Nº 9 (2024)

5–6 июня 2024 г. в Москве прошла XXII Международная научно-практическая конференция «Развитие керамической промышленности России: КЕРАМТЭКС-2024». В ее работе приняли участие более ста руководителей и ведущих специалистов кирпичных заводов, представителей машиностроительных и инжиниринговых компаний, ученых отраслевых исследовательских и учебных институтов из двадцати девяти регионов России, а также Казахстана, Италии, Испании, Китая и Турции.

The data on the annual release of ash and slag waste as a result of the operation of thermal power plants (TPP) in Siberia and the Far East of the Russian Federation are presented. The main reasons for the insignificant use of ash in the construction industry (about 5-8% of the total waste output) and the problems hindering its use for the production of ceramic wall materials are considered. A brief description of the composition and properties of the raw materials used in this work for the manufacture of ceramic wall materials is given. The compositions of the developed fly ash-based charges and the method of manufacturing ceramic samples with a matrix structure are given. The results of the study of the structure of ceramic materials by optical microscopy are presented. It is established that during the firing process, a matrix (dispersion medium) is formed from the fusible shell of aggregated complexes, and granules from fly ash are transformed into cores (dispersed phase) of a ceramic matrix composite. It was revealed that the kernels have an oval shape due to the deformation of the granules during pressing. Clusters are formed in the nuclei, consisting of a large number of small crystalline grains connected by an amorphous substance and edged with thin chains of pores. It is shown that the developed pore space inside the cores is mainly represented by frost-proof and reserve pores, which ensures high frost resistance of ceramic samples based on fly ash.

The current economic situation and increased attention to environmental protection encourage manufacturers of building materials, in particular ceramic bricks, to look for alternative types of raw materials that make it possible to reduce its cost with good quality of finished products. Mining waste is especially promising, among which peridotites stand out, which have huge reserves and are practically not used. The purpose of the work is to obtain building ceramics with the addition of peridotite and study its mechanical properties.The chemical and mineralogical compositions of raw materials have been determined. Silicon and aluminum oxides account for 78.5% in clay and 61% in peridotites.The latter are characterized by a high content of calcium, magnesium and iron oxides (34.65%). Clay is composed of clay minerals, as well as quartz and feldspar. Tremolite, enstatite and olivine are present in peridotites. The dependence of the mechanical strength of ceramic samples on their firing temperature, the content of the additive and the degree of its grinding has been established. The optimal amount of peridotite is 10%, at which the compressive strength has the maximum value over the entire grinding range of the additive. With an increase in the firing temperature to 1050^оC, a slow increase in the strength of the samples occurs. At 1100^оC, there is a sharp jump in strength parameters, which increase by 3.6–4.7 times, depending on the granulometric composition of the additive.The main properties of the obtained ceramics were determined. It has been established that peridotites are a promising additive for the production of ordinary bricks with a compressive strength of up to 60 MPa and an average density of up to 2400 kg/m³.

The use of brick breakage in concretes and in binder compositions is a promising direction for the development of recycling ceramic bricks. The purpose of the present research was to evaluate the possibility of using mineral powders obtained from brick breakage as an effective dispersed component in the production of fine-grained concrete. In the work, mechanical grinding of ceramic raw material was carried out at different grinding times. It wasestablished that for brick-breakage powders, an increase in the grinding time does not lead to a proportional increase in the specific surface area of the powders.The maximum effective increase in the specific surface area of the obtained powders is fixed at a grinding duration of up to 5 minutes. Using differential thermal analysis, it is shown that crushed brick is not an active mineral additive, but can act as crystallization centers during the formation of hydrosilicates in the structure of composites. Samples of fine-grained concrete were produced, in which part of the cement was replaced with ceramic powders obtained at different grinding duration. It was determined that the replacement of cement in concrete mixtures with this highly dispersed additive in an amount of 20% (by weight), obtained at an optimal grinding time in a ball mill, does not lead to a change in the physico-chemical characteristics of the final concrete composite.

The problem of assessing the prospects of silicate bricks in the domestic market of small wall materials is discussed. The solution to this problem is based on the results of the analysis of the market situation, consumer preferences and competitiveness of silicate bricks. It is shown that in the period from 2014 to 2021 due to the stronger competitive position of autoclaved aerated concrete blocks and face ceramic bricks, the capacity of the market of silicate bricks decreased, its production volume and share in the structure of consumption of small-piece wall materials. The results of marketing research conducted on the basis of online questionnaires of respondents are presented, according to which the majority of respondents consider face ceramic bricks to be the material that best meets their requirements in terms of quality and appearance. The calculations showed that despite the fact that ceramic bricks have almost equal positions in terms of technical parameters and worse positions in terms of aesthetics, the most competitive material is, nevertheless, silicate bricks, which have a relatively low price. A number of threats for silicate brick producers include a decrease in demand for products, a high degree of wear and tear of technological equipment, dependence on foreign supplies of pigments, spare parts and components for equipment, insufficient level of professional competence of the personnel, etc. It is expected that in the future a number of manufacturers of sand-lime bricks will have to face the following challenges. It is assumed that in the future the ordinary silicate bricks will apparently “leave” the construction market, in connection with which manufacturers will have to focus on improving the quality and aesthetic parameters of facial silicate bricks while maintaining an attractive price for consumers.

This work discusses the use of a modifying complex additive to concrete with the inclusion of carbon nanotubes “Taunit-M” and the SP-3 plasticizer. Two methods of introducing nano-sized additives into the composition of fine-grained concrete, as well as their combination, are considered. The results of a series of tests of beam samples aged 28 days are presented using two methods of introducing nanotubes, namely: the use of an ultrasonic dispersant and the use of a linear induction rotator (LIR). The positive effect of introducing nanotubes on the strength characteristics of concrete has been established. It has been determined that the use of LIR technology provides an increase in strength due to a double effect: activation of the cement binder and distribution of the nanoadditive using active mixing due to vortex action. Ultrasonic dispersion, in turn, ensures the effective introduction of the plasticizer into the mixing water.