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INDUSTRIAL  APPLICATION  OF  BARYTA. 
In  the  author's  process  a  mixture  of  suitable  proportions  of 
native  sulphate  of  baryta,  chloride  of  manganese  and  charcoal,  is 
converted  in  the  same  way  into  insoluble  sulphuret  of  manganese 
and  chloride  of  barium,  which  is  easily  separated  by  lixiviation. 
The  reaction  may  be  expressed  by  the  following  formula  : — 
BaO,  S03+MnCl+4O=BaCl+MnS+4C0. 
An  analogous  reaction  may  likewise  be  established  for  the 
chloride  of  iron  which  always  accompanies  the  chloride  of  man- 
ganese. The  charcoal  always  acts  as  a  deoxidizing  agent,  and 
becomes  converted  into  oxide  of  carbon. 
After  some  trials  to  ascertain  a  good  proportion,  the  author 
arrived  at  a  result  which  exceeded  his  hopes,  allowing  the  native 
sulphate  to  be  converted  into  chloride  of  barium,  without  a 
greater  loss  than  3  or  4  per  cent,  of  the  sulphate  employed. 
The  mode  of  operation  is  as  follows  : — The  transformation 
above  mentioned  is  effected  in  large  reverberatory  furnaces  of 
the  same  construction  as  the  soda-furnaces,  or,  what  is  better, 
the  furnaces  for  the  decomposition  of  common  salt,  in  which  the 
bed  is  divided  into  two  compartments  by  a  low  ridge.  When 
these  furnaces  have  been  heated  for  some  time,  a  finely  powder- 
ed mixture  of  native  sulphate  of  baryta  and  coke  is  introduced 
into  the  compartment  furthest  from  the  fire  ;  over  this  is  poured 
the  crude  residue  of  the  manufacture  of  chlorine,  after  its  excess 
of  acid  has  been  saturated  with  a  little  chalk  or  native  carbonate 
of  baryta.  The  action  of  the  heat  upon  this  mass  thickens  it  by 
degrees.  When  brought  to  the  condition  of  a  firm  paste,  it  is 
puslu  d  by  means  of  suitable  iron  instruments,  over  the  separa- 
ting ridge,  into  the  compartment  nearest  to  the  fire.  Here  the 
mass  swells  up,  and  soon  emits  small  flames  of  oxide  of  carbon, 
like  those  which  are  observed  at  a  certain  period  in  the  soda  fur- 
naces, but  which  derive  a  slight  greenish  color  from  the  baryta. 
After  an  hour  of  calcination  at  a  red  heat,  a  semifluid  paste  of 
rather  more  consistency  than  crude  soda,  is  turned  out ;  on  cool- 
ing, this  furnishes  a  black  mass,  formed  of  chloride  of  barium 
a  little  hyposulphite  of  baryta,  and  sulphurets  of  manganese  and 
iron.  After  exposure  to  the  air  for  a  few  days  this  crude  chloride 
of  barium  becomes  disaggregated  ;  the  hyposulphite  contained  in 
it  passes  to  the  state  of  sulphate.  The  lixiviation  is  then  effected 
by  the  aid  of  heat  in  the  apparatus  usually  employed  in  the  lix- 
iviation of  soda. 
