Study On Titanates Synthesis

Potassium titanate whisker is an advanced material with micrometers length. Itincludes K2Ti40, K2Ti6Ot3 and K2Ti8O17 whiskers and is widely used in the field ofcomposite reforcement, ion-exchange and photocatalysis for degradation of wasterwater. In our study, potassium tetratitanate whisker K2Ti409 was firstly synthesized bycalcinations method. Then K+ ion in the layer of K2Ti409 was stepwise exchanged byH+ ion in the acid solution. Other titanate derivatives can be obtained by heattreatment in a suitable temperature. In order to accurately control the extraction of K+ ion from K2Ti409, previousresearchers in our group studied the process of thermodynamic and kinetic of ionexchange and an experimental installalation to monitor the process of ion exchangehas also been established. However, the method of manual manipulation to maintainthe pH value of solution was troublesome and brought deviation. In this paper, anautomat instead of maual manipulation to titrate acid was established, the titers weremeasured by electronic balance and the data were recorded by computer. Finally allover the process of ion exchange was measured automatically and so the deviationwas decreased. Because the above method need sinter at very high temperature and very longtime, the cost of production is very high and then restrict the use of the advancedmaterials. To reduce the cost of production and make the products cheaper, a newmethod, synthesis by microwave, was studied in this paper. The effectsto result of themicrowave medium, synthesis time and the ratio of Ti and K were studied. Thepotassium titanatc whiskers were synthesized by microwave. The time of synthesiswas decreased to 20 minutes from 3 hours. Among the rest, the condition for K2Ti409whisker synthesis is Ti/K=3, in the medium of CuO or Fe304 and 10 minutes inmicrowave radiation, that for K2Ti6O13 whisker is Ti/K=3.5, in the medium of Fe304and 20 minutes in microwave radiation; that for K2Ti6O13 in high crystallinity isTi/K=4, in the medium of Fe304 and 20 minutes in microwave radiation. BaO-TiO2 series microwave ceramics, particularly BaTi409 and Ba2Ti9020 wereconcerned because of their excellent microwave dielectric property, Nowadays, themain synthesis method for BaO-TiO2 system is solid phase synthesis. However,their single-phase area is very narrow from phase-diagram, which causes therequirement Ibr cxact control with the ratio of Ba and Ti. It is difficult to make rawmaterials uniform mixing by convcntional high temperature synthesis. In this paper,the method of the I2Ti409 fibcr and Ba(Oll)2 solution exchange was proposed firstly.By controlling the amount of Ba2+ in exchange process, the uniform mixing of Baand Ti in atomic unit was made, then sitering it and relatively pure BaTi409 wasobtained.