The Experimental Study of Preparation of Unburned Ceramsite and Its Reaction Mechanism

This experiment adopts steam curing method to prepare unburned fly ash ceramsite using power plant fly ash, cement, lime, gypsum as main raw material, CaCl₂, Na₂SO₄ and NaCl as activating agent, through a single factor experiment to prepare the unburned fly ash ceramsite and obtain the optimal dosage of materials, then analyzing the reaction mechanism of different materials in the reaction system. The results shows that the optimum dosage of fly ash, cement, lime, gypsum, CaCl₂, Na₂SO₄ and NaCl is 16g, 32g, 1.6g, 0.4g, O.lg, 0.4g, O.lg respectively. And, cement and lime can provide an effective alkaline environment to fly ash, but excessive amount of cement and lime will lower the strength of ceramsite. Gypsum can provide Ca²⁺ sources to the system, and have the role of dispersant, both of which can make the ingredients of system have a full reaction, but excessive gypsum can reduce the ceramic strength. CaCl₂, Na₂SO₄ and NaCl as activating agent, provide a sufficient alkaline environment for the reaction of the initial system, and can efficiently increase the initial strength of ceramsite, so it is helpful for the strength of ceramsite to add some suitable activating agent.