CARBONATED ALKALIES.
127
The average composition of themolasses is as follows:—
refined potash obtained
from the
Carbonate of potash
8873
Carbonate of soda ..
6-44
Sulphate of potash
2-27
Chloride of potassium ..
1*00
Iodide of potassium
0*02
Water .
139
Insoluble substances
.
0*12
The crude potash from beet-root sugar works gives on analysis resultswithin the following limits :—
Carbonate of potash.32-9 to 79-0
Carbonate of soda . 143 „ 23-1
Sulphate of potash . rig ,, 14-0
Chloride of potassium . 2'8 ,, ig-6
The percentage of carbonate of potash contained in a solution may,according to Dr. Gerlach, be roughly estimated from the sp. gr. At 15° C. thedensities and percentages are :—
Specific Gravity.
Percentage.
Specific Gravity.
Percentage.
1*009
I
I*3°I
30
I'0l8
2
i '358
35
1*036
4
1-418
40
1*045
5
1-480
45
1*092
10
i ''544
5 °
1*141
15
1357
5 i
1*192
20
I ' 57 °
52
1*245
25
The alkalimetrical estimation of soda-ash is proceeded with in the samemanner as that of potash, the test acid being adjusted so as to saturate anequivalent of soda. 10 grms. of the soda-ash are to be dissolved in water, andthe solution diluted to 250 c.c. The solution, if not clear, should be filtered.The water itself must be freed from carbonic acid by boiling, or distilledwater should be employed. From the filtrate 50 c.c are to be measured out,containing, as 10 grms. were taken, 2 grms. of soda. These 50 c.c. are tobe coloured blue with the litmus solution, then titrated with the normal acidsolution, of which an excess may be employed, the solution being titratedhack with the normal soda solution. Suppose 30 c.c. of normal acid to havebeen employed together with 4 c.c. of normal soda solution, then as 4 c.c.of acid had been added in excess, the difference shows 26 c.c. to have beennecessary for the neutralisation of the alkaline carbonate. As 0-053 grm. ofcarbonate of soda corresponds to 1 c.c. of the normal acid solution, we have°'°53 X 26 = 1378 grm. of carbonate of soda in 2 grms. soda-ash. The per-centage can then, of course, be obtained by the following equation :—
2: 1378 = 100 : x ,
or x = 68-g per cent of carbonate of soda. That is, 100 lbs. of soda-ashcontain 68-g lbs. of pure carbonate of soda and 31-1 lbs. of impurities.