scholarly journals The influence investigation of moisture and pressure on the compressibility of mass from zirconia stabilized by yttrium oxide and the properties of samples from it

2018 ◽  
Vol 118 ◽  
pp. 26-33
Author(s):  
V. V. Primachenko ◽  
I. G. Shulik ◽  
T. G. Galchenko ◽  
E. B. Protsak ◽  
L. V. Belik
Keyword(s):  
Yttrium Oxide ◽  
Apparent Density ◽  
Open Porosity ◽  
Optimum Moisture Content ◽  
Specific Pressure ◽  
Crushing Strength ◽  
Cold Crushing Strength ◽  
Dry Pressing ◽  
Operation Duration ◽  
The Given

The compressibility of mass with a particular composition — from fused zirconia, stabilized by ~ 10 % yttrium oxide, as well as the properties of samples from it depending on its moisture (2.5; 3.0; 3.5; 4.0; 4.5 %) and specific pressure (50, 75, 100 N/mm2) have been investigated. The optimum moisture content of the forming mass (3.5—4.0 %) and pressure (100 N/mm2) were established, providing fresh-formed samples with the maximum possible for the given mass apparent density of 4.78—4.79 g/cm3, dried — with an apparent density of 4.71—4.72 g/cm3 and with an apparent density, open porosity and cold crushing strength of the fired samples respectively 4.66—4.67 g/cm3, 21.0—21.4 %, 38.6—39.0 N/mm2. As a result of the carried out studies, the production technology of TsIS-1T brand products from fused zirconia, stabilized by ~ 10 % yttrium oxide, by the method of semi-dry pressing was improved. This technology ensures a reduction in open porosity of these products by ~ 2—3 % and an increase in their cold crushing strength by ~ 11.4 % (rel.) The use of these products in single crystal growing plants will provide their higher durability in service and the operation duration of these high temperature plants.

scholarly journals Special vibrocast mullite-siliceous refractories with the given properties for glass melting furnaces

2017 ◽  
Vol 117 ◽  
pp. 33-42
Author(s):  
V. V. Martynenko ◽  
V. V. Primachenko ◽  
I. G. Shulik ◽  
S. V. Chaplianko ◽  
L. P. Tkachenko
Keyword(s):  
Thermal Conductivity ◽  
Open Porosity ◽  
Mass Fraction ◽  
Glass Melting ◽  
Crushing Strength ◽  
Technological Factors ◽  
Cold Crushing Strength ◽  
Side Walls ◽  
Calcined Kaolin ◽  
The Given

Technologies have been developed for the production of special vibrocast large-sized mullite-siliceous and mullite-siliceous low-cement refractories with specified properties for the laying of side walls and the bottom of glass melting furnaces and other place of applications. The influence of the amount alumina and calcined kaolin fraction 3—0.5 mm on the properties of mass, raw and firing (at temperatures of 1350, 1400, 1450 оC) samples have been researched, and also the flow at vibration has been studied, stages of structure formation and technological factors, providing qualitative vibrocasting of products, have been determined. The developed mullite-siliceous and mullite-siliceous low-cement refractories in terms of properties fully meet the specified requirements: mass fraction of Al2O3 — 52.58 and 53.83 %, SiO2 — 46.11 and 45.19 %, CaO — 0.09 and 1.12 %, Fe2O3 — 1.10 and 1.06 %; apparent density — 2.21 g/cm3, open porosity — 20.2 and 20.3 %, cold crushing strength — 68 and 69 N/mm2, thermal conductivity (at 400—800 оC) — 1.237—1.637 W/(m ∙ K).

scholarly journals Influence research of an α–form alumina type on the properties of samples from vibrocasting mullite corundum granular masses

2020 ◽  
Vol 120 ◽  
pp. 39-51
Author(s):  
V. V. Martynenko ◽  
P. A. Kushchenko ◽  
I. G. Shulyk ◽  
K. I. Kushchenko ◽  
Yu. O. Krakhmal ◽  
...  
Keyword(s):  
Apparent Density ◽  
Open Porosity ◽  
Milling Time ◽  
Crushing Strength ◽  
Heat Resistant ◽  
Cold Crushing Strength ◽  
High Level ◽  
Kinetics Of ◽  
Grinding Time ◽  
Vibration Mill

The technology of refractories vibrocasting was developed by JSC "URIR named after A. S. Berezhnoy" in particular highly refractory mullite corundum crucibles for melting of heat-resistant alloys in induction furnaces. At manufacturing of highly refractory vibrocasting mullite corundum refractories a-form alumina, as a dispersion binder, which milling to a particles size of less than 10 μm (the content of particles less than 4 μm in such alumina is more than 50 %) is used. For improvement the casting characteristics of vibrocasting masses dispersants are used. At research milling kinetics alumina of all brands was milling in a vibration mill for a specified time. For this research a certain amount of the investigated alumina of each brand was loaded into a vibration mill, and after a specified grinding time (30, 45, 60, 75 and 90 min), a sample of alumina after milling was taken in a specified amount. In this work, the kinetics of changes the dispersion of alumina (S, N and NR brands) during their milling was studied. The dispersion of alumina which were needed (the content of particles less than < 10 μm in such alumina is not less than 90 %, the content of particles less than < 4 μm — not less than 50 %) was achieved in almost the same milling time was found (~ 45 min). With a further increase of milling time to 60, 75 and 90 minutes, the dispersion of alumina N and NR brands increases in comparison with alumina S brand and after 90 minutes of milling, the content of particles < 4 μm in alumina, respectively, is ~ 60, ~ 75 and ~ 80 %. After fired at a temperature of 1580 °C the properties of vibrocasting mullite corundum samples, which contain alumina S, N and NR brands, are characterized by a high level of apparent density (above 3 g/cm3), open porosity (less than 16 %) and cold crushing strength (above 140 N/mm2). The high properties make it possible to use a-form alumina N and NR brands along a-form alumina S brand in the technology of vibrocasting mullite corundum refractories, including the highly refractory mullite corundum crucibles.

scholarly journals Effect investigation of a new plasticizing additive on the refractories properties from fused zirconia stabilized with yttrium oxide for single crystal growing units

2020 ◽  
Vol 120 ◽  
pp. 29-38
Author(s):  
I. G. Shulik ◽  
T. G. Galchenko ◽  
E. B. Protsak ◽  
L. V. Belik
Keyword(s):  
Single Crystal ◽  
Yttrium Oxide ◽  
Thermal Shock Resistance ◽  
Outer Diameter ◽  
Crushing Strength ◽  
Manufactured Products ◽  
Cold Crushing Strength ◽  
Technical Specifications ◽  
Inner Diameter ◽  
Shock Resistance

The effect of a new plasticizing additive on the properties and structure of samples from fused ZrО2 stabilized by ~ 10 % Y2О3 was investigated. It was established that, the effectiveness of the new plasticizing additive based on polycarbonate is not inferior to the LST binder currently used in the manufacture of products from fused zirconia stabilized with yttrium oxide. The samples from fused ZrO2 stabilized by ~ 10% Y2O3, containing this new plasticizing additive, after firing at a temperature of 1580 ºС are characterized by high properties (open porosity — 21.6 %, apparent density — 4.65 g/cm3, cold crushing strength — 40 N/mm2, thermal shock resistance (1300 ºС — water) — 8 thermal cycles), which meet the requirements of technical specifications.The obtained research results were used at pilot batch out put of refractory products in the form of a cylinder with an outer diameter of 104 mm, an inner diameter of 83 mm, and a height of 30 mm from fused ZrO2 stabilized with ~ 10 % Y2O3. The manufactured products are characterized by high indicators of properties that meet the requirements of technical specifications, and are supplied to the consumer for use in single crystal growing units.

scholarly journals Research of kind and quantity of chromic oxide addition influence on alumina-chromia-zirconium silicate refractories properties

2017 ◽  
Vol 117 ◽  
pp. 24-32
Author(s):  
V. V. Martynenko ◽  
V. V. Primachenko ◽  
I. G. Shulyk ◽  
Yu. Ye. Mishnyova ◽  
K. I. Kushchenko ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Open Porosity ◽  
Thermal Shock Resistance ◽  
Chromic Oxide ◽  
Crushing Strength ◽  
Mass Part ◽  
Oxide Addition ◽  
Zirconium Silicate ◽  
Cold Crushing Strength ◽  
Shock Resistance

Research of pigment chromic oxide addition influence on properties of alumina-chromia-zirconium silicate refractories simples with a mass part 30 and 15 % Cr2O3 got by the semidry pressing method is carried out. It is set, that in samples made from batch with 30 % Cr2O3 optimal quantity of pigment chromic oxide, which provide achieving close properties indexes compared to indexes of samples without this component should be considered 10 %, and in samples made from batch with 15 % Cr2O3 — 6 %. The properties indexes of samples with 30 % Cr2O3 containing 10 % pigment chromic oxide are: mass part of Al2O3 — 62.7 %, Cr2O3 — 30.3 %, ZrO2 — 5.8 %, open porosity 22.6 %, apparent density 3.27 g/cm3, cold crushing strength 123 N/mm2, thermal shock resistance on the mode 950 оC — water 4 thermal cycles, residual changes of sizes at a temperature 1650 оC, exposition 2 hours 0 %. The properties indexes of samples with 15 % Cr2O3 containing 6 % pigment chromic oxide are: mass part of Al2O3 — 76.4 %, Cr2O3 — 15.2 %, ZrO2 — 6.1 %, open porosity 22.4 %, apparent density 3.17 g/cm3, cold crushing strength 145 N/mm2, thermal shock resistance on the mode 950 оC — water 4 thermal cycles, residual changes of sizes at a temperature 1650 оC, exposition 2 hours 0 %. Obtained results are used at making of products for glass melting furnace of industrial lining for fiberglass production from E glass.

Fabrication of Stainless Steel Foams Using Polymeric Sponge Impregnation Technology

2014 ◽  
Vol 1035 ◽  
pp. 219-224 ◽  
Author(s):  
Hui Wang ◽  
Xiang Yang Zhou ◽  
Bo Long
Keyword(s):  
Stainless Steel ◽  
Apparent Density ◽  
Open Porosity ◽  
316L Stainless Steel ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Foam Sample ◽  
Cell Network ◽  
Mass Fractions ◽  
Steel Foam

316L stainless steel foams (SSFs) are fabricated successfully by polymeric sponge impregnation technology. The effects of mass fractions of PVA and powder on LOAD in impregnated sponge samples are investigated, and the effects of sintering temperature on apparent density, open porosity and bending strength of SSFs samples are also discussed. The experimental results show that the impregnated sponge samples may hold excellent 3D open-cell network structure and uniform muscles when the mass fractions of PVA and powder in slurry are kept in 9-13 % and 52-75% respectively; with rising the sintering temperature, the apparent density and bending strength of SSFs gradually increases, the open porosity reduces. After the temperature exceeds 1260°C, the bending strength reduces oppositely. A stainless steel foam sample with open porosity of 81.4% and bending strength of about 56.8 Mpa can be obtained after sintering at 1260 °Cfor 30min.

Preparation of high-strength biochar composite briquette for blast furnace ironmaking

2021 ◽  
Vol 118 (1) ◽  
pp. 109
Author(s):  
Zi Yu ◽  
Zhu Liu ◽  
Huiqing Tang ◽  
Qingguo Xue
Keyword(s):  
Blast Furnace ◽  
Heating Temperature ◽  
High Strength ◽  
Utilization Efficiency ◽  
Structure Evolution ◽  
Crushing Strength ◽  
Preparation Conditions ◽  
Cold Crushing Strength ◽  
Average Size ◽  
Experimental Findings

In this research, using iron-oxide fines (average size: 2.5 μm) and biochar fines (average size: 50.0 μm), the biochar composite briquette (BCB) for blast furnace (BF) application was prepared by cold briquetting followed by heat treatment. The preparing conditions were optimized regarding its cold crushing strength. Anti-pulverization capability, reaction development, and structure evolution of the optimally-designed BCB under simulated BF conditions were then examined. Results of optimizing BCB preparation conditions showed that a heating temperature of 1073 K was optimal for preparing the BCB. The optimally-designed BCB contained 11.10 wt.% carbon, 72.21 wt.% Fe3O4, 11.25 wt.% FeO, and 0.77 wt.% Fe, 6.44 wt.% gangue, and had a cold crushing strength of 1800 N/briquette. Results of BCB behavior under simulated BF conditions showed that the cold crushing strength after partial reaction of the BCB ranged from 1500 N/briquette to 5500 N/briquette and its maximum volume shrinkage degree was 0.45. The high anti-pulverization capability of the BCB was supported by the slag matrix or the iron network. Under the simulated BF conditions, the BCB underwent five stages of reduction by atmosphere, partial self-reduction and reduction by atmosphere, full self-reduction, partial self-reduction and gasification by atmosphere, and gasification by atmosphere. It is inferred from the experimental findings that, by charging the BCB in BF, an increase of top gas utilization efficiency could be realized, and a favorable influence on lowering the temperature level of the thermal reserve zone could be obtained.

Performance Studies on In Situ Spinel Solid Solution Bonded Periclase Refractories

2014 ◽  
Vol 633 ◽  
pp. 245-248
Author(s):  
Xin Lin ◽  
Yong Li ◽  
Yan Jing Li ◽  
Jun Jie Zhang ◽  
Chang He Gao ◽  
...  
Keyword(s):  
Solid Solution ◽  
Phase Composition ◽  
Performance Studies ◽  
Magnesium Aluminate ◽  
Spinel Solid Solution ◽  
Magnesium Aluminate Spinel ◽  
Crushing Strength ◽  
Cold Crushing Strength ◽  
Shock Resistance

Specimens were prepared using iron-rich magnesia (3~1 mm、≤1 mm) and high purity magnesia (≤0.088 mm) as the main starting materials, adding tabular alumina at different size (3~2、2~1、≤1 mm) and content:3%、6%、9%、12%、15% to discover the influence of tabular alumina on sample performance. Phase composition and microstructure were also analyzed. The results show that specimen with content of 6% of corundum possessed the best comprehensive performance:apparent porosity 17%, bulk density 2.95 g·cm-3, cold crushing strength 74 MPa, refractoriness under load 1700 °C, heat shock resistance of up to 18 times. The formations of magnesium aluminate spinel and hercynite solid solution were enhanced by Fe ion at high temperatures in the iron-rich magnesia-corundum system at the presence of iron oxides, which are able to largely dissolved in periclase.

scholarly journals Influence of an addition amount of a new type of alumina on the properties of ramming mullite-corundum mixes and samples from them

2020 ◽  
Vol 120 ◽  
pp. 66-82
Author(s):  
V. V. Primachenko ◽  
I. G. Shulik ◽  
I. V. Khonchik ◽  
T. G. Tishina
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Chemical Properties ◽  
Size Composition ◽  
Synthesis Process ◽  
Crushing Strength ◽  
Cold Crushing Strength ◽  
Shock Resistance ◽  
Spherical Alumina ◽  
Addition Amount

Effect investigation of an addition amount of spherical alumina on the properties of ramming mullite-corundum mixes of the MMK-90 (on a binder of an aqueous solution of orthophosphoric acid) and MMKPBF (with a MgO addition on a borophosphate binder) brands, as well as samples from them, have been carried out. As a result of the carried out studies, it was found that the use of an optimal amount (4 %) of spherical alumina in the composition of ramming mullite-corundum mixes provides an increase in by 30 % in the cold crushing strength of samples made from them, fired at a temperature of 1580 °C, while maintaining at sufficiently high level indicators of their thermal shock resistance and slag resistance. The indicated alumina use in the composition of the MMK-90 mix during high-temperature firing of samples leads to an intensification of the mullite synthesis process. In fired samples from the MMKPBF mix, the spherical alumina forms a dense intergrowth of "felt-like" structure, which reinforces the structure, increasing the strength and thermal shock resistance of the samples. Indicators of physical and chemical properties of ramming mullite-corundum mixes of improved composition and samples made from them (for MMK-90 and MMKPBF mixes, respectively): chemical composition, wt. %: Al2O3 — not less than 90.0 and 85.0; SiO2 — within 3.2-5.0 and no more than 2.5; Fe2O3 — no more than 1.0 and 0.6; P2O5 — in the range of 2.5-3.5 and 0.5-1.0; grain size composition, mm — 3-0; cold crushing strength after firing at a temperature of 1580 °С — 110 and 70 N/mm2; thermal shock resistance — > 20 thermal cycles 950 °С — water. Ramming mullite-corundum mixes of improved composition are recommended for use in various heating units with high specific mechanical loads on the lining.

scholarly journals Researches on development of alumina-chromia-zirconium silicate refractories containing 60 % Cr2O3

2020 ◽  
Vol 120 ◽  
pp. 12-28
Author(s):  
P. O. Kushchenko ◽  
V. V. Primachenko ◽  
I. G. Shulyk ◽  
Yu. Ye. Mishnyova ◽  
K. I. Kushchenko ◽  
...  
Keyword(s):  
Corrosion Mechanism ◽  
Pressing Method ◽  
Refractory Structure ◽  
Oxide Addition ◽  
Zirconium Silicate ◽  
Cold Crushing Strength ◽  
Cr2o3 Content ◽  
Corrosive Effect ◽  
Dry Pressing ◽  
Shock Resistance

Researches of a branch composition and firing atmosphere influence on structure and properties of pressed alumina-chromia-zirconium silicate refractories with 60 % Cr2O3 content were carried out. The optimal branch composition which after firing in oxidizing atmosphere provides obtaining of samples with open porosity 24.8 %, apparent density 3.46 g/cm3, cold crushing strength 78 N/mm2 and thermal shock resistance by 950 ºС — water — 7 thermal cycles was established. The phase composition of samples was determined. It has been shown that, firing in a reducing atmosphere, as well as titanium oxide addition, have no significant effect on samples properties. Corrosion resistance comparative researches of alumina-chromia-zirconium silicate refractories with 60 % Cr2O3 content and refractory brand KHTSS-30 with 30 % Cr2O3 content to glass «E» and basalt melts by crucible method at a temperature of 1580 °C with an exposure time of 8 hours were carried out. It has been established that, glass «E» and basalt impregnate refractories, moreover for samples with the developed optimal composition the impregnation depth was the smallest in comparison with samples of other compositions. The corrosion mechanism has been established, which consists in the penetration of glass «E» and basalt melts into refractory with further dissolution of corundum grains in them. Sintered Cr2O3 and solid solutions based on it in the composition of samples prevent corrosion, reducing the interaction area of melts with corundum grains, and when exposed to basalt melt, also forming spinelid with its components, which slows down further penetration of melt into refractory structure, thereby reducing its corrosive effect on the refractory. Based on the obtained results, a technology of a new domestic type of product (alumina-chromia-zirconium silicate refractories with 60 % Cr2O3 content manufactured by semi-dry pressing method) was developed.

scholarly journals Effect study of an amount of active alumina addition on the properties of alumina refractories with a complex additive of chromium oxide and zirconium dioxide

2020 ◽  
Vol 120 ◽  
pp. 3-11
Author(s):  
I. G. Shulik ◽  
T. G. Galchenko ◽  
E. B. Protsak ◽  
L. V. Belik
Keyword(s):  
Chromium Oxide ◽  
Zirconium Dioxide ◽  
Effect Study ◽  
Pressing Method ◽  
Complex Additive ◽  
Active Alumina ◽  
Cold Crushing Strength ◽  
Dry Pressing ◽  
Alumina Addition ◽  
Carbon Black Production

An effect of active alumina amount introduced into a batch (7.5 - 22.0 %) on the properties of alumina samples containing a complex additive of chromium oxide (10 %) and zirconium dioxide (3 %) was studied. The optimal amount of introduced active alumina (12.5 %) was established, which ensures the production of samples fired at a temperature of 1580 ºС, with the lowest open porosity (18.2 %), the highest apparent density (3.25 g/cm3) and the highest cold crushing strength (117 N/mm2), refractoriness under a load of 0.2 N/mm2 > 1700 ºС, thermal shock resistance (in the mode of 1300 ºС — water) not less than 7 thermal cycles.The results of carried out studies were used in the development of production technology of domestic refractory products based on fused corundum, α-form alumina, active alumina, containing the complex addition of chromium oxide and zirconium dioxide, by semi-dry pressing method. These refractory products characterized by high properties and intended for service at a temperature of 1850 ºС in the combustion chamber of carbon black production reactors.The use of these refractories in the lining of above mentioned high-temperature industrial units will allow to increase a duration of their operation due to an increase in the refractory durability in service, as well as to save material and energy resources associated with a relining of the reactors.

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