The refractory products are selected from the principle of selection of aluminum dihydrogen phosphate, especially non-fired refractory products and unshaped refractories. Their mechanical strength (structural strength) is mainly provided by aluminum dihydrogen phosphate. However, there are many kinds of aluminum dihydrogen phosphate for refractory materials, and the bonding mechanism is also different. Therefore, in actual production and use, suitable aluminum dihydrogen phosphate should be selected according to refractory material, molding or construction method, and use conditions. The selection principles are as follows:
The nature of the aluminum dihydrogen phosphate must be compatible with the properties of the refractory material being bonded. For example, the Kelly kiln considers acidic, neutral and weakly alkaline dihydrogen phosphates for acidic and neutral refractories. For alkaline refractory materials, acidic aluminum dihydrogen phosphate cannot be used directly. Neutral or alkaline aluminum dihydrogen phosphate can only be used. If it is used under reducing conditions, organic aluminum dihydrogen phosphate with high residual carbon can also be used.
The selected aluminum dihydrogen phosphate should be compatible with the molding method or workability (construction performance) of the material. The fired refractory products generally use temporary aluminum dihydrogen phosphate (such as lignosulfonate), while the non-fired refractory products generally use chemical aluminum dihydrogen phosphate (such as aluminum dihydrogen phosphate, water glass, etc.); Condensed and hardened aluminum dihydrogen phosphate at room temperature, such as hydration-bonded, or chemically bonded (hardener), or agglomerated (additional) aluminum dihydrogen phosphate, ramming and plastics Adhesive bonded or chemically bonded, or ceramic bonded aluminum dihydrogen phosphate is used; and the sprayed refractory material may be selected from aluminum hydride similar to the cast refractory.
The selected aluminum dihydrogen phosphate must be compatible with the high temperature performance of the material, and should not reduce or reduce the high temperature structural strength, corrosion resistance (corrosion) and slag penetration resistance of the material. For high alumina or clay castables, ordinary calcium aluminate cement or combined clay can be used as the aluminum dihydrogen phosphate, and corundum or corundum spinel castables should be pure calcium aluminate cement or reactive alumina. Used as aluminum dihydrogen phosphate.
