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不同活化条件下粉煤灰中锂的酸碱溶出特性研究
赵泽森,高建明,郭彦霞,陈荣峰,程芳琴,等
作者单位E-mail
赵泽森 山西大学 国家环境保护煤炭废弃物资源化高效利用技术重点实验室 山西低附加值煤基资源高值利用协同创新中心 山西太原030006 147713207@qq.com 
高建明 山西大学 国家环境保护煤炭废弃物资源化高效利用技术重点实验室 山西低附加值煤基资源高值利用协同创新中心 山西太原030006  
郭彦霞 山西大学 国家环境保护煤炭废弃物资源化高效利用技术重点实验室 山西低附加值煤基资源高值利用协同创新中心 山西太原030006  
陈荣峰 山西大学 国家环境保护煤炭废弃物资源化高效利用技术重点实验室 山西低附加值煤基资源高值利用协同创新中心 山西太原030006  
程芳琴 山西大学 国家环境保护煤炭废弃物资源化高效利用技术重点实验室 山西低附加值煤基资源高值利用协同创新中心 山西太原030006  
摘要:
粉煤灰提取氧化铝作为其资源高值利用的重要途径之一引起广泛关注。由于粉煤灰中还含有一定丰度锂元素,在提取氧化铝的同时实现锂的协同提取对于进一步提高粉煤灰的资源利用效益意义重大。为认识粉煤灰中锂(Li)的溶出特性,分别考察了原粉煤灰、CaO煅烧活化粉煤灰和Na2CO3煅烧活化粉煤灰中Li在盐酸和NaOH溶液中的溶出特性,并采用X–射线衍射(XRD)分析了粉煤灰浸取前后的物相变化,结合Li溶出率的变化,阐释了Li在不同浸出条件下溶出率差异的原因。结果表明:在相同浸出温度(100 ℃)下粉煤灰直接在盐酸溶液和NaOH溶液中的溶出率相对较低,分别仅为28%和36%;而经CaO和Na2CO3活化后粉煤灰中Li的溶出率显著提高,活化后粉煤灰中Li在盐酸溶液中的溶出率可达到98%和86%,均高于NaOH溶液中Li的溶出率(86%和67%)。XRD的分析结果进一步表明,部分Li可能赋存于非晶相或晶相表面,这部分Li易于被酸或碱直接浸出;部分Li可能镶嵌在莫来石、石英等晶相内部,不易被溶出,经CaO和Na2CO3助剂活化后,部分Li又重新嵌入到钙黄长石、霞石等新生成物相的晶格中,而这些物相更易于与酸反应,因而酸性溶液中Li的溶出率普遍高于NaOH溶液中的结果。
关键词:  粉煤灰,锂,活化,溶出特性
DOI:
分类号:
基金项目:国家重点研发计划(2017YFB0603101),山西省煤基低碳科技重大专项(MC2016-05)。
Study on the acid-alkali dissolution characteristics of lithium in fly ash under different activation conditions
ZHAO Zesen,GAO Jianming,GUO Yanxia,CHENG Rongfeng,CHENG Fangqin,et al
Abstract:
The extraction of alumina from fly ash is one of the important ways to use high value of its resources. As the fly ash contains a certain abundance of lithium elements, the extraction of alumina at the same time to achieve the synergistic extraction of lithium to further improve the utilization efficiency of the resources of fly ash is significant. In order to understand the dissolution characteristics of lithium (Li) in fly ash, the dissolution characteristics of Li in hydrochloric acid and NaOH solution in the original fly ash, CaO–Calcined activated fly ash and Na2CO3–calcined fly ash were investigated, and the phase change of fly ash before and after leaching was analyzed by X– Ray diffraction (XRD). According to the change of the dissolution ratios of Li, the reason of the difference of dissolution ratios of Li under different leaching conditions was explained. The results show that the dissolution ratios of fly ash directly in hydrochloric acid solution and NaOH solution at the same leaching temperature (100 ℃) is relatively low, respectively only 28% and 36%, and the dissolution ratios of lithium in fly ash after CaO and Na2CO3 activation is significantly improved. The dissolution ratios of Li in hydrochloric acid solution can reach 98% and 86% in the activated fly ash, which is higher than the dissolution ratios of Li in NaOH solution (86% and 67%). XRD analysis shows that some Li may be deposited on amorphous or crystalline surfaces, this part of Li is easy to be directly leached by acid or alkali; some li may be embedded in mullite, quartz and other crystalline phase, not easily dissolved, after CaO and Na2CO3 promoter activation, some Li again embedded in calcium melilite and nepheline. The dissolution ratios of Li in acidic solution is generally higher than that in NaOH solution because of the more easy to react with acid in the lattice of new generation phase of calcium melilite and nepheline.
Key words:  fly  ash, lithium, activation, extraction