The Preparation Of Organphosphorus Extractants And In The Study Of Extraction Of Lithium Ions

Lithium,compounds of lithium, and lithium alloy, because of its excellentcharacteristics, showed an increasingly important role in the modern industry, dailylife, and the field of science and technology,expecially lithium batteries commonly areused in everyday life. Salt lake lithium resources are abundant and competitive forlow extraction costs, small power consumption, therefore extracting lithium from SaltLakes Brine by resources is the general trend. However, because the properties ofmagnesium and lithium is very similar, and coexist in salt lake brine, extractinglithium from salt lake brine is very difficult, but in China there are more salt lakebrine with high magnesium lithium ratio, so extracting lithium from salt lake brinewith high magnesium lithium ratio is still a big problem.Oxygen of phosphoryl in the organphosphorus extractants is a strong electrondonor.According to HSAB, the atom belongs to strong base and it tends to form astrong bond with lithium which belongs to strong acid. On these grounds，a kind oforganophosphonic resin and organophosphonic extraction agent have beensynthesized, and are applied to Li-Mg separation research in hope for finding newmaterial which is able to extract Li selectively from high Li-Mg ratio salt lake brine.In the first system novolac were penetrated in polyurethane foam to formimprove commixed foam. Via bromine methylation reaction、diethyl phosphitenucleophilic substitution reaction and Arbuzov rearrangement reaction, theorganophosphonic resin was gained. The synthetic products were characterized. themeasured results was compared with the Gaussian theory calculation results in orderto confirm the existence of the main functional groups of synthetic products. theorganophosphonic resin was conducted in lithium magnesium separation adsorption experiment. The experimental results show that organophosphonic resin has asaturated adsorption capacity of lithium ion for2.3mmol/g, while0.56mmol/g whenit replaced with Mg ion.As lithium ion can form complex which the best coordination number is5,crown ether and Organophosphonic extraction system are applied together in thesecond system. Hydroxyl (4-hydroxyl phenyl) methyl diethyl phosphate extractingagent and1,1,6,6,11,11,16,16-octan ethyl-21,22,23,24-tetraoxaquaterene weresynthesized. Structure of two synthetic products were characterized. Then they wereapplied to liquid membrane ion transportation evaluation experiment of U-tube. Theexperimental results show that when crown ether alone is used separated as extractionagent to proceed U tube liquid membrane ion transportation experiment, almost notransmission effect of both of lithium and magnesium ion was proved, while hydroxyl(4-hydroxyl phenyl) methyl phosphate diethyl used in u-tube liquid membranetransport experiments, a little transmission ability of the lithium and magnesium ionwas possessed. On condition of initial concentration ratio c(Mg2+)/c(Li+)=75.89/9.857=7.7（time）,the average rate of organophosphorus transporting lithium, magnesiumions is0.073mmol/h、0.31mmol/h，selectivity coefficient is0.24. While crown etherand hydroxyl (4-hydroxyl phenyl) methyl phosphate diethyl extracting lithium、magnesium ions together in U-tube liquid membrane transport experiments, oncondition of initial concentration ratio c(Mg2+)/c(Li+)=75.89/9.857=7.7(time), theaverage collaborated extracting transportation rates of lithium、magnesium ion arerespectively：1.31mmol/h、0.31mmol/h，the selectivity coefficient is4.2. It showedthat when organophosphorus and crown ether extract ion together，the transportationrate of lithium increased much, the rate increased to18times, the selectivitycoefficient improved17.5times.