Study On Separation And Adsorption Of Titanium(?) From High Sulfur Bauxite Calcined Leaching By Task-specific Waste Materials

It is a high efficient and green technology to recover and separate of titanium ions from high sulfur bauxite leaching solution by solid-liquid adsorption,not only for the benefit of environment protection but also great economic value.In this thesis,several wastes were used as raw materials to prerare different characteristics of adsorbents,and Ti???exists in the form of TiO²⁺ in the leaching solution.The adsorption behaviors of the adsorbents towards titanium ions were investigated systematically,such as the adsorption kinetics,thermodynamics and the adsorption mechanisms.Results are shown as follows:First of all,raw material sodium alginate was prepared from seaweed.Then it was impregnated with extractant P204,obtained an adsorbent named CA-P204.As a comparative experiment,D301 resin impregnated with extractant P507 and TBP mixture have been prepared,obtained an adsorbent named D301-TBP-P507.The gels were characterized by FTIR and SEM,which were confirmed as successful modification.The maximum adsorption capacity of Ti???for CA-P204 and D301-TBP-P507 were 66.79 mg g^-1 and 55.61 mg g^-1.The results of regeneration and durability show that CA-P204 has better stability and cycling ability,so it can be concluded that CA-P204 has better adsorption performance than D301-TBP-P507.Adsorption mechanism for Ti???by CA-P204 is ion exchange and coordination.Experimental results show that the adsorption process accords with Langmuir single molecule adsorption and pseudo-second-order model.Moreover,its excellent adsorption properties and applicability for Ti???were demonstrated by the recovery and separation of Ti???from high sulfur bauxite leachate by dynamic adsorption column experiment.Secondly,the THB-EN-Cl-CPT were prepared using Persimmon tannin as a raw materials.The synthetic steps include curing,chlorination,ammoniation and Schiff base functional.The maximum adsorption capacity was evaluated as 47.22 mg g^-1.The THB-EN-Cl-CPT gel was characterized by FTIR,SEM,Surface functional group titration,which was confirmed as successful modification.The adsorption mechanism is chelation and ion exchange reaction confirmed by FTIR and XPS.THB-EN-Cl-CPT gel can be used repeatedly at least three times without significantly losing the adsorption capacity for titanium.Thirdly,high sulfur bauxite is considered as a potential supplementary for the recovery metals from solutions.In order to make full use of high sulfur bauxite,TiO₂-slag gels were prepared with the leaching slag and TiCl₄ as titanium source by sol-gel and high-temperature calcination crystallization method.In a single system,the adsorption rate of Ti???has reached 95%,and the maximum adsorption capacity of Ti???was evaluated as 45.10 mg g^-1.It is found that the adsorbent has good adsorption performance and selectivity for Ti???.The TiO₂-slag gel was characterized by FT-IR,SEM,XRD,N₂ adsorption and XPS,which showed that TiO₂ was successfully immobilized on the surface of slag.The adsorption mechanism could be explained by the fact that the hydroxyl groups on the surface of the adsorbent reacted with Ti???.The recovery of Ti???can still reach more than 85 % by using 1 mol L^-1 H₂SO₄ as eluent and three elution-cycle experiments.