Hi. Im studying for a chemistry exam, and im a bit unsure about something. As part of the electrochemistry component of the course i am required to know and understand various metal extraction processes. My book is fairly good for learning them, but one thing i am not sure about concerns the precipitation part of the bayer process. Once the aluminate solution has been obtained, it is cooled and then seeded with pure aluminium hydroxide. I know the cooling is required to bring aluminium hydroxide out of solution, but why is the pure Al(OH)3 added? Whats the purpose of it? Thanks in advance, Dan.