Recover a little more from your copper factory.

Tellurium adds a rare byproduct to copper processing and a small refining chain to make use of it. Turn the residue into precision copper alloys and optical crystals, or add Bismuth and build thermoelectric components for cooling and laser equipment. With compatible mods, tellurium also improves synthetic rubber production and goes into optical instruments and power regulators.

It starts after sulfur processing: put copper ore through trace recovery, keep the copper moving, and save the occasional tellurium residue. A steady copper line will supply the new chain. There are no ore patches to find.

Factorio 2.1 only.

Recommended: Bismuth. It opens the thermoelectric branch, from bismuth telluride to cooling components. Tellurium also works without it.

What it adds

• Tellurium copper for substations and beacons, plus power regulators with Them Thar Hills. A little tellurium goes a long way: one metal makes twenty alloy plates.
• Optical crystals for laser turrets and satellites, plus scanners and spectroscopes with Lasing Around. Glass-producing mods give crystal growth a use for their glass, with bismuth glass preferred when available.

• Thermoelectrics, with Bismuth: combine the two metals, then make cooling components for speed module 3 and personal laser defense. Other mods can supply the solder, ceramics and heatsinks.

• More rubber from the same feedstock, with BrimStuff: an optional synthetic-rubber recipe yields a third more rubber for the same upstream ingredients and crafting time. It uses one tellurium metal and returns it in 99% of batches, so the line needs only occasional top-ups.

There are also optional ways to recover and refine it: crushed-copper and trace-gold processing, K2 copper enrichment, Vulcanus ore and lava melting, and Fulgora scrap recovery. Chloride and peroxide improve extraction yield; coke, charcoal, graphite, hydrogen and electrolysis provide reduction options. Argon improves bismuth-telluride yield. Foundries and kilns can handle the alloys, and supported glass, ceramics, solder, heatsinks and cooling fans adapt the existing recipes to your factory.

With K2 and Bismuth, thermoelectric components also go into research servers and quantum computers. IntermediatesForYou moves the satellite's crystal requirement into its satellite body. Startup settings let you bypass individual recipe changes and list the recipes Tellurium modifies.

The research tree stays small: processing, optics, and thermoelectrics when Bismuth is installed. Better refining methods use the provider technologies and materials you already have; Tellurium does not add new prerequisites to broad upstream polymer, gold or atmosphere research. Material selection favors enabled, reachable earlier routes, so the thermal branch does not wait for unnecessary bismuth enrichment or a late argon technology.

With Space Age, the thermal assembly recipe remains usable in assemblers and can also run in an electromagnetic plant. Crystal growth remains usable in chemical plants and can also run in a cryogenic plant. Existing recipe bypasses leave the named host recipe unchanged, including its ingredients, outputs and unlocks.

Integration with other mods

The integrations give existing materials a job in the chain. Coke, charcoal or graphite replaces coal when a suitable production route is available. Peroxide improves extraction yield. Indium solder and tantalum heatsinks become part of the same thermoelectric recipe. Lasing Around uses one crystal per batch of twenty scanners or spectroscopes; Them Thar Hills uses one alloy per batch of ten HV power regulators. Shared laser emitters keep their existing inputs.

These integrations are optional. Choose the mods you want to play, using their Factorio 2.1 versions.

Some Ashier and Timeken integrations were tested with their maintainers’ 2.1 GitHub builds; the Mod Portal downloads with the same version number can still target 2.0. Timeken and the tested legacy BZ collection exclude Space Age. The supported families are not a promise that every upstream mod loads with every other one.

Getting started

Research Tellurium processing and select Copper trace recovery in a chemical plant. Supply copper ore, sulfuric acid and water, and keep removing the copper plates. At vanilla defaults, each twenty-ore batch has a 10% chance of yielding one residue. Several empty batches in a row are normal.

Refine the residue into dioxide, then choose where it goes: metal for alloys, crystals for optics, or bismuth telluride for cooling components. Give the residue a small buffer; production comes in bursts.

You can add Tellurium to an existing save without exploring new terrain. Its recipe changes apply to that factory too. A startup setting lets you bypass individual recipe modifications.

For recipe-by-recipe changes and refining ratios, see the FAQ tab.

Credits

Tellurium is by fluffy_penguin. Its approach owes a lot to:

• Brevven, for BZ Mods and the idea that one extra material can make a familiar factory more interesting.
• trikop, for Bismuth and Manganese.
• Planetfall and AtelierAmber / Ashier, for the nickel, brass, sulfur, gold and laser mods this chain connects to.
• Timeken, for the original resource mods; cackling fiend, Morganite / Morganni and pla, for maintaining and porting the collections used in testing.

The thumbnail is original. The tellurium metal, crystal, bismuth telluride and thermoelectric icons were made with image-generation tools; some remaining icons reference tinted Factorio assets. No artwork from the credited mods is bundled. Code and original artwork use the MIT license; Factorio assets remain Wube’s.