People request for it, it wasn't just a block, it was a custom block:
-A good textures and model.
-An awesome GUI which was perfect.
-A fully-complete functionality.
-No perfomance problems.
It will be used for red alloy ingot, sandy coal, infused silicon, and you can make it more usseful:
-Combine a lamp with a color = A new color lamp.
-Same with wires.
I have a instace of 1.6.4 just to get this furnace back, and i'm missing a lot of the new stuff, pipes for example, grab code from a older version of the project and put it in the new one is not to hard and i see other people request it before, please consider it.

So @MrTJP Can you add it back please ?

Maybe add an option in the confing file to enable it.

A config option for an entire block? Why? Either it's in the mod and required, or it doesn't make sense for it to be there. There could be an optional recipe set, but that seems really stupid/convoluted.

I'd like to have that, never try it but a i see a bevoLJ video about it, very fancy...

Older version of the project? Do you mean RedPower? We're not allowed to steal code.

Nope, install the 1.6.2 version of ProjectRed and you will see the alloy smelter, which is the Projectred version of the Alloy furnace:

Mmm...the model that i saw was different, anyways that is better than what i saw :D.
Also, i'd like automate the alloy smelter with the new ProjectRed pipes, awesome!

There's been a lot of stuff removed (trees are one thing that comes to mind), and I think @MrTJP has plans.

Oh, sad :(, i never try that furnace and i had so much plans to it :((

I like the idea

I didn't know that ProjectRed had a alloy furnace, that is awesome, hopefully it'll be back.

You are literally inquiring about one of the most insignificant thing ever. It was removed became it was poorly coded and it will not be added back unless there is a good reason, and it definitely won't be added until if I add other processing machines.

So if somebody makes a PR it will be accepted?

Probably.
(Just if you finish before me ;D ).