Effect of Ultrasonically Modified Cationic Polyacrylamide on the Flocculation Settlement and Dewatering Performance of Coal Slime Water

QIAO Zhizhong; LIU Libo; HU Jinliang; LIU Xiao

doi:10.13779/j.cnki.issn1001-0076.2023.05.013

2023 Vol. 43, No. 5

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Article navigation > Conservation and Utilization of Mineral Resources > 2023 > 43(5): 114-119

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QIAO Zhizhong, LIU Libo, HU Jinliang, LIU Xiao. Effect of Ultrasonically Modified Cationic Polyacrylamide on the Flocculation Settlement and Dewatering Performance of Coal Slime Water[J]. Conservation and Utilization of Mineral Resources, 2023, 43(5): 114-119. doi: 10.13779/j.cnki.issn1001-0076.2023.05.013

Citation:

QIAO Zhizhong, LIU Libo, HU Jinliang, LIU Xiao. Effect of Ultrasonically Modified Cationic Polyacrylamide on the Flocculation Settlement and Dewatering Performance of Coal Slime Water[J]. Conservation and Utilization of Mineral Resources, 2023, 43(5): 114-119. doi: 10.13779/j.cnki.issn1001-0076.2023.05.013

Effect of Ultrasonically Modified Cationic Polyacrylamide on the Flocculation Settlement and Dewatering Performance of Coal Slime Water

China Shenhua Energy Co., Ltd. Shenhua Zhungeer Energy Company Coal Preparation Plant, Ordos 010300, Inner Mongolia , China

Received Date: 10 August 2023

Publish Date: 25 October 2023

Abstract

Abstract

Flocculation settlement and dewatering through filtration are common methods used for treating slime water. The efficiency of flocculation directly impacts the dewatering process of coal slime. This paper introduces a novel technology to enhance the flocculation and dewatering process of coal slime water by utilizing ultrasonically modified cationic polyacrylamide (CPAM). The characteristics of CPAM solutions pretreated with ultrasonic treatment for different durations were examined using a rheometer. The impact of ultrasonically modified flocculants on the settling of coal slime water was analyzed through settlement and turbidity tests. Floc properties of various modified CPAMs in the treatment of slime water were observed using the focused beam reflectance measurement system and the particle observation system. Furthermore, a correlation was established between the floc properties and the characteristics of the filter cake formed during the filtration of coal slime water. Experimental results indicate that after 40 seconds of ultrasonic treatment, CPAM demonstrates the most effective slime flocculation with the lowest supernatant turbidity, approximately 180 NTU. Under these conditions, coal slime filtration occurs at the fastest rate, reducing filtration time by about 25 seconds compared to cases without ultrasonic treatment. Additionally, the moisture content of the filter cake obtained under these conditions is the lowest, around 29%. This phenomenon can be attributed to the formation of multi−molecular−weight polymers in the CPAM solution following 40 seconds of sonication. Low−molecular−weight agents gradually aggregate coal slime particles into small flocs, while high−molecular−weight agents further link these small flocs together. Coal slime particles become tightly bound within the polymer matrix through a complex system of multi−component polymers. As the flocs settle, they create a denser structure and sedimentary bed. This sediment layer, composed of dense flocs, offers lower filtration resistance, enhancing filtration speed, and resulting in a reduced moisture content in the filter cake post−filtration.
- cationic /
- polyacrylamide /
- ultrasonic /
- flocculation /
- filtration

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References

[1]	张志军, 孟齐, 刘炯天. 选煤水化学−循环煤泥水系统的水化学性质[J]. 煤炭学报, 2021, 46: 614−623. Google Scholar ZHANG Z J, MENG Q, LIU J T. Water chemical properties of circulating coal slime water system[J]. Journal of China Coal Society, 2021, 46: 614−623. Google Scholar
[2]	董宪姝. 煤泥水处理技术研究现状及发展趋势[J]. 选煤技术, 2018, 3: 1−8. Google Scholar DONG X S. Research status and development trend of coal slime water treatment technology[J]. Coal Preparation Technology, 2018, 3: 1−8. Google Scholar
[3]	陈军, 闵凡飞, 彭陈亮, 等. 煤泥水中微细粒在季铵盐作用下的疏水聚团特性[J]. 中国矿业大学学报, 2015, 44(2): 332−340. Google Scholar CHENG J, MIN F F, PENG C L, et al. Hydrophobic aggregation characteristics of fine particles in coal slime water under the action of quaternary ammonium salt[J]. Journal of China University of Mining & Technology, 2015, 44(2): 332−340. Google Scholar
[4]	P. OFORI, A. V. NGUYEN, B. FIRTH, C. MCNALLY, O. Ozdemir, Shear−induced floc structure changes for enhanced dewatering of coal preparation plant tailings[J], Chemical Engineering Journal, 2011, 172: 914−923. Google Scholar
[5]	杨彦斌, 屈进州, 朱子祺, 等. 难沉降煤泥水全流程处理技术研究进展[J]. 洁净煤技术, 2021, 27(5): 106−114. Google Scholar YANG Y B, QU J Z, ZHU Z Q, et al. Research progress of the whole process treatment technology for difficult−to−settle slime water[J]. Clean Coal Technology, 2021, 27(5): 106−114. Google Scholar
[6]	P. MPOFU, J. ADDAI−MENSAH, J. Ralston, Flocculation and dewatering behaviour of smectite dispersions: effect of polymer structure type[J]. Minerals Engineering, 2004, 17: 411−423. Google Scholar
[7]	M. LEMANOWICZ, Z. JACH, E. KILIAN, A. Gierczycki, Ultra−fine coal flocculation using dual−polymer systems of ultrasonically conditioned and unmodified flocculant[J]. Chemical Engineering Journal, 2011, 168: 159−169. doi: 10.1016/j.cej.2010.12.057 CrossRef Google Scholar
[8]	M. LEMANOWICZ, A. KUS, A. T. Gierczycki, Influence of ultrasonic conditioning of flocculant on the aggregation process in a tank with turbine mixer[J]. Chemical Engineering and Processing:Process Intensification, 2010, 49: 205−211. doi: 10.1016/j.cep.2009.12.007 CrossRef Google Scholar
[9]	孙浩. 超声波预处理—复合絮凝剂作用下铅锌尾矿颗粒聚集沉降行为研究[D]. 武汉: 武汉科技大学, 2021. Google Scholar SUN H. Study on aggregation and settlement behavior of lead−zinc tailings particles under the action of ultrasonic pretreatment−compound flocculant[D]. Wuhan: Wuhan University of Science and Technology, 2021. Google Scholar
[10]	G ANTTI, P PENTTI, K Hanna. Ultrasonic degradation of aqueous carboxymethylcellulose: effect of viscosity, molecular mass, and concentration[J]. Ultrasonics Sonochemistry, 2008, 15: 644−648. doi: 10.1016/j.ultsonch.2007.09.005 CrossRef Google Scholar
[11]	A GRÖNROOS, P PIRKONEN, O Ruppert. Ultrasonic depolymerization of aqueous carboxymethylcellulose[J]. Ultrasonics Sonochemistry, 2004, 11: 9−12. doi: 10.1016/S1350-4177(03)00129-9 CrossRef Google Scholar
[12]	程效锐, 张舒研, 房宁. 超声空化技术在化工领域的应用研究进展[J]. 应用化工, 2018, 8: 1753−1757. Google Scholar CHENG X R, ZHANG S Y, FANG N. Research progress and application situation of the ultrasonic cavitation technology in chemical industry field[J]. Applied Chemical Industry, 2018, 8: 1753−1757. Google Scholar
[13]	ZHOU S, BU X, M. Alheshibri, et al. Floc structure and dewatering performance of kaolin treated with cationic polyacrylamide degraded by hydrodynamic cavitation[J]. Chemical Engineering Communications, 2022, 209(6): 798−807. doi: 10.1080/00986445.2021.1919652 CrossRef Google Scholar
[14]	H. Anlauf, Wet Cake Filtration: Fundamentals, Equipment, and Strategies, John Wiley & Sons2019. Google Scholar
[15]	HU P, LIANG L, WANG W, et al. Filtration of coal tailings aided by a novel physical conditioner carbon–containing fly ash[J]. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020: 1−13. Google Scholar
[16]	CAO B, ZHANG W, WANG Q. Wastewater sludge dewaterability enhancement using hydroxyl aluminum conditioning: Role of aluminum speciation[J]. Water Research, 2016, 105: 615−624. doi: 10.1016/j.watres.2016.09.016 CrossRef Google Scholar