Effect Of Additives And Impurities On Lithium Carbonate Crystallization

Lithium carbonate is a very important lithium salt which used widely in battery,glass,ceramics,lubricants,energy,medicine and other important industrial fields.With the growing of clean energy,the role of lithium carbonate is particularly important.The domestic research on the preparation of lithium carbonate has been relatively mature at present,but it still exists many problems about the products in the actual production process,such as agglomeration,dispersibility and poor fluidity.These problems can be adjusted by changing the lithium carbonate morphology.In this work,surfactant,polymer,surfactant/polymer,inorganic impurity ions are used to regulate the lithium carbonate.The’morphology,particle size,particle size distribution,the trend of the number of particles of crystal were characterized by XRD,SEM,laser particle size analyzer,FBRM,SEM-EDS.The main conclusions are as follows:1.Cationic surfactant cetyltrimethylammonium bromide(CTMAB)can ease the coalescence for fine crystal of lithium carbonate,promote crystal growth,increase crystal size;Non-ionic surfactant PGFE can change the morphology of crystal,induce the formation of irregular massive particles,increase the coalescence number of fine lithium carbonate crystal,increase particle size.The fluidity is improved and the wettability become lower.2.CTMAB/sodium polyacrylate(SPAA),polyacrylamide(PAM)/SPAA was added to the aqueous solution of lithium chloride and sodium carbonate reaction system.The morphology are petal-shaped spherical,the moisture content are decreased,the particle size is increased and the fluidity is remarkably improved for the lithium carbonate crystal.3.Investigated the influence polymers SPAA,PAM,Polyvinylpyrrolidone(PVP),Polyethylene glycol(PEG)on the lithium carbonate crystallization process,respectively.The results show that macromolecule polymer have a significant effect on the crystal morphology.The morphology of crystal varies with the change concentration of SPAA.Adding appropriate concentration of SPAA can obviously improve the phenomenon of sticky wall,reduce the moisture content,increase the particle size and improve the uniformity of the lithium carbonate crystal and in the end spherical lithium carbonate with a smooth surface can be obtained.The crystal morphology is also different with the change concentration of PAM,adding a suitable concentration of PAM can make the crystal size become larger,the moisture content become lower,the fluidity become better for lithium carbonate particles.In addition,adding a certain concentration of PVP,the amount of coalescence of the fine crystals of lithium carbonate was reduced,the morphology of crystals are changed from columnar to flake compared without additives.However,PEG has little effect on the morphology of the crystal.4.The XRD spectrum of the crystal which obtained after add the polymer have a good agreement with the standard spectrum of lithium carbonate,but the crystal orientation are changed,maybe the additive maybe adheres to the crystal surface or interact with the crystal surface.5.The presence of impurity ions can affect crystal morphology from needle to sheet impurity ions.However,the crystal size which SPAA and impurity coexist are smaller than which only SPAA,implying that inorganic impurity ions interact with SPAA and weakened the SPAA promote the impact of crystal growth.