PREPARATION  OF  SULPHATE  OF  MANGANESE. 
A  NEW  MODE  FOR  THE  PREPARATION  OF  SULPHATE  OF 
MANGANESE. 
By  F.  Mahla. 
The  methods  for  the  preparation  of  Sulphate  of  Manganese 
as  suggested  in  the  various  hand-books  of  chemistry  do  not 
only  give  unsatisfactory  results— they  are  also  difficult  and 
exceedingly  unplesant  to  execute.  It  seems  to  me,  therefore, 
that  a  new  mode  for  the  manufacture  of  this  salt  would  be  accept- 
able to  the  profession. 
I  use  as  material  for  the  preparation  of  Sulphate  of  Man- 
ganese the  liquid  which  remains  in  the  retorts  after  a  chlorine 
generation.  To  this  I  add  carbonate  of  soda  in  a  sufficient 
quantity  to  throw  down  all  metallic  oxides,  or  until  it  has 
acquired  a  slight  alkaline  reaction.  The  precipitate  thus  pro- 
duced is  collected  on  a  muslin  filter  and  washed  with  pure  water 
until  the  filtrate  does  not  produce  any  more  a  marked  reaction 
with  nitrate  of  silver. 
Three-fourths  of  the  moist  magma  are  now  placed  into  a  porce- 
lain evaporating  dish,  and  dilute  sulphuric  acid  added  in  suffi- 
cient quantity  to  effect  a  complete  solution.  This  is  heated  to  near 
the  boiling  point,  and  the  reserved  one-fourth  of  the  precipitate 
added  in  small  portions  at  a  time,  until  the  liquid  after  filtration 
is  not  blackened  any  more  by  the  addition  of  tannin.  The 
entire  bulk  of  solution  is  then  passed  through  a  filter  and  the 
filtrate  with  wash  waters  evaporated  to  crystallization,  which 
does  not  take  place  till  the  liquid  has  acquired  almost  a  syrupy 
consistency.  The  first  crop  of  crystals  is  sometimes  contam- 
inated with  sulphate  of  lime,  owing  to  the  presence  of  carbonate 
of  lime  in  the  commercial  peroxyd  of  manganese.  It  is  easy  to 
separate  this  compound  by  evaporating  the  liquid  to  dryness, 
when,  on  redissolving  the  dry  residue  in  a  small  quantity  of  water, 
the  sulphate  of  lime,  owing  to  its  lesser  solubility,  remains  as  an 
insoluble  body,  from  which  the  solution  of  Sulphate  of  Man- 
ganese can  be  separated  by  filtration. — Pharmacist,  March,  1869, 
Chicago^  February  16,  1869. 
