硅酸及其盐的研究(ⅩⅥ)——硅酸胶凝作用中的离解常数  

Studies on Silicic Acid and Its Salts(ⅩⅥ)——Dissociation Constants of Silicic Acid in Gelation Process

作　　者：陈荣三[1] 陈月华 柳海澄[1] 戴安邦[1] Chen Rongsan;Chen Yuehua;Liu Haicheng;Tai Anpang(Coordination,Chemistry Institute,Nanjing University,Nanjing)

机构地区：[1]南京大学配位化学研究所

出　　处：《高等学校化学学报》1984年第6期769-774,共6页Chemical Journal of Chinese Universities

摘　　要：以HOAc和H_(2)SO_(4)为酸化剂,研究了不同SiO_(2)/Na_(2)O摩尔比的硅酸钠在酸化后胶凝时间和pH的关系.从“N”曲线的结构求得了硅酸在胶凝作用中的各级离解常数.Using HOAc and H_(2)SO_(4)as acidifying agents,the relationship of the gelation time and pH of the solution containing SiO_(2)/Na_(3)O ratio of 1.0,2.0 and 3.0,has been studied.The curve which expresses the relationship is of N-shape.At the minimum point of the curve,the pH is equal to pK_(1),at maximum point,the pH is equal to(pK_(0)+pK_(1))/2 and on the right side of the minimum point where,the pH is equal to(pK_(1)+pK_(2))/2.Therefore,from the structure of N-shape curves,dissociation constants of various species of silicic acid can be obtained.The results indicate that the dissociation constants of silicic acid in gelation process vary with the acidiffying agent,total salt concentration and the degree of polymerization of silicic acid,that when the total salt concentration of the solution maintained constant and the acidfying agent is same,the dissociation constants of silicic acid would not change with the concentration of the acid,and that the pK 1 of silicic acid and ionic strength of its solution bear a linear relationship,in which the slop represents coordination energy of anion of the corresponding salt with silicic acid and the intercept represents dissociation constant of silicic acid in the gelation process when the salt effect is eliminated.

关 键 词：胶凝作用 离解常数 胶凝时间 硅酸钠 酸化剂 

分 类 号：TQ1[化学工程]