818  CHLORIDE  OP  POTASSIUM  FROM  CARNALLITE. 
The  selling  price  varies  according  to  the  amount  of  chloride 
of  potassium.  A  salt  containing  18  per  cent,  is  called  rich,  one 
of  15  per  cent,  is  of  common  quality.  In  1865  the  rich  salt  cost, 
in  lumps,  21  francs  25  centimes  per  ton ;  the  common,  23  francs 
15  centimes. 
These  prices  lasted  for  some  months,  when  a  reduction  of  two 
francs  took  place.  By  later  accounts,  the  Prussian  government, 
in  accordance  with  that  of  Anhalt,  have  reduced  the  price  of 
the  average  salt  in  lumps  to  12  frcs.  50  cent.  (1866). 
Only  the  chloride  of  potassium  has  as  yet  been  obtained  from 
the  carnallite  ;  the  chloride  of  magnesium  is  lost.  The  process 
consists  of  the  following  operations  : 
1.  The  treatment  of  the  carnallite  with  hot  water  in  sufficient 
quantity,  by  which  chloride  of  potassium  and  chloride  of  magne- 
sium are  chiefly  dissolved,  and  the  largest  part  of  the  chloride 
of  sodium  and  sulphate  of  magnesia  remain  undissolved. 
2.  The  crystallisation  of  the  chloride  of  potassium  by  cooling. 
3.  The  evaporation  and  cooling  of  the  mother  liquors,  by 
which  a  second  crop  of  crystals  of  chloride  of  potassium  is  ob- 
tained. 
4.  Further  evaporation  and  cooling  of  the  mother  liquors,  by 
which  a  double  salt  of  chloride  of  potassium  and  chloride  of  mag- 
nesium is  obtained  (KCl+2MgCl+12HO).  This  is  then  treat- 
ed as  the  natural  salt. 
5.  Washing,  drying  and  packing  of  the  chloride  of  potassium. 
The  chloride  of  potassium  purified  by  washing  is  quickly  dried 
in  an  oven,  where  it  undergoes  a  slight  calcination,  or  upon  the 
metallic  floor  of  a  chamber  which  is  heated  by  tubes,  through 
which  the  hot  air  from  a  coal  fire  is  drawn. 
After  drying,  the  salt  is  collected,  sifted,  and  packed  in  casks 
holding  about  500  kilogrammes.  They  are  loaded  in  the  facto- 
ries upon  the  cars  of  the  Magdeburg  Railroad,  and  sent  to  the 
different  European  markets. 
The  whole  number  of  factories  of  Stassfurth  and  Anhalt  pro- 
duced, in  1864,  16,500  tons  of  chloride  of  potassium. 
In  the  beginning  of  1863  100  kilogrammes  of  chloride  of  po- 
tassium of  80  per  cent,  were  worth,  at  Stassfurth,  40  francs.  In 
the  early  part  of  1865  the  price  had  fallen  to  29  francs,  and  by 
the  end  of  the  same  year  to  18  francs  70  centimes* 
