摘要
In recent years, the interest of the relationship between microelement and human health increased. Vanadium absence may have negative effects, and it also can be toxic if exposure occurs at high enough levels. It has strong transfer ability in environment. This ability related to the solubility of vanadium in soil solution. Panzhihua, Sichuan is an important production base of vanadium and titanium magnetite. The vanadium storage is 64% of the total vanadium in China. The vanadium mining and smelting accelerated the vanadium diffusion in soil and water. It causes special environmental problems of vanadium in Panzhihua. Different surface soil in the region, the average mass fraction of vanadium is over 100 X 10 (super -6) ,[1] far exceeding the background values of Chinese soil vanadium 86 X 10 (super -6) .[2] The amount of vanadium in the soil surrounding smelter is 16.5 times of contrast values. The amount of vanadium in the plant samples is 6.6 times of contrast values.[3] The solubility of vanadium in soil solution is effected by coexisting ions in soil, such as potassium, sodium, phosphorus and so on. In order to investigate the relationship of solubility between vanadium and the other co-existing ion in soil, the phase equilibria of the quinary system NaVO (sub 3) + KVO (sub 3) + NaH (sub 2) PO (sub 4) + KH (sub 2) PO (sub 4) + (NH (sub 2) ) (sub 2) CO + H (sub 2) O and its five quaternary sub-systems were studied at 298 K with isothermal dissoluble method. According to the experimental results, the crystallization form of metavanadate is polyoxovanadate in the weakly acid system. The dissolution and migration of vanadium in aqueous solution has negative correlation with H (sub 2) PO (sub 4) (super -) and (NH (sub 2) ) (sub 2) CO. The existing of K (super +) has little effect on the solubility of vanadium. This suggest that in similar soil environment, the solubility of vanadium was restrained by the increase of H (sub 2) PO (sub 4) (super -) and (NH (sub 2) ) (sub 2) CO, which can affect the transfer ability of vanadium.