It's not practical to re-cast the stuff without a lot of expensive heating and chilling, so you'd probably need to find someone who can use those specific sizes and shapes. I have no clue about finding them.
As an aside, white cast iron also is used as the feedstock for making malleable iron. But there isn't much of that made today. It requires days of soaking time in a heat-treating oven to convert it to malleable, and the fuel costs are prohibitive. Malleable has been hostly replaced by ductile cast iron and steel.
Good luck. They make nice conversation pieces. d8-)
Three issues to deal with: The soaking temperature may be a little higher than that. They use 1650 deg. F to 1750 F in industry. You'd probably need a forced draft.
Second, the soak times range from around 20 hours to 72 hours. Ouch.
Third, a white-iron brick that large may actually be chilled iron -- gray iron in the center. That part of it won't convert to malleable.
Most of the malleable produced today is in pretty thin sections, compared to your bricks.
If you want to experiment, and if you don't mind tending your wood fire in the middle of the night , you could have some fun and learn a few things by giving it a try. Just assume you won't get it right the first time around.
Look up "malleable iron." There's a lot of literature on it; it's been around for a very long time.
BTW, what you're doing, when you heat-soak white iron, is you're putting the carbon that's held as iron carbide back into solution. Then you're soaking it long enough to nodularize the iron. You then cool it slowly so the iron and carbon don't form something you don't want -- more carbide, or whatever. I forget what happens if you don't cool it correctly.
The result is something close to low-carbon steel -- very malleable and ductile, not expecially strong, but very useful stuff.
Another thing: Iggy, I think you'd be a good candidate for becoming an expert on iron and steel metallurgy. I find it fascinating, although I'm sort of half-fast at it and I haven't studied it closely since I was materials editor at American Machinist, decades ago. With your native curiosity, I'll bet you'd find it really interesting, too.
And there is a practical side to it in your business. It would help you identify the materials you're dealing with and give you a sense of their use and value.
Not many people, even in the metalworking trades, really know much about it, outside of their narrow range of interest. And they often are full of old-wives' tales and old misinformation. It could give you a leg up.
Aack! I meant "nodularize the graphite." In both malleable iron, which is nodularized by soaking it above the transition temperature, and ductile iron, which is nodularized by specific alloying, retains free graphite in the form of roundish nodules. That makes if less brittle and more malleable/ductile than gray iron, in which the free graphite is in the form of flakes.
Ed, you are right this time. Messing trying to convert one form of junk into another is simply not worth the while. Heat treating is a little bit like woodoo magic, if you do not align the snake teeth with scorpion fangs properly, the woodoo magic will not work.
Ed, I am fascinated by metallurgy and spent hours, as an amateur, reading about alloys, metals, and other related topics. This has allowed me to notice some things that other people walk right past by. I am sure though that I do walk past some great stuff without noticing. Thank you for your encouragement. I am sure that I will never be a metallurgy expert, but I do find it to be a great topic to learn about.
There are a lot of practical heat-treaters and other metalworking people who operate close to the voodoo level on metallurgy; nonetheless, they produce good results, mostly from experience, even if they have msconceptions about what they're doing.
It you study it today, you'll find a lot of the fog has cleared. Electron microscopes have helped to clear up a lot of old uncertainties and ambiguities.
I would have thought something like Hadfield steel would have been a far more appropriate material for that sort of application. I have an ore crusher knuckle which I use on occasions as a metal working stake and I suspect that is Hadfield steel.
I don't know what Hadfield steel is, but white cast iron is widely used for ore crushers, digger teeth, and so on. It's very hard, as a hardness tester would measure it -- well over Rc 60 -- and the iron carbides are much harder than that. It's the carbides that provide the wear resistance.