Structure and microstructure behavior of iron doped potassium sodium niobate powders

In this paper, the synthesis and characterization of the potassium sodium niobate doped with iron powders have been studied. Solid-state oxide reaction sintering was used. The powders produced in this work exhibit no homogeneous microstructure, which introduced the growth of random cylindrical structures and will can contribute to the increased porosity ceramics. It was observed average particle size of 3μm, besides, also it was observed the formation of agglomerations and an increase in the size of these clusters with the increase in the amount of iron. The calcination temperature was 950 °C. This is slightly higher than other potassium sodium niobate powders systems. In addition to the physical and microstructural properties, structural properties are presented and analyzed for the first-time using Mössbauer spectroscopy as complementary technique in Fe 3+doped potassium sodium niobate powders. This work is important to state solid physics because establishes the influence of iron in the potassium sodium niobate system, and so the future obtaining of multifunctional materials that have piezoelectric and magnetic properties.

EXPERIMENTAL METHODS FOR STUDYING THE RESOURCE VALUE OF DUMP BLAST FURNACE SLAGS

The study of the properties of blast-furnace slags requires an integrated approach, including various research methods. The purpose of the work is to substantiate the resource value of the Zaporizhstal dump blast furnace slag. The research methods were used: X-ray phase, petrographic, gamma-spectrometric analysis and electron probe microanalysis. The slag is dispersed into fractions, since the slag minerals have different hardness. Fractions (mm) were investigated in the work: >20 2.5–5, <0.63. X-ray phase analysis made it possible to reveal in the crystalline part of blast-furnace slag minerals that are technically valuable in the production of binders: 3CaO∙2SiO2, SiO2, 2CaO∙Al2O3∙SiO2, α-2CaO∙SiO2, 2CaO∙MgO∙2SiO2, α-CaO∙SiO2. Minerals akermanite, bredigite, pseudo-wollastonite have hydraulic activity. It is shown that the mass fraction of the amorphous component is half the mass of the blast furnace slag. The high content of substances in the amorphous state confirms the possibility of sorption of extraneous ions and compounds. The found elements Potassium, Sodium, Sulfur, Chlorine, Cuprum and Titanium are not part of the minerals. Slag contains less than 1% of the total amount of Fe, Ti and Cu, belonging to the 3rd class of hazardous substances. The maximum content of Potassium, Sodium and Titanium is typical for the fraction 2.5–5 mm. The most basic is the fraction <0.63 mm (pH 9.7), for the 2.5–5 mm fraction pH 9.1, the most acidic fraction >20 (pH 8.2). By the value of the toxicity index (4.3–5.4) and the III hazard class, dump blast furnace slag «Zaporizhstal» as a moderately hazardous waste can be used as a secondary raw material in the construction industry. The database on the content of natural radionuclides in technogenic raw materials has been updated. It has been proven that slag and its individual fractions contain natural radionuclides 40К, 226Ra, 232Th. The main contribution to the value of Сef is made by the 226Ra radionuclide, then by 232Th. The excess of specific activity is expressed for the 2.5–5 mm fraction. The I class of radiation hazard is defined, which allows the use of slag in construction without restrictions. Dump blast furnace slag «Zaporizhstal can be recommended in the production of inorganic binders « by the totality of chemical indicators.