Separation And Extraction Of Ti-bearing Blast Furnace Slag And The Main Compenents In Hydrochloric Acid Leaching Solution

The vanadium titanium magnetite in Panxi areas is the world's leading multi-metal deposits, in which the titanium resource is very rich specielly. But as so far, the utilization rate of titanium in the vanadium titanium magnetite was only 15%. About 50% titanium with the iron ore was entry into blast furnace to become blast furnace slag. The quantite of TiO₂ in this blast furnace slag was about 20-26%. During 1970-1992, Panzhihua Iron and Steel Co. has been produced more than 30 million tons of slag which was posed in the West slag champ of Jinsha River bank, So there are about more than 600 million tons of TiO₂ contained by the blast furnace slag only in the West slag champ, and add at least 600 thousad tons of TiO₂ per year. According estimates, as so far, the amount of TiO₂ has been nearly 25 million tons, this is undoubtedly a great treasure of titanium resources. But, together with the slag, it was heaped up at the Jinsha River bank as industrial solid waste which not only counld not be utilized but also caused grave environmental and economic burden for the local place. How to develop and utilize this such high artificial titanium slag of secondary resources, particularly its titanium resources, has become an important and urgent issue.In this paper, a low temperature chemical metheod was used to separate titanium component from the Ti-bearing blast furnance slag according to its component performance characteristics. After the impurity components such as SiO₂, MgO, CaO and Al₂O₃ et al. were removed from the blast furnace slag, the titanium enriched relatevlly and which can be used for industrial production as titanium-rich materials. Then the separated and extracted of the main components from the acid leaching solution. There are 2 steps of test process: The first step is to make 5～6mol/L hydrochloric acid mixed with blast furnace slag, by slag/acid mass ratio of 0.9:1～1:1 ratio, at 100℃reaction for 4h. So that the major acid-soluble components of magnesium, aluminum, calcium were separated; The second step is to separate and extract the main components of CaO,MgO,Al₂O₃ and so on from the acid leaching solution by precipitation. Because of use sulfuric acid to leach blast furnace slag will produce calcium sulfate jelly, which could affecting the further leaching of slag, so in this paper hydrochloric acid was used as leaching agent.And during the whole reaction process (acid dissolve and hydrolysis), in fact TiO₂ didn't consume hydrochloric acid, for this principle, take advantage of the feature of strong ability to remove impurity of hydrochloric acid, use appropriate amount of hydrochloric acid to remove the slag of Ca, Mg, Al and other valuable elements from the Ti-bearing slag, so that Ti element enter into the slag as a form of H2TiO3 and the titanium concentrated into the resedue, and then by follow-up treatment to extract titanium from the residue.With a small amout of hydrochloric acid in the treatment of the Ti-containing slag to study the experimental conditions, mainly investigated the hydrochloric acid concentration, reaction time, reaction temperature and slag/acid mass ratio and so on, which effects the leaching rate on the titanium slag of calcium, magnesium, aluminum, titanium. By experiment, a lower TiO₂ and higher CaO, MgO and Al₂O₃ of the leaching rate conditions are obtained: hydrochloric acid of 6mol/L, reaction temperation of 100℃, time of 4h and acid residue of 1:1.The solid sediment of CaSO₄, Fe₂O₃, Al₂O₃, Mg(OH)₂ was respectively obtained by adjusting the pH of solution accoding to the difference of metal elements precipitation pH and the residues such as silicon was separated also. It must be attention that the solubility of CaSO₄ is changed with temperature when the separation of Ca. the results of experiment are 0.1928g/100g water at 10℃, 0.2097 at 40℃and down to 0.1619 at 100℃. The solution should be boiled for 1 hour or so to decrease the calcium content in solution. The residues of Mg, Al and silicon must be washed fully because there are NaCl in them. The main usefull components in the slag were been separated and extracted by the treatment of the acid leaching method.