Binders also help to sinter the castables by providing nascent fine particles, so that the compaction process does not result in castables with poor densification and strength. Alumina cement and hydratable alumina binders work on the principle of hydration, but the decomposition of hydrated phases during firing has a deleterious effect …
BSA Frankfurt/Main96 is a refractory aggregate with an Al 2 O 3 content greater than 96 %. The ma-jor impurities are SiO 2, TiO 2 and smaller amounts of Na 2 O and MgO …
Analysis of the effect of three sintering parameters (sintering temperature, heating rate and holding time) on the density of alumina ceramics was performed using the response surface...
Ferrotitanium slag was used as a sintering aid to prepare high-performance alumina (Al2O3) ceramics by pressureless sintering at different temperatures. The bulk density, apparent porosity, bending strength, and hardness of the 99 wt% Al2O3 ceramics after sintering at 1420 °C were 3.91 g/cm3, 0.16%, 389.37 (± 7.61) MPa, and 15.64 (± …
Finally, thanks to a fully-automatized system this apparatus was used to sinter large size (~30 cm 3) low-loss dielectric alumina samples. The sintered materials were subsequently characterized in terms of density, grain size distribution, and homogeneity. The reproducibility was also discussed, demonstrating the process …
The present study investigated pressed high-purity alumina refractories containing either white fused or tabular (sintered) alumina aggregates under comparable conditions. Using factorial experiments especially the effects of the pressing pressure, …
Alumina refractories contain a minimum of 60 wt% Al 2 O 3, ... grains size repartition and shape as well as to the individual transformation and interactions of components during the sintering process . In general, initial compositions are selected to attain the desired performance of final products. In the case of refractory materials ...
In this work, our aim is to develop a fully-controlled microwave heating process to sinter low-loss dielectric refractory materials. For this purpose, a 915 MHz single-mode rectangular cavity was chosen, as it provides a high volume chamber and, compared to the common and widely spread 2.45 GHz frequency, the 915 MHz one …
Experimental process As proposed by Cias [12], at temperatures above 920 1C, sublimated Mn can react with water vapour in the sintering To study corrosion in refractory materials, Cremer Thermo- atmosphere, producing H2, according to the reaction described prozessanlagen provided porous alumina bricks that are by Eq.
2.2 Heating Rate Effects. The importance of heating rate effects is known since the 1980s [17, 18] and relies on the existence of different mass transport mechanisms at different temperatures. The most relevant transport mechanisms for sintering are surface, grain boundary, and volume diffusion (Figure 3).Typically, the activation energy …
Red mud, which could cause numerous problems to the environment, is a hazardous waste generated from the alumina smelting industry. In general, the storage and harmless utilization of red mud are hard to implement due to its fine particle size and high alkalinity. This study put forward a novel process to separate iron (MgFe2O4) and …
Micronized refractory MgAl2O4-spinel as chromium-free bricks was prepared by powder-mixing defined amounts of aluminium and magnesium-hydroxides in two firing stages (900-1400 °C and 1600 °C).
In addition of graphite fine powder to the alumina-chrome refractory i.e 0.5 wt% and 1.0 wt% shows similar trend of % firing shrinkage but in case of 1.5 wt% carbon addition to the alumina-chrome refractory shows some abnormal trend of firing shrinkage i.e it shows more firing shrinkage with increasing temperature and at 1550⁰ C come to 1.0 ...
SiC and MoSi 2 are used as sintering additives to minimize ZrO 2 formation during sintering and fabricate a pore free ZrB 2-based composite 15,16.Although the mean density of the best DRS specimen ...
calcined (fired) alumina for ceramics and refractory materials production, which represents a final product of thermal decomposition of aluminum hydroxides. The baking process is conducted in drum and tunnel furnaces in a fluidized layer. The process yields a brittle polycrystalline α-Al 2 O 3.
These tests also suggest that sillimanite or other high-alumina refractories could also be made from beneficiated Kansas clay enriched with alumina produced by the lime-sinter process. Pure sillimanite contains 62.85 percent alumina and 37.15 percent silica and melts at 3280° F.
The cold sintering process is successfully applied to one of the most refractory solid-state sodium-ion electrolytes, namely sodium beta alumina (SBA). By using a hydroxide …
Fig. 2. Hot modulus of rupture of high-alumina castables bonded with colloidal silica (CS) or calcium aluminate cement (CAC) and containing 0 or 1 wt% of a boron source as sintering additive (SA). All samples were pre-fired at 800 °C, 1000 °C, 1200 °C or 1400 °C for 5 h before testing [2].
The sintered high alumina aggregate BSA 96 has a similar bulk density to tabular alumina. Water absorption and open po-rosity are also in the same range (Tab. 1). The bulk density of BSA 96 is lower when compared to brown fused alumina. This is a typical feature of sintered aggregates. The ceramic sinter process permits a well-
DOI: 10.1016/J.CERAMINT.2018.03.066 Corpus ID: 139623281; Sintering effect of calcium carbonate in high-alumina refractory castables @article{Luz2018SinteringEO, title={Sintering effect of calcium carbonate in high-alumina refractory castables}, author={Ana P. Luz and L. B. Consoni and C. Pagliosa and Christos Georgios Aneziris …
Refractories containing fused and sintered alumina aggregates: Investigations on processing, particle size distribution and particle morphology. Authors: …
The sintering of alumina (Al 2 O 3) traditionally occurs at high temperatures (up to ca. 1700 °C) and in significantly long times (up to several hours), which are …
Alumina is one of the most versatile of refractory ceramic oxides and finds it's use in a wide range of applications. Among the oxide ceramics, Alumina, Al2O3, is the most …
Unshaped refractory materials in the process of gradually sintering. From a process point of view, sinter is a sturdy, low porosity (almost airless 7L) stone made from a powder at high temperatures. Refractories degree of flexibility of the signs, usually with the object size reduction (the so-called shrinkage), reduced porosity and bulk ...
The cold sintering process is successfully applied to one of the most refractory solid-state sodium-ion electrolytes, namely sodium beta alumina (SBA). By using a hydroxide-based transient solvent ...
The sintering property of fused magnesia refractory was investigated by the fused magnesia powder as matrix and the synthetic magnesia-alumina spinel precursor sol as binder. The spinel precursor sol was prepared by co-precipitation method and was characterized by its particle size, thermal analysis, microstructure, phase development …
This paper provides a historical perspective on the elaboration and the use of silica-alumina refractory, reviews applications for refractory oxides, describes typical …
The refractory quality of high-alumina is usually higher than that of fireclay bearing refractories (better creep resistance and corrosion resistance). Alumina refractories contain a minimum of 60 wt% Al 2 O 3, although the Al 2 O 3 content can be >99% for specialty products. This type of refractories can be produced from fire clays …
The rate of shrinkage is a direct measure of the sintering process in each ceramic compact. The titania doped alumina-excess spinel composition achieves highest shrinkage rate of 8.6×10 −4 °C −1 at 1500 °C. Whereas the undoped composition MA90 could reaches only 0.41×10 −4 °C −1 at highest temperature. Similar rate was achieved …
In this work, alumina (Al2O3) ceramics were prepared using an environmentally friendly slip casting method. To this end, highly concentrated (70 wt.%) aqueous suspensions of alumina (Al2O3) were …
1. Introduction. Magnesium oxide is the main component of fused magnesia refractories, which are widely applied in steel making industry due to good corrosion resistance and high refractoriness under load [1], [2].However, the use of MgO refractory for many applications are restricted due to its poor sintering performance [3].Many …
Along these lines, magnesia and alumina were used as raw materials to prepare spinel by the solid-phase sintering method at 1500–1600 °C. Particularly, the impacts of the different MgO/Al 2 O 3 molar ratios on the microstructural densification, sintering process and mechanical property of the fabricated materials were …
for such refractory when 0.5 wt% CAC was not added to this. composition and also compares it with an alumina-based casta-. ble bonded with 4 wt% of hydratable alumina. SZ castab le (with-. out CAC ...
The content of Al 2 O 3 in the slag for high-Al containing steelmaking is rather high, and C/S ratio of the slag has a significant impact on the corrosion behavior of alumina-based refractory ceramics [59].Hence, the CaO–Al 2 O 3 –SiO 2 slags with different C/S ratios were chosen. Lime powder (analytical reagent; 98 wt% CaO), …
Iron ore fines are the main source for sinter, and the chemical composition of the iron. Iron ore sinter constitutes a major proportion of blast furnace burden. Hence, its quality and consistency have a significant impact on blast furnace performance. Iron ore fines are the main source for sinter, and the chemical composition of the iron
