淘洗六水氯化铝过程中晶体沉降速度与纯化规律分析

doi:10.16085/j.issn.1000-6613.2020-0524

摘要/Abstract

摘要：

针对粉煤灰酸法制氧化铝工艺中六水氯化铝结晶纯度难以控制、需进一步纯化的问题建立液固淘洗过程模拟实验，考察了液相密度、黏度、颗粒粒度及体积分数对颗粒沉降速度的影响，并用液体对颗粒的抵抗阻力对其修正，建立了关于沉降速度的计算模型，相对误差小于10%，能够较好地预测该体系下颗粒的沉降速度。按照淘洗过程模拟实验条件及对应的颗粒沉降速度设计静态实验，考察了钠、钙、镁和钾4种杂质离子随淘洗时间的变化规律，得到较优淘洗时间为60s。实验结果表明，杂质离子脱除率依次为Na⁺>Ca²⁺>Mg²⁺>K⁺，且最高脱除率均可达80%以上，杂质离子脱除率随着液固比的增大而提高，与沉降速度计算模型趋势一致，研究结果可为淘洗工艺的设计计算和优化提供参考。

关键词: 六水氯化铝, 淘洗, 液固两相流, 沉降速度, 晶体纯化

Abstract:

Aiming at the problem that the crystal purity of aluminum chloride hexahydrate was difficult to control in the process of preparing alumina from the fly ash by acid method and further purification was needed, a simulation experiment of liquid-solid elutriation process was established. The effects of liquid phase density, viscosity, particle size, and particle volume fraction on the settling velocity of the particles were investigated and corrected by the resistance of the liquid to the particles, and a calculation model for settling velocity was established, which had relative error of less than 10% and could better describe the settling velocity under the system. Designing the static test according to the simulated experimental conditions of the elutriation process and the corresponding particle settling velocity, the change rule of four impurity ions of sodium, calcium, magnesium and potassium with elutriation time was investigated, and the better elutriation time was 60s. Experimental results show the removal rate of impurity ion is Na⁺>Ca²⁺>Mg²⁺>K⁺, and the highest removal rate of each ion can reach more than 80%; the impurities elutriation removal rate of the crystals increase with the increase of the liquid-solid ratio, which is consistent with the settling velocity calculation model; and the research result provides a reference for the design calculation and optimization of the elutriation process.

Key words: aluminum chloride hexahydrate, elutriation, liquid-solid two-phase flow, settling velocity, crystal purification

中图分类号:

TQ133.1

梁高峰, 陈学青, 王德武, 张少峰, 刘燕, 张继军. 淘洗六水氯化铝过程中晶体沉降速度与纯化规律分析[J]. 化工进展, 2021, 40(1): 386-393.

Gaofeng LIANG, Xueqing CHEN, Dewu WANG, Shaofeng ZHANG, Yan LIU, Jijun ZHANG. Analysis of crystal settling velocity and purification law in the elutriation process of aluminum chloride hexahydrate[J]. Chemical Industry and Engineering Progress, 2021, 40(1): 386-393.

图/表 13

参考文献 27

1	DING J, MA S H, SHEN S, et al. Research and industrialization progress of recovering alumina from fly ash: A concise review[J]. Waste Management, 2016: S0956053X16303142.
2	李来时.粉煤灰中提取氧化铝研究新进展[J]. 轻金属, 2011(11): 12-16.
	LI L S. New achievements of extracting alumina from fly ash[J]. Light Metals, 2011(11): 12-16.
3	王爱爱. 高铝粉煤灰提取氧化铝技术的研究现状[J]. 当代化工研究, 2019(2): 131-133.
	WANG A A. Research status of extraction of alumina from high-aluminum fly ash[J]. Modern Chemical Research, 2019(2): 131-133.
4	WU C Y, YU H F, ZhANG H F. Extraction of aluminum by pressure acid-leaching method from coal fly ash[J]. Transactions of Nonferrous Metals Society of China, 2012, 22(9): 2282-2288.
5	SHEMI A, NDLOVU S, SIBANDA V, et al. Extraction of alumina from coal fly ash using an acid leach-sinter-acid leach technique[J]. Hydrometallurgy, 2015, 157: 348-355.
6	张梓越, 陈学青, 梁高峰, 等. 高铝粉煤灰综合利用中氯化铝淘洗纯化影响因素的研究[J]. 现代化工, 2020, 40(3): 103-106, 111.
	ZHANG Z Y, CHEN X Q, LIANG G F, et al. Study on influencing factors for purifying aluminum chloride in comprehensive utilization of high alumina fly ash[J].Modern Chemical Industry, 2020, 40(3): 103-106, 111.
7	马振国. 粉煤灰酸法生产氧化铝工艺中结晶氯化铝洗涤除杂研究[J]. 化工管理, 2019(19): 211-212.
	MA Z G. Study on washing and decontamination of crystalline aluminum chloride in the production of alumina by fly ash acid[J]. Chemical Enterprise Management, 2019(19): 211-212.
8	RICHARDSON J F, ZAKI W N. Sedimentation and fluidization: Part Ⅰ[J]. Transactions of the Institution Chemical Engineers, 1954, 32(1): 35-53.
9	GARSIDE J, AI-DIBOUNI M R.Velocity-voidage relationships for fluidization and sedimentation in solid-liquid systems[J]. Industrial & Engineering Chemistry Process Design and Development, 1977, 16(2): 206-214．
10	STEINOUR, HAROLD H. Rate of sedimentation nonflocculated suspensions of uniform spheres[J]. Industrial & Engineering Chemistry, 1944, 36(7): 618-624.
11	NEWITT D M, RICHARDSON J F, GLIDDONl B J.Hydraulic conveying of solids in vertical pipes[J]. Transactions of the Institution Chemical Engineers, 1961, 39: 93.
12	王子宁, 董兴海, 朱家骅, 等. 多层双锥液固逆流浸洗塔颗粒停留时间分布研究[J]. 高校化学工程学报, 2014, 28(6): 1198-1203.
	WANG Z N, DONG X H, ZHU J J, et al. Investigation on the particle residence time distribution in a multistage double cones liquid-solid countercurrent extraction column[J]. Journal of Chemical Engineering of Chinese Universities, 2014, 28(6): 1198-1203.
13	刘赛赛. 小尺度颗粒在液固两相流体中的迁移特性研究[D]. 青岛: 中国海洋大学, 2015.
	LIU S S. Mechanism study into the transport process of micro-particle in liquid-solid two-phase flow field[D]. Qingdao: Ocean University of China, 2015.
14	王丽燕, 孙志强, 周天, 等. 基于PIV图像处理法的管内低浓度液固两相流颗粒运动特性研究[J]. 工程热物理学报, 2018, 39(9): 1970-1978.
	WANG L Y, SUN Z Q, ZHOU T, et al.Flow characteristics of particles in liquid-solid two-phase flow in pipes at low solid volume fractions using PIV[J]. Journal of Engineering Thermophysics, 2018, 39(9): 1970-1978.
15	王聪慧. 稠密液固两相湍流混合的数值分析及应用[D]. 长春: 吉林大学, 2010.
	WANG C H. Numerical analysis of dense liquid-solid two-phase turbulent mixing and its application[D]. Changchun: Jilin University, 2010.
16	钟剑锋. 熔融结晶法净化磷酸过程研究[D]. 上海: 华东理工大学, 2015.
	ZHONG J F. Research on purifying phosphoric acid with melt crystallization process[D]. Shanghai: East China University of Science and Technology, 2015.
17	李达, 程芳琴, 张洪满. 反应结晶过程中晶粒沉降速度模型研究[J]. 无机盐工业, 2007(5): 40-42.
	LI D,CHENG F Q, ZHANG H M. Study on the settling velocity model of crystal granula in the reactive crystallization process[J]. Inorganic Chemicals Industry, 2007(5): 40-42.
18	赵国彦, 林春平, 洪昌寿. 垂直管道颗粒沉降速度的影响因素[J]. 科技导报, 2016, 34(2): 162-166.
	ZHAO G Y, LIN C P, HONG C S.Influencing factors for particles settling velocity in vertical pipes[J]. Science & Technology Review, 2016, 34(2):162-166.
19	孙玉波. 重力选矿[M]. 北京: 冶金工业出版社, 1982．
	SUN Y B. Gravity beneficiation[M]. Beijing: Metallurgical Industry Press, 1982.
20	CHENG N S. Simplified settling velocity formula for sediment particle[J]. Journal of Hydraulic Engineering, 1997, 123(2): 149-152.
21	WU W, WANG S S Y.Formulas for sediment porosity and settling velocity[J]. Journal of Hydraulic Engineering, 2006, 132(8): 858-862.
22	AHRENS John P. A fall-velocity equation[J]. Journal of Waterway, Port, Coastal and Ocean Engineering, 2000, 126(2): 99-102.
23	WILSON K C, ADDIE G R, SELLGREN A, et al. Slurry transport using centrifugal pumps[M]. London: Springer Science & Business, 2009.
24	赵利安. 大颗粒浆体管内流动规律研究[D]. 阜新: 辽宁工程技术大学, 2011.
	ZHAO L A.Study on flow law of large particle slurry in pipeline[D]. Fuxin: Liaoning Technical University, 2011.
25	佐藤博. スラリ-输送工学[M]. 秋田: 秋田活版印刷株式会社, 1989: 103-147.
	SATO Hiroshi.Slurry transmission engineering[M].Akita: Akita Printing Corporation, 1989: 103-147.
26	SHOOK C A, ROCO M C.Slurry flow:principles and practice[M].Boston: Butterworth Heinemann, 1991: 116-118.
27	张相洋. 杂质存在条件下的乳酸锌结晶行为研究[D]. 上海: 华东理工大学, 2010.
	ZHANG X Y.Crystallization behaviour of zinc lactate in presence of impurities[D]. Shanghai: East China University of Science and Technology, 2010.

溶液编号	目标密度 /g·mL^-1	实际密度 /g·mL^-1	目标黏度 /mPa·s	实际黏度 /mPa·s
1	1.00	0.98	1	1.1
2	1.00	0.99	10	9.8
3	1.00	0.98	20	21.3
4	1.00	1.02	30	30.1
5	1.10	1.12	1	1.2
6	1.10	1.11	10	10.3
7	1.10	1.11	20	20.9
8	1.10	1.10	30	30.3
9	1.20	1.21	1	1.2
10	1.20	1.18	10	10.2
11	1.20	1.20	20	19.1
12	1.20	1.21	30	29.8
13	1.30	1.28	1	1.2
14	1.30	1.31	10	10.3
15	1.30	1.29	20	19.8
16	1.30	1.31	30	30.1

溶液编号	目标密度 /g·mL^-1	实际密度 /g·mL^-1	目标黏度 /mPa·s	实际黏度 /mPa·s
1	1.00	0.98	1	1.1
2	1.00	0.99	10	9.8
3	1.00	0.98	20	21.3
4	1.00	1.02	30	30.1
5	1.10	1.12	1	1.2
6	1.10	1.11	10	10.3
7	1.10	1.11	20	20.9
8	1.10	1.10	30	30.3
9	1.20	1.21	1	1.2
10	1.20	1.18	10	10.2
11	1.20	1.20	20	19.1
12	1.20	1.21	30	29.8
13	1.30	1.28	1	1.2
14	1.30	1.31	10	10.3
15	1.30	1.29	20	19.8
16	1.30	1.31	30	30.1

温度/℃	黏度/mPa·s
26	27.6
40	18.7
50	14.8
60	12.5
70	11.0
80	9.8

温度/℃	黏度/mPa·s
26	27.6
40	18.7
50	14.8
60	12.5
70	11.0
80	9.8

编号	体积分数/%	溶液黏度/mPa·s	对应转速/r·min^-1
a	15	30	337
b	15	20	302
c	25	30	376
d	25	20	330
e	45	30	442
f	45	20	385