酸洗对龙口油页岩化学结构的影响分析

Analysis of effects of demineralization on Longkou oil shale chemical structure

为研究脱灰对龙口油页岩的影响,采用HCl→HF→HNO3三级酸洗法脱灰,用XRD以及FT-IR法分别分析酸洗前后矿物质和化学结构的变化.结果表明:油页岩含氧官能团主要包含醚氧、羧基、羟基和羰基4类,酸洗制得的有机质纯度较高,酸洗后油页岩灰分的质量分数低于1%.酸洗对油页岩的化学结构产生影响,酸洗过程发生了水解反应,油页岩烷基醚、芳基醚含量减少;酸洗破坏了含氧官能团与无机盐之间的离子交联作用,将有机盐转化为有机酸,羧酸和酚羟基含量显著上升;羟基结构在酸洗前后都以环羟基、OH—O和OH—OH这3种形式为主,酸洗对环羟基、OH—O影响较大,对OH—OH影响很小;脂肪族在酸洗后部分CH伸缩振动和不对称的CH3伸缩振动转变成不对称的CH2伸缩振动,脂肪链长度增加.

To investigate the effect of demineralization on Longkou oil shale,the oil shale was acid demineralised in three steps with HCl→HF→HNO3,XRD and FT-IR was respectively used to analysis the compounds of minerals the change of chemical structure information before and after acid-treatment. The results show that oil shale mainly contains four oxygen-containing function groups,ether oxygen,carboxyl,hydroxyl and carbonyl,organic matter made by acid-treatment is really pure,the ash weight percentage is less than 1% after acid-treatment. acidtreatment has effect on the chemical structure in oil shale,hydrolysis reaction is occurred during the acid-treatment,alkyl ether and aromatic ether in the oil shale is decreased after acid-treatment; Carboxylic acid and phenolic hydroxyl are obviously increased,this is because acid-treatment breaks the ion exchange interaction between oxygen-containing groups and inorganic salts,then organic salts convert into organic acid; Hydroxyl structure both mainly contains structures of ring hydroxyl,OH—O and OH—OH before and after the acid-treatment,The acidtreatment has obvious effect on ring hydroxyl,OH—O,and has little effect on OH—OH; To the aliphatic structure,Acid-treatment makes the CH stretching vibration and CH3 asymmetric stretching vibration convert to CH2 asymmetric stretching vibration,the aliphatic chain is becoming longer.