Hey folks, it’s your boy back again with another hands-on project to share. Today, we’re diving into the world of high alumina bricks. I gotta say, this was a bit out of my usual wheelhouse, but who doesn’t love a good challenge, right?
So, first things first, I started by gathering my materials. I needed some heavy high aluminum bauxite abrasive powder, with about 55% Al2O3 content. Also grabbed some binding clay fines, which had around 31-32% Al2O3. The recipe I found called for a 9:1 ratio of the bauxite to the clay. I got my trusty ball mill out, dumped everything in with about 48-50% water, and let it grind away for a solid couple of hours. It needs to get real fine, like passing through a 0.2mm sieve fine.
Mixing and Molding
Mixing was a bit of a workout, gotta be honest. I mixed and mixed until I got a good, workable consistency. The mixture was pretty thick. If you have used some cheap bricks before, I think you can feel the difference between them.
The Waiting Game
Next came the not-so-fun part: waiting. I placed those bricks under a damp cloth, then covered it all with a plastic sheet, like I was tucking them in for a nap. I let them rest for 24 hours, just chilling and setting up. And the waiting game has started, I checked on them now and then.
The Firing
Now, for the main event, I carefully loaded the bricks into my little kiln. This was the real test. I cranked up the heat slowly, following a firing schedule I found. High alumina bricks can handle some serious heat, the more alumina, the better, and mine was a relatively high proportion. I ended up firing them at a scorching 1400°C, and they needed to bake at that temperature for about 6 hours.
Cool Down and Check
After the long bake, I turned off the kiln and let those bricks cool down nice and slow. This whole process took a few days. When I finally opened up the kiln, I was pretty stoked with what I saw. I put the bricks on the ground and I saw those bricks, solid as a rock, with a nice, uniform color. I gave them a tap, and they had that solid, dense feel you want in a good refractory brick. They didn’t feel like those cheap, light bricks that crumble if you look at them wrong.
I’ve got a few projects in mind where these bad boys will come in handy. I’m thinking about lining my forge with them, maybe even building a little outdoor oven. These bricks are super versatile because they have high temperature performance, great corrosion and wear resistance, high bulk density, and low iron content. I might use them in my garden. High alumina bricks are super versatile. I heard they’re used a lot in mining, cement making, and even in the chemical industry. From steel-making, and cement ovens, to chemical vessels, they are real workhorses.
Anyways, that’s my high alumina brick adventure. It was a lot of work, a lot of waiting, but totally worth it in the end. If you’re looking for a challenging project and want to make something that can literally stand the heat, give this a try. Until next time, keep making, keep experimenting, and keep those kilns burning!
