توصيفگر ها :
بازيافت , تالك , مجتمع گل گهر , فلوتاسيون , ليجينگ , جدايش مغناطيسي
چكيده انگليسي :
Gol-Gohar iron ore processing complex has 7 iron ore processing lines. These lines have three waste thickeners named as central thickener, enrichment thickener and Polycom. The thickener feed has passed all stages of the magnetic separation and many iron-containing minerals are removed by magnetic drums and a small part along with talc goes to the tailings. In the beginning, sampling from thickeners, mixing samples, mineralogical studies and their XRD and XRF analyses were performed. The results of XRF analysis showed that the tailings had an average of about 12% iron, and there was also about 34% talc in these tailings, which was a significant amount. From the XRD analysis, it was found that talc was one of the main phases in the tailings. After preparing the samples, flotation, magnetic separation and finally leaching tests were performed on a laboratory scale and the results were analyzed. At first, several tests of low intensity magnetic separation (LIMS) with field intensity of 1500 G with solid percentage of 10, 20 and 30% and high intensity magnetic separator (HIMS) in the intensities of 2500, 3500, 4500, 5000 and 8000 G were done. The results showed that in the optimal conditions of the magnetic tests, about 54% of the iron in the feed could be removed. According to the results of the magnetic separation tests, it can be said that despite the increase in the magnetic field intensity, there was no significant improvement in the removal of iron. Therefore, using the magnetic field intensity of 1500 G was sufficient to remove as much iron as possible. To determine the optimal chemicals for flotation, initially 10 tests with different chemicals, such as polypropylene glycol and MIBC as frother, oil and oleic acid as collectors, dextrin and starch as inhibitors, and sodium hexametaphosphate as dispersant at pH 7 and 11 was conducted. The results showed that, if MIBC was used as a frother, a product with 4.9% iron could be obtained. The results showed that if only one foaming agent was used, it would be possible to obtain talc concentrate with a purity of more than 97% and a weight recovery of about 5%. Also, several flotation tests were performed with regard to the optimal results of flotation on the non-magnetic product. The results of these tests showed that it was possible to obtain talc concentrate with a purity of 84.7% and a weight recovery of 14.8% with 1.4% of iron. The results of the supplementary flotation tests showed that the use of oleic acid and oil greatly increased the recovery and decreased the grade, and also the use of starch did not have a great effect on iron depression, on the other hand, the use of sodium hexametaphosphate dispersant improved the grade. The optimal supplementary flotation test was carried out by using MIBC and sodium hexametaphosphate in three stages of rougher, cleaner and re-cleaner. The results of the supplementary flotation test of the rougher stage showed that a product with 2.4 iron and 79% talc purity obtained with a weight recovery of 17%. In the cleaner stage, a product with 3.8 iron and 93% talc and 11.2% weight recovery was obtained. Finally, the re-cleaner stage showed that it was possible to obtain a product with 1.3% iron, 97.6% talc and 7.5% weight recovery. Finally, in order to remove more iron in the final concentrate of the re-cleaner test, leaching tests were performed with sodium dithionite and oxalic acid under different conditions. The results of these tests showed that leaching with oxalic acid had a greater effect on the iron removal. In these experiments, temperature had less effect than the solid percentage and oxalic acid concentration. The results of these experiments showed that in the optimal conditions of leaching, i.e. temperature of 80 °C, solid content of 7.5%, 1 M oxalic acid and pH = 2 in a period of 2 h, the percentage of iron could be reduced to 0.8%.
