Molten Salt

Molten Salt is the liquid state of the element Salt in Oxygen Not Included. It appears as the high‑temperature, molten form of Salt and behaves as a liquid for the purposes of piping, storage, and heat transfer. Molten Salt is distinct from Table Salt, which is a refined food ingredient produced from Salt; Table Salt is not an element and is handled as an inventory/consumable item rather than a material element.

Molten Salt is used primarily for thermal engineering. Because Molten Salt and Salt Gas have different heat capacities and phase change properties, repeatedly vaporizing Molten Salt and then liquefying the resulting Salt Gas provides a reliable method of transferring and producing heat. This phase‑change cycling can be exploited to move thermal energy between systems, act as a high‑temperature heat reservoir, or drive heat‑dependent processes when properly integrated with boilers, condensers, and insulated piping.

Practical notes and interactions:

• Molten Salt functions as a normal liquid for pumps, valves, and liquid pipes; treat it like any other conductive liquid when designing plumbing and thermal circuits.
• Use heat exchangers and insulated pipes to control where Molten Salt releases or absorbs heat; its utility comes from phase changes between molten and gaseous Salt.
• Salt Gas is the gaseous counterpart involved in the vaporization/liquefaction cycle; designs that deliberately vaporize Molten Salt and condense Salt Gas can concentrate thermal output in desired locations.
• Salt (the base element) can be refined into Table Salt via the Rock Crusher: 100 kg Salt produces Table Salt plus Sand. Table Salt is used by Duplicants at Mess Tables (each Mess Table stores up to 5 g; each use consumes 1 g and grants +1 morale).
• Plan designs around Molten Salt’s temperature thresholds and required boilers/condensers to ensure controlled phase changes and avoid unintentional loss of material or overheating of nearby systems.

Molten Salt is especially useful in advanced thermal engineering and rocket/industrial setups where high‑temperature heat storage and controlled release are required. Designs that leverage its phase‑change properties can be more compact and efficient than equivalent systems that rely solely on conduction or single‑phase fluids.