... Industrial Grade Purity: 46% Appearance: flakesApplication: mgo board production K: less than 0.01 Na: Less than ... , ventilation pipes, anti-theft covers, fireproof doors and Windows, fire prevention board, partition board, the production of artificial marble ... clay, high quality system of fire prevention board, magnesium magnesium packing, decoration board, light wallboard, abrasive, stoves, fireworks ...