Hydration resistance of dolomite sand

Dolomite sand loses strength or even pulverizes due to the action of water in the environment, which is the hydration of dolomite sand. The hydration degree of dolomite sand price is generally expressed by the hydration weight gain rate. 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:

①Increase the bulk density of clinker and reduce the penetration of water or water vapor in the air.

②Add additives to form a low melting point phase covering the surface of the calcite crystal, reducing the contact between calcite and water.

dolomite sand price

③ Surface treatment of clinker.

How much is dolomite sand

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

Crystal size and porosity and hydration resistance of dolomite sand

The addition of Fe2O3, ZrO2 rare earth oxides and their mixtures can obviously improve the hydration resistance of dolomite sand. Figure 2 shows the effect of adding Fe2O3, La2O3, CeO2 and compound additions (REO 0.50%, Fe2O3 0.25%) on the hydration resistance of dolomite clinker (fired at 1600℃×4 hours). The composite effect of Fe2O3 and mixed rare earth oxides. The reason why the additive improves the hydration resistance of dolomite sand is that firstly, it increases the density of clinker; secondly, the rare earth additive promotes the development and growth of periclase and calcite crystals; The rare earth oxides such as C2F, C4AF, C3S and CeO2 between the calcite grain boundaries separate and surround the calcite grains.