scholarly journals Crack-free caustic magnesia-bonded refractory castables

2021 ◽  
Author(s):  
V.C. Miguel ◽  
D.S. Fini ◽  
V.S. Pinto ◽  
M.H. Moreira ◽  
V.C. Pandolfelli ◽  
...  
Keyword(s):  
Refractory Castables ◽  
Caustic Magnesia

scholarly journals Refractory castables based on SiC slab waste

2010 ◽  
Vol 118 (1374) ◽  
pp. 122-127 ◽  
Author(s):  
Emad Mohamed M. EWAIS ◽  
Nagy M. KHALIL
Keyword(s):  
Refractory Castables

Production of Fine-Ground NK-Alumina 11 and NK-Alumina 14 for Low-Cement Refractory Castables

2021 ◽  
Author(s):  
V. I. Kuzin ◽  
R. V. Zubashchenko ◽  
D. A. Timoshenko ◽  
M. A. Trubitsyn
Keyword(s):  
Refractory Castables

Mechanical and Thermal Properties of Magnesia Binder Based on Natural and Technogenic Raw Materials

2021 ◽  
Vol 320 ◽  
pp. 181-185
Author(s):  
Elvija Namsone ◽  
Genadijs Sahmenko ◽  
Irina Shvetsova ◽  
Aleksandrs Korjakins
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Raw Materials ◽  
High Strength ◽  
Strength Properties ◽  
Waste Materials ◽  
Mechanical And Thermal Properties ◽  
Experimental Part ◽  
Technogenic Raw Materials ◽  
Caustic Magnesia

Because of low calcination temperature, magnesia binders are attributed as low-CO2 emission materials that can benefit the environment by reducing the energy consumption of building sector. Portland cement in different areas of construction can be replaced by magnesia binder which do not require autoclave treatment for hardening, it has low thermal conductivity and high strength properties. Magnesium-based materials are characterized by decorativeness and ecological compatibility.The experimental part of this research is based on the preparation of magnesia binders by adding raw materials and calcinated products and caustic magnesia. The aim of this study was to obtain low-CO2 emission and eco-friendly material using local dolomite waste materials, comparing physical, mechanical, thermal properties of magnesium binders.

Influence of Silicon Nitride on Properties of Corundum Based Castable

2013 ◽  
Vol 634-638 ◽  
pp. 2358-2361
Author(s):  
Jun Cong Wei ◽  
Li Rong Yang
Keyword(s):  
Electron Microscopy ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Cold Strength ◽  
X Ray ◽  
Refractory Castables ◽  
Shock Resistance ◽  
Scanning Electron

The effects of Si3N4 addition on the room temperature physical properties and thermal shock resistance properties of corundum based refractory castables were investigated using brown corundum, white corundum and alumina micropowder as the starting materials and pure calcium aluminate as a binder. The phase composition, microstructure, mechanical properties of corundum based castables were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that as the increase in Si3N4 addition, the bulk density decreased and apparent porosity increased, the cold strength deduced. However, the residual strength rate increased. That is, the thermal shock resistance was improved. This is because even though the introduction of Si3N4 inhibited the sintering of material and deduced the compactness, microcracks were produced in the materials due to a difference in thermal expansion coefficient. So the thermal shock resistance of corundum based castable was improved.

scholarly journals PEAT-CONTAINING COMPOSITION CONTAINING MAGNESIA BINDER

2018 ◽  
Vol 61 (8) ◽  
pp. 81
Author(s):  
Natalia A. Mitina ◽  
Vasiliy A. Lotov ◽  
Margarita A. Kovaleva ◽  
Natali O. Kopanitsa
Keyword(s):  
Water Resistance ◽  
Vertical Direction ◽  
Water Soluble ◽  
Fluid Mixing ◽  
Thin Plates ◽  
Hydration Reaction ◽  
Strength Parameters ◽  
Hydrogen Carbonates ◽  
Hardening Coefficient ◽  
Caustic Magnesia

Based on the new hydraulic magnesia binder, the compositions of the peat-containing composite material have been proposed and investigated. Hydraulic magnesia binder is an astringent composition of hydration-reaction hardening, which consists of an active caustic magnesia powder and a mixing fluid. As the fluid mixing an aqueous solution of magnesium bicarbonate Mg(HCO3)2 with a concentration of 13 g/l was used. Hardening forms water-insoluble products - magnesium hydroxide Mg(OH)2 and magnesium bicarbonates of general formula MgCO3·zMg(OH)2·nH2O, which makes it possible to harden and used products based on such a binder as in the air, and in water. The use of peat as a filler of the developed compositions will make it possible to obtain lightweight waterproof materials and products of heat-insulating purpose. It has been shown that the peat-and-magnesian compositions of all compositions have a hydration hardening coefficient of more than 1.0, which indicates intensification of the hydration and hardening processes in water conditions in comparison with air and large strength parameters. Using XRD the phase composition of peat products and peat- magnesium hardening compositions was established. Thermal analysis showed the presence of magnesium hydrogencarbonates in samples of compositions that are in the form of slightly crystallized neoplasms. Investigations by electron microscopy confirmed the presence of hydrocarbons such as magnesium particles dipingite Mg5(CO3)4(OH)2·5H2O and hydromagnesite Mg5(CO3)4(OH)2·4H2O in the form of thin plates with the vertical direction of crystallization. Increased water resistance of compositions based on hydraulic magnesia binder with non-water-resistant filler peat is due to mineralization of peat particles due to their impregnation with a solution of magnesium bicarbonate and the formation of water-soluble magnesium hydrogen carbonates in the loose porous structure of peat.

scholarly journals Binder effect on ZnAl2O4-containing high-alumina refractory castables

2022 ◽  
Author(s):  
V.S. Pinto ◽  
A.P. Luz ◽  
O.H. Borges ◽  
V.C. Pandolfelli
Keyword(s):  
High Alumina ◽  
Refractory Castables ◽  
Alumina Refractory

scholarly journals Sizing of Refractory Castable Gas-Burner Using Thermomechanical Simulations

2010 ◽  
Vol 70 ◽  
pp. 173-178
Author(s):  
Fabien Nazaret ◽  
Thierry Cutard ◽  
Olivier Barrau
Keyword(s):  
Damage Model ◽  
Peak Stress ◽  
Internal Length ◽  
Damage Level ◽  
Refractory Castables ◽  
Before And After ◽  
Tension And Compression ◽  
Material Choice ◽  
Gas Burner ◽  
Refractory Structures

Damage is a crucial characteristic of refractory castables and has to be considered to simulate correctly the behaviour of refractory structures. But, damage modelling by finite element simulations remains difficult. Indeed, the use of a continuum damage model with softening leads to strain localization phenomena. Numerical results depend on the mesh. Several numerical methods allow solving this meshing dependence by introducing an internal length in the material constitutive laws. In this paper, a regularization method has been applied with the damage plasticity model, considering a scalar value for damage. This model enables to take into account permanent strains due to plasticity and damage before and after the peak stress in tension and compression. Thermomechanical simulations are performed with this model to predict damage in a gas-burner. The damage level is evaluated after a thermal simulation generating high temperature gradients. Interests to take into account damage in the refractory structures are discussed. Sensitivity of results to material properties is studied. This work gives an example of using thermomechanical simulations to improve the design of refractory castable structures and to help in the material choice.

Statistical Modelling of the Particle Size Composition of an Alumina Matrix for No-Cement Self-Flowing Refractory Castables

2006 ◽  
Vol 514-516 ◽  
pp. 604-608 ◽  
Author(s):  
Abílio P. Silva ◽  
Ana M. Segadães ◽  
Tessaleno C. Devezas
Keyword(s):  
Particle Size ◽  
Water Content ◽  
Raw Materials ◽  
Size Composition ◽  
Statistical Modelling ◽  
Matrix Composition ◽  
Mechanical Resistance ◽  
Particle Size Composition ◽  
Refractory Castables ◽  
System Properties

In the processing of any particulate system (including refractory castables), the finer sized particle fraction (matrix or filler) is mostly responsible for the final system properties. Alumina fine powders were used in this work as raw materials, namely two tabular alumina fractions (–500 mesh and –230 mesh) and a commercial reactive alumina. Statistical modelling and the Response Surface Methodology (Statistica, Mixtures Designs and Triangular Surfaces module) were used to optimise the particle size composition of the three-component mixtures leading to matrix maximum flowability. The mixing methodology, aimed at minimising the water content, was kept constant. No-cement alumina castables produced with the various fine size powder mixtures, were used to prepare test-pieces. After drying and sintering, their mechanical resistance (MoR), density, porosity, water absorption, thermal shock behaviour and microstructure were evaluated. The results obtained evidenced the relevance of variables such as the water content per unit specific surface area, needed to reach the self-flow “turning point”, and validated the statistical optimisation method used. Moreover those results showed the existence of a matrix composition range, which favours the formation of a flow-bed that enables the aggregate self-flow.

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