Process for the preparation of lithium carbonate, characterized in that in a first process step a.), the calcium and magnesium ions are precipitated from a brine containing at least lithium ions, calcium and magnesium ions by means of addition of a precipitant, generating a supernatant, and then in a process step b.), the supernatant from a.) is contacted with at least one chelating resin containing functional groups of structural element (I) in which is the polystyrene copolymer skeleton and R 1 and R 2 independently of one another are -CH 2 COOX, -CH 2 PO(OX 1 ) 2 , -CH 2 PO(OH)OX 2 , -(CS)NH 2 , -CH 2 -p yridyl or hydrogen, where R 1 and R 2 cannot both simultaneously be hydrogen and X, X 1 and X 2 independently of one another are hydrogen, sodium or potassium, and in a process step c.), the mobile phase from process step b.) containing lithium in a concentration by weight of from 1 ppm to 500 ppm is contacted with at least one chelating resin containing functional groups of structural element (I) and a total capacity of from 2.0 mol/l to 3.5 mol/l in which and R 1 and R 2 have the meanings given in process step b.), and 30% to 96% of the total capacity of the macroporous, monodisperse chelating resin containing functional groups of structural element (I) are loaded with lithium, and in a process step d.), the lithium adsorbed on the chelating resin containing functional groups of structural element (I) in process step c.) is eluted by addition of inorganic acids and the eluate is optionally adjusted to a pH > 7 and optionally recycled back into process step c.) and in a process step e.), the lithium-containing eluate from process step d.) is admixed with at least one carbonate or with carbon dioxide or the acid thereof. in a first process step a.), the calcium and magnesium ions are precipitated from a brine containing at least lithium ions, calcium and magnesium ions by means of addition of a precipitant, generating a supernatant, and then in a process step b.), the supernatant from a.) is contacted with at least one chelating resin containing functional groups of structural element (I) in which is the polystyrene copolymer skeleton and R 1 and R 2 independently of one another are -CH 2 COOX, -CH 2 PO(OX 1 ) 2 , -CH 2 PO(OH)OX 2 , -(CS)NH 2 , -CH 2 -p yridyl or hydrogen, where R 1 and R 2 cannot both simultaneously be hydrogen and X, X 1 and X 2 independently of one another are hydrogen, sodium or potassium, and in a process step c.), the mobile phase from process step b.) containing lithium in a concentration by weight of from 1 ppm to 500 ppm is contacted with at least one chelating resin containing functional groups of structural element (I) and a total capacity of from 2.0 mol/l to 3.5 mol/l in which and R 1 and R 2 have the meanings given in process step b.), and 30% to 96% of the total capacity of the macroporous, monodisperse chelating resin containing functional groups of structural element (I) are loaded with lithium, and in a process step d.), the lithium adsorbed on the chelating resin containing functional groups of structural element (I) in process step c.) is eluted by addition of inorganic acids and the eluate is optionally adjusted to a pH > 7 and optionally recycled back into process step c.) and in a process step e.), the lithium-containing eluate from process step d.) is admixed with at least one carbonate or with carbon dioxide or the acid thereof. <EOS>