334 
ON  THE  MANUFACTURE  OF  TARTARIC  ACID,  ETC. 
purified  bitartrate  of  potash  obtained,  by  decomposing  the  said 
tartrate  of  potash  and  ammonia  with  bisulphate  of  potash  or  bisul- 
phate  of  soda,  or  acid  sulphate  of  potash  or  soda  in  the  same 
manner,  and  in  the  same  proportions,  as  described  under  the 
process  for  decomposing  tartrate  of  potash  and  soda  with  acid 
sulphate  of  soda  and  acid  sulphate  of  potash,  for  every  188  parts 
by  weight  of  bitartrate  of  potash  originally  contained  in  the  im- 
pure bitartrate  of  potash.  If  bisulphate  of  potash  is  employed, 
bitartrate  of  potash  is  precipitated,  and  sulphate  of  potash  and 
sulphate  of  ammonia  remain  in  solution  with  a  certain  amount  of 
bitartrate  of  potash.  The  solution  is  kept  neutral  or  alkaline  by 
the  addition  of  ammonia  or  the  volatile  salts  thereof  as  before 
mentioned,  and  when  evaporated  to  a  sp.  gr.  of  about  1.350  at 
212°  F.  a  solution  of  bisulphate  of  potash  or  sulphuric  acid  may 
be  added,  in  sufficient  quantity  to  neutralize  the  ammonia  exist- 
ing in  excess,  and  also  that  which  is  combined  as  tartrate  of  pot- 
ash and  ammonia.  The  resulting  bitartrate  of  potash  which 
precipitates  is  separated,  and  the  solution  neutralized  with 
ammonia,  or  potash,  or  their  carbonates,  or  sulphides  of  the  same, 
and  evaporated,  in  order  to  obtain  by  crystallization  the  sulphate 
of  potash  and  sulphate  of  ammonia.  The  tartrate  of  potash  and 
ammonia  existing  in  the  mother-liquors  may  be  decomposed  as 
before  mentioned. 
Or,  sulphuric  or  hydrochloric  acid  may  be  employed  to  decom- 
pose the  tartrate  of  potash  and  ammonia  obtained  by  neutralizing 
impure  bitartrate  of  potash  by  means  of  gas-liquor,  ammonia,  car- 
bonate of  ammonia  or  sulphides  of  ammonia,  obtained  by  decom- 
posing citrates  on  tartrates  of  ammonia,  by  means  of  hydrated 
caustic  lime,  carbonate  of  lime,  or  sulphides  of  calcium,  sulphides 
of  barium  or  sulphides  of  strontium,  in  the  proportion  of  50  parts 
of  monohydrated  sulphuric  acid,  and  37  parts  of  actual  hydro- 
chloric acid  contained  in  any  dilute  acid  solution,  to  every  188 
parts  of  bitartrate  of  potash  existing  in  the  crude  argol  or  crude 
tartar,  and  now  existing  in  solution  as  tartrate  of  potash  and 
ammonia;  after  separating  the  precipitated  bitartrate  of  potash, 
the  resulting  solution,  containing  the  sulphate  or  muriate  of  am- 
monia, may  be  separated  by  crystallization.  The  tartrate  of  pot- 
ash and  ammonia  remaining  in  the  solution,  is  to  be  decomposed 
with  an  equivalent  proportion  of  either  sulphuric  or  hydrochloric 
acid. 
