Effect Of Magnesia On Strength Of Hydratable Aluminaalumina Magnesia Refractory Castable

Rheology of refractory concrete An article review

Castables are composed of refractory aggregates with different sizes from 300 μm to 20 mm for strength and hot properties beside matrix components bonding agents modifiers and admixtures as shown in Table 2 The most abundant aggregates are fused or sintered alumina because they have low thermal expansion coefficient and high strength

6 KO Y C CHAN C F Effect of spinel content on hot strength of alumina spinel castables in the temperature range 1 000 J 1 Eur Ceram Soc 1999 19 2633–2639

Hydratable Alumina Bonded Suspensions Evolution of

Hydratable alumina HA is a calcium free and high refractoriness binder for alumina based suspensions Although recent studies have improved its dispersion mixing and drying behaviours a drawback related to its loss of strength between 250 and 900°C remains unexplored Pores generated after decomposition of HA curing products are usually an explanation for the effect however no

An experimental investigation of hydration mechanism of

Magnesia MgO is widely used in the production of refractory materials due to its ultra high melting point and ability to form the binding system based on M–S–H M≡MgO S≡SiO 2 H≡H 2 O phase under moist conditions and in the presence of for example silica fume 1 2 3 4 Magnesium oxide with high chemical activity can be obtained by optimizing the technological parameters

MECHANISMS OF WEAR OF REFRACTORY MATERIALS IN SNORKELS OF

the effect of hydratable alumina on the properties of the sic high alumina and mgo based self flowing castables new approachs to waste magnesia chrome bricks recycling for refractory castable production used at iranian sarcheshmeh copper complex alumina magnesia castables the effect of curing conditions and matrix composition on the

Refractory castablesIspatGuru

Refractory castables Refractory castables comprise a large and diverse group of materials in the family of monolithic shapeless refractories Their use has grown significantly in the past 30 years Progressing from simple mixes refractory castables today comprise some very complex and technical formulations finding use in a variety of very

MOISTURE PICK UP AND STRENGTH OF HYDRAULIC

However the overall strength level of this castable after drying at 450°C is considerably lower when compared to those dried at 200 or 350°C 12 vs 16 and 21MPa Therefore drying at 450°C seems in general not to be recommended for Alphabond bonded pre cast shapes Only the VIB AB F does not show the strength loss after 450°C drying

Selection of binders for in situ spinel refractory

This effect can counterbalance the in situ spinel expansion affecting the volumetric stability of alumina–magnesia refractory castables Considering these aspects the objective of this paper is to analyze the effect of partial or total replacement of calcium aluminate cement with hydratable alumina on the expansion behavior of alumina–magnesia

Hydration of refractory oxides in castable bond systems I

Such a large and delayed heat evolution might explain serious problems sometimes observed when mixed Al 2 O 3 –MgO bond systems are used in castable refractories Abstract Isothermal conduction calorimetry ICC of hydratable alumina and reactive magnesia revealed that alumina was partially hydrated to bayerite while magnesia was fully hydrated to brucite after curing for 22 h at 20 and 30 °C

The role of hydraulic binders on magnesia containing

Magnesia containing refractory castablesMagnesia containing castables present high refractoriness and alkaline slag and thermal shock resistances due to their high melting point 2800 °C and ability to generate in situ spinel MgAl 2 O 4 when combined with Al 2 O 3

CASTABLE REFRACTORY COMPOSITIONCALDERYS FRANCE

A castable refractory composition may include from 5 to 95 by weight of alumina aluminosilicate or mixtures thereof from 0 5 to 1 5 by weight alkaline earth metal oxide and/or hydroxide and 0 1 to 5 by weight of silica having a surface area of at least about 10 m 2 /g The refractory composition may include no more than 0 5 by weight of cementitious binder

Al2O3 MgO refractory castables with enhanced explosion

The effect of these phases i e derived from MgO and hydratable alumina interaction when contained in the matrix of magnesia or alumina based castables has been reported elsewhere These studies pointed out that the compositions with in situ hydrotalcite generation presented higher mechanical strength after curing and drying steps than hydratable alumina free refractory systems

Binders for Refractory Castables An Overview SpringerLink

Among the other sol bonding systems mainly alumina mullite magnesia and spinel sols are tested for refractory castables But there is not enough literature available on such studies The major hindrances for such applications are various processing difficulties such as a lower solid content of sol leading to poor bonding activity weak stability of sol a high water demand for processing etc 31 32

Effect of particle size distribution and calcium

Abstract Previous works based on statistical design of experiments DoE defined a model all alumina self flow refractory castable SFRC with optimized particle size distribution for simultaneous high flowability index FI and superior post sintering performance This work compares the SFRC rheological behaviour and setting time with those of alternative all alumina castables with different

Characterization of tensile failure behaviour of magnesia refractory materials by a modified dog bone shape direct tensile method and splitting tests Ceramics International

Calorimetry and other methods in the studies of reactive

Ye G Troczynski T Effect of magnesia on strength of hydratable alumina bonded castable refractories J Mater Sci 200540 3921–6 CAS Article Google Scholar 15 Szczerba J Prorok R Śnieżek E Madej D Maślona K Influence of time and temperature on ageing and phases synthesis in the MgO–SiO 2 –H 2 O system Thermochim Acta 57–64

US Patent for Cement free refractory castable system for

A method of applying a cement free refractory castable to the surface of a refractory structure comprising the steps of a preparing an intimately mixed refractory castable having alumina aggregate and a cement free binder comprised of hydratable aluminab conveying the refractory castable under pressure through a delivery hose to a dispensing nozzle for applying the refractory castable

PDF Monoaluminum phosphate bonded refractory

Phosphate bonded refractories may be applied as repairing materials due to their short setting time and good thermo mechanical properties in the °C temperature range This works addresses the development of vibratable high alumina castables

Binders for Refractory Castables An Overview SpringerLink

Abstract A binder for refractory castables is a bonding material that bonds a loose powdery mix retains its shape after casting and allows the cast shape to set and harden for handling and further processing A binder also improves sintering as the castables are not compacted during shaping causing poor densification and strength Initially plastic clay was used as a binder for castables

Cement free refractory castable system for wet process

A method of applying a cement free refractory castable to the surface of a refractory structure comprising the steps of a preparing an intimately mixed refractory castable having alumina aggre Cement free refractory castable system for wet process pumping/sprayingNorth American Refractories Co

Papersrefractories worldforum

Keywords magnesia chromite bricks alumina spinel castable corrosion ladle slag RH degasser ladle thermochemical calculations FactSage Abstract References Full Article Corrosion of Al2SiO5–SiC and Al2SiO5–ZrSiO4 Refractories in the Corroding

Nanotechnology in castable refractoryScienceDirect

Nano scaled binding agents used in castable refractory system include HA CA CS micro silica etc HA based castables require higher water contents and longer mixing time when compared to CAC based castables The mechanical strength of colloidal binder containing castables CA and CS increases as the sintering temperature increases

The Influence of TiO 2 Addition on the Modulus of Rupture

Considering the raw materials effect on the overall expansion behavior of this sort of refractory as reported in the literature the addition of hydratable alumina colloidal alumina suspension or nanomagnesia can be alternatives to lower the spinel formation starting temperature and reduce the final dimensional variation Ref 3 4 An effective option to master the expansion behavior of alumina magnesia castables

Monolithic Refractory Research PapersAcademia edu

Influence of phosphate binders on the physical and mechanical properties of magnesia carbon monolithics composed of recycled refractory aggregates In this study the effect of using phosphate bonding materials such as sodium hexametaphosphate SHMP and sodium tripolyphosphate was investigated in the presence of water and recycled magnesia

The Third International Symposium on Refractories

Factors Affecting Performance of T Type Tundish Castable Refractory in China Steel 86 Yu Chen Lee Taiwan China Study on MgO CaO Coating Material Used for Tundish 91 Zhu Dezhi He Zhiyong and Zhang Xiaojun China Development and Application of Magnesia Based Dam Block 95 Rong Wei and Yin Jianshu China

Evolution of in Situ Refractories in the 20th Century

S Mukhopadhyay and P K Das Poddar Effect of preformed and in situ spinels on microstructure and properties of a low cement refractory castable Ceramics International 30 3 369 2004 Crossref

Al2O3 MgO refractory castables with enhanced explosion

The effect of these phases i e derived from MgO and hydratable alumina interaction when contained in the matrix of magnesia or alumina based castables has been reported elsewhere These studies pointed out that the compositions with in situ hydrotalcite generation presented higher mechanical strength after curing and drying steps than

Reasons for crack propagation and strength loss in

alumina reactive alumina hydratable alumina calcium aluminate cement silica fume and colloidal suspen sions etc Therefore when cement is used in a refractory castable s matrix the amount of cement as well as the content of Al 2O 3 in the cement will strongly affect the castable

Calorimetry and other methods in the studies of reactive

Ye G Troczynski T Effect of magnesia on strength of hydratable alumina bonded castable refractories J Mater Sci 200540 3921–6 CAS Article Google Scholar 15 Szczerba J Prorok R Śnieżek E Madej D Maślona K Influence of time and temperature on ageing and phases synthesis in the MgO–SiO 2 –H 2 O system Thermochim Acta 2013

Ceramics and refractories elastic moduli measurement

Ceramics and refractories elastic moduli characterization The brittleness of ceramic materials and the presence of aggregates are not obstacles for the elastic modulus measurement by Sonelastic Systems It does not apply static loads to perform the characterization of the elastic moduli only small amplitude impulse excitation and vibration

Nanotechnology in castable refractoryScienceDirect

Silicon carbide SiC is popular among researcher as a refractory material because SiC can be stable above 2700 °C and it has high strength 800–1000 MPa and fracture toughness 6–10 MPa m 1/2 can also be used in aggressive environments due to the formation of a protective coating of SiO 2 on its surface at high temperature SiC refractories are available as both non oxide and

Mullite based refractory castable engineering for the

Moreover the combination of CAC and hydratable alumina gave rise to an improved refractory M–2CAC–2HA–S showing a transient liquid formation at an increased temperature high thermal shock resistance no E decay after 8 thermal cycles ΔT=800°C and high mechanical strength at

Reasons for crack propagation and strength loss in

alumina reactive alumina hydratable alumina calcium aluminate cement silica fume and colloidal suspen sions etc Therefore when cement is used in a refractory castable s matrix the amount of cement as well as the content of Al 2O 3 in the cement will strongly affect the castable

Improving MgO containing castable refractories without

The only sample that had strength comparable to the MgO free control sample had a 3 mass percent addition of Mg OH 2 precursor that had been calcined at 600ºC and dried at 1000ºC which showed that within a narrow range magnesia can be part of a castable binder formulation