Study On The Structure And Properties Of Silicate Alkali-resistant Glass Prepared From Red Mud And Blast Furnace Slag

The rapid development of industrialization has brought about a series of problems of environmental pollution and over-exploitation of resources.The increase in solid waste discharge caused by industrial production has exacerbated the seriousness of environmental problems.The traditional landfill treatment of industrial waste can not solve the environmental problems they bring,on the contrary it will cause pollution of soil,groundwater and air.The problem of turning industrial waste into treasure has attracted more and more attention from scientists and industrial production companies.The main components of the mud are SiO₂,Al₂O₃ and Fe₂O₃.The main components of the blast furnace slag are Si O₂,CaO,MgO,Al₂O₃,etc.They are similar to the main components of ordinary silicate glass.Therefore,in this paper,red mud and blast furnace slag are used as the main raw materials to prepare glass.The effects of SiO₂,Al₂O₃,CaO,Fe₂O₃/Al₂O₃,Fe₂O₃/CaO,and ZrO₂ on the glass structure,thermal stability,density,and chemical stability were studied.The following conclusions were obtained:（1）The structural unit with the highest content in glass silicon-oxygen tetrahedron is Q³which contains three bridge oxygens.When the content of SiO₂ increases and the content of Al₂O₃ and CaO decreases,the tightness of the glass network structure increases.Combining the infrared spectrum and the area ratio of Qⁿ,we can find that when the glass composition is SiO₂ 59g,Al₂O₃ 15g and CaO 8g,the glass network structure is the densest.The thermal stability of glass is most affected by the change of SiO₂ content.The component with the densest structure has the best alkali resistance,the corrosion mass loss is 1.17%,the components with the best water resistance are SiO₂ 61g,Al₂O₃ 11g and CaO 12g,and the mass loss is 0.35%.（2）With the increase of Fe₂O₃/Al₂O₃,the change trend of the tightness of the glass network structure is to increase first and then decrease.Among the samples with SiO₂ content of 61.46wt%,FA-5 sample with Fe₂O₃ and Al₂O₃ content of 7.0wt%and 14.88wt%respectively had the highest structural density,thermal stability and chemical stability.The mass loss in the alkaline solution is 1.096%.In the component with SiO₂ of 58.16wt%,the coefficient of thermal expansion between 100°C and 500°C decreases first and then increases within the range of 5.97-5.77×10^-6 When the Fe₂O₃ and Al₂O₃ contents are 8.0wt%and13.43wt%,the minimum is reached.At this time,the alkali resistance is optimal,and the alkali corrosion mass loss is 1.066%.（3）Increasing the Fe₂O₃/CaO ratio reduces the free oxygen in the network structure and increases the bridge oxygen content.The glass network skeleton is more complete and the structural stability is increased.The increase ofΔT value from 246°C to 307°C indicates that the thermal stability of the glass increases gradually.The alkali resistance of the glass increases first and then decreases.The alkali resistance is optimal when the Fe₂O₃ and CaO contents are 7.5wt%and 10.87wt%,respectively,and the mass loss is 1.063%.（4）Adding ZrO₂ to the glass component can not only form an octahedron,but Zr⁴⁺also has an"accumulation"effect.The combined effect of these two aspects makes the glass network structure more compact.The measured density of glass gradually increased from 2.67g/cm³ to2.72g/cm³,and the molar mass increased from 66.03g/mol to 67.22g/mol.When the ZrO₂content is 5.0wt%,the mass loss of the glass in the aqueous solution and the alkaline solution is0.270%and 0.989%,respectively,and the chemical stability is optimized.