Phosphate bonded castable

Phosphate bonded refractory castable is a castable refractory material prepared with phosphate as a binder. Commonly used phosphate binders include aluminum dihydrogen phosphate, sodium phosphate, and orthophosphate, while aggregates are divided into high alumina, clay, silicon, and magnesium.

Details

The composition of phosphate bonded refractory castables is similar to that of general refractory castables. Aluminum phosphate, phosphoric acid, and neutral and acidic aggregates only react slowly at room temperature. To give the castable room temperature hardening performance, a hardening agent must be used. Hardening agents include active aluminum hydroxide, talc, ammonium fluoride, magnesium oxide, alkaline aluminum cyanide, pure calcium aluminate cement, etc. Magnesium oxide is a commonly used hardening agent with good hardening effect, but the heat resistance of the magnesium phosphate generated by the reaction is poor, resulting in a decrease in hot strength. The hardening time of magnesium oxide as a hardening agent varies significantly with temperature.

The reaction of aluminum phosphate and phosphoric acid with aggregates can cause aging changes in the material due to the formation of insoluble substances, which means that the construction performance of the material decreases to failure after being stored for a period of time. When aluminum dioxide phosphate liquid is used as a binder, the following reactions can occur quickly, causing aging changes.

Physical and chemical indexes of products

Performance

Fireclay

High alumina

High aluminaII

AL2O3%

45

60

75

Volume density after drying g/cm3

2.23

2.34

2.6

Cold compressive strength MPa

110℃, 24h

26

28

34

1000℃, 3h

22.6

26

29

1400℃, 3h

32

31

41

Hot compressive strength MPa

1000℃, 3h

30

30

29

1400℃, 3h

6

9

8.6

Number of thermal shocks

800℃ (water-cooling )

>50

>50

>50

Linear change rate after burning %

1400℃, 3h

0.8

0.72

0.5

0.2MPa
Refractoriness under load/℃

0.60%

1140

1190

1250

4%

1410

1470

1450

Refractory materials with different indicators can be customized according to demand. Call 400-188-3352 for details