Vol 74, No 5-6 (2017)

The technological particulars of using secondary products in silicate materials technology are examined. The basic problems that must be taken into account in using secondary products and unconditioned raw material are designated. Concrete examples of using technological wastes in production are presented. The results of exploratory tests and adoption of certain secondary products are presented.

The published data on sulfate-containing glass in silicate, borate, and phosphate systems are reviewed. The experimental data confirm the presence of [SO₄]^2– groups in an isolated state in all systems, but the possible amount of SO₃ in the glass composition is considerably higher in borate and phosphate systems.

The operation of internal cullet lines in the production of sheet glass is analyzed. Different variants of the arrangements of technological equipment used for transporting and crushing cullet are presented, and some technical solutions for storing and batching cullet are given. Measures to increase the dust-catching efficiency in crushing sheet glass wastes are determined.

A new approach is proposed for analyzing the efficiency of fume heat recovery. The theoretically attainable temperature of air heating is calculated for a 450 tons/day glassmaking furnace with fume temperature 1450 – 1500°C at the entry and 325 – 450°C at the exit of the checkerwork. The regenerator structural and regime parameters required to heat air to 1300°C are determined.

The chemical and isotopic compositions of glass fragments found on the site of a former 18th – 19th glass plant in Kazan are studied. The finds are divided into three basic groups in terms of three types of glass from which they are fabricated: Ca–K, Ca–K–Na, and Ca–Na–K. The data on the chemical and isotopic composition show difference between the glasses in terms of recipe and raw material source. Comparison of the analytical and historical data suggested that each group of glasses corresponds to a definite time period of production. The composition of one group indicates the possibility that soda ash was added to the recipe.

The production of composites based on nanopowders synthesized by the sol-gel method in the system aluminum oxide and tetragonal zirconium dioxide stabilized by cerium cations (Al₂O₃–[Ce–TZP]) is described. It is shown that modification of the compositions by calcium oxide promotes the formation of composites of a dispersion-hardening phase in the form of long-prismatic grains in the sintering process. The presence of this phase affects the increase of strength and resistance to brittle fracture of composites with a ZrO₂ matrix and with an Al₂O₃ matrix. The strength in static bending of the composites reaches 1000 MPa and the cracking resistance K_1c increases to 11.0 MPa·m^1/2.

The degree of polymerization and the sizes of silicon-oxygen anions in liquid-glass solutions were studied as functions of the silicate modulus, silica density (concentration), and nature of the alkali cation by means of kinematic colorimetry. The degree of polymerization increased appreciably when the modulus increased above 2.6 and density above 1.3. In addition, the liquid glass modulus was the most important factor in the range of the studied characteristics. Above the critical values of the silicate modulus and concentration of the dissolved silicate the system transforms from the true solution of a polyelectrolyte, characterized by the presence of discrete polymer anions, into a coherent-disperse colloidal system with a high degree of volumetric polymerization.

Different methods are proposed for protecting the surfaces of silicon substrates in the fabrication of silicon transistors. The results of thermal operations with technological regimes for obtaining a low-melting glassy layer in order to protect the surface of p – n junction substrates from different external actions are presented.

The effect of the granulometric parameters of crystalline lead titanate on the CLTE of soldering glass compositions used for low-temperature vacuum-tight soldering of corundum parts was studied. The optimal values of the specific surfaces of the filler were determined.

Calcium phosphate powder was synthesized from calcium formiate Ca(CHO₂)₂ and ammonium hydrophosphate (NH₄)₂ HPO₄ with Ca/P ratio in the initial water solutions equal to 1. The phase composition of the powders synthesized from 0.5M solutions was represented by brushite CaHPO₄ · 2H₂O and octacalcium phosphate Ca₈(HPO₄)₂ (PO₄)₆ · 6H₂O. After firing at 1100°C the phase composition of the powder was represented by calcium pyrophosphate β-Ca₂P₂O₇ and tricalcium phosphate β-Ca₃ (PO₄)₂. The synthesized powder can be used to obtain biocompatible resorbable biphase ceramic materials and composites with a polymer matrix.

SHS-Metallurgy methods were used to obtain samples in the form of aluminum oxynitride Al₅O₆N ingots (AlON) using mixtures of the thermit type. The experiments were performed in SHS reactors at initial nitrogen pressure 5 MPa. The optimal conditions for the synthesis of the most stable phase of aluminum oxynitride Al₅O₆N were determined. Regimes were developed for comminuting the synthesized ingots into powder with definite fractions. Spark plasma sintering (SPS) was used to obtain from them experimental samples with high density, hardness, and transparency.

ThSe structure and properties of newly developed high-alumina articles based on aluminum silicate fiber are shown. The application of the new NK-29 articles in the lining of high-temperature heat assemblies used in the ceramic industry is examined.