Dolomite sand loses strength or even powders due to the action of water in the environment. Dolomite powder is the hydration of dolomite sand. The degree of hydration is generally expressed by the rate of hydration weight gain. The hydration resistance of dolomite sand is very important for the production, preservation and use of dolomite refractory products.

The main methods to improve the hydration resistance of dolomite sand and magnesia dolomite sand are:

①Improve the volume density of the clinker and reduce the penetration of water or steam in the air.

②Add additives to form a low-melting phase to cover the surface of calcite crystals, reducing the contact of calcite with water.

③ Surface treatment of clinker.

Dolomite powder price

The hydration resistance of high-purity dolomite sand mainly depends on its calcination temperature. As shown in Figure 1a, when the calcination temperature increases, the size of periclase and calcite crystals increases, which increases the resistance to hydration; the same relationship is also reflected in the effect of the clinker porosity on the resistance to hydration. The hydration resistance of the material is improved, as shown in Figure 1b. Therefore, all measures to increase the density of dolomite sand are beneficial to the improvement of its hydration resistance.

Crystal size and porosity and the hydration resistance of dolomite sand

The addition of Fe2O3, ZrO2 rare earth oxides and their mixtures can significantly improve the hydration resistance of dolomite sand. Figure 2 shows the effect of Fe2O3, La2O3, CeO2 and compound addition (REO 0.50%, Fe2O3 0.25%) on the anti-hydration performance of dolomite clinker (fired at 1600℃×4 hours). It can be seen that the addition of Fe2O3 and mixed rare earth The composite effect of oxides. The reason why additives improve the anti-hydration ability of dolomite sand is that one is to increase the density of clinker; the other is that rare earth additives promote the development and growth of periclase and calcite crystals; and the third is that it exists in periclase and The rare earth oxides such as C2F, C4AF, C3S and CeO2 between the calcite grain boundaries separate and surround the calcite crystal grains.