EXPERIMENTAL STUDIES ON INTERACTION OF COPPER,SALT AND ORGANIC MATTER
Zhuang Hanping; Ran Chongying; Lu Jialan (① Institute of Geochemistry, The Chinese Academy of Sciences, Guiyang 550002)(② Geology Department, Kunming Institute of Technology)(③ Guangzhou Institute of Geochemistry, CAS)
A series of experiments were carried out to investigate the mechanism of mobilization and transport of copper in the system of coexisting metallic copper, salt and organic matter. The results demonstrated that there were various mobilization abilities among various reaction agents. Alanine might be potential factor for copper mobilization, with a higher copper concentration of 236.45 × 10￣(-6) at the temperatures lower than 150℃. Fulvic acid could not mobilize effectively copper dispersing in rocks due to its being absorbed by clay minerals. However, it is impossible for cysteine to activate copper from rock because it would decompose and form H_2S even at lower temperatures. Among the inorganic solutions, CaCl_2 and NaCl solutions had potential ability to activate copper, and could reach a copper concentration of 339.6 × 10￣(-6) under appropriate conditions. The HCO- and SO-bearing solutions could, at some cases, leach copper in which copper concentrations exceeded the limit for mineralization.Mobilization and transport of copper were related to the characteristics of organic matters in the water-rock reaction system of coexisting metallic copper, salt and organic matter. At the temperatures lower than 100℃, fulvic acid is difficult to transport copper due to its flocculating in high concentration salts. However, alanine and salts enhance the mobilization ability of copper so as to reach a maximum copper concentration of 460×10￣(-6). Organic matter would decompose when t100℃,and organic ligands were replaced gradually by inorganic ones and the latters occupy predominant position in the mixing solution. The activation abilities of salts are controlled by HS formed due to decomposing of cysteine in the solution of cysteine and salts, and copper could not be transported in this mixing solution. In addition,mobilization of copper was related to the associations of copper in samples, and copper in absorption state was easily activated.