新疆高碱煤分选组分中碱性矿物赋存及差异演化研究

林雄超; 杨远平; 徐荣声; 李首毅; 岳文菲; 王永刚

新疆高碱煤分选组分中碱性矿物赋存及差异演化研究

中国矿业大学(北京)化学与环境工程学院, 北京 100083

基金项目:

国家自然科学基金 21406261

十二五”国家科技支撑计划重点项目 2012BAA04B02

详细信息

通讯作者:
林雄超,Tel:010-6233-9882,E-mail:linxiongchao@163.com

中图分类号: TQ546
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- 被引次数: 0
出版历程
- 收稿日期: 2016-10-26
- 修回日期: 2016-12-17
- 网络出版日期: 2021-01-23
- 刊出日期: 2017-02-10

Occurrence and transformation behavior of AAEMs in the flotation fraction of a typical Xinjiang coal

School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083, China

Funds:

National Natural Science Foundation of China 21406261

12th Five-Year Plan of National Science and Technology Support 2012BAA04B02

More Information

Corresponding author: Tel:010-6233-9882,E-mail:linxiongchao@163.com

摘要

摘要: 以新疆五彩湾高碱煤为原料，通过有机重液浮选和理化分析及热力学模拟解析活性矿物质热演化特性。结果表明，五彩湾煤以密度在1.40-1.50 g/cm³的组分为主（质量分数超过70%）。可溶性Na和K等主要存在于较低密度组分（-1.40 g/cm³）中；在高密度（+1.50 g/cm³）组分中发现了以硅铝酸盐形式存在的碱及碱土金属（AAEMs）。Ca主要以方解石形式存在，伴随高岭土和石英富集在高密度组分中。在低温（500℃）灰化时少量Na释放，大量可溶钠盐的残留导致各分选组分中Na的扩散量相差不大。在815℃热处理温度下，低密度组分中大部分Na挥发到气相中；高密度组分中的部分碱金属可被黏土（高岭土）和石英等矿物质捕获，抑制其释放。FactSage热力学模拟发现，温度低于550℃时Na盐仍稳定存在于灰中；温度高于550℃时Na盐开始挥发，同时部分Na向NaAlSiO₄转化；在约620℃时，Na盐消失，同时NaAlSiO₄的含量逐渐趋于稳定。SiO₂含量的差异显著影响含Na等矿物质的演变行为。在500-815℃，Ca以CaSO₄和硅铝酸钙的形式稳定存在，而Mg则在不同形式的硅酸盐之间发生转变。
- 分选 /
- 赋存形态 /
- 演化差异 /
- 新疆煤
Abstract: The occurrence and thermal transformation behaviors of AAEMs (alkali and alkaline earth metal species) in a typical Xinjiang coal (Wucaiwan) were systematically investigated.The raw coal sample was primarily separated to four fractions based on different densities by float-sink experiments using organic heavy solutions.Subsequently, the BSE-EDX (backscattered electron-energy dispersive X-ray detector) and XRD were employed to analyze the mineral matters in coal fractions.Moreover, the thermal transformation behaviors of minerals in coal were simulated using FactSage.The results show that the active minerals (i.e., AAEMs) in coal vary with the flotation density and exhibit quite different transformation characterizations.Samples with density of 1.40-1.50 g/cm³ are the major fraction (70%) for Wucaiwan coal.The Na and K exist principally in the lower density (-1.40 g/cm³) fraction;in contrast, the AAEMs are combined with the alumina-silicate in the high density (+1.50 g/cm³) fraction.Additionally, Ca is mainly in the form of calcite;and kaolinite and quartz are enriched in the high density fraction.Less Na could release at lower heat treatment temperature (500℃);thus the release amounts of Na in four fractions present less difference.The majority of Na is volatilized from the low density coal sample at 815℃;but for the high density coal samples the clay (mainly kaolinite) and quartz could capture Na and restrain its release.According to the FactSage calculation, the NaCl is found to be still stable in the coal ash at 550℃;it would start evaporate over 550℃ and generate NaAlSiO₄.The NaCl would vanish at 620℃ and the NaAlSiO₄ gradually becomes constant.Moreover, at the temperature range of 500-815℃, Ca is mainly in the form of CaSO₄ and Ca-Si-Al, while Mg varies in several forms.
- flotation /
- occurrence /
- transformation distinction /
- Xinjiang coal

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图 1 密度分选组分分布

Figure 1 Distribution of density dependent float-sink fractions

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图 2 各密度样品的XRD谱图

Figure 2 XRD analysis of coal samples from float-sink experiments

Q: SiO₂; K: Al₂(Si₂O₅)(OH)₄; Pe: FeS₂; Ph: KCa(Al₂Si₅O₁₆)·6H₂O; Ma: NaHSO₄·H₂O

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图 3 五彩湾不同密度样品的电子背散射照片

Figure 3 SEM-BSE analysis of different density samples of W coal

: organic matter;: mineral matter

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图 4 五彩湾各分选部分煤样萃取

Figure 4 Extraction results of fractions with different densities

(a): Na; (b): K; (c): Mg; (d): Ca: water soluble；: ammonium acetate soluble；: hydrochloric soluble

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图 5 不同密度样品的反应性能

Figure 5 Reactivity variation of the fractions with different densities

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图 6 五彩湾煤样在500和815 ℃灰化后的XRD谱图

Figure 6 XRD analysis of coal ash prepared at 500 and 815 ℃

Q: SiO₂; P: MgO; A: CaSO₄; Tr: Na_0.58K_0.42(Al₃(SO₄)₂(OH)₆); Fi: Na₂SiF₆; Y: KNa₃AlSi₄O₁₆; Py: Mg₃Al₂Si₃O₁₂；Z: Ca₅(SiO₄)₂CO₃; Cl: MgSiO₃; V: FeMnO₃; F: Na_3.5K_4.5(AlSiO₄)₆(ClO₃)_1.91(OH)_0.09); C: CaCO₃; E: Al₂SiO₅

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图 7 矿物质演变的热力学分析

Figure 7 FactSage analysis on mineral transformation behavior

(a): sample with low SiO₂ content; (b): sample with high SiO₂ content

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表 1 原煤及分选组分的工业分析、元素分析和灰成分分析

Table 1 Proximate,ultimate and ash composition analyses of coal samples

Sample			Proximate analysis w_ad/%						Ultimate analysis w_daf/%
Sample			M	A	V		FC		C	H		N	S_td
W			11.81	6.24	27.01		54.94		79.07		4.05	0.79	0.51
W1			5.18	2.80	32.78		59.24		74.62		4.33	0.57	2.74
W2			7.88	2.98	34.27		54.87		73.05		4.79	0.83	0.52
W3			8.13	3.17	35.98		52.72		73.02		4.00	0.90	0.48
W4			5.85	31.63	29.83		32.69		74.44		4.64	1.14	3.25
Compositions of W ash w/%
SiO₂	Al₂O₃	Fe₂O₃	CaO	K₂O	Na₂O	MgO	SO₃	SrO	TiO₂	BaO	P₂O₅	MnO	Cr₂O₃
17.77	10.30	4.21	29.55	0.32	2.40	9.45	22.84	1.24	1.23	0.35	0.06	0.10	0.06

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表 2 五彩湾煤样的X射线能谱分析

Table 2 EDX analyses of Wucaiwan coal samples

Testing point	Atom w/%
Testing point	Si	Al	O	Ca	Fe	Na	K	Mg	S	P	Cl	Ti	Cr
a	20.42	24.51	55.07	-	-	-	-	-	-	-	-	-	-
b	-	-	71.96	28.04	-	-	-	-	-	-	-	-	-
c	-	-	47.81	-	-	-	-	-	-	-	-	-	52.19
d	20.93	21.41	57.66	-	-	-	-	-	-	-	-	-	-
e	-	4.63	82.55	7.20	-	-	-	2.61	3.01	-	-	-	-
f	1.33	-	44.33	-	49.91	-	-	-	-	-	-	4.44	-
g	42.77	2.39	51.34	-	2.04	0.78	0.69	-	-	-	-	-	-

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表 3 样品煤岩组分分析

Table 3 Maceral distribution of the flotation fractions

Sample	W2	W3	W4
Vitrinite(de mineral basis)	62.27	34.51	40.21
Inertiniete(de mineral basis)	37.73	65.49	59.79

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表 4 五彩湾煤在500和815 ℃下灰的化学组成

Table 4 Ash compositions of Wucaiwan coal prepared at 500 and 815℃

Sample		Chemical composition w/%
Sample		SiO₂	Al₂O₃	Fe₂O₃	CaO	K₂O	Na₂O	MgO	SO₃	SrO	TiO₂	BaO	P₂O₅	MnO	Cr₂O₃
500 ℃	W2	6.18	14.26	2.07	39.50	0.07	3.51	9.44	22.25	1.59	0.70	-	0.19	0.12	0.11
	W3	7.78	12.03	2.47	41.72	0.06	3.57	9.98	19.92	1.59	0.40	-	0.27	0.12	0.08
	W4	63.18	13.16	8.53	4.38	0.89	0.67	1.52	4.34	0.30	2.39	0.32	0.07	0.04	0.10
815 ℃	W2	7.54	15.74	2.85	31.17	-	0.52	16.25	22.87	1.80	0.88	-	0.09	0.14	0.08
	W3	10.26	12.32	3.66	32.05	-	0.29	19.05	19.66	1.86	0.47	-	0.12	0.13	0.03
	W4	64.61	12.59	9.31	4.12	0.83	0.49	1.49	2.94	0.30	2.62	0.38	0.03	0.04	0.09

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