亚铁氰化钾对氯化钠的结晶抑制作用

Effect of potassium ferrocyanide on sodium chloride crystallization

目的:提出了1种新的利用K_4Fe(CN)_6的结晶抑制作用脱出石材孔隙NaCl可溶盐的方法.方法:通过X线衍射(XRD)、场发射扫描电镜(FSEM)对脱盐样品进行表征.以山西砂岩和四川砂岩为例,研究了不同的孔隙结构对K_4Fe(CN)_6结晶抑制性能的影响,初步探讨了K_4Fe(CN)_6对NaCl的结晶抑制作用的过程和机理.结果:K_4Fe(CN)_6对Na^+具有吸附作用,这阻碍了离子的迁移,抑制晶核的形成,在结晶过程中使Na Cl由原来的立方晶型变成树枝状晶型,促使晶体不均衡性生长形成树枝状结构,发生"盐岩蠕变",石材毛细管结构越丰富,越利于盐岩蠕变的发生.结论:在一定浓度范围内,K_4Fe(CN)_6的浓度越大,Na Cl在岩石表面析出的量越多.考虑到脱盐后岩石表面的状况和孔隙残留量,选取0.01 mol/kg K_4Fe(CN)_6溶液作为最佳脱盐浓度.

The influence of potassium ferrocyanide on sodium chloride crystallization behaviers was studied.The products were characterized via X-ray diffraction （XRD）and field emission scanning elec-tron microscopy （FSEM）.The effectiveness of two types of sandstone rocks with significantly different pore structures was also studied,which reflected the mechanism of desalination for crystallization inhibi-tors.The results show that potassium ferrocyanide acts a strong nucleation inhibitor for NaCl,impeding the migration of Na ＋ ions,inhibiting the formation of crystal nucleus,changing the cubic type into den-dritic crystal type,generating “gypsum creep”.The more capillary texture,the easier gypsum creep. The result also shows that the supersaturation of NaCl solution increases with inhibitor concentration. Considering the corrosion and residue inside the rock,the experiment determined the optimum concenta-tion of potassium ferrocyanide for 0.01mol /kg.