Study On Alkali Resistance And Mechanical Properties Of Glass Fiber Prepared From Red Mud

During the production of alumina,the aluminium industry generates red mud,which is a solid waste with limited utility due to its high salt and alkaline properties.In China,a significant alumina producer,a considerable amount of red mud is inadequately disposed of,leading to an accumulation of waste These accumulated wastes can only be stored in dams,resulting in land wastage,human and material resource depletion,and endangering the ecological environment and public safety.It is therefore imperative to find a way to use red mud in a rational and efficient way.In this paper,glass fibers were prepared from red mud as the main raw material,together with industrial raw materials such as quartz sand,alumina and dolomite.By adjusting the components of the glass,the laws of influence of different Si O₂/Fe_xO_y ratios,Zr O₂content on the structure of glass fibers,as well as including alkali resistance and mechanical properties,were systematically investigated.The results of the study are as follows:（1）XRD analysis results show that the samples are amorphous.According to the XPS analysis,the iron in the glass is mainly present in the form of Fe³⁺.As iron oxides replace Si O₂ in glass,the denseness of the network structure diminishes gradually.This causes a reduction in the glass transition temperature（T_g）and thermal stability parameter（ΔT）,leading to a decline in the overall thermal stability of the glass.At the same time,as the Si/Fe mass ratio decreases from 16.82 to 9.41,the tensile strength of the raw glass fibers decreases from 1949±28 MPa to 1464±53 MPa.In contrast,the alkali resistance of glass fibers improves as the Si/Fe ratio decreases.Optimal resistance occurs when the Si/Fe ratio is 9.41,where the mass loss rate and strength loss rate of the fibers after 72 hours of corrosion are the lowest,measuring at 3.94%and 73.2%,respectively.However,this ratio also results in the lowest tensile strength of the raw glass fiber wire.Taking into account both the alkali resistance and tensile strength of glass fibers,it has been discovered that the optimal composition within the SF group is achieved when the Si/Fe ratio is 14.16.At this ratio,the tensile strength of glass fibers reaches 1883±26MPa,with a strength loss rate of 74.1%and a mass loss rate of 4.02%.（2）Based on the previous chapter,different mass percentages of Zr O₂ were added to improve the glass properties.XRD analysis shows that the samples are amorphous.The glass network structure’s degree of connectivity and thermal stability demonstrates a rising trend,followed by a decline,as the Zr O₂ content increases.At a Zr O₂ content of 1.5 wt%,the glass network structure is the densest,the glass transition temperature T_g and the thermal stability parameterΔT reach the maximum,and the glass has the best thermal stability.Simultaneously,with an increase in Zr O₂ content,the tensile strength of fresh fiber exhibits an initial incline followed by a decline.The highest tensile strength of glass fibers is achieved at a Zr O₂ content of 1.0 wt%.When the Zr O₂content is 2.5wt%,the tensile strength of glass fibers is the smallest,which is1927±34MPa and 1740±68MPa respectively.The alkali resistance experiment revealed that the glass fiber’s resistance to alkali gradually improves when the Zr O₂ content is kept between 0-1.5 wt%.When the Zr O₂ content is greater than 1.5wt%,the excess Zr O₂ will destroy the network structure of the glass,while Zr O₂ as a nucleating agent makes the glass easier to crystallise and the alkali resistance of the fibers gradually decreases.After 72h alkali corrosion,by comparing the mass loss rate and strength loss rate of each group of fibers,it is found that the tensile strength of the glass fibers at1.5wt%Zr O₂ is 1901±39MPa,the tensile strength loss rate is 63.8%and the mass loss rate is 3.45%,which is the component with the best overall performance in the Zr group.A study of the alkali resistance and mechanical properties of glass fibers of different compositions has shown that it is practical to use red mud to prepare glass fibers.The preparation of glass fibers from red mud is feasible.The glass fibers produced have excellent alkali resistance and mechanical properties.