In this dissertation,the"phase transfer-aging"method was used to study the aging separation conditions of calcium citrate hydrate prepared from industrial solid waste phosphogypsum as raw material and ammonium citrate as phase transfer agent.Through single factor experiment and orthogonal experiment,the optimum aging separation process conditions were investigated and determined as follows:aging temperature 90℃,aging time 150min,stirring rate 400r/min.Under the optimum condition,the yield of hydrated calcium citrate reached 92.22％.According to FE-SEM and FE-TEM characterization,the prepared calcium citrate hydrate samples under optimized conditions are rectangular sheets with a length of about 1-10 μm and a width of about 1 μm.The results of XRD and TG analysis show that the prepared calcium citrate hydrate samples are calcium citrate tetrahydrate.The sample was prepared by carbonizing precipitation with calcium citrate hydrate as calcium source and CO2 as carbonizing precipitator.The results of XRD and FE-SEM analysis show that the prepared sample is the mixed phase of calcite(c)(JCPDS 86-2334)and aragonite(v)(JCPDS 72-0506)CaCO3 and its morphology is irregular spherical with a particle size of about 200nm.
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维普
