I've encountered two problems with the blast furnace in the mod's current version:

• In contrast to what the ponder indicates, items cannot be inserted through the top blast furnace hatch (the one used to collect furnace gas). I've tried simply dropping them in manually, as well as via hoppers, funnels, and chutes.
• The blast furnace doesn't appear to actually... operate. Using the nether quartz + coke → liquid silicon recipe, for instance, it simply hangs at "time left: 37" on the furnace block display once the appropriate materials are provided, and never consumes any inputs or yields any output.