Yes, you can do that. Just copy the folder to another drive, and then open the folder and double click the catalog file to start Lightroom. From now on, Lightroom should know that it should use this catalog (but do check this in the preferences). If everything is fine, then you can delete the folder from the original drive. If moving the Lightroom folder also includes moving the folder with the original images, then you may have to 'reconnect' these.