This factory will turn the stone byproduct into refined concrete, whatever is left you can hook up to a combinator to throw into lava if you don't need it, but since the iron magma production is 112,440 P/m I figured there is no reason to not be making it since its already easily available.
You could also take off parts of it if you just wanna make some concrete with it. The only thing need to add onto this is the steam condensation for water.
It makes around 700 P/m when fully used but eventually the belts will over saturate a little and it will drop to about 500 RC P/m, which is still solid enough to build items and ship if you wanted since its basically free