IMPROVEMENTS IN THE MANUFACTURE OF THE ACETATES AND. CARBONATES OF SODIUM AND OF POTASSIUM
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by Edward Sonstadt at the Office
of the Commissioners of Patents, with his Petition, on the 14th
January 1871.
I, EDWARD SONSTADT, of Port Lewdigue, in the Parish of Manghold,
in the Isle of Man, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF THE ACETATES AND.
CARBONATES OF SODIUM AND OF POTASSIUM," to be as follows:-
'
:-
This Invention has for its object improvements in the manufacture of
the acetates and carbonates of sodium and of potassium.
I find that when a solution of sulphide of sodium or of potassium is:
boiled down to dryness with sawdust or vegetable matter, and the dry
mass charred at a temperature below redness, but high enough to make
the mass black and friable, and water is added, the alkali salt
passes into.
solution chiefly as acetate accompanied by a soluble sulphur compound'
and highly colored organic products. I find further that the sulphur is
more or less completely separated on exposure to the air, leaving a viscid
solution of alkali salt. I find further that when lime is boiled with the
solution of the charred sulphide and sawdust above mentioned the sulphur

page_text: is carried down in an insoluble state by the lime leaving in solution
impure sodic or potassic acetate. The same reaction takes place in the
cold although less readily. I find further that this compound of lime
and sulphur is not decomposed at a red heat.
In using lime to withdraw sulphur from the compound already
described I prefer to proceed as follows:- -I prepare sulphide of sodium
or of potassium in the ordinary way from the corresponding sulphates,
that is, by heating together the alkali sulphate with carbonaceous matter,
but I find it neither necessary nor convenient to raise the heat high
enough or to continue it long enough to effect complete decomposition.
The suphide is dissolved out by water, most of the undecomposed salt
remaining in the residue, which may be dried to form the basis of another
similar operation. The solution of alkali sulphide is boiled down with
sawdust or with spent dye wood, or other like matter, and is heated till
completely charred, but below redness, and care must be taken that it
does not take fire. To the mass thus obtained water is added when the
mass is cool enough, and lime, all of which are boiled together until a
small portion of the solution proves on testing to be free or nearly free
from sulphur, the liquid may then be separated by filtration or otherwise
and boiled down and strongly heated, though not above dull redness if
acetate is required, but to full redness continued until all the organic
acid is decomposed if carbonate is wanted; but I prefer to dry up at
once the liquid obtained by boiling the lime with the solution of the
charred mass without previous filtration. The dry mass can be heated
to low redness to obtain alkali acetate or to full redness for alkali car-
bonate, as in the other case. In any case the mass after heating may be
lixiviated for the alkali salts it contains, which are thus obtained in a
high degree of purity..
The process above set forth is applicable to the highly sulphuretted
mother liquors left after crystallising out soda crystals from the solution
of soda ash.