Influence of Glass Dust on Properties of Alumina-carbon Refractories

In order to improve the properties of alumina-carbon refractories,specimens were prepared using white fused corundum,zirconia-mullite and flake graphite as the raw materials,phenolic resin as the binder,adding different mass fractions(1.5%,2.0%,and 2.5%,respectively)of glass dust,cold isostatic pressing by 120 MPa,drying and firing at 900℃for 3 h.Effects of the glass dust addition on the apparent porosity,bulk density,cold modulus of rupture,hot modulus of rupture and thermal shock resistance were studied.The results show that the cold modulus of rupture of the specimens is improved significantly as the results of glass dust accelerating sintering.However,the hot modulus of rupture decreases.As the glass phase buffers the strain produced by thermal shock,the thermal shock resistance of alumina-carbon specimens is improved,especially for low carbon alumina-carbon materials.

Corrosion behavior of co-gasification slag of furfural residue and coal on alumina-silica refractories

Gasification of furfural residue with coal can realize its efficient and clean utilization.But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory.Two gasification coals with different silica alumina ratio and a furfural residue were selected in the study.The effects of furfural residue additions on corrosion of silica brick,corundum brick,high alumina brick and mullite brick were investigated by using XRD,SEM-EDS and Factsage Software,and the corrosion mechanism was analyzed.With increasing furfural residue addition,the permeability of the slags to high-aluminium-bearing refractories first decreases and then increases,while the permeability on silica brick shows a slight decrease trend.Leucite(KAlSi_(2)O_(6))with high-melting temperature is generated from the reaction of K_(2)O and SiO_(2)in slag with Al_(2)O_(3)in refractories after furfural residue is added,which hinders the infiltration of slag in refractories.Kaliophilite(KAlSiO_(4))of low-melting point is formed when K_(2)O content increases,and this contributes to the infiltration of slag in refractories.The acid-base reaction between slag and silica brick is distinctly occurred,more slag reacts with SiO_(2)in the silicon brick,resulting in a decrease in the amount of slag infiltrating into the silicon brick as furfural residue is added.The corrosion of silica brick is mainly caused by the acid-base reaction,while the corrosion of three alumina based refractory bricks of corundum,mullite and high alumina brick is determined by slag infiltration.A linear correlation between the percolation rate and slag viscosity is established,the slag permeability increases with decreasing viscosity,resulting in stronger permeability for the high Si/Al ratio slag with lower viscosity.

Investigation of Microstructure and Phase Composition of Chromic Oxide, AZS/Cr and High-alumina Refractories after Exposure of Basalt and Aluminaboronsilicate Glasses Melts

The microstructure and phase composition of high-alumina,chromic oxide,and AZS/Cr refractories containing 30%and 60%(by mass)Cr_(2)O_(3) after exposure to aluminaboronsilicate glasses and basalt melts depending on the type of melts and temperature have been studied.The mechanisms of refractory corrosion by the used melts and the factors contributing to the inhibition of corrosion development have been investigated by the method of petrographic analysis.On the basis of obtained results,the use of high-alumina,chromic oxide,and AZS/Cr refractories in the sections of glass furnace linings,experiencing the intensive impact of aluminaboronsilicate glasses and basalt melts,has been confirmed and scientifically substantiated.

The 9^(th) International Symposium on Refractories

Organizedby The Chinese Society for Metals The Chinese Ceramic Society Sinosteel Luoyang Institute of Refractories Research Co.,Ltd.Sponsored by Refractories Committee of The Chinese Society for Metals Sinosteel Luonai Materials Technology Corporation Co-Sponsoredby State Key Laboratory of Advanced Refractories The State Key Laboratory of Refractories and Metallurgy Refractories Press Indian Refractory Makers Association The Federation for International Refractory Research and Education.

Microwave-assisted Synthesis of Al_(4)SiC_(4) and Its Effect on Properties of MgO-C Refractories

Al_(4)SiC_(4) was synthesized from Al powder, silicon carbide, and graphite by microwave sintering, and characterized by XRD and SEM. Then the synthesized material was added to the magnesia carbon refractory brick to study its effect on the oxidation resistance, apparent porosity, bulk density, elastic modulus, and modulus of rupture. It is found that Al_(4)SiC_(4) can be synthesized by microwave sintering at 1 300 ℃ and the addition of Al_(4)SiC_(4)-containing material as an antioxidant can enhance the oxidation resistance of the magnesia carbon refractory brick.

Effect of ZrC Modified Graphite on Structure and Properties of Low-carbon Al_(2)O_(3)-C Refractories

To address the issues of reduced performance and shortened lifespan during the low-carbonizating process of Al_(2)O_(3)-C refractories,nano-crystalline ZrC modified graphite was prepared using Zr powder and flake graphite as raw materials,with NaCl and NaF mixed salt serving as the medium.The flake graphite was gradually replaced by ZrC modified graphite in the preparation of Al_(2)O_(3)-C refractories,and its impact on the material’s structure and properties was investigated.The results indicate that,compared to samples with only flake graphite,the introduction of 1 mass%to 5 mass%nano-crystalline ZrC modified graphite can significantly enhance the mechanical performance of low-carbon Al_(2)O_(3)-C refractories.When 5 mass%ZrC modified graphite is added,the mechanical properties of the samples are optimal,with the cold modulus of rupture and elastic modulus reaching 22.5 MPa and 65.0 GPa,respectively.

Effects of Al_(2)O_(3)-SiO_(2) Raw Material Types on Properties of Anorthite Based Insulation Refractories

To optimize their Al_(2)O_(3)-SiO_(2) raw materials,anorthite based insulation refractories were prepared by the in-situ sintering process combined with the foaming method after sintering at 1350℃for 3 h,using green and pollution-free kaolin,kyanite,andalusite and sillimanite as Al_(2)O_(3)-SiO_(2) raw materials,respectively,and industrial CaCO_(3) as the CaO source.Effects of Al_(2)O_(3)-SiO_(2) raw material types on the physical properties,phase composition and microstructure were investigated.The results are as follows.All samples prepared by different Al_(2)O_(3)-SiO_(2) raw materials have hexagonal flake anorthite and a small amount of mullite and corundum.Their bulk density and thermal conductivity decrease in the order of using kaolin,andalusite,kyanite and sillimanite as the Al_(2)O_(3)-SiO_(2) raw material,but their apparent porosity increases.Moreover,in the sample with kaolin,the bonding between anorthite crystals on the pore walls is closer than that of the other samples,which is conducive to increasing the cold crushing strength.The bonding between anorthite crystals on pore walls gradually decreases in the order of using kyanite,andalusite and sillimanite as the Al_(2)O_(3)-SiO_(2) raw material,thus their cold crushing strength decreases accordingly.In comprehensive consideration,the properties of the sample from kyanite are the optimal.Its apparent porosity,thermal conductivity and cold crushing strength are 84.6%,0.141 W·m^(-1)·K^(-1) and 1.89 MPa,respectively.

Risk stratification for radioactive iodine refractoriness using molecular alterations in distant metastatic differentiated thyroid cancer

Objective: Patients with radioactive iodine-refractory differentiated thyroid cancer(RAIR-DTC) are often diagnosed with delay and constrained to limited treatment options. The correlation between RAI refractoriness and the underlying genetic characteristics has not been extensively studied.Methods: Adult patients with distant metastatic DTC were enrolled and assigned to undergo next-generation sequencing of a customized 26-gene panel(Thyro Lead). Patients were classified into RAIR-DTC or non-RAIR groups to determine the differences in clinicopathological and molecular characteristics. Molecular risk stratification(MRS) was constructed based on the association between molecular alterations identified and RAI refractoriness, and the results were classified as high, intermediate or low MRS.Results: A total of 220 patients with distant metastases were included, 63.2% of whom were identified as RAIRDTC. Genetic alterations were identified in 90% of all the patients, with BRAF(59.7% vs. 17.3%), TERT promoter(43.9% vs. 7.4%), and TP53 mutations(11.5% vs. 3.7%) being more prevalent in the RAIR-DTC group than in the non-RAIR group, except for RET fusions(15.8% vs. 39.5%), which had the opposite pattern. BRAF and TERT promoter are independent predictors of RAIR-DTC, accounting for 67.6% of patients with RAIR-DTC. MRS was strongly associated with RAI refractoriness(P<0.001), with an odds ratio(OR) of high to low MRS of 7.52 [95%confidence interval(95% CI), 3.96-14.28;P<0.001] and an OR of intermediate to low MRS of 3.20(95% CI,1.01-10.14;P=0.041).Conclusions: Molecular alterations were associated with RAI refractoriness, with BRAF and TERT promoter mutations being the predominant contributors, followed by TP53 and DICER1 mutations. MRS might serve as a valuable tool for both prognosticating clinical outcomes and directing precision-based therapeutic interventions.

Abstracts Selectedfrom Naihuo Cailiao(Refractories)——A Bimonthly in Chinese

Research progress on hydration resistance of magnesia-calcia refractories/Huang Ren,Li Kezhuo,Xie Houbo,Gao Ruihong,Huang Zhong,Zhang Haijun,Zhang Shaowei//Naihuo Cailiao.-2022,56(4):277Abstract:Magnesia-calcia refractories are widely used in the iron and steel smelting industry because of their advantages of steel liquid purification,high refractoriness,good thermal shock resistance and high corrosion resistance in basic slag.However,MgO and CaO usually hydrate in the process of manufacturing.

Abstracts Selectedfrom Naihuo Cailiao (Refractories)--A Bimonthly in Chinese

Preparation of lightweight insulation materials from forsterite and fly ash cenesphere/Xie Zhe,Deng Chengji,Dong Bo,Ding Jun,Zhu Hongxi,Zhou Nian,Yu Chao//Naihuo Callao-202256(5);:369 Abstract:In order to reduce the raw material cost and the sintering temperature,lightweight insulation materials were fabricated using forsterite and fly ash cenesphere as main raw materials,and borax as the texturizer,heat treating at 800。C for 1 h.The influence of the borax addition(5%,10%,20%and 30%,by mass)on the phase.composition,the microstructure,and the properties of the materials was studied.

Call for Papers of ISR2024 The 9th International Symposium on Refractories

International Symposium on Refractories(ISR)is a serial international symposium and has been held successfully for eight sessions:the 1^(st)(ISR1988)in Hangzhou,the 2^(nd)(ISR1992)in Beijing,the 3^(rd)(ISR1998)in Beijing,the 4^(th)(ISR2003)in Dalian,the 5^(th)(ISR2007)in Beijing.

Steam Oxidation Resistance Comparison of Several Silicon Carbide Refractories at Elevated Temperatures

The oxidation tests of different SiC refractories including Si3N4-SiC bricks,Si3N4-Si2N2O-SiC bricks from China(SNO-1),Si3N4-Si2N2O-SiC bricks from overseas(SNO-2),SiAlON-SiC bricks,oxides bonded SiC bricks,self-bonded SiC bricks as well as SiC castables were carried out in the steam atmosphere(1 000 ℃,32 kg·m-3·h-1)for different durations(100,200,300,400 and 500 h).The mass,the volume,the bulk density and the apparent porosity before and after the oxidation were tested.The XRD and SEM analyses were conducted.The results indicate that:(1)under the steam atmosphere condition(1 000 ℃,32 kg·m-3·h-1),as the oxidation time increases from 0 to 500 h,the volume and the mass of the silicon carbide refractories increase,while the bulk density decreases;in terms of the apparent porosity,oxides bonded SiC bricks and SiC castables present an increasing trend,Si3N4-SiC bricks,SiAlON-SiC bricks and self-bonded SiC bricks present an increasing trend first and then a decreasing trend,and Si3N4-Si2N2O-SiC bricks present a decreasing trend or a trend of decreasing first and then increasing;(2)as for Si3N4-Si2N2O-SiC bricks,SNO-1 and SNO-2 have basically the same chemical and phase composition,SNO-2 has the lower mass change rate than SNO-1 during oxidation from 200-500 h,which indicates that SNO-2 has the better steam oxidation resistance than SNO-1.

Effect of Ferric Nitrate Loading Mode on Properties of Si_(3)N_(4) Composite MgO-C Refractories Prepared by Nitridation

In order to investigate the effect of the catalyst loading mode on the mechanical properties of Si_(3)N_(4) composite MgO-C refractories prepared by nitridation,fused magnesia,flake graphite,silicon powder,and phenolic resin were used as the main raw materials,and ferric nitrate as the catalyst to prepare refractories by nitriding at 1350℃.The effects of different catalyst supports(silicon powder,silicon powder+phenolic resin)on the formation of Si_(3)N_(4) in MgO-C refractories and the properties of refractories were studied.The results show that the silicon powder+resin catalyst support promotes the participation ofα-Si_(3)N_(4) in the reaction to generateβ-Si_(3)N_(4) and MgSiN_(2),and generates more SiC.However,this loading mode causes more gas to escape from the refractories and loosens the material structure,which reduces the mechanical properties.On the contrary,MgO-C refractories prepared by nitridation with silicon powder-supported catalysts under the same conditions show higher density and better mechanical properties.

Effect of Al Powder and Si Powder Additions on Structure and Properties of Unburned Magnesium Aluminate Spinel Refractories

Unburned magnesium aluminate spinel refractories were prepared using sintered magnesium aluminate spinel as the main raw material,phenolic resin as the binder,aluminum powder(2%,4%,and 6%by mass)and silicon powder(when Al powder addition is 4%,Si powder addition varies:1%and 2%,by mass)as additives.The effects of the Al powder and Si powder additions on the properties and microstructure of the refractories heat treated at different temperatures(1000,1400,and 1600℃for 3 h)were studied.The results show that the Al powder addition can greatly enhance the cold modulus of rupture of the samples fired at 1000 or 1400℃,and meanwhile AlN reinforcement phase forms in the matrix,which greatly improves the hot modulus of rupture of the samples at 1400℃;however,the heat treatment at 1600℃has little influence on the strength;the addition of Al powder and Si powder results in the formation of low melting point phases,greatly reducing the hot modulus of rupture.However,the low melting point phases promote sintering,which enhances the density and the cold modulus of rupture,and decreases the volume change during heating.The samples added with Al and Si all have higher cold modulus of rupture than those added with Al powder only.

Identification of the key genes and mechanisms associated with transcatheter arterial chemoembolisation refractoriness in hepatocellular carcinoma

BACKGROUND Transcatheter arterial embolisation(TACE)is the primary treatment for intermediate-stage hepatocellular carcinoma(HCC)patients while some HCC cases have shown resistance to TACE.AIM To investigate the key genes and potential mechanisms correlated with TACE refractoriness in HCC.METHODS The microarray datasets of TACE-treated HCC tissues,HCC and non-HCC tissues were collected by searching multiple public databases.The respective differentially expressed genes(DEGs)were attained via limma R package.Weighted gene co-expression network analysis was employed for identifying the significant modules related to TACE non-response.TACE refractoriness-related genes were obtained by intersecting up-regulated TACE-associated and HCC-associated DEGs together with the genes in significant modules related to TACE nonresponse.The key genes expression in the above two pairs of samples was compared respectively via Wilcoxon tests and standard mean differences model.The prognostic value of the key genes was evaluated by Kaplan-Meier curve.Multivariate analysis was utilised to investigate the independent prognostic factor in key genes.Single-cell RNA(scRNA)sequencing analysis was conducted to explore the cell types in HCC.TACE refractoriness-related genes activity was calculated via AUCell packages.The CellChat R package was used for the investigation of the cell–cell communication between the identified cell types.RESULTS HCC tissues of TACE non-responders(n=66)and TACE responders(n=81),HCC(n=3941)and non-HCC(n=3443)tissues were obtained.The five key genes,DLG associated protein 5(DLGAP5),Kinesin family member 20A(KIF20A),Assembly factor for spindle microtubules(ASPM),Kinesin family member 11(KIF11)and TPX2 microtubule nucleation factor(TPX2)in TACE refractoriness-related genes,were identified.The five key genes were all up-regulated in the TACE non-responders group and the HCC group.High expression of the five key genes predicted poor prognosis in HCC.Among the key genes,TPX2 was an independent prognostic factor.Four cell types,hepatocytes,embryonic stem cells,T cells and B cells,were identified in the HCC tissues.The TACE refractoriness-related genes expressed primarily in hepatocytes and embryonic stem cells.Hepatocytes,as the providers of ligands,had the strongest interaction with embryonic stem cells that provided receptors.CONCLUSION Five key genes(DLGAP5,KIF20A,ASPM,KIF11 and TPX2)were identified as promoting refractory TACE.Hepatocytes and embryonic stem cells were likely to boost TACE refractoriness.

Recent Progress on Al_(2)O_(3)-C Refractories with Low/ultra-low Carbon Content:A Review

This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon content.It covers three parts:carbon materials,microstructure optimization of the refractory matrix by ceramic phases,and application of metal Al as raw material.Carbon black,expanded graphite,and ultrafine microcrystalline graphite,as price-competitive carbon materials,can be chosen to prepare the low-carbon Al_(2)O_(3)-C refractories after some special treatment.Ni/Co/Fe-catalyzed phenolic resin contributes to improving the properties of the low-carbon Al_(2)O_(3)-C refractories.The performance deterioration of the low-carbon Al_(2)O_(3)-C refractories can also be improved by in-situ formed or pre-synthesized ceramic phases.Metal Al,characterized by plasticity forming,acceleration of sintering,oxidation resistance,and high reactivity,can be used as raw materials to completely replace graphite,and the prepared resin bonded Al-Al_(2)O_(3)based refractories are one novel development direction of the ultra-low carbon Al_(2)O_(3)-C refractories.

Effect of Zircon Addition on Properties of Low Carbon AL_2O_3-C Refractories

Using tabular alumina as aggregate,tabular alumina fines,reactive alumina ultra-fines,aluminum powders,silicon powders,carbon black,flake graphite,B4 C and zircon fines as matrix,low carbon Al2O3-C refractories were prepared.Influences of zircon powders additions （0,3%,5% and 7%,in mass,the same hereinafter） on properties,phase composition and microstructure were investigated.The results show that the ZrO2-nitride can be in-situ formed through carbothermal reduction and nitridation in Al2O3-C refractories.With the increase of zircon powder,the oxidation resistance of the Al2O3-C refractories improves obviously,the oxidized layer thickness decreases from 7.94 mm without zircon to 2.71 mm with 5% zircon.HMOR at 1 400 ℃ of the Al2O3-C refractories reaches the maximum 14.9 MPa when zircon addition is 5%.With the increase of zircon powder,the apparent porosity and bulk density change a little,CMOR and CCS increase.

Replacement of Flake Graphite in Aluminacarbon Refractories by Hexagonal Boron Nitride

Three kinds of composite alumina refractories were prepared with tabular alumina （3-1 and 1-0 mm） as aggregates,tabular alumina powder,α-Al2 O3 micropowder,and Si powder as matrix,adding 3 mass％ hexagonal boron nitride （h-BN）,3 mass％ flake graphite and 10 mass％ flake graphite,respectively.Cold physical properties,hot modulus of rupture,oxidation resistance,thermal shock resistance and slag corrosion resistance of the specimens were compared.The results show that：（1） physical properties and hot modulus of rupture of Al2 O3-h-BN refractories are slightly different from those of low carbon Al2 O3-C refractories,but better than those of traditional Al2 O3-C refractories with 10 mass％ graphite ; （2） Al2 O3-h-BN refractories have better thermal shock resistance and oxidation resistance than the carbon containing refractories,while similar slag resistance with low carbon Al2 O3-C refractories ; （3） h-BN can replace flake graphite as a starting material for the preparation of composite alumina refractories,considering the overall properties of the material.

Microstructures and Corrosion Resistance of Al_2O_3-C Based Refractories to the Melts Containing Titania

The corrosion resistance of the Al2O3-C based refractories in melts containing titania has been studied by quasi-station immersion and rotary immersion. The corrosionrate is decreased with the addition of graphite carbon, and ZrO2 in the refractories . The corrosion, mechanism of Al2O3-C refractories, is. the oxidization of graphite carbon by the oxides of the melts the formation of deteriorate layer, For the Al2O3-C-ZrO2 refractories, the corrosion behavior is due to the, interaction between melts and refractories . The new compounds of FeO. SiO2, SiZrO4, FeO. 3 CaO, 2CaO. SiO2 and CaO. SiO2 are formed in the deteriorate layer.

Major Trends in Refractories Industry at the Beginning of the 21^(st) Century

An analysis of the present and of the future of the refractories industry is being presented , considering some important technical, economical, human and environmental issues , on a worldwide basis. Refractories are still neededas confinement materials to prevent heat and mass transferlosses in many diverse manufacturing industries , and will remain so , but the main challenges , this industry do needto meet, are to adjust to an overcapacity production , to cope with new needs of the customers , in particular the'outsourcing' , which is a new customer / supplier relationship being adopted by many of them, and to keep the research and development alive in a more and more competitive arena. Among the direct consequences , are the need to keep the education world in refractory engineering training alive and to cope with macro and micro projects to change the image of the Refractories , from a commodity material to a sophisticated 'high-tech' composite material . Some suggestions are provided in the text.