fused mullite is made from pure quarz and industrial alumina in super-large electric arc furnace . fused mullite has a high content of mullite crystals which has a lot of advantages such as high melting point,excellent thermal stability ,low reversible thermal expansion ,resistance to thermal shock and chemical corrosion at high temperature.fused mullite is widely used as lining brick glass body kiln and large hot wind furnace in iron-making blast furnace ,as well as in ceramic kiln ,petroleum and chemistry. specification first type: al2o3: 70-74% fe2o3:0.1%max sio2:25-28% na2o: 0.25%max specification second type: al2o3: 74-77% fe2o3:0.1% max sio2:22-25% na2o: 0.30%max we have strict control about company & quality;our service is full-around and first-class. so we¡¯re you wise choice.don¡¯t hesitate to contact us. contact person: ms. liang xiaofei(sales manager) helen(at)rs-abrasive.com