I have an old electric kiln, that was about 3' across. The kiln is not worth saving, but it does leave me with a lot of the liner brick, which are very soft. I have attached a picture of a small forge setup I made by sandwiching two of the bricks together and digging out the center. I know they are very fragile, but also can take a lot of heat. Has anyone used these for a heat riser? The could also be ground up and used in some sort of matrix.
These insulating firebrick will make a fine heat riser, or any part of the system that doesn't get a lot of abrasion. They would probably not last long in the feed tube or burn tunnel, just from mechanical damage.
Common Weeds And Wild Edibles Of The World (HD video)