全尾砂无耙深锥稳态浓密性能分析
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摘要
结合沉降和压滤实验,对脱水性能数据进行曲线拟合获得连续网状结构形成浓度、压缩屈服应力和干涉沉降系数,引入Usher提出的稳态浓密性能预测算法,建立了无耙深锥浓密模型,分析了絮凝剂单耗、底流中固相的体积分数、泥层高度等对固体通量和固体处理能力的影响规律.研究结果表明:絮凝剂添加量对沉降区域影响大于压密区域,20 g·t-1时浓密性能较好,底流中固相的体积分数越大固体通量越小;在沉降区域,固体通量仅与浓度有关,不受泥层高度影响;在压密区域,固体通量为浓度与泥层高度的方程;模型参数范围内,当泥层高度<3. 5 m时,固体处理能力为浓度与泥层高度的方程,当泥层高度> 3. 5 m时,固体处理能力与固体通量随底流中固相的体积分数变化规律一致.
Typical tailings discharge at low solids concentrations can cause serious environmental pollution and disasters,including tailings dam failures and the collapse of underground voids. High-density cemented backfill,which consists of unclassified mine tailings,binders,additive agents,and water,are increasingly being considered as simple and effective means for reducing the hazards of conventional slurry deposition and recovering water for recycling. Gravity thickening has been widely used in the minerals industry to increase solids concentrations of tailings. The prediction of gravity thickener performance by characterizing relevant material properties is of great importance,and batch settling and pressure filtration have proven to be the most useful methods for characterizing the dewaterability of tailings for gravity thickener performance predictions. In this research,batch settling and pressure filtration experiments were conducted to obtain dewatering data with respect to gel point,compressive yield stress,and hindered settling function by curve fitting. A predictive algorithm of steady-state thickening,proposed by Usher,was introduced and a rakeless deep cone thickener model was constructed to analyze the effect of flocculant dosage,underflow concentration,and mud height on solid flux and solid throughput.The results indicate that flocculant dosage has a greater impact on the settling zone than on the compaction zone,optimum thickening performance is obtained at a dosage of 20 g·t-1,and as underflow concentration increases,solid flux decreases. Solid flux was determined to be related to the concentration,and not influenced by mud height in the settling zone,whereas,in the compaction zone,solid flux is a function of concentration and mud height. In the range of the model's parameters,solid throughput is a function of concentra-tion and mud height at heights less than 3. 5 m,and the change law of solid throughput is similar to that of solid flux.
Typical tailings discharge at low solids concentrations can cause serious environmental pollution and disasters,including tailings dam failures and the collapse of underground voids. High-density cemented backfill,which consists of unclassified mine tailings,binders,additive agents,and water,are increasingly being considered as simple and effective means for reducing the hazards of conventional slurry deposition and recovering water for recycling. Gravity thickening has been widely used in the minerals industry to increase solids concentrations of tailings. The prediction of gravity thickener performance by characterizing relevant material properties is of great importance,and batch settling and pressure filtration have proven to be the most useful methods for characterizing the dewaterability of tailings for gravity thickener performance predictions. In this research,batch settling and pressure filtration experiments were conducted to obtain dewatering data with respect to gel point,compressive yield stress,and hindered settling function by curve fitting. A predictive algorithm of steady-state thickening,proposed by Usher,was introduced and a rakeless deep cone thickener model was constructed to analyze the effect of flocculant dosage,underflow concentration,and mud height on solid flux and solid throughput.The results indicate that flocculant dosage has a greater impact on the settling zone than on the compaction zone,optimum thickening performance is obtained at a dosage of 20 g·t-1,and as underflow concentration increases,solid flux decreases. Solid flux was determined to be related to the concentration,and not influenced by mud height in the settling zone,whereas,in the compaction zone,solid flux is a function of concentration and mud height. In the range of the model's parameters,solid throughput is a function of concentra-tion and mud height at heights less than 3. 5 m,and the change law of solid throughput is similar to that of solid flux.
引文
[1] Wu A X,Wang Y,Wang H J. Status and prospects of the paste backfill technology. Met Mine,2016(7):1(吴爱祥,王勇,王洪江.膏体充填技术现状及趋势.金属矿山,2016(7):1)
[2] Gao Z Y,Wu A X,Peng N B,et al. Research on the flocculation settlement rules and parameters optimization of filling tailings. Met Mine,2017(6):186(高志勇,吴爱祥,彭乃兵,等.充填尾矿絮凝沉降规律及参数优化.金属矿山,2017(6):186)
[3] Li H,Wang H J,Wu A X,et al. Pressure rake analysis of deep cone thickeners based on tailings'settlement and rheological characteristics. J Univ Sci Technol Beijing,2013,35(12):1553(李辉,王洪江,吴爱祥,等.基于尾砂沉降与流变特性的深锥浓密机压耙分析.北京科技大学学报,2013,35(12):1553)
[4] Jiao H Z,Wu A X,Wang H J,et al. Experiment study on the flocculation settlement characteristic of unclassified tailings. J Univ Sci Technol Beijing,2011,33(12):1437(焦华喆,吴爱祥,王洪江,等.全尾砂絮凝沉降特性实验研究.北京科技大学学报,2011,33(12):1437)
[5] Wang H J,Chen Q R,Wu A X,et al. Study on the thickening properties of unclassified tailings and its application to thickener design. J Univ Sci Technol Beijing,2011,33(6):676(王洪江,陈琴瑞,吴爱祥,等.全尾砂浓密特性研究及其在浓密机设计中的应用.北京科技大学学报,2011,33(6):676)
[6] Yang Q P,Li H,Zhang J J,et al. Process and equipment of paste backfill in Chambishi Copper. Mod Mine,2015(9):185(杨清平,李辉,张晋军,等.谦比希铜矿膏体充填工艺及其装备.现代矿业,2015(9):185)
[7] Buscall R,White L R. The consolidation of concentrated suspensions. Part 1.—The theory of sedimentation. J Chem Soc Faraday Trans 1,1987,83(3):873
[8] Green M D. Characterisation of Suspensions in Settling and Compression[Dissertation]. Melbourne:The University of Melbourne,1997
[9] Landman K A,White L R,Buscall R. The continuous-flow gravity thickener:steady state behavior. AIChE J,1988,34(2):239
[10] Landman K A,White L R. Solid/liquid separation of flocculated suspensions. Adv Colloid Interface Sci,1994,51:175
[11] Garrido P,Burgos R,Concha F,et al. Software for the design and simulation of gravity thickeners. Miner Eng,2003,16(2):85
[12] Usher S P. Suspension Dewatering:Characterisation and Optimisation[Dissertation]. Melbourne:The University of Melbourne,2002
[13] Usher S P,De Kretser R G,Scales P J. Validation of a new filtration technique for dewaterability characterization. AIChE J,2001,47(7):1561
[14] de Kretser R G,Usher S P,Scales P J,et al. Rapid filtration measurement of dewatering design and optimization parameters.AIChE J,2001,47(8):1758
[15] Fitch B. Current theory and thickener design. Ind Eng Chem,1966,58(10):18
[16] Coe H S,Clevenger G H. Methods for determining the capacities of slime-settling tanks. Trans Am Inst Min Eng,1916,60:356
[17] Usher S P,Scales P J. Steady state thickener modelling from the compressive yield stress and hindered settling function. Chem Eng J,2005,111(2-3):253
[2] Gao Z Y,Wu A X,Peng N B,et al. Research on the flocculation settlement rules and parameters optimization of filling tailings. Met Mine,2017(6):186(高志勇,吴爱祥,彭乃兵,等.充填尾矿絮凝沉降规律及参数优化.金属矿山,2017(6):186)
[3] Li H,Wang H J,Wu A X,et al. Pressure rake analysis of deep cone thickeners based on tailings'settlement and rheological characteristics. J Univ Sci Technol Beijing,2013,35(12):1553(李辉,王洪江,吴爱祥,等.基于尾砂沉降与流变特性的深锥浓密机压耙分析.北京科技大学学报,2013,35(12):1553)
[4] Jiao H Z,Wu A X,Wang H J,et al. Experiment study on the flocculation settlement characteristic of unclassified tailings. J Univ Sci Technol Beijing,2011,33(12):1437(焦华喆,吴爱祥,王洪江,等.全尾砂絮凝沉降特性实验研究.北京科技大学学报,2011,33(12):1437)
[5] Wang H J,Chen Q R,Wu A X,et al. Study on the thickening properties of unclassified tailings and its application to thickener design. J Univ Sci Technol Beijing,2011,33(6):676(王洪江,陈琴瑞,吴爱祥,等.全尾砂浓密特性研究及其在浓密机设计中的应用.北京科技大学学报,2011,33(6):676)
[6] Yang Q P,Li H,Zhang J J,et al. Process and equipment of paste backfill in Chambishi Copper. Mod Mine,2015(9):185(杨清平,李辉,张晋军,等.谦比希铜矿膏体充填工艺及其装备.现代矿业,2015(9):185)
[7] Buscall R,White L R. The consolidation of concentrated suspensions. Part 1.—The theory of sedimentation. J Chem Soc Faraday Trans 1,1987,83(3):873
[8] Green M D. Characterisation of Suspensions in Settling and Compression[Dissertation]. Melbourne:The University of Melbourne,1997
[9] Landman K A,White L R,Buscall R. The continuous-flow gravity thickener:steady state behavior. AIChE J,1988,34(2):239
[10] Landman K A,White L R. Solid/liquid separation of flocculated suspensions. Adv Colloid Interface Sci,1994,51:175
[11] Garrido P,Burgos R,Concha F,et al. Software for the design and simulation of gravity thickeners. Miner Eng,2003,16(2):85
[12] Usher S P. Suspension Dewatering:Characterisation and Optimisation[Dissertation]. Melbourne:The University of Melbourne,2002
[13] Usher S P,De Kretser R G,Scales P J. Validation of a new filtration technique for dewaterability characterization. AIChE J,2001,47(7):1561
[14] de Kretser R G,Usher S P,Scales P J,et al. Rapid filtration measurement of dewatering design and optimization parameters.AIChE J,2001,47(8):1758
[15] Fitch B. Current theory and thickener design. Ind Eng Chem,1966,58(10):18
[16] Coe H S,Clevenger G H. Methods for determining the capacities of slime-settling tanks. Trans Am Inst Min Eng,1916,60:356
[17] Usher S P,Scales P J. Steady state thickener modelling from the compressive yield stress and hindered settling function. Chem Eng J,2005,111(2-3):253