 4 ( Ln denotes a mixture of all the lanthanides except promethium ) , and the third is a fluorocarbonate LnCO3F . Monazite also contains thorium and yttrium , which complicates handling because thorium and its decay products are radioactive . For the extraction from the ore and the isolation of individual lanthanides , several methods have been developed . The choice of method is based on the concentration and composition of the ore and on the distribution of the individual lanthanides in the resulting concentrate . Roasting the ore and subsequent acidic and basic leaching is used mostly to produce a concentrate of lanthanides . If cerium is the dominant lanthanide , then it is converted from cerium ( III ) to cerium ( IV ) and then precipitated . Further separation by solvent extractions or ion exchange chromatography yields a fraction which is enriched in europium . This fraction is reduced with zinc , zinc / amalgam , electrolysis or other methods converting the europium ( III ) to europium ( II ) . Europium ( II ) reacts in a way similar to that of alkaline earth metals and therefore it can be precipitated as carbonate or is co @-@ precipitated with barium sulfate . Europium metal is available through the electrolysis of a mixture of molten EuCl3 and NaCl ( or CaCl2 ) in a graphite cell , which serves as cathode , using graphite as anode . The other product is chlorine gas . 
 4 ( Ln <a href='uninflect' title='1'><mark>denotes</mark></a> a mixture of all the lanthanides except promethium ) , and the third <a href='drop_aux' title='2'><mark>is</mark></a>a fluorocarbonate LnCO3F . Monazite also <a href='uninflect' title='3'><mark>contains</mark></a> thorium and yttrium , which <a href='uninflect' title='4'><mark>complicates</mark></a> handling because thorium and its decay products <a href='drop_aux' title='5'><mark>are</mark></a>radioactive . For the extraction from the ore and the isolation of individual lanthanides , several methods <a href='been_done' title='6'><mark>have</mark></a> been developed . The choice of method is based on the concentration and composition of the ore and on the distribution of the individual lanthanides in the resulting concentrate . Roasting the ore and subsequent acidic and basic leaching is used mostly to produce a concentrate of lanthanides . If cerium <a href='drop_aux' title='7'><mark>is</mark></a>the dominant lanthanide , then it is converted from cerium ( III ) to cerium ( IV ) and then precipitated . Further separation by solvent extractions or ion exchange chromatography <a href='uninflect' title='8'><mark>yields</mark></a> a fraction which is enriched in europium . This fraction is reduced with zinc , zinc / amalgam , electrolysis or other methods converting the europium ( III ) to europium ( II ) . Europium ( II ) <a href='uninflect' title='9'><mark>reacts</mark></a> in a way similar to that of alkaline earth metals and therefore it can be precipitated as carbonate or <a href='drop_aux' title='10'><mark>is</mark></a>co @-@ precipitated with barium sulfate . Europium metal <a href='drop_aux' title='11'><mark>is</mark></a>available through the electrolysis of a mixture of molten EuCl3 and NaCl ( or CaCl2 ) in a graphite cell , which <a href='uninflect' title='12'><mark>serves</mark></a> as cathode , using graphite as anode . The other product <a href='drop_aux' title='13'><mark>is</mark></a>chlorine gas . 
4 ( Ln denote a mixture of alll da lanthanides except promethium ) , and the third a fluorocarbonate LnCO3F . Monazite also contain thorium and yttrium , which complicate handling because thorium and its decay products radioactive . fa tdaextraction from thdare and the isolation of individual lanthanides , several methods done been developed . Thedaoice of method is based on the concentration and composition of the da and on the distribution of the individual lanthanides in the resulting concentrate . Roasting the ore and subsequent acidic and basic leaching is used mostly to produce a concentrate of lanthanides . If cerium the dominant lanthanide , then it is converted from cerium ( III ) to cerium ( IV ) and then precipitated . Further separation by solvent extractions or ion exchange chromatography yield a fraction which is enriched in europium . dis fraction is reduced with zinc , zinc / amalgam , electrolysis or other methods converting the europium ( III ) to europium ( II ) . Europium ( II ) react in a way similar to that of alkaline earth metals and therefore it can be precipitated as carbonate or co @-@ precipitated with barium sulfate . Europium metal available through the electrolysis of a mixture of molten EuCl3 and NaCl ( or CaCl2 ) in a graphite cell , which serve as cathode , usin graphite as anode . The odar product chlorine gas .