Improvements in or appertaining to the Distillation or Treatment of Ammonium Chloride with Le Blanc Alkali Waste or kindred substances.
Year: 1890

page_text: Date of Application, 18th Feb., 1890
omplete Specification Left, 18th Nov., 1890-Accepted, 24th Jan., 1391
PROVISIONAL SPECIFICATION.
Improvements in or appertaining to the Distillation or Treatment
of Ammonium Chloride with Le Blanc Alkali Waste or kindred
substances.
I, JOHN LEITH of The Grove Knowsley Road St. Helens in the County of
Lancaster Chemical Manufacturer do hereby declare the nature of this invention to be
as follows:-
In the treatment of Le Blanc alkali waste with ammonium chloride in a distillation
tower about twenty per cent. of the sulphur is usually lost owing to having to employ
more than the theoretical quantity of waste in order to prevent loss of ammonit. It
is well known however that if the ammonium chloride be in excess all the sulphur
can be eliminated but in such case a large quantity of undecomposed ammonium
chloride runs to waste.
Now my invention is designed to enable one to use an excess of ammonium
chloride to the waste and yet prevent the loss of this valuable salt. I add un excess
of the ammonium chloride at the top of the tower and thus decompose all the waste→
but near the bottom I add milk of lime sufficient to decompose all the excess of
ammonium chloride which would otherwise be lost. The result is that all the
ammonia is recovered, and the effluent gases are somewhat richer in ammonia as
compared with the amount of sulphuretted hydrogen. Besides alkali waste other
sulphide of calcium and probably if it were desirable sulphate of calcium or other
sulphur salts of calcium can be used for this purpose.
1 T
... 1000
WM. P. THOMPSON & Co.,
.
6, Lord Street, Liverpool, Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or appertaining to the Distillation or Treatment
of Ammonium Chloride with Le Blanc Alkali Waste or kindred
substances.
I, JOHN LEITH of The Grove Knowsley Road, St. Helens in the County of
Lancaster, Chemical Manufacturer do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
In the treatment of Le Blanc alkali waste (or kindred substances, such as
sulphydrate of calcium) with ammonium chloride in a distillation tower, about
twenty per cent. of the sulphur is usually lost owing to the hitherto necessary employ-
ment of more than the theoretical quantity of waste in order to prevent loss of
ammonia. It is well known, however, that if the ammonium chloride be in excess
all the sulphur can be eliminated, but in such case a large quantity of undecomposed
ammonium chloride runs to waste.
Now my invention is designed to enable one to use an excess of ammonium
chloride to the waste or other suitable sulphur compound of lime and yet prevent
the loss of ammonia. I add an excess of the ammonium chloride at the top of the
tower and thus decompose all the waste, but near the bottom I add milk of lime
sufficient to decompose all the excess of ammonium chloride which would otherwise be
lost. The result is that all the ammonia is recovered and the effluent gases are somewhat
richer in ammonia as compared with the amount of sulphuretted bydrogen. Instead
of alkali waste or sulphydrate of calcium, other sulphides of calcium can be used
for this purpose. There are also some other salts available for this purpose, but they

page_text: are all more costly and less advantageous than the ones named, so it is no use
specifying them.
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
In the distillation or treatment of ammonium chloride with Le Blanc alkali waste
or other kindred substance such as described, the use of an excess of ammonium
chloride and the addition near the completion of the process of milk of lime to the
nearly exhausted materials containing the excess of ammonium chloride, whereby
the latter is decomposed and thus an increased relative proportion of ammonium
chloride can be economically employed.
Dated this 17th day of November 1890
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.