DEVELOPMENT OF RESOURCE-SAVING TECHNOLOGY OF POROUS-HOLLOW CERAMIC STONES

A resource-saving technology of porous ceramic materials using low-quality non-sintering sandy loam as a basic raw material has been developed. Based on the analysis of the plastic properties of two- and three-component ceramic masses, including sandy loam, expanded clay and fuel slag in various ratios, it was found that the required level of their plasticity provides the content of the main raw material in the following range (wt%): fuel slag – 15 – 20; sandy loam – 50 – 65; expanded clay – 20 – 30. By the method of planning the experiment, the rational composition of the three-component ceramic mass was substantiated. This which contains: 62.5 wt. % sandy loam, 20 wt. % medium-sintering plastic clay as a plasticizer and 17.5 wt. % fuel slag of TPP as a porous agent. For the developed mass, the main technological properties were investigated, which made it possible to recommend the drying mode of the raw material – 60 hours, the optimal firing temperature – 950 °С. Such conditions ensure that samples are obtained without drying cracks and signs of deformation. Оn the results of dilatometric analysis of mass the rational mode of firing high-hollow semifinished products was designed. The firing mode provides for a 44-hour firing and a decrease in the heating rates in the areas of dehydration of clay minerals, direct quartz transition and intensive sintering of the mass, as well as a decrease in the cooling rate in the area of the reverse quartz transition. The proposed firing mode provides the degree of sintering and their properties necessary for ceramic materials. Based on the developed mass under the recommended drying and firing modes, porous ceramic materials with an apparent density of 1.48 g/cm3, a compressive strength of 18.2 MPa and frost resistance of 30 cycles were obtained. The developed materials belong to the group of conditionally effective, and if 50% of the voids are organized, they can be classified as effective.

Investigation of the structure and properties of ceramic materials with a rigid system of microfiltration transport pores based on basalt fibers

The report provides information on the formation of the structure of porous ceramic materials made of basalt fiber obtained by pressing with subsequent sintering. The phase composition, structure, and properties of ceramics are studied. The relationship between the structure, phase composition, and properties of the ceramic material is established.

CERAMICS BASED ON ORGANOSILICON POLYMERS-PRECURSORS: MICROSTRUCTURE AND PROPERTIES (review). Part 1

The paper considers the process of pyrolysis of polymers-precursors, and also shows the influence of various parameters of technological processes for obtaining ceramics on its composition, structure, and properties. The main types of binary, ternary and multicomponent silicon-based ceramics, methods of its preparation, features of structure and properties are considered, and promising directions of application of ceramics are determined. The possibility of obtaining porous ceramic materials (ceramic foams) with controlled porosity and ceramic composite materials with a given composition is noted.

Evaluation of the parameters of the porous structure and permeability of monofraction ceramics

A method for assessing the structure parameters of porous ceramic materials by porosity and particle size is presented. Based on it, a physically more rigorous than the well-known Cozeny formula is obtained, a formula for determining the average (hydraulic) radius of the capillaries of permeable materials. The presented results of the calculation of the average radius of the capillaries of porous ceramics based on electrocorundum according to the obtained formula are in better agreement with experimental data than the calculations by the Cozeny formula.