Improvements in the Treatment of Waste Liquors from Metallurgical Processes to Obtain Sulphurous or Sulphuric Acid and Oxide of Iron.
Year: 1891

page_text: Date of Application, 11th June, 1891
Complete Specification Left, 10th Mar., 1892-Accepted, 30th Apr., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Waste Liquors from Metallurgical
Processes to Obtain Sulphurous or Sulphuric Acid and Oxide of
Iron.
I, ALLAN TWISLETON HALL, F.C.S., of Inglebank, Newland, Hull, do hereby
declare the nature of this invention to be as follows:-
I add to the waste chloride of iron or sulphate of iron liquors from tin plate or
galvanizing works a solution obtained by boiling alkali waste (polysulphide of
calcium) with lime. A black precipitate results containing sulphide of iron. This
precipitate is burnt in an ordinary furnace and sulphurous acid is given off
which may be employed for the manufacture of sulphuric acid in the usual way.
The residue in the furnace is oxide of iron if a chloride solution is employed or a
mixture of oxide of iron and sulphate of lime if a sulphate solution.
Soda ash or other alkaline material may be substituted for the lime and sulphides
of the alkaline earths for the alkali waste and lime.
The process is applicable to other liquors containing salts of iron.
Dated this 11th day of June 1891.
CARPMAEL & Co.,
Agents for the Applicant.
Improvements in the Treatment of Waste Liquors from Metallurgical
Processes to Obtain Sulphurous or Sulphuric Acid and Oxide of
Iron.
I, ALLAN TWISLETON HALL, F.C.S., of Inglebank, Newland, Hull, 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:-
I add to the waste chloride of iron or sulphate of iron liquors from tin plate
or galvanizing works a solution or cream obtained by boiling alkali waste (poly-
sulphides of calcium) with about 1 of its weight of lime or a mixture of alkali
waste and lime may be added to the solution of iron and then boiled and agitated.
A black precipitate results containing sulphide of iron. Sufficient alkali waste
and lime should be added to precipitate nearly but preferably not quite all the
iron it being desirable to avoid an excess of lime salts. This precipitate is burnt in
an ordinary furnace and sulphurous acid is given off which may be employed for
the manufacture of sulphuric acid in the usual way. The residue in the furnace is
oxide of iron if a chloride solution of iron is employed or a mixture of oxide of
iron and sulphate of lime if a sulphate solution of iron is used.
Soda ash or other alkaline material may be substituted for the lime and sulphides
of the alkaline earths for the alkali waste and lime.
The process is applicable to other liquors containing salts of iron.

page_text: 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 :-
The treatment of waste liquors from metallurgical processes to obtain sulphurous
or sulphuric acid and oxide of iron substantially as described.
Dated this 7th day of March 1892.
Witness to the above signature-
G. CARR ROBINSON.
ALLAN T. HALL.