Try an industrial ventilation handbook. Graphite dust can be controlled with ordinary industrial hygiene dry collection methods. In general, set your collection point as close to the dust source as possible. If the dust has an initial velocity, try to collect it downstream so you're not changing the direction of travel. If the operation is enclosed, a hood face velocity of around 100 fpm should be OK. In the open the collection velocity will depend on initial dust velocity geometry of the collection zone, hood design etc. A good industrial ventilation text will give you plenty of ideas. I have seen Torit dust collectors used effectively. Word to the wise, keep the dust out of your lungs (good advice for any dust) and keep it out of your electronics.