Improvements in and connected with the Manufacture of Alkaline Carbonates.
Year: 1895

page_text: Date of Application, 14th May, 1895-Accepted, 15th June, 1895
COMPLETE SPECIFICATION.
Improvements in and connected with the Manufacture of Alkaline
Carbonates.
WLADIMIR VON BARANOFF of 26 Rue des Batignolles, Paris in the Republic
of France, Doctor of Philosophy do hereby declare the nature of my invention
and in what manner the same is to be performed to be particularly described
and nscertained in and by the following statement
-
My invention has for its object to obtain alkaline carbonates from alkaline
sulphates together with the bye-products produced therewith, more economically
and in a puier condition than has been possible hitherto with similar processes.
According to my invention the alkaline sulphate is treated with sulphide of
barium or strontium, whoreby an alkaline sulphido together with an insoluble
sulphate of either barium or strontium is obtained. The product of this reaction,
that is the alkaline sulphide is then treated with carbome acid, whereby an alkaline
carbonate or bicarbonate is formed, while sulphuretted hydrogen is set free, which
latter may be employed for the regeneration of sulphur oi for the manufacture of
sulphuric acid, or treated in any other suitable manner. The sulphate of bariumi
or strontium produced in this operation may be used for regenerating the sulphide
of barium or strontium produced in the first enction. The operations which I
have described may be represented by the following reactions.
These cnctions are well known, but up to the present time it has not been
practicable to employ them commercially in the trade, by reason of certain defects
existing therein.
Thus in the decomposition of sulphate of barium by heating with carbon, as
shown in equation (1), according to the well-known processes, it is found that
there is always a considerable amount of sulphate which has not been decomposed.
By my invention I obtain a yield of sulphide in which only a very slight
proportion of sulphate is left undecomposed, and I effect this by the employment
of carbon in or about the amount theoretically necessary for bunging about the
required decomposition, instead of in excess as has been the custom hitherto.
When sulphide of barium is dissolved in water as hitherto to obtain a solution
thereof, a rapid oxydation of part of the sulphur takes place with formation of a
hyposulphite or other sulphin compound Lence in the treatment of sulphate of
soda by this sulphide as shown theoretically in the reaction (2) the alkalime
sulphide produced also contains some hy posulphite or other sulphur compound
which will be found to remain in the final product, chiefly in the shape of alkahme
sulphate To prevent the formation of hyposulphite or the like, I tient the
solution of sulphate of soda in water duectly with solid sulphide of bauum in &
powdered condition, avoiding the contact with an as much as possible, and I ment
thus mixune directly, without filtering, with carbonic acid, by this means a neuly
pure carbonate of soda is finally obtained.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what 1
claim 19.-
1. Preparing barium or strontium sulphide of a purer quality than has been
hither to obtained by beating an intimate mixture of finely ground barium or
strontium sulphate with only the theoretically necessary quantity of carbon, or
thereabouts substantially in the manner herein before described.
2. Treating a solution of an alkaline sulphate with the necessary quantity of
finely ground solid barium or strontium sulphide, and thereupon treating the
mixture with as much carbonic acid as is required for couverting the alkaline
sulphide into carbonate, thus avoiding the oxydation of the sulphide by atmospheric
oxygen, and utilising the bye-products of the reaction in well-known ways
substantially as hereinbefore described.
Dah J..
1005
JOHNSONS & WILLCOX,
47, Lincoln's Inu Fields, London, W.C., Agents.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.