Yes, I saw how white your refractory was in the photo. It might be better stuff (higher temperature) than what I'm using. https://www.amazon.com/Rutland-Castable-Refractory-Cement-25-Pound/dp/B008BQQASQ
I recently made stove lids for some TLUD stoves out of a home-made mix of plaster/perlite/glass and they work well if you leave them in the metal container for use. One of the two I made cracked, and I don't know if it got dropped or what, but after reading on the web, I decided to try the refractory cement. (Store bought.) I don't think the plaster/pearlite mix is very durable.