Done. That's right, now you can create your own resources by merging different quantities of resources.
First step: to choose the resources that you want to merge.
Second step: click 'Start refining', pay the tax (5% of the unit market cost of each resource).
Up to 24h later, you'll have found (or not!) a new resource. If you have a recipe, then try and use the right proportions to get that resource again. Good luck refining resources.
These new resources can be commercialised, and in the future they'll be able to be used in assembling new spacecrafts (roadmap feature).