Characterization and extraction studies of rare earth elements in Apatite concentrate of Chadormalu plant (Iran)

摘要

Different samples have been prepared from different products in Chadermalu iron ore concentrator plant: Low intensity magnetite separator concentrate (magnetite concentrate), reverse flotation tail (final hematite concentrate), flotation concentrate (apatite concentrate), final tail (L.I.M.S. tail + reverse flotation concentrate+ apatite flotation tail). The samples were used for REEs distribution and origin studies. The assay of REEs was determined by ICPMS spectrometry. The amount of total (light and heavy) REEs were 9631, 291, 199, 2236 ppm and the distribution were 19.3, 3.6, 10.1, 67 percent in flotation concentrate (apatite concentrate), reverse flotation tail (hematite concentrate), magnetite concentrate and total tail respectively. About 19.3 percent of total REEs were distributed in apatite concentrate with an assay of 9631 ppm. Therefore further studies have been conducted on this product. According to the Xray studies the minerals of Fluorapatite, Ankerite and Calcite are the main mineral phases in apatite concentrate which the Apatite is dominant among them. The SEM microscopic studies are shown that the high amount of REEs distributed on Fluorapatite mineral. The results are clearly shown that the apatite concentrate that is a by product of iron dressing in Chadormalu plant, with a low economical value and left without any further treatment, can be used as a significant source of REEs. The extraction of a mixed rare earth elements from apatite concentrate was studied with the total dissolution of the ore in nitric acid. The parameters of acid concentration from 20 to 50 percent and solid to liquid from 30 to 50 percent were investigated and optimized in temperature, particle size, agitation rate and leaching time of 60 deg C , < 50 micron, 200 rpm and 10 minute respectively.