After my company R & D personnel efforts, big grain size high temperature alumina ( 3-7 / M ) product development success, and through the test. This product features: the use of alumina as raw material, with different formulations of high-temperature calcination, high product purity, high melting point, uniform particle size, good fluidity, low conductivity, grain size controllable, stable performance, difficult to dissolve in acid and alkali. Widely used in stereotypes and unshaped refractory materials, polishing and grinding materials, high temperature resistant, wear resistant alumina ceramics, high temperature ceramics sticks, electronic devices and light emitting materials.