Hydrometallurgical recovery of mechanochemically synthesized Ti-Mg alloy powder from milled Tio2-Mg powder mixture

摘要

Ti-Mg alloy has desirable mechanical and other properties but is difficult to form byudconventional ingot metallurgy. This work reports the results of a hydrometallurgicaludinvestigation on the recovery of Ti-Mg alloy powder synthesized fromudmechanochemical processing (MCP) of TiO2 with Mg (15 wt.% beyondudstoichiometric). The MCP synthesized alloy powder is intrinsically mixed with MgOudand other oxides of Ti. The objective was thus to find a leachant that can leach out theudby-products of the MCP process. Different inorganic and organic acid media, andudtheir combinations, were used to try and recover a pure isolated Ti-Mg powder.udFor comparison purposes, the dissolution of individual particulate polycrystallineudMgO and TiO2, and Ti-20Mg (obtained from milling blended elemental powders) wasudalso investigated. The study indicated that separation with inorganic acids (HCl,udH2SO4, and aqua regia) was not possible since as high as 80% of the milled Ti-Mgudalloy powder was dissolving, yet the target TiO2 was still undissolved under the sameudconditions. Recovery of Ti-Mg powder was not achieved with organic acids as welludbecause MgO and TiO2 showed marked resistance to dissolution and hence wouldudcontaminate the alloy powder. There was drastic co-dissolution of MCP TiO2-Mg inudcombined HCl/organic acids while the TiO2 resisted dissolution.