Hydrometallurgy liquid-liquid extraction technology to extract scandium metal
solvent extraction are mainly liquid liquid extraction, its basic principle is to make the extraction material and extraction agent combined into without charge, poorly soluble in water and soluble in organic solvents of aojiang compound, at the same time by organic solvent extraction. In the leaching liquid � � � into a certain amount of organic solution as extraction agent, and metal ions, formation of complex compound into organic solvent, thereby realize the concentration of the metal enrichment, improve the selectivity of metal ions, become a kind of method for obtaining the best pretreatment of rare metals.
1 extraction instance 1. 1
of extracting scandium element scandium distributed widely and widely exists in GongShengKuang, such as stone coal, phosphorus salt and scandium qin magnetite ore deposit, the grade at 0. Between a 5% and 2%. Therefore appropriate USES hydrometallurgy is extracted, the traditional extraction process for sodium roasting monohydrate dip a acid precipitation, alkali soluble hinge salt precipitation flops scandium acid hinge pyrolysis, the biggest drawback is sodium salt consumption is big, the production cost is high, the emissions from a large number of HCI, Cl2 and other poisonous gases and waste water, on the surrounding environment pollution is serious, burning kiln covers an area of big, bad for mechanized production, scandium recovery is only 40% ~ 50%.
along with the continuous improvement of the technology of scandium, has achieved a more environmental protection, economy of scandium process, and has widely applied in many companies, have achieved good economic benefits, the process is shown in figure 1.
soaking with sulfuric acid containing scandium mineral, can leach 80% of scandium, with P204 (then 2, 2 - Ethyl hexyl) Phosphoric acid) And the TBP ( Tributyl phosphate) Sulfonated kerosene solution for extraction, P204 as acid extraction agent, so need NaOH solution will leach liquor pH adjustment to 1. 5 - 2. 0, after 3 ~ 4 extraction can continue to back washing with sulfuric acid solution, under the appropriate acid concentration on loaded organic phase 2} Reverse extraction, so as to extract the scandium, then used sodium chlorate oxidant such as oxidation of the extract, the price of five scandium, sunken scandium by salt precipitation in scandium acid according to the form, the calcine precipitation again can obtain high purity V205 0
the above process adopts the ore direct leaching, reduced sodium roasting process, in which exhaust pollution, the production of sewage and waste residue after lime milk neutralization treatment can direct emissions.
1。 The extraction of scandium
2 sharp for the scattered elements, its distribution characteristic is fragmented and content is very few, grade ( Sc2O3) At zero. 025% ~ 0. 05%, most of the occurrence in bauxite, phosphate rock, or after the selected tungsten, chin and rare earth elements in the tailings has a certain amount of scandium.
among them, the kia white waste acid is sulfuric acid method from qin in iron making qin white powder of waste liquid and waste liquid containing 5 ~ 20 mg/L of scandium, by P204 and recycle the TBP kerosene synergistic extraction and reverse extraction, at the same time, need to get rid of the qin qin, iron, manganese and other interference in ore impurities, extracted from qin white waste acid oxidation process of sharp as shown in figure 2.
in the process of extraction, 25% P204 the TBP + 4% + 61% kerosene mixed organic solvent for extraction, and iron and manganese in the hydrochloric acid washing, and to extract suitable for the extraction of pH value. After removing impurity with NaOH as an extraction solvent for extraction, extraction of sediment in hydrochloric acid solution with Na2CO3 adjust the pH value of solution, heat to boil the Ti ( 哦) 4 hydrolysis for Ti02, thus get rid of the qin. To fully in addition to qin, secondary extraction must be conducted in removing impurity, then through extraction, by secondary oxalic acid precipitation, filtration, burning purification, can obtain high purity of Sc2O3.
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