Hardening effect and application of aluminium dihydrogen phosphate

The hardening mechanism of phosphate bonded high alumina refractories is the result of chemical reaction and adhesion between phosphate cementing agent and materials. The chemical reaction is due to the formation of water-bearing aluminum dihydrogen phosphate, aluminum monohydrogen phosphate and their polymerization. The complete neutralization of orthophosphate and phosphate in the cementing agent results in the formation of water-insoluble aluminium phosphate, which gives the material strength.

The original or newly formed phosphate in cementing agent was initially in colloidal state in the material, while there was a colloidal film of phosphate or orthophosphate on the surface of the material particles, which played an adhesive role, but the strength was low. In the drying process, the material loses physical water and part of chemical bound water due to heating, which increases the concentration of phosphate. At the same time, during the heating process, phosphate reacts with oxides, and aluminum dihydrogen phosphate is converted to aluminum monohydrogen phosphate, so that the material changes from adhesion to chemical action. Heating contributes to the formation of new compounds in cementing agents and improves the adhesion properties. The curing principle of aluminium dihydrogen phosphate is also improved. The colloidal phosphate is transformed into crystalline form. The use of aluminium dihydrogen phosphate curing agent improves the strength of materials. With the increase of heating temperature, the strength increases further, which is due to the formation of chain and ring tetrahedrons of aluminium phosphate and alumina to form a polymer framework.

Phosphate-bonded high alumina refractories have virtually no strength loss or little loss when heated at medium temperature (300-1000C). This is because the chemical bonding water is gradually lost and the phosphate bonding is gradually replaced by the ceramic bonding.

Yucai Phosphate Chemical Plant specializes in producing: sodium hexametaphosphate, sodium pyrophosphate, sodium tripolyphosphate, sodium hydrogen phosphate, industrial phosphoric acid, trisodium phosphate, aluminum dihydrogen phosphate, solid aluminum dihydrogen phosphate, liquid aluminum dihydrogen phosphate, sodium dihydrogen phosphate and other phosphate series products after more than 30 years of continuous pursuit and development, relying on skilled chemical technology and product development, equipment updating and many universities. Established a good cooperative and sharing relationship, in the chemical industry played a (Yucai phosphate) brand!