An Improved Process for Producing Sulphate of Calcium.
Year: 1890

page_text: Date of Application, 25th July, 1890
Complete Specification Left, 25th Apr., 1891-Accepted, 30th May, 1891
PROVISIONAL SPECIFICATION.
An Improved Process for Producing Sulphate of Calcium.
I, THOMAS ELLIOT, of Backhall Chambers, Baldwin Street, in the City and
County of Bristol, Produce Broker, do hereby declare the nature of this invention
to be as follows:-
The improved process for producing sulphate of calcium in which this invention
consists is applicable to treating liquids in which calcium chloride is held in
solution.
The waste liquid resulting from any process of manufacture of soda or bleaching
powder involving the use of ammonia contains chloride of calcium in solution and is
therefore adapted for treatment in accordance with this invention.
The liquid to be treated having been collected in tanks, sulphuric acid diluted
with about 80 per cent. to 90 per cent. of water is added thereto.
The result is that sulphate of calcium is precipitated in the collecting tanks.
Instead of first running the liquid containing the chloride of calcium into tanks
and then adding the diluted sulphuric acid thereto, as above described, the order of
addition may be reversed. The approximate proportion of diluted sulphuric acid
is about one part to about two parts of the liquid containing the chloride of
calcium.
Dated this 24th day of July 1890.
NICHOLAS WATTS,
Bristol Bank Buildings, Bristol, Agent.
COMPLETE SPECIFICATION.
An Improved Process for Producing Sulphate of Calcium.
I, THOMAS ELLIOT, of Backhall Chambers, Baldwin Street, in the City and
County of Bristol, Produce Broker, 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:—
This invention consists in an improved process of producing sulphate of calcium
from liquids in which calcium chloride is held in solution, such as the waste liquid
resulting from any process of manufacture of soda or bleaching powder involving
the use of ammonia.
The liquid to be treated is run into a tank or vat and to it is added sulphuric
acid diluted with about 80 to 90 per cent. of water.
The effect of adding the diluted sulphuric acid is to cause precipitation of
sulphate of calcium in the tank or vat. The sulphate of calcium is recovered after
the liquid has been run off.
Under an alternative method the diluted sulphuric acid is first run into the tank
or vat, and the liquid containing the chloride of calcium is subsequently added.
A suitable proportion of diluted sulphuric acid is about one part to about two
parts by volume of the liquid containing the chloride of calcium.
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 :-
A process for the production of sulphate of calcium from liquids containing
calcium chloride, the said process consisting in associating together such liquids

page_text: and sulphuric acid diluted with from 80 to 90 per cent. of water in proportions of
about one part of sulphuric acid so diluted to two parts of the liquid containing the
chloride of calcium, substantially as hereinbefore described.
Dated this 22nd day of April 1891.
NICHOLAS WATTS,
Bristol Bank Buildings, Bristol, Agent.