Unlike Buckets the Refractory Fluid Container can be partially filled with fluid up to 1000 mB. and it is able to interact with tile entities. When a tile entity is right-clicked while holding a Container it can transfer fluid from the tile entity to the Container or from the Container to the tile entity if the Shift key is held at a rate of 100 mB/t.
If the Container is completely empty it can pick up fluids from the world by right-clicking. If it is full the fluid can be placed in the world by holding the shift right-clicking.