Жерновский Игорь Владимирович, кандидат геолого-минералогических наук, профессор кафедры материаловедения и технологии материалов.

Experience is given for the application of x-ray total profile quantitative phase analysis for a comparative study of the quartz component of raw material and HCBS based on it. It is detected that the quartz component of silica-containing raw material is a heterogeneous phase and dimensional composition, represented by aand b-quartz.Keywords: mechanochemical activation, highly concentrated ceramic binder suspensions (HCBS), a-and b-modifications, system phase composition, Rietveld method.It is well known [1] that grinding, connected directly with mechanochemical activation of a solid phase surface of a system, promotes an increase in its internal energy and an increase in reaction capacity. During fine grinding of mineral particles they are subject to marked non-hydrostatic stresses [2]. We have made an assumption that during preparation of highly concentrated ceramic binder suspensions (HCBS) there are qualitative and quantitative changes in the phase composition of a system in the direction of greater activity.In order to confirm this hypothesis comparative analysis is necessary for quantitative and qualitative mineralogical characteristics of a starting raw material and a finished product. An x-ray analysis method was used in order to estimate values of the sizes of crystallites of the original raw material and a quartz base HCBS of silica composition. The possibility of determining dimensions of the field of coherent scattering (FCS) (minimum crystallite dimensions) using x-ray diffraction emerges from the dependence of the half-width of the profile (its angular width over half of the height) of a reflection on the value of the FCS. The x-ray patterns of nanodispersed material (NDM) were obtained in a DRON-4 diffractometer using Cu-anode radiation (Ni-filter for weakening b-components of radiation). The scanning step was 0.05°and the duration of measuring intensity at scanning points was 0.02 sec.The relative intensity of reflections and angular position of their maxima corresponding to low-temperature quartz. However, a typical feature was detected for the x-ray patterns obtained (Fig. 1), i.e. asymmetry of the x-ray reflection profile and their low-angle field. The most contradictory explanation of this fact was the assumption of presence within the HCBS quartz composition alongside the low-temperature modification of b-quartz close to it in crystallographic structure a high-temperature phase of a-quartz (Fig. 2). It should be noted that presence of phases, similar to a-quartz has been noted in [3] during dispersion of quartz specimens.The solution of this problem (with superimposition of reflections of different phases for one diffraction profile) is only possible with the use of calculation approaches based on the Rietveld method [4,5]. On the basis of this method, also called total profile, lies the procedure of minimizing the difference between experimental and calculated diffraction spectra. The latter is considered proceeding from the model of a crystalline structure of substances, comprising a polyco...

Информация об авторах Кожухова Наталья Ивановна, кандидат технических наук, доцент кафедры материаловедения и технологии материалов.

No abstract

Synthesis of binders and materials characterized by polycomponent composition, generally, is associated with necessity of improvement of certain properties or formation of principally new characteristics in this materials. In this paper hybrid geopolymers based on fly ash were synthesized using different types of mineral modifiers such as Portland cement (PC), kaolin, metakaolin (MK). It was defined, that values of compressive strength, water resistance and water absorption for PC-containing geopolymers are better than free of modifier geopolymer as well as for kaolin- and MK-containing geopolymers. It was determined that high-temperature treatment (at 600 °C) provides with reinforcing and improvement of water resistance of kaolin- and MK-containing hybrid geopolymers. PC-containing hybrid geopolymers demonstrated a sharp reducing in compressive strength and average density. For this system, in temperature range of 400–600 °C a dramatic growth of compressive strength is observed when average density grows or a constant. Thus, PC-containing hybrid geopolymers are not thermal resistant, that confirmed by degradation of its performance characteristics under high temperature effect.