Distribution and forms of copper in copper tailings as influenced by lanthanum and Lolium perenne

The effect of lanthanum and growth of Lolium perenne on the distribution of different forms of copper in copper tailings was studied by pot experiments. The results showed that, the growth of Lolium perenne on the soil significantly enhanced the copper contents of exchangeable, carbonate combined, Fe-Mn oxides combined and organic combined forms of copper compared to the control group which without plant cultivation. While the copper content of the residual form decreased significantly. Compare to the group which without lanthanum, the vast majority of copper fraction was residual form, and the exchangeable form of copper was decreased when soil was added lanthanum. As the lanthanum concentration increased, the copper content of exchangeable, carbonate combined, Fe-Mn oxides combined and organic combined forms increased. The greatest increases were in the exchangeable and Fe-Mn oxides combined, while the carbonate combined forms changed the least. Cultivation of Lolium perenne and adding of lanthanum, the percentages in total Cu content of the exchangeable, carbonate combined, Fe-Mn oxides combined and organic combined forms enhanced compared to the group which cultivation of Lolium perenne but without lanthanum.