水泥熟料中硅酸盐矿物的溶解反应机理
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摘要
为研究水杨酸甲醇溶液(SAM)对水泥熟料中硅酸盐矿物的溶解反应机理,采用足量SAM来溶解水泥熟料的晶体产物并培养单晶体,经X射线衍射(XRD)单晶结构分析后,确定所培养的单晶体为水杨酸钙(C_(14)H_(10)O_4Ca·2H_2O).水杨酸钙属于单斜晶系的非心Cc空间群,在不对称单元中Ca与水杨酸中6个羧基氧原子和2个水分子氧原子形成了八配位的八面体结构.用红外光谱(FTIR)检测到了该晶体在3487cm~(-1)处的结合水和在3519cm~(-1)处羧基的—OH伸缩振动峰消失,羰基伸缩振动峰从1656cm~(-1)迁移至1548cm~(-1).该晶体的~(13)C NMR谱中苯环C基本未变化,因羧基的—OH参与化合反应,C7位移δ从171.80转移至176.09;~1H NMR谱检测到了该晶体在δ=4.9500处的结合水.试验表明:铝酸钙和铁铝酸钙在SAM溶液中是稳定相,水杨酸中羧基与硅酸盐矿物中CaO化合生成了易溶于甲醇的水杨酸钙;水杨酸与硅酸盐矿物反应的化学计量关系是2摩尔水杨酸结合1摩尔CaO,当两者摩尔比小于2时,生成的晶体不溶于甲醇,不能用于熟料矿物分离.
The mechanism of dissolution reaction of cement clinker silicate minerals by salicylic acid methanol(SAM)has been investigated.Crystal product made from dissolution of cement clinker by mixing it with sufficient SAM was extracted and cultured.XRD single crystal structure analysis was used to identify the monocrystalline product as calcium salicylate(C_(14) H_(10) O_4 Ca·2 H_2 O),which is classified as the noncentral Cc spatial group of monoclinic crystal system.In the asymmetric unit,Ca was found to be coordinated with six carboxylate O from the salicylic acid and two water molecules O,giving rise to the formation of an eight-coordinate octahedral structure.The FTIR spectrum of the crystal showed that a peak at 3 487 cm~(-1)-1 appeared to correspond to boned water molecules,and the peak at 3 519 cm~(-1)-1 disappeared,indicating the disappearance of—OH stretching vibration of the carboxyl group.The peak at 1 656 cm~(-1)-1 shifted to lower frequency at 1 548 cm~(-1)-1 representing the carbonyl C=O stretchingvibration.In the ~(13) C NMR spectrum of the crystal,the benzene ring Cδ was largely the same as that of salicylic acid.The C7 δ shifted from171.80 to 176.09 because the —OH of the carboxyl group takes part in the combination reaction.In ~1H NMR spectroscopy the crystal bound water arises at δ=4.950 0.The results have shown that calcium aluminate and calcium ferroalumnates are inert phases in SAM.Calcium salicylate is here synthesized using the carboxyl groups of salicylic acid and CaO of silicate minerals,then dissolved in methanol.The stoichiometric ratio of salicylic acid to CaO from silicate minerals is 2∶1.When the stoichiometric ratio fell below this value,the product became insoluble in methanol so the case is not adopted for clinker mineral separation.
The mechanism of dissolution reaction of cement clinker silicate minerals by salicylic acid methanol(SAM)has been investigated.Crystal product made from dissolution of cement clinker by mixing it with sufficient SAM was extracted and cultured.XRD single crystal structure analysis was used to identify the monocrystalline product as calcium salicylate(C_(14) H_(10) O_4 Ca·2 H_2 O),which is classified as the noncentral Cc spatial group of monoclinic crystal system.In the asymmetric unit,Ca was found to be coordinated with six carboxylate O from the salicylic acid and two water molecules O,giving rise to the formation of an eight-coordinate octahedral structure.The FTIR spectrum of the crystal showed that a peak at 3 487 cm~(-1)-1 appeared to correspond to boned water molecules,and the peak at 3 519 cm~(-1)-1 disappeared,indicating the disappearance of—OH stretching vibration of the carboxyl group.The peak at 1 656 cm~(-1)-1 shifted to lower frequency at 1 548 cm~(-1)-1 representing the carbonyl C=O stretchingvibration.In the ~(13) C NMR spectrum of the crystal,the benzene ring Cδ was largely the same as that of salicylic acid.The C7 δ shifted from171.80 to 176.09 because the —OH of the carboxyl group takes part in the combination reaction.In ~1H NMR spectroscopy the crystal bound water arises at δ=4.950 0.The results have shown that calcium aluminate and calcium ferroalumnates are inert phases in SAM.Calcium salicylate is here synthesized using the carboxyl groups of salicylic acid and CaO of silicate minerals,then dissolved in methanol.The stoichiometric ratio of salicylic acid to CaO from silicate minerals is 2∶1.When the stoichiometric ratio fell below this value,the product became insoluble in methanol so the case is not adopted for clinker mineral separation.
引文
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[13] LAZO D E,DYER L G,ALORRO R D,et al.Silicate,phosphate and carbonate mineral dissolution behaviour in the presence of organic acids:A review[J].Minerals Engineering,2017,100:115-123.
[14] 陈小明,蔡济文.单晶结构分析原理与实践[M].2版.北京:科学出版社,2007:44-45.CHEN Xiaoming,CAI Jiwen.Principle and practice of single crystal structure analysis[M].2nd Edition.Beijing:Science Press,2007:44-45.(in Chinese)
[2] LOTHENBACH B,WINNEFELD F.Thermodynamic modelling of the hydration of Portland cement[J].Cement and Concrete Research,2006,36(2):209-226.
[3] LOTHENBACH B,WINNEFELD F.Effect of temperature on the pore solution,microstructure and hydration products of Portland cement pastes[J].Cement and Concrete Research,2007,37(4):483-491.
[4] TAVAKOLI D,TARIGHAT A.Molecular dynamics study on the mechanical properties of Portland cement clinker phases[J].Computational Materials Science,2016,119:65-73.
[5] WALENTA G.Advances in quantitative XRD analysis for clinker,cements,and cementitious additions[J].Powder Diffraction,2004,19(1):40-44.
[6] CAMPBELL D H.Microscopical examination and interpretation of Portland cement and clinker[M].Skokie:Portland Cement Association,1999:147-148.
[7] TAKASHIMA S.Systematic dissolution of calcium silicate in commercial Portland cement by organic acid solution[J].Jpn Cem Eng Assoc,1958(5):12-13.
[8] 冯铭芬,文秀萍,郁卫国.含硫、氟熟料化学相分离方法的研究[J].硅酸盐通报,1986(5):50-57.FENG Mingfen,WEN Xiuping,YU Weiguo.Study on chemical separation methods for clinker containing fluorine or sulfur[J].Bulletin of the Chinese Ceramic Society,1986(5):50-57.(in Chinese)
[9] GUTTERIDGE W A.On the dissolution of the interstitial phases in Portland cement[J].Cement and Concrete Research,1979,9(3):319-324.
[10] GARCíA-DíAZ I,PUERTAS F,GAZULLA M F,et al.Effect of ZnO,ZrO2 and B2O3 on clinkerization process.Part Ⅱ.Phase separation and clinker phase distribution[J].Materiales de Construcción,2009,294(59):53-74.
[11] HJORTH L,LAURéN K G.Belite in Portland cement[J].Cement and Concrete Research,1971,1(1):27-40.
[12] 李伟峰,王京刚,侯贵华,等.水杨酸溶液萃取转炉钢渣中硅酸盐相的研究[J].硅酸盐通报,2008,27(2):365-370.LI Weifeng,WANG Jinggang,HOU Guihua,et al.study of silicate phase extraction from converter slag by salicylic acid methanol(SAM) solution[J].Bulletin of the Chinese Ceramic Society,2008,27(2):365-370.(in Chinese)
[13] LAZO D E,DYER L G,ALORRO R D,et al.Silicate,phosphate and carbonate mineral dissolution behaviour in the presence of organic acids:A review[J].Minerals Engineering,2017,100:115-123.
[14] 陈小明,蔡济文.单晶结构分析原理与实践[M].2版.北京:科学出版社,2007:44-45.CHEN Xiaoming,CAI Jiwen.Principle and practice of single crystal structure analysis[M].2nd Edition.Beijing:Science Press,2007:44-45.(in Chinese)