【作者】 王磊；

【导师】 马玉龙；

【作者基本信息】 宁夏大学 ， 材料与化工硕士（专业学位）， 2024， 硕士

【摘要】 近年来,我国通过降低能耗强度、调整能源结构、推广和发展先进煤气化技术等举措,以助力“碳达峰”和“碳中和”目标的实现。消耗大量煤炭资源所带来巨大产能的同时,煤气化渣的堆存量也日益增多,对生态环境造成危害。煤气化粗渣因其残碳量较少,主要应用在路基填筑、墙体材料等领域,而其自身所含的多种金属氧化物,也具有可开发和利用的价值。以煤气化粗渣作为本研究对象,先对研磨后的煤气化粗渣粉末进行酸浸,优化浸出条件,再对有价金属锰、铬进行萃取分离。为实现高效萃取,设计两种协同萃取体系,并对萃取和反萃取的条件进行优化。最后采用优化的萃取工艺从煤气化粗渣的酸浸液中提取锰、铬,具体研究内容及结果如下:(1)研究了酸浸工艺中的各种参数,包括酸浸试剂的种类、酸浓度、液固比、搅拌速率、反应时间等对预处理后的煤气化粗渣中各金属浸出的影响。试验结果表明,浸出效果较佳的条件:浓度为4mol/L的盐酸作浸出剂,液固比为10ml/g,时间为12h,搅拌速率为600r/min。(2)D2EHPA与PC-88A组成的协同萃取体系对锰萃取的研究。先研究了该协萃体系萃取锰的工艺参数,优化了萃取条件:萃取相比(O/A)为3:1、pH为4.56、混合萃取剂浓度为30 vol.%且VD2EHPA:VPC-88A=7:3、萃取时间为15min。在此优化条件下,锰的萃取率达到98.62%。并用优化的萃取工艺对锰和铬的混合溶液进行萃取分离,结果发现,两者间的分离在较低的pH条件下分离效果更好;其次研究该共萃取系统的反萃取性能,在优化的反萃取条件下,锰的反萃取率达到96.79%。最后用傅里叶红外光谱技术表征来解析协萃体系的协同作用以及萃取锰的机理,结果表明萃取反应属于阳离子交换反应,混合萃取剂官能团P-OH上的氢与Mn2+发生交换,同时还存在P=O与Mn2+间的配位。(3)Cyanex272与MIBK组成的协同萃取体系对铬萃取的研究。锰、铬混合溶液经D2EHPA与PC-88A萃取分离后,针对萃余液中的铬,设计Cyanex272-MIBK协萃体系对其实现高效萃取。首先,系统地研究了不同的反应条件对萃取的影响。从结果中得到,该体系萃取的优化条件为:相比(O/A)=2:1、pH=6.05、VCyanex272=25 vol.%、VMIBK=30 vol.%,铬的萃取率可达 97.69%;其次用紫外-可见光谱与傅里叶红外光谱表征,对Cyanex272-MIBK的协同作用以及萃取铬进行研究。结果显示,MIBK的增溶作用使协萃体系的萃取能力强于单一萃取剂Cyanex272。最后采用两种协同萃取剂的优化工艺对气化粗渣酸浸液中的锰、铬进行萃取,结果表明,经过三次连续萃取,锰的提取可达75.69%,铬的提取为58.95%。更多还原

【Abstract】 In recent years,China has taken such initiatives as reducing energy intensity,adjusting energy structure,and promoting and developing advanced coal gasification technology in order to achieve the goals of "carbon peaking" and "carbon neutrality".While the use of advanced coal gasification technology brings huge production capacity,the stockpile of coal gasification slag is also increasing,which is harmful to the ecological environment.Coal gasification slag is mainly used in the fields of roadbed filling and wall materials because of its low residual carbon content,while it contains a variety of metal oxides of its own,which have the value that can be developed and utilized.In this study,the coal gasification slag is taken as the research object,and the acid leaching is carried out on the milled coal gasification slag powder firstly,and optimize the leaching conditions.Then the valuable elements of manganese and chromium are extracted and separated.In order to achieve efficient extraction,two synergistic extraction systems were designed and the process conditions of extraction and counter-extraction were optimized.Finally,the optimized extraction process was used to extract manganese and chromium from the acid leach solution of coal gasification crude slag,the specific research contents and results are as follows:(1)The effects of various parameters in the acid leaching process,including the type of acid leaching reagent,acid concentration,liquid-solid ratio,stirring rate,and reaction time,on the leaching of each metal in the pretreated coal gasification slag were investigated.The test results showed that the better leaching effect was achieved under the following conditions:hydrochloric acid with a concentration of 4 mol/L as leaching reagent,a liquid-solid ratio of 10 ml/g,a time of 12 h,and an agitation rate of 600 r/min.(2)Study of manganese extraction by the co-extraction system composed of D2EHPA and PC-88A.Firstly,the process parameters of manganese extraction by this co-extraction system were investigated,and the extraction conditions were optimized:the extraction ratio(O/A)was 3:1,the pH was 4.56,the concentration of the mixed extractant was 30 vol.%and VD2EHPA:VPC-88A=7:3,the extraction time was 15 min.Under these optimized conditions,the manganese extraction rate reached 98.62%.The optimized extraction process was used to extract and separate the mixed solution of manganese and chromium,and it was found that the separation between the two was better under the lower pH condition;secondly,the counter-extraction behavior of the co-extraction system was investigated,and under the optimized counter-extraction conditions,the counter-extraction rate of manganese reached 96.79%.Finally,Fourier infrared spectroscopy was used to characterize and analyze the mechanism of manganese extraction by the co-extraction system and the synergistic effect,which showed that the extraction reaction belongs to the cation-exchange reaction,and the hydrogen on the functional group P-OH of the mixed extractant was exchanged with Mn2+,and there also existed the coordination between P=O and Mn2+.(3)Study of chromium extraction by a synergistic extraction system consisting of Cyanex272 and MIBK.After the manganese and chromium mixed solutions were extracted and separated by D2EHPAPC88A,a Cyanex272-MIBK co-extraction system was developed for the efficient extraction of chromium in the extraction residue.The effect of different reaction conditions on the extraction was systematically investigated,and from the results,the optimized conditions for the extraction of this system were as follows:(O/A)=2:1,pH=6.05,VCyanex272=25 vol.%,VMIBK=30 vol.%,the extraction rate of chromium could reach 97.69%;Secondly,the chromium extraction by Cyanex272-MIBK and the synergistic effect were investigated by UV-Vis and FTIR spectroscopic characterization.The results show that the solubilizing effect of MIBK makes the extraction capacity of the co-extraction system stronger than the single extractant Cyanex272.Finally,the optimized process with two synergistic extractants was used to extract manganese and chromium from the acid leach solution of gasification crude residue,and the results showed that the extraction of manganese reached 75.69%and chromium 58.95%after three successive extractions.更多还原