Improvements in the Production of Bicarbonate of Soda and Sulphuretted Hydrogen and in Apparatus therefor.
Year: 1890

page_text: Date of Application, 27th Dec., 1890-Accepted, 28th Feb., 1891
COMPLETE SPECIFICATION.
Improvements in the Production of Bicarbonate of Soda and
Sulphuretted Hydrogen and in Apparatus therefor.
I, JOHN LEITH, of Knowsley Road, St. Helens, in the County of Lancaster,
Manufacturing Chemist, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
The invention relates to the production of bicarbonate of soda from chloride of
sodium and practically pure sulphuretted hydrogen from sulphide of calcium
preferably in the form of Le Blanc alkali waste by the aid of carbonic acid and
sulphide of ammonium.
The main object is to obtain the above products by a cycle of operations so
conducted that loss of ammonia is reduced to a minimum, practically all the sulphur
of the sulphide of calcium is obtained in the form of strong sulphuretted hydrogen
of high strength, and greater economy in manufacture and more durable and
efficient plant is obtained.
The invention consists essentially in a cycle of the following reactions.
(a) Between chloride of sodium sulphide of ammonium produced in reaction (c)
below and carbonic acid. (b) Between sulphuretted hydrogen evolved in (a) and
sulphide of calcium. (c) Between chloride of ammonium produced in (a) and
sulphydrate of calcium produced in (b).
I now proceed to explain these reactions more fully.
First. I cause brine or chloride of sodium in solution, sulphide of ammonium and
carbonic acid to react on each other under pressure until bicarbonate of soda is
formed and sulphuretted hydrogen evolved, chloride of ammonium remaining in
solution.
Second. I cause the sulphuretted hydrogen so evolved under pressure to react on
a mixture of sulphide of calcium and water until the sulphuretted hydrogen is
absorbed and the sulphide of calcium rendered soluble as sulphydrate. When the
usual source of carbonic acid namely lime kiln gas is used the nitrogen and any
inert gases mixed with the sulphuretted hydrogen are allowed to escape into the
atmosphere preferably after passing through a purifier to remove any traces of
sulphuretted hydrogen.
Third. The solution of chloride of ammonium resulting from the first reaction
containing bicarbonate of soda is filtered in the usual manner to separate the
bicarbonate of soda from the chloride of ammonium.
Fourth. The sulphydrate and chloride of ammonium solutions obtained as above
described are brought together and heated until sulphide of ammonium together
with practically pure sulphuretted hydrogen are driven off-chloride of calcium in
solution remains behind and is disposed of in any suitable way and by preference as
hereinafter described.
Fifth. The sulphide of ammonium is passed into the carbonators with brine or
chloride of sodium in solution where it meets with carbonic acid as first above set
forth and the subsequent reactions repeated in continuous order. The sulphuretted
hydrogen is burned to produce sulphurous acid or sulphur or is otherwise
disposed of.
Apparatus under my invention has at least the following parts in combination,
carbonators (b) filter beds or equivalent devices (e) sulphydrate chambers
(d) still and (e) pressure producing appliances. In addition to these there are
absorbers, coolers, washers, storage tanks, mixers and the usual accessories and
connections.
The drawing appended hereto is a diagram shewing the arrangement of apparatus

page_text: under my invention the various parts being of any usual construction, 1 are
carbonators, 2 carbonic acid gas supply pipes, 3 brine and sulphide of ammonium
supply pipe, 5 sulphuretted hydrogen escape pipe, 6 washer, 7 brine inlet pipe
8 brine outlet pipe, 9 pipe for washed sulphuretted hydrogen, 10 sulphydrate
chambers, 11 sulphide of calcium mixer and forcing vessel, 12 pipe leading from the
vessel 11 to the chambers 10, 13 sulphide of calcium washer, 13 pipe leading from
the washer 13 to the vessel 11, 14 agitators, 15 discharge pipe for sulphydrate,
16 settling vessels, 17 pipe leading from the vessels 16 to the still 18, 19 discharge
pipe for bicarbonate of soda and chloride of ammonium, 20 filter beds, 21 settling
vessels, 22 pump connected with the vessels 21 by a pipe, 23 pipe leading from the
pump 22 to the still 18, 24 worm pipe leading from the still 18 to the absorbing
chamber 25, 26 pipe leading from the washer 27 to the chamber. 25, 28 brine inlet,
29 sulphuretted hydrogen outlet, 30 pipe leading from the chamber 25 to the
washer 27. Valves, return pipes, discharge cocks, and like adjuncts are placed as
required and their arrangement is well understood.
The operation is as follows:-Brine enters the chamber '25 through the pipes 7
and 28, washers 6 and 27 and pipes 8 and 26, and flows thence after having absorbed
sulphide of ammonium through the pipe 3 into the carbonators 1. The carbonators
are worked singly, in batteries or in series as found most convenient (and so as to
prevent carbonic acid from passing) the cocks and connections being arranged
according to the system followed. Carbonic acid gas generally from a lime kiln is
forced by means of a pump through the pipe 2 into the carbonators where by
reaction bi-carbonate of soda and chloride of ammonium are produced with the
evolution of sulphuretted hydrogen. The bicarbonate of soda and chloride of
ammonium are forced by the pressure within the carbonators on to the filter beds 20
by the pipe 19 and the chloride of ammonium solution passes through the filter beds
into the vessels 21. The sulphuretted hydrogen passes by the pipe 5 into the
washer 6-where it-meets with entering brine and has any carbonate and sulphide of
ammonium removed and carried forward with the brine into the chamber 25. The
sulphuretted hydrogen then passes through the pipe 9 into the sulphydrate
chambers 10 which are worked in series. Sulphide of calcium is mixed with water
in the washer 13 the fine particles passing through a sieve to the bottom whilst the
coarse particles are retained and removed. The fine mixture of sulphide of calcium
and water then passes through the pipe 13x to the chamber 11 where it is further
mixed and forced by the pressure of the sulphuretted hydrogen from the carbonators
into the sulphydrate-vessels 10 any nitrogen and inert gases escaping into the
atmosphere from the last chamber of the series preferably after passing through a
purifier in the usual manner. The sulphydrate partly in solution produced passes
by the pipe 15 into the settling tanks 16 from which it is forced (preferably by a
pump or by the pressure of the sulphuretted hydrogen from the carbonators)
through the pipe 17 into the still 18 where it meets with chloride of ammonium
pumped from the settling vessels 21. The still is heated to about 100° C. and
sulphide of ammonium and practically pure sulphuretted hydrogen are evolved
whilst chloride of calcium remains in solution and is run off.
The sulphide of ammonium and sulphuretted hydrogen pass by the worm pipe 24
in which they are cooled into the absorber 25 where they meet with brine and
where the sulphide of ammonium is absorbed and carried into the carbonators. The
sulphuretted hydrogen passes off through the pipe 30 into the washer 27 where it
meets with brine and has any traces of ammonia removed and carried with the
brine by the pipe 26 into the chamber 25 whence it passes into the carbonators.
The purified sulphuretted hydrogen passes off by the pipe 29 to à gasholder or
other suitable place.
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 I
claim is :-
First. The production of-bicarbonate of soda and sulphuretted hydrogen by the

page_text: cycle of reactions between chloride of sodium, sulphide of ammonium (produced as
hereinbefore described) and carbonic acid, between sulphuretted hydrogen (pro-
duced as hereinbefore described) and sulphide of calcium and between chloride of
ammonium and sulphydrate of calcium (respectively produced as hereinbefore
described) substantially as herein set forth.
Second. The combination of apparatus arranged and working substantially in the
manner and for the purpose set forth.
Third. Plant consisting of absorbers carbonators sulphydrate chambers, washers,
storage tanks, filters, pumps, and connections for the production of bicarbonate of
ammonia and sulphuretted hydrogen combined and operating substantially as set
forth.
Dated LIIS 1 wenty-th
Or December 1890.
Per pro J. T. KING,
J. Johnson,
Agent,
Per pro J. T. KING,
J. Johnson,
Agent,