Aluminum Phosphate Refractory Castable

Aluminosilicate phosphate refractory castables are the most commonly used varieties, with a service temperature of 1400~1600℃. The concentration of phosphate binder is 40%~60%, and the dosage is 10%~14%; aluminate cement is commonly used as a coagulant, with a dosage of 0.5%~3.0%. If magnesium oxide is used as a coagulant, the dosage is 0.3%~1.0%.

There are many kinds of aluminum phosphates, the most commonly used is aluminum dihydrogen phosphate, also known as dihydrogen aluminum phosphate, collectively referred to as aluminum phosphate. In addition, magnesium phosphate, sodium phosphate, zinc phosphate, boron phosphate, calcium phosphate and ammonium phosphate can also be used as binders, but they are rarely used in actual projects. Aluminum phosphate binder can be used in combination with any refractory raw materials to make refractory castables with better performance and obtain a good soft use effect. However, when used in combination with magnesium materials, due to the strong chemical reaction, inhibitors or retarders need to be added before construction.

 

The preparation process of aluminum phosphate refractory castable is the same as that of phosphoric acid refractory castable. It should be pointed out that before using aluminum phosphate solution, it should be stirred evenly before use. If aluminum phosphate solution is prepared on site, it should be left for a day and night, stirred evenly before use, and the density should be measured at the same time. It can only be used after meeting the requirements.

The type and amount of coagulant have an impact on the performance of aluminum phosphate refractory castables. In general, when aluminate cement is selected as a coagulant, it is advisable to add as little coagulant as possible while ensuring the technical requirements of room temperature strength; the concentration and amount of aluminum phosphate solution also affect its performance. Generally speaking, the concentration of aluminum phosphate solution is about 50%. Under the condition of ensuring the workability of the material, aluminum phosphate solution should be added as little as possible; when solid aluminum phosphate is used, its amount is not more than 7%, and the mixing water amount is not more than 14%. The amount of the two should be selected appropriately, which can reduce costs on the one hand and improve the performance of refractory castables on the other hand; when MgO fine powder is used as a coagulant, it will undergo a polymerization and dehydration reaction with aluminum phosphate, so that the refractory castable obtains room temperature strength.

The characteristics, preparation methods, raw material technical requirements, particle grading, coagulation and hardening mechanism and application of phosphoric acid and aluminum phosphate high-alumina refractory castables are basically the same as those of silicon phosphate refractory castables. At the same time, magnesium phosphate solution is also used to prepare siliceous refractory castables, whose performance is similar to that of aluminum phosphate siliceous refractory castables, but the strength at low temperature stage is slightly lower. Magnesium phosphate solution is prepared with 50% phosphoric acid and industrial magnesium hydroxide in a mass ratio of 7:1. The prepared magnesium phosphate solution needs to be left to stand for a day and night and filtered to remove impurities before use.

Hot Tags: aluminum phosphate refractory castable, China aluminum phosphate refractory castable manufacturers, suppliers, factory, Hot Blast Furnace Refractory Spray Coating, Refractory Repair Material, Silicon Carbide Ramming Mass, Self-flowing Castables, Refractory Ramming Mass, High Strength and Wear-resistant Castable