Geochemistry of rare earth elements and yttrium in Late Permian coals from the Zhongliangshan coalfield, southwestern China

doi:10.1007/s11707-022-1018-x

Front. Earth Sci.

2023, Vol. 17

Issue (1) : 230-250 https://doi.org/10.1007/s11707-022-1018-x

RESEARCH ARTICLE

Geochemistry of rare earth elements and yttrium in Late Permian coals from the Zhongliangshan coalfield, southwestern China

Qingfeng LU^1,^2,³, Shenjun QIN²(

), Hongyang BAI^1,³, Wenfeng WANG^1,³(

), De’e QI², Xin HE^1,³, Bofei ZHANG^1,³

¹. School of Resources and Geosciences, China University of Mining & Technology, Xuzhou 221116, China
². Key Laboratory for Resource Exploration Research of Hebei Province, Hebei University of Engineering, Handan 056038, China
³. Key Laboratory of Coalbed Methane Resources & Reservoir Formation Process, Ministry of Education, China University of Mining & Technology, Xuzhou 221008, China

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Abstract

Rare earth elements and yttrium (REY) in coal deposits are considered promising alternative sources for these resources owing to their increasing global demand. This paper reports the geochemical characteristics of REY in the Late Permian coals from an underground K1a seam section of the Zhongliangshan coalfield in Chongqing, southwestern China. The mineralogy, degree of enrichment, distribution patterns, modes of occurrence, and sediment origin of REY were investigated. Compared with the average of world coals, the concentration of REY in the K1a coals were normal, dominated by light REY (LREY), with less medium and heavy REY (MREY, HREY). The fractionation degree of the MREY and HREY are higher than that of LREY in most K1a coal samples, deduced from the mixed enrichment type of REY, mainly including M-H-type, and a few L-M type and H-type. In addition, the combination of anomalies of Ce, Eu, Gd, and Al₂O₃/TiO₂ parameters, the terrigenous materials in the K1a coal were derived from the felsic-intermediate rocks at the top of the Emeishan basalt sequence, and the samples were affected by seawater intrusion during early peat accumulation. Although the minerals primarily consist of kaolinite, illite, pyrite, and small amounts of quartz, calcite and anatase, REY are correlated with ash yield, SiO₂, and Al₂O₃, revealing that the REY mainly occur in aluminosilicate minerals, especially kaolinite and illite. Meanwhile, REY positively relate to P₂O₅ and Zr, which may exist in phosphate-containing minerals or zircon. Furthermore, most samples in the K1a coal or ash do not reach the cut-off grade for the beneficial recovery of REY. With the exception of central Guizhou, southwestern Chongqing, and the junction of western Guizhou and northeastern Yunnan, the REY content in coals from southwestern China are high, and its by-products are suitable as potential REY sources.

Keywords rare earth elements and yttrium Zhongliangshan K1a coal sediment source modes of occurrence geochemical characteristics

Corresponding Author(s): Shenjun QIN,Wenfeng WANG

About author:

^* These authors contributed equally to this work.

Online First Date: 28 October 2022 Issue Date: 03 July 2023

Cite this article:

Qingfeng LU,Shenjun QIN,Hongyang BAI, et al. Geochemistry of rare earth elements and yttrium in Late Permian coals from the Zhongliangshan coalfield, southwestern China[J]. Front. Earth Sci., 2023, 17(1): 230-250.

URL:

https://academic.hep.com.cn/fesci/EN/10.1007/s11707-022-1018-x
https://academic.hep.com.cn/fesci/EN/Y2023/V17/I1/230

Fig.1 Location of five coalfields (ZLS, Zhongliangshan; TF, Tianfu; YR, Yongrong; SZ, Songzao; NT, Nantong).

Fig.2 Stratigraphic column of the Late Permian Longtan Formation from the Zhongliangshan, Chongqing.

Tab.1 The proportions of minerals in the Zhongliangshan coal LTAs (%)

Fig.3 Minerals in the Zhongliangshan K1a coal.

Samples	LREY					MREY					HREY					Sum
Samples	La	Ce	Pr	Nd	Sm	Eu	Gd	Tb	Dy	Y	Ho	Er	Tm	Yb	Lu	Sum
ZLS-R	37.46	70.03	8.55	36.83	7.24	1.52	5.67	0.68	3.31	16.00	0.65	1.76	0.25	1.58	0.28	191.8
ZLS-1	18.04	33.58	3.74	16.95	3.09	0.63	2.76	0.36	1.94	10.94	0.42	1.18	0.19	1.15	0.20	95.17
ZLS-2	16.00	28.33	2.55	13.59	2.86	0.49	2.52	0.33	1.87	9.36	0.37	1.08	0.16	1.05	0.17	80.73
ZLS-3	10.17	18.91	2.11	9.38	1.87	0.34	1.85	0.27	1.50	9.74	0.31	0.84	0.13	0.75	0.12	58.29
ZLS-4	7.70	16.88	1.24	7.97	1.57	0.30	1.58	0.26	1.45	10.00	0.30	0.90	0.13	0.76	0.13	51.17
ZLS-5	6.43	11.46	1.25	5.72	1.22	0.23	1.39	0.24	1.47	10.27	0.32	0.90	0.14	0.85	0.14	42.03
ZLS-6	6.58	11.26	1.21	5.52	1.20	0.22	1.32	0.23	1.33	9.59	0.30	0.83	0.12	0.80	0.13	40.64
ZLS-7	6.36	11.23	1.24	5.40	1.11	0.20	1.28	0.22	1.29	8.84	0.29	0.79	0.13	0.77	0.13	39.28
ZLS-8	10.87	16.59	1.87	8.70	1.86	0.32	1.86	0.29	1.69	9.45	0.36	0.99	0.16	0.96	0.15	56.12
ZLS-9	13.06	28.31	2.76	11.70	2.19	0.38	2.12	0.31	1.80	10.96	0.41	1.13	0.18	1.16	0.18	76.65
ZLS-10	11.24	21.53	2.03	9.25	0.99	0.36	1.92	0.30	1.57	10.24	0.40	1.02	0.16	0.90	0.15	62.06
ZLS-11	8.95	17.10	1.94	8.72	1.75	0.34	1.79	0.27	1.56	11.18	0.33	0.91	0.14	0.83	0.14	55.95
ZLS-12	9.36	21.57	2.37	9.37	2.12	0.40	1.90	0.29	1.56	10.57	0.37	0.96	0.15	0.90	0.15	62.04
ZLS-13	14.98	26.75	2.96	12.91	2.39	0.42	2.22	0.29	1.55	10.97	0.33	0.95	0.14	0.89	0.15	77.9
ZLS-14	13.26	25.26	2.86	11.29	2.40	0.47	2.24	0.30	1.64	11.24	0.32	0.93	0.14	0.81	0.14	73.3
ZLS-15	11.68	22.34	2.63	11.96	2.44	0.50	2.31	0.33	1.74	12.85	0.35	0.95	0.15	0.82	0.14	71.19
ZLS-16	20.37	28.97	3.03	19.56	3.06	0.57	3.03	0.42	2.37	13.70	0.46	1.24	0.19	1.00	0.16	98.13
ZLS-17	24.51	43.91	4.79	21.20	3.87	0.89	3.71	0.49	2.52	15.99	0.51	1.38	0.21	1.20	0.20	125.4
ZLS-18	20.33	40.24	4.57	21.00	4.03	1.00	4.02	0.60	3.03	21.24	0.63	1.86	0.26	1.57	0.24	124.6
ZLS-19	16.79	34.35	4.30	20.45	4.25	1.12	4.43	0.63	3.65	26.34	0.75	2.08	0.30	1.69	0.28	121.4
ZLS-P	18.27	30.24	3.02	19.24	3.96	1.00	4.24	0.62	3.02	28.24	0.71	2.02	0.25	1.29	0.28	116.4
ZLS-20	15.69	31.87	3.85	18.26	3.89	0.98	4.22	0.61	3.58	30.19	0.78	2.09	0.31	1.72	0.28	118.3
ZLS-21	15.24	29.55	2.24	11.02	3.02	0.27	3.06	0.52	2.35	21.26	0.24	1.20	0.20	0.46	0.12	90.75
Av.1	13.22	24.76	2.64	12.38	2.44	0.50	2.45	0.36	1.97	13.57	0.41	1.15	0.17	1.00	0.16	77.18
Av.2	27.86	50.13	5.79	28.03	5.60	1.26	4.95	0.65	3.17	22.12	0.68	1.89	0.25	1.43	0.28	154.1
World	11	23	3.5	12	2	0.47	2.7	0.32	2.1	8.4	0.54	0.93	0.31	1	0.2	68.47

Tab.2 Concentration of rare earth elements and yttrium in the ZLS K1a coal (μg/g)

Fig.4 Concentration distribution of LREY, MREY, and HREY in the ZLS K1a coal.

Fig.5 Vertical distribution of REY in the ZLS K1a coal (μg/g).

Fig.6 Concentration coefficients (CC) of REY in the ZLS K1a samples.

Samples	$L R E Y M R E Y$	$L R E Y H R E Y$	$M R E Y H R E Y$	$L a N L u N$	$L a N S m N$	$G d N L u N$	Type	$L a N Y b N$	$C e N C e N ∗$	$E u N E u N ∗$	$G d N G d N ∗$
ZLS-R	5.89	35.42	6.01	1.43	0.78	1.71	L-M	1.74	0.89	1.21	1.20
ZLS-1	4.53	24.01	5.30	0.96	0.88	1.16	M-H	1.15	0.93	1.11	1.20
ZLS-2	4.35	22.38	5.15	1.01	0.84	1.25	L-M	1.12	0.99	0.93	1.19
ZLS-3	3.10	19.74	6.37	0.90	0.82	1.30	M-H	0.99	0.93	0.93	1.16
ZLS-4	2.60	15.93	6.12	0.63	0.74	1.02	M-H	0.74	1.22	0.93	1.07
ZLS-5	1.92	11.10	5.79	0.49	0.79	0.84	H	0.55	0.92	0.86	1.07
ZLS-6	2.03	11.82	5.82	0.54	0.82	0.86	H	0.60	0.90	0.84	1.06
ZLS-7	2.14	12.01	5.61	0.52	0.86	0.83	H	0.61	0.91	0.82	1.08
ZLS-8	2.93	15.23	5.19	0.77	0.88	1.04	M-H	0.83	0.83	0.85	1.11
ZLS-9	3.73	18.96	5.09	0.77	0.89	0.99	H	0.83	1.07	0.89	1.15
ZLS-10	3.13	17.13	5.47	0.80	1.70	1.08	H	0.92	1.02	1.35	1.31
ZLS-11	2.54	16.37	6.44	0.68	0.77	1.08	M-H	0.79	0.93	0.97	1.15
ZLS-12	3.04	17.70	5.82	0.67	0.66	1.07	M-H	0.76	1.04	0.98	1.09
ZLS-13	3.88	24.39	6.28	1.07	0.94	1.25	L-M	1.23	0.91	0.94	1.22
ZLS-14	3.47	23.53	6.79	1.01	0.83	1.35	L-M	1.20	0.93	1.04	1.20
ZLS-15	2.88	21.18	7.36	0.89	0.72	1.39	M-H	1.04	0.92	1.07	1.16
ZLS-16	3.73	24.59	6.59	1.36	1.00	1.59	L-M	1.49	0.82	0.96	1.20
ZLS-17	4.16	28.08	6.74	1.31	0.95	1.56	L-M	1.50	0.92	1.22	1.23
ZLS-18	3.02	19.77	6.55	0.90	0.76	1.41	M-H	0.95	0.95	1.25	1.15
ZLS-19	2.22	15.71	7.09	0.64	0.59	1.33	M-H	0.73	0.92	1.33	1.20
ZLS-P	2.01	16.42	8.16	0.70	0.69	1.28	M-H	1.04	0.91	1.25	1.19
ZLS-20	1.86	14.20	7.64	0.60	0.61	1.27	M-H	0.67	0.93	1.25	1.20
ZLS-21	2.22	27.51	12.37	1.35	0.76	2.15	L-M	2.43	1.12	0.43	1.05
Av.1	3.02	19.11	6.46	0.85	0.85	1.23	-	1.01	0.96	1.00	1.15
Av.2	3.95	25.92	7.09	1.06	0.73	1.49	-	1.39	0.90	1.23	1.19

Tab.3 Geochemical parameters of rare earth elements and yttrium in the ZLS K1a coal

Fig.7 Distribution patterns of REY in the ZLS K1a coal (UCC values are those of Taylor and McLennan, 1985).

Fig.8 Diagram of Ba vs. Eu (a), and Al₂O₃ vs. TiO₂ (b) of the K1a coal.

Fig.9 Correlation between REY and A_d, SiO₂, Al₂O₃, SiO₂ + Al₂O₃, P₂O₅, S_t,d, S_i,d, S_o,d, Fe₂O₃, CaO, and Zr.

Fig.10 Correlation between LREY, MREY, HREY with A_d, SiO₂, Al₂O₃, SiO₂ + Al₂O₃, Fe₂O₃, S_t,d, CaO, P₂O₅, and Zr.

Fig.11 Evaluation of REY in ZLS K1a coal ash (roof and parting are presented by black point).

Region coalfield		Mine	Seam	Age	T	A_d	La	Ce	Pr	Nd	Sm	Eu	Gd	Tb	Dy	Y	Ho	Er	Tm	Yb	Lu	REY	REO	Coutl	Ref.
Chongqing	ZLS	ZLS	K1a	P₂l	2.1	15.1	13.22	24.76	2.64	12.38	2.44	0.5	2.45	0.36	1.97	13.57	0.41	1.15	0.17	1	0.16	77.2	607.4	1.13	This paper
Chongqing	ZLS	ZLS	K1a	P₂l	1.2	18.7	17	36	4	17	0.6	0.1	0.3	0.1	0.1	12	0.6	1.4	0.1	1.2	0.1	90.6	572.9	0.81	Zhuang et al., 2005
Chongqing	ZLS	ZLS	K1b	P₂l	2	29.6	25	54	7	29	2.2	0.1	2.5	0.1	2.4	21	0.9	2.3	0.2	2.2	0.2	149.1	595.6	0.95	Zhuang et al., 2005
Chongqing	TF	MXP	K2	P₂l	3.1	14.5	49.12	72.45	9.93	32.48	5.67	0.6	5.75	1.03	4.3	33.83	1.18	2.54	0.49	2.27	0.48	222.1	1810.6	0.97	Qin et al., 2018a
Chongqing	TF	MXP	K2	P₂l	0.4	12.1	52.1	95.1	10.7	40.9	6.96	0.87	9.01	1.34	8.26	46.1	1.68	5.13	0.72	4.83	0.69	284.4	2777.6	1.00	Dai et al., 2017
Chongqing	TF	MXP	K1	P₂l	0.4	41.5	62.3	107	16.5	71.1	14.9	3.45	16.6	2.35	14	95.3	2.74	7.9	1.04	6.68	0.97	422.8	1210.7	1.64	Dai et al., 2017
Chongqing	TF	MXP	K2	P₂l	4	27.2	91	177	20	85	11	0.3	12	0.1	9.5	53	2.2	6.4	0.9	6.6	0.8	475.8	2063.0	0.82	Zhuang et al., 2005
Chongqing	TF	MXP	K4	P₂l	0.5	22.6	50	113	13	48	5.4	0.1	4.7	0.1	4.8	32	1.5	3.6	0.5	4.1	0.3	281.1	1467.6	0.74
Chongqing	TF	MXP	K5	P₂l	0.6	25.2	29	65	7	31	2.3	0.1	3.4	0.1	3.7	32	1.4	3	0.7	3.4	0.4	182.5	858.6	0.99
Chongqing	TF	MXP	K7	P₂l	0.6	40.0	34	77	9	43	4	0.1	2.8	0.1	2.1	17	0.9	2.1	0.2	2.5	0.3	195.1	574.2	0.80
Chongqing	NT	DL	4	P₂l	2.03	13.5	17.8	34.8	3.9	15	2.99	0.55	3.3	0.46	2.7	13.4	0.52	1.53	0.21	1.44	0.2	98.8	867.0	0.91	Chen et al., 2015
Chongqing	NT	DL	6	P₂l	0.72	10.9	19.9	39.3	4.43	16.8	3.32	0.42	3.78	0.56	3.51	18.4	0.7	2.08	0.28	1.94	0.28	115.7	1253.8	0.98	Chen et al., 2015
Chongqing	SZ	-	12	P₂l	0.48	69.18	174.8	18.37	72.48	12.97	1.96	11.71	1.754	10.86	68.34	2.34	7.43	0.988	6.63	0.99	460.8	69.18	1548.2	0.88	Dai et al., 2010b
Chongqing	SZ	-	11	P₂l	0.24	33.2	71.5	137	16.2	58.5	10.6	1.32	8.77	1.32	7.9	42.1	1.6	4.95	0.67	4.49	0.66	367.6	1305.7	0.80
Chongqing	SZ	-	10	P₂l	0.36	31.9	58.3	108	13.6	51.2	10.3	1.74	8.94	1.3	7.55	38.8	1.55	4.86	0.66	4.42	0.65	311.9	1154.2	0.91
Chongqing	SZ	-	9	P₂l	0.41	34.2	14.3	28	3.38	12.9	2.72	0.5	2.81	0.5	3.13	18.8	0.67	2.12	0.3	2.02	0.31	92.5	321.2	1.21
Chongqing	SZ	-	8	P₂l	1.83	15.5	26.2	49.3	5.8	21.3	4.18	0.75	3.71	0.59	3.6	18.8	0.73	2.21	0.3	1.98	0.29	139.7	1067.7	0.90
Chongqing	SZ	-	7	P₂l	0.51	26.0	28.1	51.3	6.1	23.5	4.72	1.11	4.17	0.6	3.6	19.2	0.72	2.25	0.29	2.01	0.3	148.0	672.3	0.92
Chongqing	SZ	-	6	P₂l	1.16	25.7	12.9	25	3.09	12.2	2.57	0.61	2.53	0.4	2.59	14.4	0.53	1.69	0.23	1.59	0.24	80.6	371.2	1.16
Chongqing	SECQ	DG	K1	P₂wjp	0.85	24.5	26	48.6	7.27	31.1	6.96	1.55	8.56	1.3	8.12	61.4	1.68	5.04	0.66	4.25	0.63	213.1	1038.8	1.94	Zou et al., 2020
Guizhou	QDB	YD	4	P₂wjp	1	24.2	116.3	241.2	24.32	88.95	18.49	1.417	16.51	2.395	15.79	86.75	3.26	9.17	1.324	9.535	1.358	636.7	3105.0	0.80	Li et al., 2020b
Guizhou	QDB	JQ	4	P₂wjp	1.18	25.2	122	242	24.59	88.15	18.87	1.541	17.83	2.698	19.32	113.5	3.841	10.9	1.538	10.37	1.418	678.6	3186.2	0.91	Li et al., 2020b
Guizhou	LPS	TC	3	P₂l	1.62	14.7	11.1	23.3	2.62	10.6	2.16	0.38	2.26	0.31	1.86	10.4	0.38	1.12	0.15	1.04	0.16	67.8	546.6	0.99	Liu et al., 2020
Guizhou	LPS	TC	6	P₂l	1.45	20.4	14.2	30.9	3.62	15.3	3.36	0.67	3.67	0.54	3.39	18.6	0.69	2.02	0.28	1.911	0.28	99.4	578.7	1.19	Liu et al., 2020
Guizhou	LPS	DHB	D101	P₂l	0.89	18.0	73.3	158	18.8	72	13.2	2.05	13	1.6	8.96	42	1.65	4.9	0.68	4.61	0.66	415.4	2715.9	0.79	Liu et al., 2019
Guizhou	LPS	WJZ	w407	P₂l	1.2	14.4	28.6	70.8	8.08	33.3	6.5	1.47	13	1.6	3.6	16.4	0.65	1.81	0.24	1.65	0.24	187.9	1537.1	0.79	Liu et al., 2019
Guizhou	LPS	YLT	19	P₂l	1.7	22.8	16.11	35.09	3.889	15.22	3.098	0.667	3.378	0.504	3.148	14.34	0.606	1.825	0.25	1.695	0.237	100.1	517.5	0.94	Wang et al., 2016
Guizhou	TZ	CLB	4	P₂wjp	2.25	15.2	22.12	40.93	4.278	16.14	3.104	0.129	2.68	0.152	1.918	12.36	0.137	1.196	0	1.184	0	106.3	824.0	0.75	Li et al., 2019
Guizhou	ZN	FHS	23	P₂l	3.29	12.2	13.58	28.27	3.14	10.76	2.31	0.77	2.28	-	1.92	9.99	-	0.96	-	-	-	74.8	836.8	0.86	Li et al., 2017
Guizhou	ZN	FHS	27	P₂l	1.26	23.8	13.97	28.70	3.30	10.89	2.17	0.67	2.18	-	2.20	12.81	-	1.41	-	1.32	-	79.6	766.0	0.93
Guizhou	ZN	WJB	6	P₂wjz	1.88	17.7	11.31	23.48	2.69	9.11	2.03	0.65	1.96	-	1.90	10.01	-	1.12	-	-	-	65.2	624.6	0.97
Guizhou	ZN	WJB	7	P₂wjz	1.05	29.7	13.57	28.71	3.27	11.08	2.22	0.70	2.19	-	2.20	10.57	-	1.18	-	1.10	-	76.9	382.0	0.86
Guizhou	ZN	KLS	6	P₂l	1.35	14.9	16.50	34.90	4.23	17.20	3.28	0.67	3.33	0.44	2.54	12.20	0.48	1.33	0.18	1.21	0.17	98.7	782.4	0.93	Liu et al., 2021
Guizhou	ZN	SJC	7	P₂l	1.75	16.6	14.40	29.80	3.27	12.70	2.52	0.44	2.72	0.40	2.50	12.70	0.50	1.45	0.20	1.34	0.19	85.1	608.2	0.94
Guizhou	GD	GC	3	P₂wjp	1.01	17.7	6.48	13.6	1.59	6.73	1.4	0.3	1.65	0.25	1.8	15.4	0.39	1.3	0.18	1.29	0.22	52.6	355.3	1.64	Dai et al., 2015b
Guizhou	GD	HST	3	P₂wjp	1.03	29.7	13.8	29.6	3.24	13.3	2.43	0.55	2.59	0.35	2.19	14	0.43	1.35	0.18	1.28	0.21	85.5	340.9	1.00	Dai et al., 2015b
Yunnan	ZX	RSH	C₅b	P₂l	1.75	29.9	18.01	37.85	5.066	20.71	4.183	0.851	4.277	0.597	3.16	13.91	0.626	1.817	0.277	1.854	0.289	113.5	447.1	1.00	Duan, 2017
Yunnan	XW	BL	C1	P₂xw	1.46	28.7	30.7	67.9	7.54	29	5.85	1.08	6.18	0.88	3.93	20.8	0.77	2.05	0.29	1.94	0.3	179.2	736.3	0.81	Li et al., 2021
Yunnan	XW	LB	C1	P₂xw	2.35	34.5	21.95	49.36	5.548	21.81	4.423	0.864	4.748	0.737	3.655	20.13	0.746	2.055	0.287	1.897	0.291	138.5	474.9	0.94	Li et al., 2021
Sichuan	GX	SP	19	P₂l	0.50	17.4	5.48	11.7	1.29	4.72	1.08	0.254	1.34	0.222	1.39	10.6	0.313	0.969	0.149	0.994	0.159	40.7	278.4	1.36	Luo et al., 2016
Sichuan	GX	SP	25	P₂l	1.30	27.3	77.86	143.5	18.6	69.1	13.28	1.347	14.16	2.16	12.74	87.25	2.672	7.771	1.111	7.149	1.048	459.7	1995.1	1.16	Luo et al., 2016
Sichuan	GX	SP	25	P₂l	1.10	21.0	51.47	90.13	10.76	41.33	7.809	0.811	8.636	1.229	7.288	46.15	1.437	4.329	0.585	3.864	0.548	276.4	1562.6	1.05	Dai et al., 2016b
Sichuan	HYS	LSD	K1	P₂l	2.03	20.9	51.5	105	12.4	46.8	8.61	1.06	8.94	1.33	7.46	41.8	1.54	4.48	0.67	4.41	0.67	296.7	1680.0	0.92	Dai et al., 2014b

Tab.4 REY concentration (μg/g) and some parameters of coals from southwestern China

Fig.12 The content contour image of total REY in coals from southwestern China.

Fig.13 Diagram of the REO vs. C_outl from some coalfields of southwestern China.

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