Bogdan Bogdanov

Study on the Synthesis of Batches of the System Y-Ba-Cu-O Using Sol-Gel Method

The study presented deal with preparation of batches of the system Y-Ba-Cu-O using sol-gel method and citric acid as precursor. Batches with particle size of 100 nm containing each of the phases Y123 and Y211 were prepared. The stoichiometric amounts of Y, Ba and Cu oxides were dissolved in 65% HNO3 until clear blue solution was observed under heating to 80 ̊С. The nitrate solutions obtained were neutralized to pH = 6 with 25% solution of NH3 (p.a.), then С6Н8О7 was added as the gels obtained were thermally treated. The transformation processes taking place under change of temperature were studied by IR, XRD, DTA and SEM.

Оbtaining of Lightweight Geopolymer Using Ash from Thermal Power Plants

A lightweight inorganic polymer is obtained using by ash from thermal power plants and lightweight aggregate from perlite . This inorganic material is activated using small amounts of sodium hydroxide and sodium silicate solution. In addition, porosity and water absorption were determined. Results showed that the lightweight geopolymer blocks with satisfactory strength and density could be made. The 28-day compressive strength of 5.2–13.8 MPa, density of 1075–1345 kg/m3, water absorption of 10–28% and porosity of 15–32% obtained. It can be used as lightweight geopolymer concrete for partition walls.