High temperature performance testing of large crystal fused magnesium aluminum

The selection of large crystal fused magnesium aluminum is very important. In the experiment, fused magnesia-chromium sands A and B and sintered magnesia sand C were used to make bricks. The chemical compositions of the raw materials were (%): SiO20.6, 1.18, 0.93; Al2O3 5.04, 6.97, 6.04; Fe2O3 6.41, 10.51, 14.04; Cr2O3 18.36, 20.40, 18.97; CaO 0.65, 1.24, 0.66; MgO 68.92, 59.70, 59.32, bulk density (g.cm-3): 3.67, 3.72, 3.50; Apparent porosity (%): 3.6, 4.1, 6.0. Magnesium calcium sand

Magnesium calcium sand

Bricks A, B and C are mixed with coarse, medium and fine particles, mixed with organic binder, formed by a friction brick press, dried and fired in a tunnel kiln at 1750°C. The physical properties of each brick were determined. The results show that the MgO content of fused magnesia-chromium sand B is about 10% lower than that of A, and the impurity components of magnesia-calcium sand except MgO and Cr2O3 are higher, but the density of fired brick B is better than that of A. The bulk densities are 3.40g.cm-3 and 3.28g.cm-3 respectively; the apparent porosity is 11.3% and 13.8%; the high temperature flexural strength and creep resistance are made of B material, and the B brick is more than A. Good; respectively 9.0MPa, 4.0MPa and 0.3%, 0.6%. The peeling resistance tests are all low. However, the A brick made of fused magnesia-chrome sand A has a relatively low breakage rate; the sintered magnesia-chrome sand C has a high compressive strength of 132MPa due to its good sinterability.