AN IMPROVED PROCESS OF PURIFYING LIQUIDS AND "OVERING MATTER CONTAINEDRE
Year: 1874

page_text: LETTERS PATENT to George Mackay, of Edinburgh, in the County
of Mid Lothian, North Britain, Manufacturing Chemist, for the
Invention of "AN IMPROVED PROCESS OF PURIFYING LIQUIDS AND
"
PROVISIONAL SPECIFICATION left by the said George Mackay at the
Office of the Commissioners of Patents, with his Petition, on the
30th October 1874.
I, GEORGE MACKAY, of Edinburgh, in the County of Mid Lothian,
North Britain, Manufacturing Chemist, do hereby declare the nature of
the said Invention for "AN IMPROVED PROCESS OF PURIFYING LIQUIDS AND
RECOVERING MATTER CONTAINED THEREIN," to be as follows, that is to
say :-
This Invention which relates to the purification of liquids and to the
recovery of matter held in suspension or solution by them has for its

page_text: or channels on the discharge thereinto of the effluent water of paper
mills, tanneries, bleaching and dye works, and similar places where
water or other liquid is used in the process of manufacture, or for
cleansing or other purposes.
And, Second, to effect the recovery of the matter whether animal,
vegetable, or mineral, which may be contained in the said water or
other liquid.
The Invention consists in the admixture with the water or other
liquid to be treated of persalts of iron in such proportions as the
impurity of the liquid and the nature of the matter held in suspension
or solution therein may require. By the combination of the persalts with
the substances contained in the liquid the substances are rendered
insoluble, and by the addition to the liquid and complete admixture
therewith of a proportional quantity of a caustic or carbonated alkali,
either liquid or solid, or alkaline earth such as limo, the persalt is
decomposed and forms peroxides of iron and insoluble sulphates, which
by reason of their greater gravity are precipitated to the bottom of the
reservoir or other receptacle containing the liquid, thus leaving the
supernatant water or other liquid in a purified state. The deposits
obtained by this process arc. in the greater number of cases again
available in the manufacture for which they were originally employed or
for other purposes, and in cases where that which has hitherto been
treated as refuse has a great affinity for water, such for instance as the
sludge" of paper mills, it may by one or more applications of the
process be entirely reclaimed and again utilized either in the manu-
facture of paper or for other purposes. The same result may be effected
with reference to quantities of "sludge" wherein the contained matter
has already been deposited by natural gravitation by the admixture with
such matter of a proportional quantity of peroxides of iron.
The persalts used are preferably those of perchloride and persulphate
of iron and need not be chemically pure, but may be used either singly
or combined with any of the subsalts of iron.
The various persalts of iron are available for the purposes of this
Invention, and the process herein-before described is applicable to the
purification of sewage as well as of other impure liquids.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Mackay in the Great Seal Patent Office
on the 26th April 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
MACKAY, of Edinburgh, in the County Mid Lothian, North Britain,
Manufacturing Chemist, send greeting.
"
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of October, in the year
of our Lord One thousand eight hundred and seventy-four, in the 38th
year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said George Mackay, Her special license that
I, the said George Mackay, my exccutors, administrators, and assigns,
or such others as I, the said George Mackay, my executors, adminis-
trators, or assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "AN IMPROVED PROCESS OF
PURIFYING LIQUIDS AND RECOVERING MATTER CONTAINED THEREIN," upon the.
condition (amongst others) that I, the said George Mackay, by an
instrument in writing under my hand and scal, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Scal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said George Mackay, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement, that is to say :-
My said Invention which relates to the purification of liquids and to
the recovery of matter held in solution or suspension by them has for
its object,
First. To obviate the pollution of rivers, lakes, and other watercourses
or channels occasioned by the discharge thereinto of the effluent water
of paper mills, tannerics, bleaching and dye works, and other similar

page_text: mills, factories, or works wherein water is used in the process of manu-
facture, or for cleansing or other purposes.
Secondly. My said Invention has for its object to effect the recovery
of the matters, whether animal, vegetable, or mineral, contained in the
said water or other liquid.
The Invention consists in admixing with the water or other effluent
liquid to be treated persalts of iron in such proportions as the impurity
of the liquid and the nature of the matter held in suspension or solution
therein may require. By the combination of the persalt with the
matters or substances contained in the liquid the substances are rendered
insoluble, and by the addition to the liquid and complete admixture
therewith of a proportional quantity of a caustic or carbonated alkali,
cither liquid or solid, or alkaline earth, such for example as lime, the
persalt is decomposed and forms peroxides of iron and insoluble
sulphates which by reason of their greater specific gravity are pre-
cipitated to the bottom of the reservoir or other receptacle containing the
liquid, thus leaving the supernatent water or other liquid in a purified

page_text: the nature of the liquid itself. When the combination or chemical
union of the salts with the matters has been effected the caustic or
carbonated alkali, either liquid or solid, or alkaline earth is added in a
proportion relatively with the liquid similar to the proportion of salt
solution employed, or in other suitable proportion, it being explained
that the quantity of alkali or alkaline carth used is sufficient to
decompose all the free chloride and other salts of iron of the salt
solution, and to form therewith peroxides of iron and insoluble sulphates,
which by reason of their greater specific gravity are precipitated to the
bottom of the tank or reservoir. The supernatent liquid thus purified
is then run off, leaving the deposit at the bottom of the tank or

page_text: The processes last described may also be applied for the recovery of
the "sludge" deposited by natural gravitation from the water or other
liquid effluent from works or manufactories other than those wherein
the manufacture of paper is carried on.
It is to be understood that although I have herein specified per-
chloride of iron, otherwise known as sesquichloride or permuriate, and
persulphate of iron as the persalts preferably employed in practising
my said Invention, that I do not confine myself to the employment of
these persalts as the various other persalts of iron are also available, and
further it is to be understood that the processes herein-before described
besides being applicable to the recovery of matters from the impure water
or other liquid effluent from works and manufactures generally are also
applicable to the purification of sewage and of other impure liquids not
specially derivable from the sources herein-before mentioned.
Having now described and particularly ascertained the nature of my
said Invention, and the system, mode, or manner in or under which the
same is or may be used, or practically carried into effect, I would
observe in conclusion that what I consider to be novel and original and
therefore claim as the Invention secured to me by the herein-before in
part recited Letters Patent is,-
First. Treating impure water and other liquids by agitating them.
with a persalt of iron or with a persalt combined with any suitable
subsalt, and thereafter adding a caustic or carbonated alkali or alkaline
earth whereby the vegetable, animal, or mineral matters contained or
.suspended in the liquids are precipitated and recovered, substantially as
bercin before described.
Second. Treating vegetable, animal, or mineral matters deposited
from impure water or other liquids by natural gravitation by mixing
such matters with water and agitating them with a persalt of iron alone
or combined with a suitable subsalt, and thereafter precipitating the
product as insoluble sulphates and peroxides of iron by means of an
alkali or alkaline carth whereby the matters are recovered for reutilization,
substantially as herein-before described.
Third. Treating vegetable, animal, or mineral matters deposited by
natural gravitation from impure water or other liquids for the recovery

page_text: and reutilization of the same by blending such matters with peroxides
of iron in suitable proportions, as herein-before described.
In witness whereof, I, the said George Mackay, have hereunto set
my hand and seal, this Twenty-third day of April, One thousand
eight hundred and seventy-five.