Selective Precipitation And Separation Of Valuable Constituent In Blast Furnace Slags

China is rich in multi-elements and complex mineral resources,such as Baiyue-Ebo deposit in Baotou and magnetite in Panzhihua representatively. Due to complexity and fine grains, it is very difficult to smelt and dress. In general, iron smelting from complex ore is main purpose with comprehensive utilizations of other valuable elements. The majority of value-nonferrous metals components in raw ores were concentrated in molten slag.The blast furnace slag bearing RE elements is the middle product which Baiyue-Ebo ore directly smelt. During smelting process , Fe,P and Nb components were reduced and poured into ferrous phase, but Rare Earths were not reduced and concentrated into slag.The blast furnace slag containing about 25%TiC>2 are produced by smelting V-Ti bearing magnetite. Ti components are dispersedly distributed in perovskite, rich-titanium diopside and titanic pyroxene. It has been showed that Ti components were concentrated into perovskite phase by oxidization of molten slag.Base on "Selective precipitation" principle suggested by professor Sui, the precipitation and growth of calcium cerite phase in blast furnace slag bearing RE elements and the separation of perovskite phase in blast furnace slag bearing titanium was studied in this dissertation. The results as following:The morphology of the solidified blast furnace slag bearing RE elements was studied by means of SEM observation with the help of EDX qualitative analysis and XRD analysis. The experimental results show that the slag is consisted by calcium cerite (RE₂O₃·CaO·2SiO₂.),cuspidine (CaF₂- 3CaO·2SiO₂), fluorite (CaF₂) and calcium sulfide (CaS) . During slow-cooling process, most rare earths elements in the slag are concentrated into one phase, which was identified as calcium cerite.The isothermal and the non-isothermal precipitation behavior of the calcium cerite phase in RE-bearing blast slag were studied by quenching method. And the kinetics of precipitate process and crystal growth of calcium cerite phase was also analyzed. The experimental results show that the nucleation and growth of calcium calcium cerite phase is related to cooling rate a, i.e. the lower cooling rate can...