Study On Releasing Characteristics Of Heavy Metal Ions Of Copper Sulfide-Mine Tailings

The sulfide-mine tailings is the main non-ferrous metal minerals tailings. The complicated phenomenon of ion release will take place under the conditions of air, rain and sunlight when the tailings are piled up naturally, and the heavy metal ions released out of the tailings will do harm to the environment. In this paper, the Copper sulfide-mine tailings in Guangxi province was taken as experimental sample, the static soaking experiments and dynamic leaching experiments were carried out to investigate the ionic release characterstics of heavy metal ions such as Cu²⁺, Zn²⁺, Pb²⁺, Cr³⁺.The conclusions can be summarized as follows:1. The ionic release process relates with pH of the solution, temperature, vibrating rate and the size of the tailings. A positive correlation between the release concentration of Cu²⁺, Zn²⁺, Pb²⁺, Cr³⁺ and temperature as well as vibrating rate can be observed. The release concentration of Cu²⁺, Zn²⁺, Pb²⁺, Cr³⁺ are negatively correlated with pH of the solution and the size of the tailings. This is in accordance with the research results of others. 2. The influence of the ratio of liquid to solid on ions release concentration is that ions release concentration, ions release amount and unit weight of releasing amount increase with the volume of soaking solution.3. The effect of sample amount on ionic release is that:(1) With the increase of sample amount, release concentration of Cu²⁺ and unit weight of releasing amount decreases, while ions release amount increases with the increase of sample amount, which is similar to the correlation between sample amount and release concentration of Pb²⁺; (2) There is a positive correlation between sample amount and release concentration of Zn²⁺, ions release amount and unit weight of releasing amount; (3) The effect of sample amount on release concentrations of Cr³⁺ and unit weight of releasing amount is slightly, but the release amount increases with the increase of sample amount.4. The bigger volume of vessel used to soak the tailings, the larger transect of the tailings pile. So the heavy metal ions are more possible to release out of the tailings. This indicates that compared with the tailings piled up, it is easier to release ions out of the loose tailings.5. In the range of conventional dosage of flotation reagents, the ion release concentration of Cu²⁺ is slightly affected by flotation reagents. But flotation reagents markedly influence the ion release concentration of Zn²⁺, Pb²⁺, Cr³⁺. And charged-air has the remarkable influence on ion release of Cu²⁺, Zn²⁺, Pb²⁺, Cr³⁺.6. The primary and secondary relations of Temperature, time, and pH affecting the ion release concentration of Cu²⁺ are: temperature＞time＞pH, and that of various factors affecting the ion release concentrations of Zn²⁺, Pb²⁺, Cr³⁺ are: temperature＞pH＞time.7,The release concentration of Pb²⁺, Cr³⁺, Cu²⁺ are little related with the grade of the tailings, which needs further research. But the release concentration of Zn²⁺ is affected by the grade of the tailings. When the grade of the tailings increases, the release concentration of Zn²⁺ goes up, which is possible to be related with metal activity of Zn.