膨润土冶金球团粘结剂中有机物的作用机理研究

Through the previous test research, theprevious test research ,the bentonite pellet binder tested,and the QSAR (quantitative structure activity relationship) of bentoniteproperties and pellet quality indicator was found out. And the built model was validated by test data. The different between the simulation results of bentonite added organic On the basis of above, organic played an important role.The bentonite pellet binder, but the mechanism is not clear.. In the project which based on the previous studies, the organic type and dosage that added to the bentonite metallurgy pellet binder were confirmed, aiming at the organic structure ,functional group,the hydrophilic and thermal stability analysis ,using infrared analysis, potentiometric analysis ,scanning elecctron microscopy(SEM) analysis, chromatography, X-ray diffraction and other test analysis methods,through the thermodynamic princile ,dynamic pinciples, pelletizing related theory and principle of hydrolysis, the hydrolysis condition and principle of organice was researched in the bentonite metallurgy pellet binder, so were the recation condition and principle and the recation manner with iron ore powder between the organic and the bentonite , etc. The action mechanism of organic was ascertained in the bentonite metallurgy pellet binder,which will have a major significance for ascertaining the action mechanism of bentonite metallurgy pellet binder and revealing the action mechanism of bentonite pellet binder and the iron ore powder,and which will lay the foundation for reducing the dosage of bentonite pellet binder.

通过前期对膨润土球团粘结剂进行了大量试验研究，找出膨润土性能与球团质量指标的构效关系模型，利用试验数据验证了所建的模型；添加有机物的改性土模拟结果与实际应用差别较大，实际应用效果较好。 据此提出有机物在膨润土球团粘结剂中起了重要作用, 但其作用机理不清。该项目在前期研究的基础上，确定出膨润土冶金球团粘结剂中添加有机物的种类和用量，从有机物的结构、官能团、亲水性及热稳定性等分析入手，采用红外、电位分析、扫描电镜、色谱、X射线衍射等试验分析手段，利用热力学原理、动力学原理和球团相关理论以及水解原理等对添加有机物的膨润土冶金球团粘结剂中的有机物的的水解条件和原理、与膨润土作用的条件与原理、与铁矿粉作用的方式等进行研究，探明膨润土冶金球团粘结剂中有机物的作用机理问题，对阐明膨润土冶金球团粘结剂的作用机制，揭示膨润土球团粘结剂与铁矿粉的作用规律有重要意义，为降低膨润土球团粘结剂的用量奠定基础。

粘结剂作为铁矿球团生产的重要辅料，其产品质量直接关系到球团矿性能的优劣。而添加有机物的膨润土基复合粘结剂在球团中的作用形式尚不明确，我们前期研究表明：根据偏最小二乘法、逐步回归法与神经网络建模分析相结合的方法，找出的膨润土性质与生球性能的构效关系模型，并不能有效预测复合粘结剂的生球性能。据此推测有机物在复合球团粘结剂中起了重要作用。为了验证上述假设，本项目研究了不同有机粘结剂与膨润土在多种复配方式下生球性能的差异，并在此基础上利用X射线衍射、电动电位和接触角等表征手段对复合粘结剂进行表征，从微观结构上探讨复合粘结剂在球团中的作用形式，阐明有机粘结剂在复合粘结剂中的强化功能及复合机制，推测出复合粘结剂“卡房式”凝胶结构形成过程。研究结果表明，膨化淀粉和羧甲基纤维素中的羧基和羟基能与膨润土表面和端面发生静电吸附和化学吸附，使膨润土表面负电位更强，减小了膨润土与铁矿表面的接触角，增强了膨润土表面的亲水性。依托于有机粘结剂的高分子链，复合粘结剂形成的“卡房式”网状结构会进一步增强其稳定性，未剥离的膨润土片层在化学键的作用下将进一步剥离，膨润土粒度变小，比表面积变大，在颗粒间的分散度提高。从而固体颗粒间的接触面积增大，分子间作用力增强，有机粘结剂会与铁矿表面发生的化学吸附进一步增多，提高了生球的力学性能。镁钙基膨润土中的 Mg2+在球团加热过程中，会与磁铁矿粉发生反应，生成镁铁矿、尖晶石固溶物等矿物，这些矿物与附着在膨润土上与Fe2O3、铁酸钙等互联和紧密胶结，形成固相连接桥，抑制了球团的膨胀，提高了球团的爆裂温度。本项目首次利用镁钙基膨润土制备复合粘结剂，研究结果将为研制新型膨润土基复合球团粘结剂提供可行思路，也将为工业生产优质球团粘结剂提供参考。