Aluminum dihydrogen phosphate should be used as binder for phosphate heat-resistant concrete.

 Phosphoric acid or phosphate heat-resistant concrete

The heat-resistant concrete is made of phosphate or phosphoric acid as cementing agent and heat-resistant aggregate. It is a kind of heat-resistant hard concrete. The use temperature of phosphate heat-resistant concrete is generally 1500 ~ 1700 ℃, and the highest temperature can reach 3000 ℃. However, phosphate refractory concrete can withstand multiple cold and heat cycles of - 30 ~ 2000 ℃ without damage. There are mainly aluminum, sodium, potassium, magnesium, ammonium phosphate or polyphosphate, of which aluminum, magnesium and sodium phosphate are most used.

Aluminum phosphate is generally a mixture of aluminum dihydrogen phosphate, aluminum hydrogen phosphate and aluminum orthophosphate, of which aluminum dihydrogen phosphate has the strongest cementation. When aluminum phosphate is used, appropriate amount of fused or sintered magnesium oxide, calcium oxide, zinc oxide and ammonium fluoride can be added as hardening accelerator in order to accelerate the hardening of concrete at normal temperature, and alkaline oxide ( such as Portland cement ) containing binding state can also be used as hardening accelerator.