Effect of lithium ion on seed precipitation from sodium aluminate solution
(School of Metallurgy and Environment, Central South University, Changsha 410083, China)
Abstract: Effect of lithium ion in sodium aluminate solution on precipitation rate, lithium content, morphology, and crystallization of alumina trihydrate (ATH) was investigated. Results showed that increasing lithium ion concentration in solution improved the precipitation rate and lithium content in ATH, whereas reduced the mass fraction of lithium precipitation from solution. Lithium ion in solution generated the fine ATH, and thereafter significantly increased the total particle number due to the preferential nucleation. Elevating temperature or reducing lithium ion concentration decreased lithium content in ATH and reduced the fine particle amount. Moreover, lithium ion in the solution changed the morphology of ATH by improving the growth of the (110) and (200) planes of gibbsite. A large amount of fine bar- or flake-shaped ATH attached on the coarse particles also benefited the secondary nucleation and led to the poor strength of alumina. All results will further contribute to improving the quality of alumina.
Key words: lithium; sodium aluminate solution; seed precipitation; alumina trihydrate