I remember someone once suggested a bloomery for dedicated iron and steel production.
For manual alloy production on a large scale you need larger vats for storing molten material, that crucible fills up pretty quickly when trying to produce say a large batch of stainless steel.
What you need are molten material containers that can be poured into a central vat, of course these need to be constantly heated at a steady heat so as not to vaporise. I’m thinking heated crucibles piped into a third, can you pipe molten material into a crucible similar to a cauldron and water?