There is no way to buy zinc with coins

iirc you can buy sphalerite ore with coins, which when smelted give you zinc ingots

iirc you can buy sphalerite ore with coins, which when smelted give you zinc ingots

While you can, I'm actually after the gallium in the zinc processing and not the zinc itself

It is known and intended that there is no coin recipe for Zinc ore. Sphalerite covers the early game, Bauxite gives massive amounts that easily covers you for the rest of the game.

then you can electrolyze the sphalerite dust to get zinc dust and sulfur dust

from the bot on the Nomifactory Discord

Electrolyze and centrifuge impure sphalerite dust.
Once you have an HV macerator, get bauxite ore and do macerate -> thermal centrifuge -> macerate for (practically) infinite gallium.