60 
SOLI' I ML IT Y IN CAl’STIL LI ML SOLUTIONS. 
In view < » I' the ra| id and complete solution of alunite in caustic 
alkalis, and to obtain a. cheaper and more readily available solvent, 
Ihe effect; of caustic lime solutions, which also contain a considerable 
concentration of hydroxyl ion, were tried on the mineral. 
The material used for the preliminary tests was 99 per cent, 
pure, containing’ K..O, 7.56 per cent.; Nad), 2.56 per cent. The 
impurities were mainly quartz and kaolin with small amounts of 
epsomite and salt. 
Several gramme lots of the mineral were placed in quartz 
beakers with 100 cc. of water and 0.25 gm. of .freshly burnt lime. 
The solutions were stirred occasionally and allowed to stand in the 
cold for periods of one, two, and eight days. The solutions were 
then filtered and the potash and soda estimated in the extract. It 
was noticed after one day that a bulky gelatinous precipitate was 
formed, quite distinct in appearance from the original alunite. This 
proved on examination to be calcium nluminate. The results ob- 
tained were — • 
Potash. 
o 
Soda. 
0/ 
Originally in Sample 

o 
7-56 
A) 
2*56 
In solution after one 
day’s treatment 
0*71 
1 • 15 
In solution after two 
days’ treatment 
1 • 09 
1*26 
In solution after eight days' treatment 
1 • 16 
1*45 
These figures were 
considered so satisfactory 
that arr; 
alignments 
were made to carry 
out a. systematic series of 
experiments* the re- 
sill Is of which are shown below. 
These tests 
oral containing 
Alunite 
Total Potash 
Total Soda ... 
were carried out on three separate lots of the min- 
I he following amounts of 
l 2 3 
95*05 96 • 55 97-31 
6*46 8 ■ 54 7*98 
3*62 2-24 2*60 
The samples were crushed to pass a 30-mesh sieve, the greater por- 
tion of which would pass a 90-mesh sieve. One half gramme of the 
mineral was placed in a resistance I lask with 400 cc. ot a lieshly 
prepared solution containing the amount of calcium hydrate shown 
in the table. (The solubility of Ca(OIl) 2 in water is 1.7 gms. per 
litre.) Several pieces of glass rod were placed in the flask which 
was then lightly stoppered with a waxed cork and the tests shaken 
vigorously from time to time. At the expiration of the time allowed 
the precipitate was filtered off, well washed with hot water, and die 
potash and soda which had passed into solution estimated by the 
platinic-chlori.de method. 
Ft was noticed that in the ease of treatment with caustic alkalis 
(he alunite goes completely into solution, but with caustic lime a 
bulky precipitate was formed. This precipitate was examined alter 
