乙二醇-EDTA滴定法与热解重量-示差热分析法相结合测定钢渣中游离氧化钙含量  

Determination of Free Calcium Oxide in Steel Slags by Combination of Glycol-EDTA Titrimetry and Thermogravimetry-Differential Thermoanalysis(TG-DTA)

作　　者：杜君[1] 刘家祥[1] 李敏[1] 

机构地区：[1]北京化工大学,化工资源有效利用国家重点实验室,材料科学与工程学院,北京100029

出　　处：《理化检验（化学分册）》2013年第8期961-964,共4页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：国家自然科学基金(51174011)

摘　　要：提出了用乙二醇-EDTA滴定法结合热解重量-示差热分析法(TG-DTA)准确测定了钢渣中游离氧化钙(f-CaO)的含量。试验表明:用乙二醇-EDTA滴定f-CaO时,共存的氢氧化钙几乎定量参与反应;因此,滴定结果实为f-CaO的合量;试验还表明:利用Ca(OH)2的TG-DTA图谱可计算钢渣中氢氧化钙的含量。由上述两方法所得结果的差值即可得到钢渣中f-CaO的含量。此外,乙二醇与f-CaO反应生成可溶性乙二醇钙的同时产生了水分,而钢渣中胶凝组分与此水分将发生水合反应而产生氢氧化钙,致使所测得的f-CaO值偏高。本方法中提出在反应体系中加入硅胶使上述反应中所生的水吸附除去,从而克服上述干扰,进一步提高了方法的准确度。Glycol-EDTA titrimetry in combination with TO-DTA was applied to the determination of free CaO （f-Ca（）） in steel slag. It was shown that Ca（OH）2 co-existed with f-CaO in the sample reacts quantitatively with EDTA in the titrimetric process, hence the result obtained is the sum of contents of CaO and Ca（OH）2 ; and it was found that the TG-DTA pattern of Ca（OH）2 can be used to calculate the content of Ca（OH）2 in slag sample. Therefore, content of f-CaO of the sample was obtained by the difference of the results obtained by glycol-EDTA titrimetry and TG-DTA. In addition, it was found that the setting components in slag sample gave extra amount of Ca（OH）2 due to their hydration with water which was produced in the reaction of f-CaO with glycol to give soluble calcium glycollate. To overcome this interference, definite amount of silica gel was added to the reaction system to remove the water by adsorption, making accuracy of the method improved still further.

关 键 词：乙二醇-EDTA滴定法 热解重量-示差热分析法 游离氧化钙 硅胶 钢渣 

分 类 号：O655.25[理学—分析化学]