稀土在土壤中运移数值模拟研究

９种不同性质土壤Ｃｅ和Ｎｄ吸附和度达５０％时，用同位素示踪法和数值模拟法对ＲＥ运移进行比较，发现两者对极大多数土壤有较好的拟合性。说明该数值模拟程序对预测稀土长期在土壤中运移具有一定的可靠性。预测结果表明，在自然降雨量情况下，ＲＥ吸附饱和度１０％时，在吸附容量小的酸性土壤中，ＲＥ下移约每年１ｃｍ，吸附容量中等的中性、策酸性土壤，每两年约下移１ｃｍ而吸附容量较大的碱性土壤，ＲＥ很难被雨水运移。

Numerical Simulation of RE Migration in Soils

omparison of numberical simulation with isotopic tracer reveals that, these two methods fit in with each other fairly well in most of the 9 types of soil on condition that the adsorption saturation of Ce and Nd was 50%, indicating the reliability of the numerical simulation program in predicting the distance of long term RE migration. Under the natural precipitation, the migration distance predicted by this program turns out to be 1 cm annually in the case of RE adsorption saturation at 10% for the acid soils with low absorbing caoacity, 1 cm biannually for the slightly acid soils with moderate capacity, and no migration for the alkaline soils with high capacity.