柠檬酸对脱硫石膏水热产品形貌的影响机理  

The influence mechanism of citric acid on the morphology of hydrothermal product by the desulfurization of gypsum

作　　者：李亮[1,3] 雷大士 王宇斌 汪潇[2] 王雯雯 金彪 井欣悦 LI Liang;LEI Dashi;WANG Yubin;WANG Xiao;WANG Wenwen;JIN Biao;JING Xinyue(College of Resource Engineering,Xi'an University of Architecture and Technology,Xi'an Shaanxi 710055,China;College of Material&Chemical Engineering,Henan University of Urban Construction,Pingdingshan Henan 467036,China;Anshan Coal Mine,Shaanxi Yongxin Mining Industry Co.,Ltd.,Yulin Shaanxi 719400,China)

机构地区：[1]西安建筑科技大学资源工程学院,陕西西安710055 [2]河南城建学院材料与化工学院,河南平顶山467036 [3]陕西涌鑫矿业有限责任公司安山煤矿,陕西榆林719400

出　　处：《矿物学报》2024年第2期253-260,共8页Acta Mineralogica Sinica

基　　金：国家自然科学基金项目(批准号:51974218);河南省重大公益专项(201300311000)。

摘　　要：本文以脱硫石膏和柠檬酸为主要原料水热制备半水硫酸钙晶体,采用XRD、FTIR等手段对晶体进行表征,研究柠檬酸对半水硫酸钙晶体形貌的影响及其反应机理。结果表明,当柠檬酸用量为0.20%时,溶液中C_(6)H_(6)O_(7)^(2-)和C_(6)H_(7)O_(7)^(-)不仅能够通过化学吸附的形式与半水硫酸钙晶体的(020)晶面、(400)晶面和(204)晶面上的Ca^(2+)生成柠檬酸钙沉淀,还可通过静电吸附的形式吸附在(204)晶面上。此外,C_(6)H_(8)O_(7)与吸附在半水硫酸钙表面的柠檬酸根通过碳链之间的缔合作用和羟基之间的氢键作用相互吸附进而包覆在晶体表面,不利于SO_(4)^(2-)等生长基元在晶体表面的沉淀,使其形貌从纤维状向六棱柱状转变。当柠檬酸用量大于0.20%时,柠檬酸在溶液中主要以C_(6)H_(8)O_(7)的形式存在,C_(6)H_(8)O_(7)与吸附在半水硫酸钙表面的柠檬酸根之间的缔合作用和氢键作用占主导地位,从而不利于半水硫酸钙晶体的(020)晶面和(400)晶面上的生长,使晶体形貌由六棱柱状向板状转变。The calcium sulfate hemihydrate crystals were prepared from raw materials of desulfurized gypsum and citric acid by using the hydrothermal method.The effect of citric acid on the morphology of calcium sulfate hemihydrate crystals and its reaction mechanism were studied based on the characterization of the crystal by using the XRD,FTIR and so on.The results show that C_(6)H_(6)O_(7)^(2-)and C_(6)H_(7)O_(7)^(-)in solution not only could be adsorbed through chemical adsorption on planes and reacted with Ca^(2+)on the(020),(400)and(204)planes of the calcium sulfate hemihydrate crystal to have formed the calcium citrate for precipitation,but also could be adsorbed on the(204)plane of the crystal by electrostatic adsorption,when citric acid dosage was 0.20%.In addition,the mutual adsorption between C_(6)H_(8)O_(7) and citrate ion on surface of the calcium sulfate hemihydrate crystal by the association interaction of carbon chains and the hydrogen bonding interaction of hydroxyls resulted in the coating of C_(6)H_(8)O_(7) on surface of the calcium sulfate hemihydrate crystal.This is unfavorable to the precipitation of growth units such as SO_(4)^(2-)on surface of the crystal.It will result in the transformation of its morphology from the fibrous to hexagonal prismatic crystals.When the doseage of citric acid was greater than 0.20%,citric acid was existed mainly in the form of C_(6)H_(8)O_(7) in solution.Thus,the association effect and hydrogen bonding interactions between C_(6)H_(8)O_(7) and citrate ion on the surface of calcium sulfate hemihydrate played dominant roles,which was unfavorable to the growth of the(020)and(400)planes of the calcium sulfate hemihydrate crystal and resulted in the transformation of its morphology from fibrous to hexagonal prismatic ones.

关 键 词：柠檬酸用量 半水硫酸钙晶体 晶体形貌 作用机理 

分 类 号：TB321[一般工业技术—材料科学与工程] TD985[矿业工程—选矿]