The Effect of Layered Nano-Silicate on Properties of Alumina Graphite Ultra Low Cement Castable

In the last two decades, many scientific researches in the field of refractories technology have focused on increasing the use of monolithic refractories. Many countries have focused more than half of their production on amorphous refractories, which is due to the advantages of these refractories, such as no need for forming and baking processes during manufacturing, and similar properties to shaped refractories. The advantages of monolithic refractories are the main driving force for increasing researchers in this area which have shown great progress. From other hand the application of nano materials in refractories researchers have recently started which might end in unexpected results. After clay purification by mechanical methods and obtaining layer nano-silicate, the characterizations were conducted by using XRD (X-ray Diffraction), SEM (Scanning Electron Microscope) and LPSA (Laser Particle Size Analyzer). Then, the produced nano-silicate particle was added to the ultra-low cement Alumina castable and rheological and mechanical properties of castable were studied before and after firing in 1000°C, 1250°C and 1500°C. Also for phase investigation XRD was used.
The results showed that d-spacing between nano-silicate layers was about 1.2 nm. Flow ability of the castable showed an increase of 5%. Which meant that filler materials such as micro silica and reactive Alumina where decreased. Finally XRD results of fired samples indicated that existence of mullite as a desired phase in the system.