Abstract
Phytomining is a technique of rare-metal acquirement that uses metal hyperaccumulator plants as the substitution of mineral ore. To date several studys have been reported, but limited to the metals such as gold, nickel and cobalt. This time we report the potential of Mn hyperaccumulator Chengiopanax sciadophylloides for phytomining of high-quality manganese. About a half of C. sciadophylloides samples collected widely from several areas of Japan contained over 10,000 mg /kg d.w. (1%) Mn, and the highest concentration was reached to 2.4% in the leaves. About a half of Mn in the leaves was extracted easily with x100 volume of water, and almost 100% of Mn was extracted by 1 hour shaking in 0.1mol/L HCl. We also established the method of collection of high quality of Mn from C. sciadophylloides leaves. Sample was burned to ash, dissolved in sulfuric acid- hydrogen peroxide mixture, and then alkalized with 1 mol/L KOH. Mn was precipitated as manganese dioxide and separated from K, Ca and Mg. Collected Mn was purified over 94% at high collection rate (over 90%). From these results, we concluded that C. sciadophylloides could be used as substitution of Mn ore to gain high quality Mn.
