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排序方式: 共有2140条查询结果,搜索用时 31 毫秒
1.
《Ceramics International》2022,48(14):20158-20167
Vacuum induction melting is a potential process for the preparation of TiAl alloys with good homogeneity and low cost. But the crucial problem is a selection of high stability refractory. In this study, a BaZrO3/Y2O3 dual-phase refractory was prepared and its performance for melting TiAl alloys was studied and compared with that of a Y2O3 refractory. The results showed the dual-phase refractory consisted of BaZr1-xYxO3-δ and Y2O3(ZrO2), exhibited a thinner interaction layer (30 μm) than the Y2O3 refractory (90 μm) after melting the TiAl alloy. Although the TiAl alloys melted in the dual-phase and Y2O3 refractory exhibited similar oxygen contamination (<0.1 wt%), the alloy melted in the dual-phase refractory had smaller Y2O3 inclusion content and size than that in the Y2O3 refractory, indicating that the dual-phase refractory exhibited a better melting performance than the Y2O3 refractory. This study provides insights into the process of designing highly stable refractory for melting TiAl alloys. 相似文献
2.
《Ceramics International》2022,48(9):12014-12027
The formed deposits wear out of refractory wall linings in the rotary kiln and may cause production disturbances. This study describes the chemical composition and mineralogical phase components at the deposit/refractory interface in the rotary kiln for fluxed iron ore pellets production. The main phases of refractory bricks are corundum and mullite, while the deposits mainly contain hematite and silicates. The main phases in the deposit/refractory brick contact zone are hematite, anorthite (CaAl2Si2O8), mullite, corundum, and silicates. Moreover, the hematite phases in the deposit/brick interface averagely contain 6.98 wt% Al and 1.38 wt% Ti. The silicates in the contact zone contain higher aluminium content and lower iron content than the silicates in the deposits. Finally, the thermodynamic analysis indicates that the main phases in the deposits can react with the refractory to form Al2Fe2O6, CaAl2Si2O8, feldspar, and liquid phases lead to the degradation of bricks in the kiln during the iron ore pellets production. 相似文献
3.
4.
《Ceramics International》2022,48(10):14141-14150
Ultralow-cement bauxite-corundum refractory castables are increasingly attracting attention because of the advantages in performance and cost. To improve its volume stability and high-temperature performance, andalusite and kyanite were incorporated into this type of refractory, respectively, and a comparative investigation of their effects on microstructure, thermo-mechanical properties, and slag corrosion resistance was carried out in this work. The expansion effects induced by the mullitization of these additives not only suppressed the sintering shrinkage but also made the matrix structure more compact and uniform, mainly owing to the generation of many new and strong mullite bonds. This improvement resulted in a significant increase in the refractoriness under load and creep resistance. This effect was far more pronounced for the andalusite-added castables, for which the RUL increased by 62 °C and the creep rate at the stationary stage decreased by 26%. Besides, adverse effects on microstructure and properties appeared when adding a higher amount of kyanite due to the excessive expansion. Moreover, the corrosion mechanisms of these refractory castables by refining slag were discussed, and the active role of andalusite addition in the corrosion resistance was also proposed. 相似文献
5.
采用多元素分析、X射线衍射、矿物解离度分析和电镜扫描等方法,开展陇南紫金金精矿的工艺矿物学研究,深入分析矿物组分、各物相赋存状态以及金的伴生规律。研究结果表明:该金精矿S和As质量分数分别为42.12%和2.31%,硫化物包裹金占比为56.19%,属于硫化物包裹难处理金矿;金矿物粒度为1~10 μm,以银金矿为主,并含有少量的自然金;金矿物的单体解离度为30%,未解离的金矿物均与黄铁矿连生,呈半包裹半裸露状或完全被包裹状。基于金矿物的单体解离度随着矿物粒度减小而增大的特性,可通过超细磨的方法,增加金与浸金试剂的接触,为提高金的回收率创造良好条件。 相似文献
6.
硅质、铝质、镁质和铬质耐火材料中MgO、Na2O、Fe2O3、MnO、Cr2O3、TiO2、P2O5、SiO2、CaO、K2O、Al2O3等组分含量的分析,一般采用EDTA滴定法、分光光度法、原子吸收光谱法测定,操作繁琐,耗时长;而使用X射线荧光光谱法分析时,4种基体的耐火材料需要采用不同的熔融方法和校准曲线。为了将4种基体的耐火材料统一制样方法,并使用同一组校准曲线同时测定MgO、ZrO2、Na2O、ZnO、NiO、Fe2O3、MnO、Cr2O3、V2O5、TiO2、P2O5、SiO2、CaO、K2O、Al2O3等主次组分,实验选用3套国外耐火材料标准样品,并对熔融温度、时间、稀释比等熔融制样条件进行优化;通过峰位及强度扫描确定各元素电压、电流、准直器等条件,达到灵敏度与分辨率最佳,通过扫描PHA确定脉冲宽度,提高准确度。理论α系数校正元素间吸收增强效应,用比例法计算校正谱线重叠,优化校准曲线,提高分析方法准确度。各组分校准曲线线性相关系数R2在0.9940~0.9999之间。按照实验方法熔融JRRM507、JRRM803、JRRM129 3个标准样品,进行方法精密度和熔片精密度试验,结果表明重复性均能达到GB/T 21114—2007要求。按照实验方法选择镁铬矿、高岭土、铝土矿3类标准物质进行正确度验证,VS P14/3、UNS KK、ZBK394标准物质中MgO、ZrO2、Na2O、ZnO、NiO、Fe2O3、MnO、Cr2O3、V2O5、TiO2、P2O5、SiO2、CaO、K2O、Al2O3等主次组分的测定结果与认定值相吻合。 相似文献
7.
Ismael Pérez Ignacio Moreno-Ventas Guillermo Ríos 《International Journal of Applied Ceramic Technology》2020,17(2):625-636
A cost driver in the copper-making industry is the periodical relining of the furnaces because of wear. This paper presents thermochemical calculations (using the FactSage™ database) focused on the evaluation of the slag-refractory chemical interaction in a submerged arc furnace (SAF) used for slag-cleaning operations. This evaluation was made under different conditions: slag-refractory volume ratio, oxygen partial pressure, and different types of slag. The new phases formed as a consequence of the slag-refractory chemical interaction were identified and quantified. To support the theoretical calculations based on thermochemistry, a postmortem study was carried out on a SAF used at the Atlantic Copper Smelter (Spain) after a 6-year campaign (4.5 mill. t. slag processed). Refractory samples were taken from different locations on the wall and analyzed using a scanning electron microscope equipped with an Energy Dispersive Spectroscopy system. 相似文献
8.
《中国有色金属学会会刊》2020,30(4):1111-1123
A novel process based on chlorination roasting was proposed to simultaneously recover gold and zinc from refractory carbonaceous gold ore by using NaCl as chlorination agent. The effects of roasting temperature, roasting time and NaCl content on the volatilization rates of gold and zinc were investigated. The reaction mechanism and the phase transition process were also analyzed by means of SEM, EDS and XRD. The results demonstrated that under the optimal conditions of NaCl content of 10%, roasting temperature of 800 °C, roasting time of 4 h and gas flow rate of 1 L/min, the rates of gold and zinc were 92% and 92.56%, respectively. During low-temperature chlorination roasting stage, a certain content of sulfur was beneficial to the chlorination reactions of gold and zinc; and during high-temperature chlorination roasting stage, the crystal structure of vanadium-bearing mica was destroyed, and the vanadium-containing oxides were beneficial to the chlorinating volatilization of gold and zinc. Eventually, the chlorinated volatiles of gold and zinc could be recovered by alkaline solution. 相似文献
9.
耐火衬里及支撑结构设计的可靠性是保证高温反应器壳体温度小于设计温度的关键因素。针对耐火衬里结构失效导致反应器壳体温度超过设计温度的问题,提出了一种双金属焊接的密封锥结构。该结构具有支撑金属衬里的作用以及将耐火材料与金属衬里之间的膨胀空间分割成多个密闭空间以阻止高温气体的流动,进而提高隔热可靠性。采用ANSYS软件中APDL语言建立了密封锥连接结构的有限元模型,通过研究密封锥不同角度以及厚度对计算结果的影响,得出了密封锥的最佳结构参数,并满足ASME标准的应力强度评定要求。模拟结果可为此类高温反应器耐火衬里结构的设计提供参考依据。 相似文献
10.
《Journal of the European Ceramic Society》2022,42(4):1804-1814
Graphite–SiC micro-composites have been prepared in–house by carbothermal reduction process. Controlling the process parameters including the weight ratio of SiO2 to graphite as well as carbothermal reduction temperature during the micro-composite preparation favors the homogeneous formation of SiC with preferred morphologies like ribbons and whiskers/fibers. The micro-composite modified low carbon MgO-C refractories have exhibited significantly improved bulk properties over the standard composition. To understand the beneficial role of SiC reinforcement on hot strength performance under air oxidizing conditions, we propose a scaling parameter known as strength factor (fs) based on the ratio of hot strength (HMOR) to cold strength (CCS). Correlating the strength factor data (fs) with oxidative damage provides new insights into the reinforcing effects of distinct SiC morphologies in this new class of micro-composite fortified refractory systems over the standard compositions. 相似文献