Calcium aluminate and Fe-Si alloys were successfully synthesized by using red mud and aluminate dross as the main raw materials in the lab-scale experiment. Three apt experimental parameters were obtained: 1.2 times of theoretical addition amount of aluminum dross, binary basicity of raw materials 0.9, 40min smelting time. The chemical compositions of calcium aluminate synthesized meet the standard of CA-60 cement of China, and the calcium aluminate can be used as pre-melted-slag in Steelmaking process.

Waste foundry sand is a kind of solid wastes produced during casting process, the casting output of China ranks first in the world for many years and the amount of waste foundry sand is huge. But the utilization rate of the waste foundry sand is low in China. It is not only a threat to the environment but also a waste.In this paper, waste foundry sand was taken as main starting material, adding proper amount of additives. The shaped samples were heated in the electric oven at the temperature of 1300°C, 1400°C and 1500°C respectively, the soaking time is 3h for all samples.The microstructure and phase composition of the samples were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The effect of the temperature on the synthesis of mullite-silica-rich glass was investigated. The results showed that the main phases were mullite and glass when the samples were heated at 1500°C, mullite grain grew well and formed network structure. This network was benefical to improve the thermal shock resistence.It opens up a new method to utilize the waste foundry sand.

This paper reports the effects of γ-Al2O3 and α-Al2O3 on the properties of lightweight insulation materials. The phase compositions, microstructure and mechanical properties of lightweight insulation materials are separately investigated by XRD, SEM and tabulate thermal conductivity apparatus methods. The results indicate that the increasing of the amount of γ-Al2O3 is beneficial to improving the bulk density, compressive strength and acid resistance of the fired specimens. The fact negatively impacts on the increasing of the apparent porosity; however, it has no significant effect on the thermal conductivity of specimens. Meanwhile, the studies highlight that when the content of γ-Al2O3 increases, the nucleation and growth of mullite is accelerated at high calcination temperature, which has positive effect on improving the physicochemical properties of lightweight insulation materials. And the γ-Al2O3-free SiO2 glass phase system is guided by theoretical analysis of reaction conditions for non-catalytic system with Factsage modelling.

The effect of reactive-Al2O3 addition on the pore size distribution and thermal conductivity of carbon blocks for blast furnace was investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray, mercury porosimetry, and a laser thermal conductivity meter. The results showed that the pore size distribution and the thermal conductivity of carbon block were mainly influenced by SiC whiskers and reactive-Al2O3. With increasing addition of reactive-Al2O3, the mean pore diameter reduced and < 1μm pore volume increased of open pores owing to the more efficient filling of pores by SiC and reactive-Al2O3, and the thermal conductivities of samples increased due to the facts that the higher thermal conductivity of reactive-Al2O3 than that of brown corundum and the more formation amount of high thermal conductivity of SiC.

Alumina lightweight insulation bricks were prepared from alumina powders using foaming method. In this paper the influences of foam addition amount (600, 800, 1000, 1200ml/kg) on properties of Alumina lightweight insulation brick were discussed. The phase composition is analyzed by XRD and the microstructure is characterized by SEM. The results show that the bulk density of alumina lightweight insulation brick is 0.63g/cm3,cold compressive strength is 10.53MPa, linear change rate after firing is -4.5% and reheat linear change rate is -0.27%,which synthesized under 1000ml/kg foam amount after firing at 1550°C for 3h. The results indicate that the density of alumina lightweight insulation brick is reduced with the increase of foam addition amount, when the addition amount is more than 1000ml/kg, cold compressive strength decreased significantly and linear shrinkage increased obviously.