Rochan Brick Factory is a location within Kyrat in Far Cry 4. If the player chooses to side with Amita, in the mission Advanced Chemistry they will be tasked with securing the factory. If they choose to side with Sabal, during the mission they will be tasked with destroying the factory.
It is likely not solely used just as a brick factory, as during the Advanced Chemistry mission Ajay will hallucinate once inside the factory. This may be drug-induced (likely a hallucinogen), caused by a drug that is being produced or processed in the factory, however the dialogue in-game never specifies what exactly is being produced (we know that it produces at least Heroin from Sabal's dialogue, but Heroin is not a hallucinogen, so there must be something else being made there).