Synergistic leaching process of waste LiFePO4 with phosphoric acid-tartaric acid system

doi:10.11949/0438-1157.20240617

Abstract

Abstract:

Recycling valuable metals from waste LiFePO₄ power batteries and realizing their resource utilization is an urgent problem at present. In this study, a mixed leaching system of phosphoric acid and tartaric acid was proposed, and the total component leaching recovery process of waste LiFePO₄ was studied. The approximate range of leaching conditions was obtained through the results of single factor experiments, and then the response surface method was used to optimize different leaching conditions to obtain the best leaching process. The results showed that the leaching rates of Li and Fe were 97.55% and 98.67% respectively when the concentration of phosphoric acid was 3.1 mol/L, the concentration of tartaric acid was 1.3 mol/L, the liquid-solid ratio was 6.8∶1, the stirring speed was 500 r/min and the reaction temperature was 65℃ for 5 h. The experimental results show that tartaric acid can be replaced with the Fe³⁺ released by phosphate, and the synergy of mixed acids will immerse all Li and Fe in the waste into the solution. By adjusting the molar ratio of Li∶Fe∶P in the leaching solution, the regenerated LiFePO₄ (RE-LiFePO₄) was synthesized by spray drying-sintering method. In the whole recovery process, there is almost no waste acid and waste gas emission, and the green recovery of all components of waste LiFePO₄ is realized.

Key words: waste LiFePO₄battery, recycle, mixed leaching, response surface method, spray drying process

摘要：

从废旧磷酸铁锂（LiFePO₄）动力电池中回收有价金属，实现其资源化利用是当前亟待解决的问题。提出磷酸-酒石酸混合浸出体系，对废旧LiFePO₄的全组分浸出回收工艺进行研究。通过单因素实验结果得到浸出条件的大致范围，再采用响应曲面法对不同浸出条件进行优化得到最佳浸出工艺。结果表明：在磷酸浓度为3.1 mol/L、酒石酸（TA）浓度为1.3 mol/L、液固比6.8∶1、搅拌速度500 r/min、反应温度65℃下反应5 h，Li和Fe的浸出率分别为97.55%和98.67%。实验结果表明，酒石酸可以与磷酸浸出释放的Fe³⁺进行络合，混合酸的协同作用几乎将废料中所有的Li、Fe都浸出到溶液中。通过调整浸出液中Li∶Fe∶P的摩尔比，采用喷雾干燥-烧结法合成再生磷酸铁锂（RE-LiFePO₄）。该工艺在整个回收过程中几乎没有废酸、废气排放，实现了废旧LiFePO₄的全组分绿色回收。

关键词: 废旧磷酸铁锂电池, 回收, 混合浸出, 响应曲面法, 喷雾干燥法

CLC Number:

O 646

Zhongliang XIAO, Yubo XIA, Liubin SONG, Youtao XIANG, Tingting ZHAO, Jing LUO, Yuanjia LIU, Penghui DENG, Qunxuan YAN. Synergistic leaching process of waste LiFePO₄ with phosphoric acid-tartaric acid system[J]. CIESC Journal, 2024, 75(12): 4780-4792.

肖忠良, 夏宇博, 宋刘斌, 向优涛, 赵亭亭, 罗静, 刘远佳, 邓鹏辉, 颜群轩. 磷酸-酒石酸体系协同浸出废旧磷酸铁锂工艺[J]. 化工学报, 2024, 75(12): 4780-4792.

Figures/Tables 19

References 33

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药品名称	分子式	规格	厂家
磷酸	H₃PO₄	AR	国药集团有限公司
酒石酸	C₄H₆O₆	AR	国药集团有限公司
碳酸锂	Li₂CO₃	电池级	上海麦克林生化科技股份有限公司
氧化铁	Fe₂O₃	AR	上海麦克林生化科技股份有限公司

药品名称	分子式	规格	厂家
磷酸	H₃PO₄	AR	国药集团有限公司
酒石酸	C₄H₆O₆	AR	国药集团有限公司
碳酸锂	Li₂CO₃	电池级	上海麦克林生化科技股份有限公司
氧化铁	Fe₂O₃	AR	上海麦克林生化科技股份有限公司

仪器名称	型号	生产厂家
恒速电动搅拌器	JJ-1B	西城新瑞仪器厂
集热式恒温加热磁力搅拌器	DF-101S	上海力辰邦西仪器科技公司
管式炉	HLG-X-16	洛阳恒立窑炉有限公司
X射线衍射分析仪	D8 Advance	德国Bruker公司
电感耦合等离子体发生光谱仪	ARCOS	德国SPECTRO公司

仪器名称	型号	生产厂家
恒速电动搅拌器	JJ-1B	西城新瑞仪器厂
集热式恒温加热磁力搅拌器	DF-101S	上海力辰邦西仪器科技公司
管式炉	HLG-X-16	洛阳恒立窑炉有限公司
X射线衍射分析仪	D8 Advance	德国Bruker公司
电感耦合等离子体发生光谱仪	ARCOS	德国SPECTRO公司

Element	Composition/%
Li	3.62
Fe	28.06
Al	0.72
P	16.28

Synergistic leaching process of waste LiFePO₄ with phosphoric acid-tartaric acid system

磷酸-酒石酸体系协同浸出废旧磷酸铁锂工艺

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Figures/Tables 19

References 33

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实验序号	搅拌速度/(r/min)	磷酸浓度/(mol/L)	酒石酸浓度/(mol/L)	液固比/(ml/g)	温度/℃	时间/h	Li 浸出率/%	Fe 浸出率/%
1	200	2.90	1.33	5∶1	70	5	89.60	88.78
2	300	2.90	1.33	5∶1	70	5	92.58	95.33
3	400	2.90	1.33	5∶1	70	5	92.59	96.34
4	500	2.90	1.33	5∶1	70	5	94.83	96.67
5	600	2.90	1.33	5∶1	70	5	93.14	97.34
6	700	2.90	1.33	5∶1	70	5	91.27	93.00

实验序号	磷酸浓度/(mol/L)	搅拌速度/(r/min)	酒石酸浓度/(mol/L)	液固比/(ml/g)	温度/℃	时间/h	Li 浸出率/%	Fe 浸出率/%
1	1.74	500	1.33	5∶1	70	5	88.93	85.38
2	2.32	500	1.33	5∶1	70	5	94.55	94.32
3	2.90	500	1.33	5∶1	70	5	96.34	96.48
4	3.48	500	1.33	5∶1	70	5	95.97	94.44
5	4.06	500	1.33	5∶1	70	5	95.12	94.35
6	4.64	500	1.33	5∶1	70	5	95.61	74.15

实验序号	酒石酸浓度/(mol/L)	搅拌速度/(r/min)	磷酸浓度/(mol/L)	液固比/(ml/g)	温度/℃	时间/h	Li 浸出率/%	Fe 浸出率/%
1	0.53	500	2.90	5∶1	70	5	93.21	24.94
2	0.80	500	2.90	5∶1	70	5	93.45	52.04
3	1.06	500	2.90	5∶1	70	5	94.03	81.83
4	1.33	500	2.90	5∶1	70	5	95.11	97.08
5	1.60	500	2.90	5∶1	70	5	95.11	94.44
6	1.86	500	2.90	5∶1	70	5	94.53	93.79

实验序号	液固比/(ml/g)	搅拌速度/(r/min)	磷酸浓度/(mol/L)	酒石酸浓度/(mol/L)	温度/℃	时间/h	Li 浸出率/%	Fe 浸出率/%
1	3∶1	500	2.90	1.33	70	5	83.92	77.84
2	4∶1	500	2.90	1.33	70	5	92.01	90.71
3	5∶1	500	2.90	1.33	70	5	94.00	97.39
4	6∶1	500	2.90	1.33	70	5	97.52	98.87
5	8∶1	500	2.90	1.33	70	5	96.53	97.71
6	10∶1	500	2.90	1.33	70	5	92.23	86.51

Factors	Code value
Factors	-1	0	1
A: H₃PO₄/(mol/L)	2	3	4
B: Tartaric acid/(mol/L)	0.8	1.3	1.8
C: L/S/(ml/g)	4∶1	7∶1	10∶1
D: Temperature/℃	40	65	90

Run	H₃PO₄ concentration/(mol/L)	Tartaric acid concentration /(mol/L)	Liquid/Solid ratios/(ml/g)	Leaching temperature /℃	Leaching rate of Li/%	Leaching rate of Fe/%
1	0	1	0	1	83.38	85.78
2	0	0	0	0	97.08	98.03
3	-1	-1	0	0	75.33	63.17
4	-1	0	1	0	63.06	62.65
5	-1	0	0	1	72.45	70.76
6	0	0	0	0	97.41	97.48
7	1	0	0	1	80.24	80.87
8	1	-1	0	0	76.08	71.25
9	0	1	0	-1	84.37	75.74
10	1	0	1	0	64.95	70.24
11	0	-1	0	-1	80.78	65.75
12	0	0	0	0	97.63	98.21
13	-1	0	-1	0	68.94	74.24
14	0	1	-1	0	77.45	85.15
15	0	-1	0	1	84.98	69.54
16	0	0	1	1	75.45	68.25
17	1	0	-1	0	75.3	81.53
18	-1	1	0	0	72.45	77.47
19	0	0	1	-1	67.26	69.36
20	1	1	0	0	78.9	83.18
21	0	0	-1	1	78.93	87.32
22	0	1	1	0	72.78	71.3
23	-1	0	0	-1	72.75	67.56
24	0	0	-1	-1	82.38	73.69
25	1	0	0	-1	72.88	71.24
26	0	-1	1	0	70.28	64.27
27	0	-1	-1	0	81.05	72.53

Source	Sum of Squares	Degree of freedom(df)	Mean Square	F	P-value Prob>F
Model	2097.05	14	149.79	156.62	<0.0001	Significant
A-H₃PO₄	45.51	1	45.51	118.05	<0.0001
B-Tartaric acid	0.0574	1	0.0574	340.48	0.7773
C-L/S ratios	210.59	1	210.59	306.26	<0.0001
D-Temperature	18.78	1	18.78	100.51	0.0002
AB	8.12	1	8.12	1.10	0.0049
AC	5.00	1	5.00	0.0177	0.0194
AD	14.67	1	14.67	8.12	0.0006
BC	9.30	1	9.30	6.14	0.0031
BD	6.73	1	6.73	7.67	0.0086
CD	33.87	1	33.87	42.68	<0.0001
A²	1206.07	1	1206.07	723.00	<0.0001
B²	259.24	1	259.50	579.92	<0.0001
C²	1117.53	1	1117.53	638.00	<0.0001
D²	278.24	1	278.24	570.96	<0.0001
Residual	8.23	12	0.6860
Lack of Fit	8.08	10	0.8079	10.54	0.0897	Not significant
Pure error	0.1533	2	0.0766
Cor total	2105.28	26
Adeq precision	55.9368
R²	0.9961
Adjusted R²	0.9915
Predicted R²	0.9777
C.V./%	1.06

Source	Sum of Squares	Degee of freedom(df)	Mean Square	F	P-value Prob>F
Model	2790.57	14	199.33	156.62	<0.0001	Significant
A-H₃PO₄	150.24	1	150.24	118.05	<0.0001
B-Tartaric acid	433.32	1	433.32	340.48	<0.0001
C-L/S ratios	389.77	1	389.77	306.26	<0.0001
D-Temperature	127.92	1	127.92	100.51	<0.0001
AB	1.40	1	1.40	1.10	0.3142
AC	0.0225	1	0.0225	0.0177	0.8964
AD	10.34	1	10.34	8.12	0.0146
BC	7.81	1	7.81	6.14	0.0291
BD	9.77	1	9.77	7.67	0.0170
CD	54.32	1	54.32	42.68	<0.0001
A²	920.15	1	920.15	723.00	<0.0001
B²	738.06	1	738.06	579.92	<0.0001
C²	811.97	1	811.97	638.00	<0.0001
D²	726.65	1	726.65	570.96	<0.0001
Residual	15.27	12	1.27
Lack of Fit	14.98	10	1.50	10.36	0.0912	Not significant
Pure error	0.2893	2	0.1446
Cor total	2805.84	26
Adeq precision	41.6701
R²	0.9946
Adjusted R²	0.9882
Predicted R²	0.9690
C.V./%	1.48

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