 143: 117 [12] Zhang L F, Wu A X, Wang H J, et al. Evolution law of yield stress in paste tailings. Chin J Nonferrous Met, 2018, 28(8): 1631張連富, 吳愛祥, 王洪江, 等. 尾礦膏體屈服應力演化規律. 中國有色金屬學報, 2018, 28(8):1631 [13] Cheng H Y, Wu S C, Zhang X Q, et al. Effect of particle gradation characteristics on yield stress of cemented paste backfill. Int J Miner Metall Mater, 2020, 27(1): 10 [14] Cheng H Y, Wu S C Wu A X, et al. Grading characterization and yield stress prediction based on paste stability coefficien. Chin J Eng, 2018, 40(10): 1168程海勇, 吳順川, 吳愛祥, 等. 基于膏體穩定系數的級配表征及屈服應力預測. 工程科學學報, 2018, 40(10):1168 [15] Zhang L F, Wu A X, Wang H J. Effects and mechanism of pumping agent on rheological properties of highly muddy paste. Chin J Eng, 2018, 40(8): 918張連富, 吳愛祥, 王洪江. 泵送劑對高含泥膏體流變特性影響及機理. 工程科學學報, 2018, 40(8):918 [16] Liu X H, Wu A X, Wang H J, et al. Influence mechanism and calculation model of CPB rheological parameters. Chin J Eng, 2017, 39(2): 190劉曉輝, 吳愛祥, 王洪江, 等. 膏體流變參數影響機制及計算模型. 工程科學學報, 2017, 39(2):190 [17] Reyes C, álvarez M, Ihle C F, et al. The influence of seawater on magnetite tailing rheology. Miner Eng, 2019, 131: 363 [18] Haruna S, Fall M. Time- and temperature-dependent rheological properties of cemented paste backfill that contains superplasticizer. Powder Technol, 2020, 360: 731 [19] Wand Y, Wu A X, Ruan Z E, et al. Temperature effects on rheological properties of fresh thickened copper tailings that contain cement. J Chem, 2018, 2018: 5082636 [20] Zhang Q L, Wang S, Wang X M, et al. Influence of anionic polyacrylamide on rheological parameters of paste-like slurry under different mass concentrations. Chin J Nonferrous Met, 2016, 26(8): 1794張欽禮, 王石, 王新民, 等. 不同質量濃度下陰離子型聚丙烯酰胺對似膏體流變參數的影響. 中國有色金屬學報, 2016, 26(8):1794 [21] Yang L H, Wang H J, Wu A X, et al. Effect of flocculation settling on rheological characteristics of full tailing slurry. J Cent South Univ Sci Technol, 2016, 47(10): 3523楊柳華, 王洪江, 吳愛祥, 等. 絮凝沉降對全尾砂料漿流變特性的影響. 中南大學學報(自然科學版), 2016, 47(10):3523 [22] Yang Y, Wu A X, Klein B, et al. Effect of primary flocculant type on a two-step flocculation process on iron ore fine tailings under alkaline environment. Miner Eng, 2019, 132: 14 [23] Cao S, Yilmaz E, Song W D. Evaluation of viscosity, strength and microstructural properties of cemented tailings backfill. Minerals, 2018, 8(8): 352 [24] Botha L, Soares J B P. The influence of tailings composition on flocculation. Can J Chem Eng, 2015, 93(9): 1514 [25] Deng X J, Zhang J X, Klein B, et al. Experimental characterization of the influence of solid components on the rheological and mechanical properties of cemented paste backfill. Int J Miner Process, 2017, 168: 116 [26] Patil D P, Andrews J R G, Uhlherr P H T. Shear flocculation—kinetics of floc coalescence and breakage. Int J Miner Process, 2001, 61(3): 171 [27] Dash M, Dwari R K, Biswal S K, et al. Studies on the effect of flocculant adsorption on the dewatering of iron ore tailings. Chem Eng J, 2011, 173(2): 318 [28] Motta F L, Gaikwad R, Botha L, et al. Quantifying the effect of polyacrylamide dosage, Na+ and Ca2+ concentrations, and clay particle size on the flocculation of mature fine tailings with robust statistical methods. Chemosphere, 2018, 208: 263 [29] Gurumoorthy A V P, Juvekar V A. Bridging flocculation: A modeling study of the role of polymer adsorption dynamics. Int J Chem Sci, 2014, 12(2): 315 [30] Daintree L, Biggs S. Particle-particle interactions: The link between aggregate properties and rheology. Part Sci Technol, 2010, 28(5): 404 [31] Avadiar L, Leong Y K, Fourie A. Effects of polyethylenimine dosages and molecular weights on flocculation, rheology and consolidation behaviors of kaolin slurries. Powder Technol, 2014, 254: 364 [32] Ji Y G, Lu Q Y, Liu Q X, et al. Effect of solution salinity on settling of mineral tailings by polymer flocculants. Colloid Surf A, 2013, 430: 29 [33] Yang L H, Wang H J, Wu A X, et al. Regulation and a mathematical model of underflow in paste thickeners based on a circular system design. Chin J Eng, 2017, 39(10): 1507楊柳華, 王洪江, 吳愛祥, 等. 基于循環系統的膏體濃密機底流調控及其數學模型. 工程科學學報, 2017, 39(10):1507 -
下載:
點擊查看大圖
圖(5)
計量
- 文章訪問數: 1521
- HTML全文瀏覽量: 876
- PDF下載量: 83
- 被引次數: 0
