﻿y-Rays 
  of 
  Uranium 
  and 
  Radium. 
  623 
  

  

  2. 
  TJie 
  Separation 
  of 
  Uranium 
  X. 
  

  

  We 
  have 
  found 
  the 
  original 
  methods 
  of 
  Sir 
  William 
  

   Crookes 
  (Proc. 
  Roy. 
  Soc. 
  1900, 
  Ixvi. 
  p. 
  409) 
  the 
  most 
  useful 
  

   in 
  the 
  separation 
  of 
  uranium 
  X. 
  W^ithout 
  entering 
  in 
  the 
  

   present 
  paper 
  into 
  any 
  detailed 
  description 
  of 
  the 
  methods 
  

   employed 
  and 
  of 
  the 
  numerous 
  trials 
  which 
  have 
  led 
  to 
  their 
  

   selection, 
  it 
  is 
  necessary 
  to 
  give 
  in 
  outline 
  some 
  description 
  

   of 
  the 
  process 
  of 
  separation 
  which 
  has 
  been 
  found 
  most 
  

   suitable 
  in 
  dealing 
  with 
  these 
  large 
  quantities 
  of 
  material. 
  

   Crookes 
  found 
  that 
  when 
  uranyl 
  nitrate 
  was 
  crystallized 
  

   from 
  water 
  the 
  photographic 
  activity, 
  which 
  is 
  due 
  solely 
  to 
  

   the 
  uranium 
  X 
  (Soddy,' 
  Trans. 
  Chem. 
  Soc. 
  1902, 
  Ixxxi. 
  p. 
  860), 
  

   of 
  the 
  crystals 
  was 
  enfeebled, 
  while 
  that 
  of 
  the 
  mother-liquor 
  

   was 
  correspondingly 
  enriched. 
  The 
  same 
  observation 
  was 
  

   made 
  by 
  Godlewski 
  five 
  years 
  later 
  (Phil. 
  Mag. 
  1905, 
  x. 
  

   p. 
  51), 
  who 
  stated, 
  without 
  giving 
  any 
  details, 
  that 
  it 
  was 
  

   possible 
  in 
  one 
  crystallization 
  to 
  obtain 
  f 
  of 
  the 
  total 
  

   quantity 
  of 
  uranium 
  X 
  in 
  the 
  mother-liquor. 
  We 
  found 
  

   that 
  the 
  maximum 
  separation 
  of 
  uranium 
  X 
  was 
  effected 
  

   when 
  about 
  two-thirds 
  of 
  the 
  total 
  quantity 
  of 
  uranyl 
  nitrate 
  

   crystallized 
  out 
  from 
  the 
  solution 
  on 
  cooling. 
  The 
  mother- 
  

   liquor 
  is 
  then 
  concentrated 
  and 
  the 
  operation 
  repeated 
  several 
  

   times 
  until 
  the 
  amount 
  of 
  uranyl 
  nitrate 
  in 
  the 
  mother-liquor 
  

   is 
  reduced 
  to 
  about 
  100 
  grams. 
  The 
  uranium 
  is 
  then 
  re- 
  

   moved 
  from 
  this 
  concentrate 
  by 
  adding 
  excess 
  of 
  ammonium 
  

   carbonate, 
  in 
  which 
  uranium 
  is 
  soluble, 
  leaving 
  behind 
  the 
  

   uranium 
  X 
  and 
  the 
  impurities 
  as 
  a 
  precipitate. 
  An 
  attempt 
  

   to 
  use 
  the 
  acetone 
  method 
  of 
  Moore 
  and 
  Schlundt 
  to 
  separate 
  

   the 
  uranium 
  X 
  from 
  a 
  concentrate 
  in 
  the 
  first 
  series 
  of 
  

   separations 
  failed 
  owing 
  to 
  the 
  considerable 
  quantities 
  of 
  

   impurities 
  present, 
  and 
  led 
  to 
  much 
  difficulty 
  and 
  loss 
  of 
  time. 
  

   Dealing 
  with 
  quantities 
  of 
  material 
  such 
  that 
  ^^ 
  per 
  cent, 
  

   of 
  impurity 
  represents 
  an 
  actual 
  weight 
  of 
  50 
  grams, 
  (yrookes' 
  

   crystallization 
  and 
  ammonium 
  carbonate 
  methods 
  are 
  still 
  

   very 
  effective, 
  but 
  indeed 
  it 
  is 
  doubtful 
  if 
  any 
  of 
  the 
  methods 
  

   subsequently 
  proposed 
  are 
  any 
  better 
  than 
  these 
  original 
  

   ones 
  in 
  ordinary 
  circumstances. 
  It 
  may 
  be 
  stated 
  that 
  the 
  

   known 
  methods 
  of 
  separation 
  take 
  advantages 
  of 
  peculiarities 
  

   in 
  the 
  properties 
  of 
  uranium 
  rather 
  than 
  of 
  uranium 
  X. 
  

   The 
  latter 
  does 
  not 
  appear 
  to 
  resemble 
  any 
  element 
  very 
  

   closely, 
  and 
  it 
  is 
  more 
  difficult 
  to 
  separate 
  it 
  from 
  admixture 
  

   with 
  other 
  elements 
  than 
  from 
  uranium. 
  

  

  The 
  crystalhzation 
  process 
  employed 
  may 
  be 
  illustrated 
  

   from 
  the 
  case 
  of 
  the 
  third 
  separation 
  after 
  considerable 
  ex- 
  

   perience 
  had 
  been 
  acquired. 
  Forty-seven 
  kilograms 
  of 
  uranyl 
  

   nitrate 
  in 
  four 
  lots 
  were 
  dissolved 
  in 
  one-sixth 
  of 
  their 
  weight 
  

  

  