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Research On The Preparation Of Borosilicate Foam Glass And Microcrystalline Foam Glass

Posted on:2012-04-25Degree:MasterType:Thesis
Country:ChinaCandidate:X TuFull Text:PDF
GTID:2121330332483940Subject:Materials science
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With the development of science and technology, material is required more for modern building, foamed glass and microcrystalline foam glass as new energy efficient and environmentally friendly building materials have been paid wide attention.Boron sludge is the waste produced by the production of borax, and 1t borax is produced when 4t Boron sludge is discharged. Waste glass is also one kind of industrial wastes with large emissions, so preparing foamed glass and microcrystalline foam glass with boron mud and waste glass as the main raw materials is not only low cost and can help to protect the environment.Compared with ordinary silicate foam glass, borosilicate foam glass has more outstanding features, such as the acid and alkali corrosion resistance, hydrolysis resistance, etc. Borosilicate microcrystalline foam glass not only inherits the features of foam glass such as lightweight and strong acid and alkali corrosion resistance, but also has the characteristics of glass ceramics such as high mechanical strength and Wide operation temperature range, widely used in high temperature pipng, sound-absorbing, moisture-proof, fire prevention, etc, and having good application prospect.Borosilicate foam glass and microcrystalline foam glass was prepared by utilizing magnesium-removal boron mud and cullet as raw materials, adding MnO2, C, Na2CO3 and CaCO3 as foaming agent, ZrO2 and TiO2 as nucleation agent, Na2SiF6 as fluxing agent and Na3PO4 as stabilizing agent through powder burning process. Firstly, the compose design of foamed glass was carried to determine the best ratio of major raw materials by contrast test, changing the ratio of magnesium-removal boron mud and cullet. Then chose the appropriate kind of additives such as foaming agent, fluxing agent and stabilizing agent and determined the optimal dosage. The temperature schedule of preparing foamed glass was studied by differential scanning calorimetry and thermogravimetric analysis (DSC-TG) and the optimum preparation parameters was determined by orthogonal experimental design. Choosing the proper type and content of nucleating agents on the basis of preparing foamed glass under optimize condition and determine the optimal heat-treated system of preparing the borosilicate microcrystalline foamed glass by orthogonal experimental design. The structure and properties of the samples such as apparent density, water absorption, compressive strength and acid resistance were studied by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and other modern testing methods.The experiment results of foam glass indicated that the proper proportion of waste glass and magnesium-removal boron mud was 8:2 and the proper dosage range of MnO2 as foaming agent, Na2SiF6 as fluxing agent and Na3PO4 as stabilizing agent were 4%6%, 4%5% and 1%2%. The foaming temperature range of foamed glass was 1000℃1200℃obtained by differential scanning calorimetry and thermogravimetric analysis (DSC-TG). The optimally technology parameters of preparing foaming glass were determined by orthogonal experimental design: the content of the MnO2 being 6%, the foaming temperature being 1150℃, the foaming time being 30min. It is tested that the apparent density of the samples was 812kg/m2, the compressive strength was 10.5MPa, the water absorption was 0.31%, the thermal conductivity was 0.18w/m·k.The experiment results of microcrystalline foam glass showed that the effect was remarkable when 3% of the ZrO2 was added as nucleating agent. The nucleating temperature of the samples ranged from 910℃to 920℃, crystallization temperature ranged from 1060℃to 1080℃, which is obtained from the different scanning calorimetry and thermogravimetric analysis (DSC-TG). And the optimum heat treatment system of micro-crystallographic foamed glass determined by orthogonal experimental design was: nucleating at 915℃for 60min with heating rate of 4℃/min, then crystallizing at 1080℃for 60 min with heating rate of 5℃/min, and at last cooling it with the furnace. The micro-crystallographic foamed glass prepared under the optimum conditions was made of 13mm pores, crystal and glass phase; diopside and wollastonite were produced in the samples showed by XRD; the apparent density of the samples was 912kg/m2, the compressive strength was 19.6MPa, the water absorption was 0.23%, the thermal conductivity was 0.24w/m·k, the mass only increased 0.05% after immersed in dilute sulphuric acid of 0.1mol/L for 14d, which were obtained by the performance test. The material has some characteristics of lightweight, high strength, low water absorption, low thermal conductivity and high resistance to acids.
Keywords/Search Tags:Waste Glass, Boron Sludge, Borosilicate, Foam Glass, Microcrystalline Foam Glass, Foaming Agent, Nucleating Agent
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