The invention discloses composite delayed coagulation type
magnesium phosphate cement and a preparation method thereof, and relates to the technical field of building materials, the composite delayed coagulation type
magnesium phosphate cement comprises a dead burned
magnesium oxide and mineral admixture mixture,
phosphate, a composite
retarder and glue-containing water, in the dead burned magnesium
oxide and the mineral admixture, the
mass ratio of dead burned magnesium
oxide to the mineral admixture is 3: 2, and the
mass ratio of phosphate to the composite
retarder to the glue-containing water is 1: 1. The
mass ratio of the dead burned magnesium oxide and mineral admixture mixture to the phosphate is 3: 1, the mass of the composite
retarder is 7-24% of the mass of the dead burned magnesium oxide and mineral admixture mixture, and the water-binder ratio in the glue is 0.18-0.20. The preparation method comprises the steps of high-temperature pretreatment of the mineral admixture, metering and
dry mixing of all the components and
cement mixing. The attapulgite and the kaolin which are treated at high temperature are mixed with dead burned magnesium oxide, so that the heat release rate at the initial stage of a
hydration reaction is reduced, the cement
setting time is prolonged, meanwhile,
micro holes and cracks in a cement matrix can be filled, the compactness of a
magnesium phosphate matrix is improved, and finally the strengths at different ages are improved.