高锂粉煤灰磁选除铁实验

臧静坤; 程伟; 潘雪玲

doi:10.3969/j.issn.1000-6532.2023.05.012

高锂粉煤灰磁选除铁实验

贵州大学矿业学院，喀斯特地区优势矿产资源高效利用国家地方联合工程实验室，贵州省非金属矿产资源综合利用重点实验室，贵州　贵阳　550025

基金项目: 国家自然科学基金项目（41802190）

详细信息

作者简介: 臧静坤（1995-），女，硕士，研究方向为难选矿石的选矿及资源综合利用

通讯作者: 程伟（1983-），男，博士，教授，研究方向为煤系资源利用与煤地球化学

中图分类号: TD952; TD97

收稿日期: 2021-12-12

刊出日期: 2023-10-25

Iron Removal from a High-lithium Coal Fly Ash by Magnetic Separation

College of Mining, Guizhou University, National & Local Joint Laboratory of Engineering for Effective Utilization of Regional Mineral Resources from Karst Areas, Guizhou Key Laboratory of Comprehensive Utilization of Non-metallic Mineral Resources, Guiyang, Guizhou, China

More Information

Corresponding author: Cheng Wei, wcheng1@gzu.edu.cn

Received Date: 12 December 2021

Publish Date: 25 October 2023

摘要

摘要:
这是一篇矿物加工工程领域的论文。本研究以贵州某电厂粉煤灰为研究对象，综合运用多种测试手段对粉煤灰进行矿物组成及元素含量测定。结果表明，粉煤灰中主要矿物为莫来石、石英和铁矿物（5.46%的磁铁矿以及4.77%的赤铁矿），主要化学成分为SiO₂、Al₂O₃和Fe₂O₃，含量分别达到36.88%、20.89%和14.58%。此外，原灰中锂的含量高达307 g/t，显示出一定的综合利用价值。粒度分析表明，粉煤灰75 μm以下累积产率高达83.4%，整体颗粒较细，且锂和铁主要富集在-75 μm的粒级中。采用还原焙烧的方法将粉煤灰中弱磁性的赤铁矿转化为强磁性的磁铁矿，再采用湿式磁选方法对粉煤灰进行除铁研究。结果表明：以粉煤灰中的残碳为还原剂，焙烧温度为700 ℃，焙烧时间为45 min，磁场强度为240 mT的条件下，采用“一次粗选-两次扫选”的磁选工艺，粉煤灰中铁去除率达到63.27%，同时锂的回收率达到80.31%，实现了铁杂质的选择性脱除。
- 矿物加工工程 /
- 粉煤灰 /
- 还原焙烧 /
- 磁选 /
- 除铁
Abstract:
This is an essay in the field of mineral processing engineering. In this study, coal fly ash from a power plant in Guizhou was used as the research object. A series of test methods were comprehensively applied to the determination of the mineral composition and element content of coal fly ash. The results show that the main minerals in coal fly ash are mullite, quartz and iron minerals (5.46% magnetite and 4.77% hematite) , and the main chemical components are SiO₂, Al₂O₃ and Fe₂O₃, with the contents of 36.88%, 20.89% and 14.58%, respectively. In addition, the content of lithium is as high as 307 g/t, which shows a certain comprehensive utilization value. Particle size analysis shows that the cumulative yield of coal fly ash below 75 μm is as high as 83.4%, which indicates that the overall particles are finer. Lithium and iron are mainly concentrated in the -75 μm fraction. Reduction roasting was used to convert the weakly magnetic hematite in coal fly ash into strong magnetic magnetite, and then the wet magnetic separation method was used to remove iron from the fly ash. The results show that with the residual carbon in coal fly ash as the reducing agent, the roasting temperature 700 ℃, the roasting time 45 min, and the magnetic field strength 240 mT, and followed by a magnetic separation process of "one roughing-two sweeping", the iron removal rate reaches 63.27%, and the lithium recovery is 80.31%.
- Mineral processing engineering /
- Coal fly ash /
- Reduction roasting /
- Magnetic separation /
- Iron removal

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图 1 粉煤灰试样X射线衍射

Figure 1.

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图 2 粉煤灰试样扫面电镜图像及能谱分析

Figure 2.

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图 3 活性炭添加量对磁选效果影响

Figure 3.

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图 4 焙烧温度对磁选效果的影响

Figure 4.

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图 5 焙烧时间对磁选效果的影响

Figure 5.

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图 6 磁场强度对磁选效果的影响

Figure 6.

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图 7 磁选工艺流程

Figure 7.

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表 1 粉煤灰试样粒度组成

Table 1. Particle gradation of coal fly ash sample

粒级/μm	产率/%		Li含量/(g/t)	Li分布率/%		Fe含量/%	Fe分布率/%
粒级/μm	各粒级	筛上累积	各粒级	各粒级	筛上累积	各粒级	各粒级	筛上累积
+125	5.1	5.1	252.9	4.50	4.50	6.38	2.78	2.34
-125+75	11.5	16.6	249.1	10.00	14.50	7.65	7.53	10.31
-75+45	18.6	35.2	262.5	17.04	31.54	10.27	16.34	26.65
-45+38	6.8	42.0	276.9	6.57	38.11	13.81	8.03	34.68
-38	58.0	100.0	305.8	61.89	100.00	13.17	65.32	100.00
合计	100.0		286.6	100.00		11.69	100.00

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表 2 粉煤灰试样中铁的物相定量分析

Table 2. Quantitative analysis of iron phase in coal fly ash sample

铁相态	金属量/%	分布率/%
磁铁矿中铁	5.46	44.35
赤褐铁矿中铁	4.77	38.75
硅酸铁中铁	1.57	12.75
碳酸铁中铁	0.42	3.41
硫化铁中铁	0.09	0.74
总铁	12.31	100.00

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表 3 粉煤灰试样的化学成分/%

Table 3. Chemical composition of coal fly ash sample

SiO₂	Al₂O₃	Fe₂O₃	TiO₂	CaO	SO₃	K₂O	Na₂O	LOI	C	Li*
36.88	20.89	14.58	3.56	2.50	2.17	1.95	1.11	5.40	4.20	307
LOI为烧失量；*单位为g/t。

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