IMPROVEMENTS IN THE MANUFACTURE CARBONATE OF STRONTIUM FROM SULPHATE OF STRONTIUM
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
"
OF
I SYDNEY PITT of Sutton in the County of Surrey Gentleman do hereby declare
the nature of my invention. for "IMPROVEMENTS IN THE MANUFACTURE
CARBONATE OF STRONTIUM FROM SULPHATE OF STRONTIUM A communication
to me from abroad by Ernest Augustus Mebus and Jacob William De Castro both
of New York City County of New York and State of New York United States
of America to be as follows:-
Carbonate of strontium has hitherto been obtained from sulphide of strontium
which was produced from the natural sulphate of strontium by reducing the same
by means of great heat and a reducing substance. Now my correspondents havo
ascertained that the conversion of the sulphate of strontium into carbonate of
strontium may be almost completely and more economically effected directly by
means of carbonate of ammonia or by ammonia and carbonic acid if the sulphate
of strontium is in a very finely divided state. They have further ascertained that
ordinary gas, water can be employed for the manufacture and that either sulphate
of ammonium of a high degree of purity can be obtained as a very valuable
by-product or that the same ammonia can be used over again in the manufacture
as often as desired.
:
To carry out my invention in practice the sulphate of strontium is if necessary dried
then crushed and ground to such a degree of fineness that it will pass at least through
an eighty mesh sieve, but it is preferred to use down to a two hundred mosh sieve.
The ground sulphate of strontium is then mixed with water and carbonate of
ammonium, or caustic ammonia or a mixture of carbonate of ammonium and
caustic ammonia and carbonic acid is passed through the mixture if it does not
already contain a sufficient quantity of the same. As a source of ammonia
ordinary gas water or gas water condensed by distillation may be employed.. It is
preferred to regulate the mixtures so as to contain for every 100 parts of sulphate
of strontium 20 parts of ammonia, 26 parts of carbonic acid and from 500 to
1000 parts of water. The mixture prepared as above is then agitated for a period

page_text: °
of about 24 hours. This period however may be considerably shortened if the
sulphate of strontium is sufficiently finely ground. After the agitation the sulphate
of strontium is found converted into carbonate of strontium by the action of the
carbonate of ammonium or of the ammonia and carbonic acid; it is then separated
from the liquid washed and dried after which it is ready for sale. The conversion
may be carried out at various temperatures and under various pressures but it is
preferred not to employ artificial heat cold or pressure.
The liquid obtained together with the washing water from the carbonate of
strontium contains sulphate of ammonium and carbonate of ammonium. This
liquid is then distilled to recover the carbonate of ammonium. The remaining
solution of sulphate of ammonium is then either evaporated to the crystallizing
point of sulphate of ammonium cooled and crystallized to obtain sulphate of
ammonium for commerce, or it is distilled with lime to recover the ammonia which
may be used over again for the conversion of fresh quantities of sulphate of
strontium into carbonate.
In the first case a highly valuable by-product is obtained viz, sulphate of
ammonium and the sulphuric acid usually employed in its manufacture is saved.
In the second case the same quantity of ammonia originally employed can convert
theoretically an unlimited quantity of sulphate of strontium. In practical working
however there is a small loss of ammonia which must be replenished from time to
time. With proper care in the manufacture this loss does not exceed three pounds
of sulphate of ammonium for every 100 pounds of carbonate of strontium
produced.
I am aware that the conversion of sulphate of strontium into carbonate by the
use of carbonate of ammonium is not new and I make no claim to such process
broadly, I am also aware that the sulphate of strontium has been converted into
the carbonate of strontium after it has been roasted in order to be converted into
the sulphide but by my process no such step is necessary and I am enabled to
produce the carbonate without such process.
CARPMAEL & Co.,
Agents for the Applicant.

page_text: "
I SYDNEY PITT of Sutton in the County of Surrey, Gentleman, do hereby declare
the nature of my invention for IMPROVEMENTS IN THE MANUFACTURE OF
CARBONATE OF STRONTIUM FROM SULPHATE OF STRONTIUM" (A communication
to me from abroad by Ernest Augustus Mebus and Jacob William De Castro, both
of New York City, County of New York and State of New York, United States
of America) and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
Carbonate of strontium has hitherto been obtained from sulphide of strontiura
which was produced from the natural sulphate of strontium by reducing the same
by means of great heat and a reducing substance. Now my correspondents have
ascertained that the conversion of the sulphate of strontium into carbonate of
strontium may be almost completely and more economically effected directly by
means of carbonate of ammonia or by ammonia and carbonic acid, if the sulphate
of strontium is in a very finely divided state. They have further ascertained that
ordinary gas water can be employed for the manufacture and that either sulphate
of ammonium of a high degree of purity can be obtained as a very valuable
by-product or that the same ammonia can be used over again in the manufacture
as often as desired.
To carry out my invention in practice the sulphate of strontium is if necessary
dried then crushed and ground to such a degree of fineness that it will pass at least
through an eighty mesh sieve but it is preferred to use down to a two-hundred
mesh sieve. The ground sulphate of strontium is then mixed with water and
carbonate of ammonium or caustic ammonia or a mixture of carbonate of ammonium
and caustic ammonia and carbonic acid is passed through the mixture if it does
not already contain a sufficient quantity of the same. As a source of ammonia,
ordinary gas water or gas water condensed by distillation may be employed. It is
preferred to regulate the mixtures so as to contain for every 100 parts of sulphate
of strontium 20 parts of ammonia, 26 parts of carbonic acid and from 500 to
1000 parts of water. The mixture prepared as above is then agitated for a period
of about 24 hours. This period however may be considerably shortened if the
sulphate of strontium is sufficiently finely ground. After the agitation the sulphate
of strontium is found converted into carbonate of strontium by the action of the
carbonate of ammonium or of the ammonia and carbonic acid; it is then separated
from the liquid, washed and dried after which it is ready for sale. The conversion
may be carried out at various temperatures and under various pressures, but it is
preferred not to employ artificial heat cold or pressure.
The liquid obtained, together with the washing water from the carbonate of
strontium contains sulphate of ammonium and carbonate of ammonium. This
liquid is then distilled to recover the carbonate of ammonium. The remaining
solution of sulphate of ammonium is then either evaporated to the crystallizing
point of sulphate of ammonium cooled and crystallized to obtain sulphate of
ammonium for commerce, or it is distilled with lime to recover the ammonia which

page_text: may be used over again for the conversion of fresh quantities of sulphate of
strontium into carbonate.
In the first case a highly valuable by-product is obtained, viz, sulphate of
ammonium, and the sulphuric acid usually employed in its manufacture is saved.
In the second case the same quantity of ammonia originally employed can convert
theoretically an unlimited quantity of sulphate of strontium. In practical working
however there is a small loss of ammonia which must be replenished from time to
time. With proper care in the manufacture this loss does not exceed three pounds
of sulphate of ammonium for every 100 pounds of carbonate of strontium
produced.
..
I am aware that the conversion of sulphate of strontium into carbonate by the
use of carbonate of ammonium.is not new and I make no claim to such process
broadly, I am also aware that the sulphate of strontium has been converted into
the carbonate of strontium after it has been roasted in order to be converted into
the sulphide, but by my process no such step is necessary and I am enabled to
produce the carbonate without such process.
.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The process of converting sulphate of strontium into carbonate of strontium
which consists in reducing said sulphate of strontium into an exceedingly fine.
condition, in mixing it with sufficient water to maintain it in suspension therein
and in treating it with carbonate of ammonium or ammonia and carbonic acid
substantially as described.
2. The process of converting sulphate of strontium into carbonate of strontium
which consists in reducing said sulphate of strontium into an exceedingly fine
condition in mixing it with sufficient water to maintain it in suspension therein
and in treating it with gas water substantially as described.
3.- The process of converting sulphate of strontium into carbonate of strontium
without the material loss of the converting agent which consists in reducing the
'sulphate of strontium into an exceedingly fine condition in mixing it with sufficient
water to maintain it in suspension therein and in treating it with carbonate of
ammonia or ammonia and carbonic acid thereby producing carbonate of strontium
and sulphate of ammonia recovering the ammonia from the sulphate of ammonia
by distillation with lime substantially as described.
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