Post Date: 4,Jul,2022
Some industrial circulation equipment for a long time in 900℃-1100℃ temperature state of work, refractory materials at this temperature is difficult to achieve ceramic sintering state, seriously affect the performance of refractory materials, sodium hexametaphosphate in refractory castable, spray in the applicable performance of the advantage is a stable good compressive strength and wear resistance and thermal shock resistance, A substance that helps to strengthen the binding structure of refractories, allowing powdery or granular refractories to bond together to show sufficient strength.
In the long developing cycle equipment, boiler, for example, due to the burning particulate fluidization velocity, high temperature of furnace lining refractory has strong erosion, wear, especially in areas such as the boiler combustion chamber and cyclone separator under grain, air flow and smoke medium wear and thermal shock effect, lead to refractory lining erosion, wear, peeling off and collapse, It seriously affects the normal operation and production of boilers.
Therefore, it is necessary to develop a new type of binder with high temperature resistance, erosion resistance, wear resistance and thermal shock resistance to improve the performance of refractory materials.
Sodium hexametaphosphate has advantages in the application of refractory castable, spray filler, through the selection of the composition ratio and preparation process parameters, the binder is a suspension and dispersion system with neutral pH value, not only strong adhesion and non-corrosive to the metal matrix, high temperature resistance and non-inorganic binder application temperature range is wide. Sodium hexametaphosphate is hydrolyzed to sodium dihydrogen phosphate (NaH2PO4) when used as a binder in refractory castable and spray filler.
NaH2PO4 and alkaline earth metal oxides, such as magnesia, can react at room temperature to form Mg (H2PO4) 2 and MgHPO4, which can be condensed into magnesium phosphate [Mg (PO3) 2] N and [Mg2 (P2O7)] N respectively by heating at about 500℃. The strength of the combination is further improved. It has a high strength over a wide temperature range (up to 800℃) before the re-emergence of the liquid phase.
Sodium hexametaphosphate is mainly used as a binder for magnesia and magnesia chrome unfired bricks, castables and basic shotfilling materials. In the preparation of castable, the concentration of its aqueous solution should be selected 25%~30% is appropriate, and the amount of addition is generally 8%~18%. Under the premise of ensuring the workability of the mixture, it should be used as little as possible to ensure the high temperature performance of the material. The coagulant may be aluminate cement or other calcium-containing materials.
Refractory materials are important basic materials for iron and steel, building materials, non-ferrous metals, petrochemical, machinery, electric power, environmental protection and other high-temperature industries. Sodium hexametaphosphate binder is also an indispensable important material for various high-temperature industrial thermal furnaces and equipment.
Post time: Jul-05-2022
