Preparation And Characterization Of Lightweight Foam Glass

Foam glass is an inorganic porous thermal insulation material with a porosity of more than 90%.It can be used in petrochemical,cold storage,refrigerated ships,fermenting and brewing industries,as well as internal and external wall insulation materials for buildings.Compared with other insulation materials,foam glass has the advantages of wide temperature range,low water absorption,corrosion resistance,wide source of raw materials,low cost,easy processing and environmental protection.However,since the foamed glass is obtained by foaming glass frit,the density is large,generally 200 kg/m³ or more,so that it is difficult to use it in an environment where high density is required in a high-rise building or the like.In this paper,waste glass powder and graphite were used as the main raw materials,and foam glass was prepared by dry pressing powder sintering foaming method.The thermal properties of raw materials?glass powder,graphite?and mixture were studied by thermal analysis method.The foaming mechanism was explored,and the basic process was developed and optimized.Based on this,the apparent density of each process parameter on foam glass products was discussed.The influence of sodium carbonate,potassium carbonate,ferric oxide,palygorskite,kaolin and other auxiliary additives on the microscopic mechanism of the foaming process and the influence on the density of the product were also discussed.At the same time,the obtained foam glass samples were carried out the characterization of pore size,water absorption,compressive strength,etc.to investigate the structure and properties of the lightweight foam glass.The main research contents of the thesis are as follows:?1?Thermal analysis of glass powder,graphite and mixture showed that foam glass mainly undergoes four stages in the process of firing:?I?below 400?,there was a mass loss mainly due to desorption of adsorbed gases in the system;?II?400-652.6?,at this time,the graphite was oxidized and the water of crystallization in the glass powder was decomposed;?III?652.6-750?,the system began to melt and the gas escape rate was slowed down;?IV?after 750?,completely melted,the bubble started to grow up.?2?The effects of process factors such as foaming agent addition,foaming temperature,holding time,ball milling speed,heating rate,ball milling time and pressure on foam glass were studied.The results showed that the first four factors had a greater impact on the density of foam glass.On the contrary,the latter three had less impact.?3?The firing results of the mixture without additives showed that the optimum foaming agent was added in an amount of 2 wt%,the foaming temperature was 930?for 40 min,and the sample's density was 163 kg/m³.The diameter is 2.04 mm,the water absorption is 3.02 wt%,and the compressive strength is 0.75 MPa.?4?The results of auxiliary additives'effect on the density of foam glass showed that the GC2NC1 mixture with a sodium carbonate addition of 1 wt%had a minimum density of 142 kg/m³ after foaming at 910?for 40 min,and its strength could reach0.55 MPa.The addition of Fe₂O₃ to foam glass reduced the uniformity of foaming and the mechanical properties are also poor.After adding 5 wt%of palygorskite,the foaming time could be extended to 120 min to maintain a good pore structure and its density was reduced to 112 kg/m³,with a strength of 0.51 MPa.When the holding time was short,the addition of kaolin could increase the strength of the foam glass sample,and we could obtain foam glass with a density of 150-200 kg/m³,which had a compressive strength of 1 MPa or more.