Preparation And Properties Of Hollow Glass Beads

Hollow glass bead is a kind of spherical powder with inert gas,hollow and thin wall(0?2?m)structure.It has a series of excellent properties,such as strong fluidity,low density,low dielectric constant,insoluble in water,acid and alkali resistance.It is a kind of high-performance functional material.Therefore,in this experiment,waste glass was used as the main raw material,and a method and device for preparing hollow ceramic microspheres were used to prepare hollow glass beads.After that,high-temperature flame rapid sintering technology was used to prepare hollow glass beads with high sphericity,good morphology,high floating rate,low density and high strength.The main contents of this paper are as follows:(1)The effects of the type of foaming agent,the content of foaming agent,the particle size of microspheres,sintering temperature,feeding air speed and cutting speed on the properties of micro beads were studied.The results show that all kinds of factors have great influence on the properties of the microspheres,among which the selection of foaming agent is more important.Because of the large particle size distribution of the microspheres,the use of composite foaming agent can greatly increase the gas evolution and improve the floating rate and compressive strength of the micro beads at the same temperature.(2)When the content of foaming agent,sintering temperature,feeding air speed and feeding speed are adjusted properly,the microspheres have higher floating rate and compressive strength.When the content of A+B is 1.5%,the sintering temperature is850°C,the feeding air speed is 1.6 m/s,and the feeding speed is 40 g/min,the performance of the microbeads is the best.The floating rate is 93%,the true density is0.75 g/cm~3,the bulk density is 0.43 g/cm~3,and the floating rate is 11.4%under the hydrostatic pressure of 30 MPa.Through flotation,the true density and bulk density are0.54 g/cm~3 and 0.25 g/cm~3 respectively.(3)Improve the performance of hollow microspheres by spray drying method,including introducing metal oxides,non-metallic mineral materials,etc.In this paper,fly ash with high activity and different clarifiers were introduced into the green body to further improve the performance of the microspheres.The results show that the floating rate and strength of the microspheres are obviously improved after adding fly ash.When the solid content of fly ash is 3%,the sintering temperature is 850°C,and the feeding air speed is 1.4 m/s,the floating rate of micro beads reaches 99.5%,and the floating rate after 30 MPa water isostatic pressing is 21%.When 2%of the composite glass clarifier was added,the true density of the beads was 0.65 g/cm~3,the packing density was 0.28 g/cm~3,and the floating rate of the microspheres was 25%at 30 MPa.Through flotation and particle size screening,more hollow and thin-walled high-performance glass beads appeared in the beads with particle size of 80?120?m.