In-situ spinel-containing refractory castable combined with magnesium oxide, and preparation method of refractory castable

The invention relates to the technical field of refractory materials, and particularly discloses an in-situ spinel-containing refractory castable combined with magnesium oxide. The refractory castable comprises the following components: 50-80% of aggregate with a particle size of 0.075-6 mm, 0-40% of aggregate with a particle size of less than 0.075 mm, 0-20% of chromium-containing powder with a particle size of less than 0.075 mm and 0.1-10% of a binding agent. A water reducing agent accounting for 0.1-10% of the total weight of the above raw materials, an additive accounting for 0.1-10% of the total weight of the raw materials and water accounting for 5-10%of the total weight of the raw materials are added into the refractory castable. The binding agent is light calcined magnesium oxide. According to the refractory castable, high-temperature liquid phases can be reduced, the high-temperature mechanical property, the slag corrosion resistance and the permeation resistance of the refractory castable can be im