﻿140 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  incendiary 
  bombs, 
  and 
  military 
  pyrotechnics. 
  Today 
  tens 
  of 
  thou- 
  

   sands 
  of 
  tons 
  are 
  required. 
  

  

  Magnesium 
  in 
  combination 
  is 
  one 
  of 
  the 
  most 
  abundant 
  elements 
  

   on 
  the 
  earth's 
  crust. 
  The 
  most 
  favored 
  source 
  is 
  magnesite, 
  which 
  in 
  

   particular 
  is 
  used 
  for 
  refractories. 
  Other 
  sources 
  are 
  dolomite, 
  which 
  

   consists 
  of 
  calcium 
  and 
  magnesium 
  carbonates, 
  and 
  carnallite 
  from 
  

   Stassfurt, 
  which 
  is 
  a 
  double 
  chloride 
  of 
  magnesium 
  and 
  potassium. 
  

  

  If 
  the 
  metal 
  is 
  to 
  be 
  made 
  by 
  electrolysis 
  — 
  hitherto 
  the 
  favored 
  

   process 
  — 
  magnesite 
  has 
  to 
  be 
  converted 
  into 
  chloride 
  by 
  briquetting 
  

   the 
  calcined 
  material 
  with 
  carbon 
  and 
  binding 
  substance 
  and 
  exposing 
  

   to 
  the 
  action 
  of 
  chlorine 
  in 
  an 
  electric 
  furnace. 
  Since 
  in 
  the 
  course 
  of 
  

   electrolysis 
  chlorine 
  is 
  evolved, 
  the 
  process 
  becomes 
  in 
  theory 
  cyclic, 
  

   although 
  in 
  practice 
  there 
  is 
  waste 
  through 
  formation 
  of 
  hydrogen 
  

   chloride. 
  

  

  Faced 
  with 
  the 
  large 
  new 
  requirements, 
  the 
  sea 
  seemed 
  an 
  obvious 
  

   source 
  of 
  magnesium 
  chloride. 
  The 
  knowledge 
  about 
  the 
  intake 
  of 
  

   sea 
  water 
  and 
  the 
  location 
  of 
  a 
  plant 
  was 
  available. 
  In 
  addition, 
  

   cheap 
  power 
  and 
  plentiful 
  supplies 
  of 
  lime, 
  the 
  other 
  necessary 
  raw 
  

   material, 
  were 
  requisites. 
  The 
  latter 
  also 
  came 
  from 
  the 
  sea 
  in 
  the 
  

   form 
  of 
  oyster 
  shells 
  dredged 
  from 
  the 
  bottom 
  of 
  Galveston 
  Bay, 
  

   which, 
  when 
  washed, 
  go 
  straight 
  to 
  the 
  lime 
  kiln. 
  Some 
  300,000,000 
  

   gallons 
  of 
  sea 
  water 
  per 
  day 
  are 
  drawn 
  into 
  the 
  plant. 
  

  

  Though 
  in 
  practice 
  the 
  recovery 
  of 
  magnesium 
  metal 
  from 
  sea 
  

   water 
  involved 
  comparatively 
  simple 
  operations 
  chemically, 
  it 
  is 
  far 
  

   from 
  being 
  an 
  easy 
  task 
  economically 
  to 
  utilize 
  a 
  raw 
  material 
  which 
  

   contains 
  only 
  about 
  1 
  part 
  of 
  magnesium 
  in 
  800 
  of 
  water. 
  Quite 
  

   unusual 
  chemical 
  engineering 
  methods, 
  equipment, 
  and 
  control, 
  had 
  

   to 
  be 
  invented. 
  Such 
  work 
  involves 
  research 
  on 
  the 
  grand 
  scale 
  by 
  

   large 
  teams 
  of 
  chemists 
  and 
  engineers. 
  It 
  is 
  Discovery 
  with 
  a 
  capital 
  

   D, 
  and 
  costs 
  very 
  large 
  sums 
  of 
  money. 
  

  

  The 
  magnesium 
  is 
  precipitated 
  as 
  hydroxide 
  by 
  means 
  of 
  lime. 
  

   This 
  is 
  collected 
  on 
  special 
  filters 
  and 
  converted 
  into 
  chloride 
  using 
  

   for 
  this 
  operation 
  a 
  10 
  percent 
  aqueous 
  solution 
  of 
  hydrochloric 
  acid 
  

   which 
  is 
  largely 
  derived 
  from 
  a 
  later 
  stage 
  of 
  the 
  operation. 
  The 
  

   magnesium 
  chloride 
  is 
  evaporated 
  and 
  dried 
  until 
  anhydrous, 
  when 
  

   it 
  is 
  electrolyzed 
  in 
  suitable 
  cells 
  to 
  produce 
  metallic 
  magnesium. 
  

   Natural 
  gas 
  is 
  used 
  as 
  the 
  source 
  of 
  power 
  and 
  heat. 
  The 
  effluent 
  water 
  

   is 
  discharged 
  7 
  miles 
  from 
  the 
  intake, 
  which 
  is 
  almost 
  30 
  feet 
  below 
  the 
  

   surface 
  so 
  as 
  to 
  obtain 
  the 
  highest 
  concentration 
  of 
  salts. 
  The 
  current 
  

   of 
  sea 
  water 
  is 
  always 
  in 
  the 
  same 
  direction, 
  which 
  prevents 
  mixing. 
  

   There 
  is 
  a 
  bromine 
  factory 
  on 
  the 
  same 
  site 
  and 
  the 
  two 
  effluents, 
  the 
  

   one 
  acid 
  and 
  the 
  other 
  alkaline, 
  mingle. 
  

  

  We 
  have 
  been 
  able 
  to 
  describe 
  the 
  work 
  done 
  in 
  the 
  United 
  States 
  

   on 
  these 
  materials 
  since 
  it 
  has 
  been 
  widely 
  published 
  in 
  the 
  technical 
  

  

  