IMPROVEMENTS IN THE PRECIPITATION AND SEPARATION OF COPPER FROM ITS SOLUTIONS
Year: 1868

page_text: LETTERS PATENT to Gustav Bischof, junior, of 14, Toppelsdorfor
Alléc, Bonn, in the Kingdom of Prussia, for the Invention of
"IMPROVEMENTS IN THE PRECIPITATION AND SEPARATION OF COPPER FROM
ITS SOLUTIONS."
Sealed the 5th March 1869, and dated the 11th September 1868.
PROVISIONAL SPECIFICATION left by the said Gustav Bischof at the
Office of the Commissioners of Patents, with his Petition, on the
11th September 1868.
I, GUSTAV BISCHOF, junior, of 14, Toppelsdorfer Allée, Bonn, in the
Kingdom of Prussia, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE PRECIPITATION AND SEPARATION OF COPPER FROM ITS
SOLUTIONS," to be as follows:-
When precipitating solutions containing copper with spongy iron by
the means hitherto known the latter is liable to cake together and to
form cakes or small lumps only externally coated with copper the
interior still containing a large proportion of metallic iron. To obviate
this I effect the precipitation in apparatus consisting of a large wooden
cask suspended horizontally on axes supported in bearings on suitable

page_text: standards. The cask has in its interior four or other number of longi-
tudinal partitions extending radially from the circumference towards
the centre. Spongy iron or copperous liquor having been introduced into
the cask an intimate mixture is effected without any caking of the
contents by turning the cask slowly on its axes. After finishing the
precipitation of coppor, the so-called spent liquor is run off from the
cask. To make sure that no particles of the fine precipitate are carried
away in running off the spent liquor and at the same time to accelerate
the separation of the precipitate from the liquor I pass the latter
through a filter of the following construction :-I take a tank of appropriate
sizo having about six inches above its bottom a perforated false bottom, on
the latter I put a bottom of wickerwork, then I spread uniformly on the
top of the latter such a quantity of moss as when firmly compressed
forms a layer of from two to three inches thick; over this there coines
again a bottom of wickerwork, and finally another perforated false
bottom, which latter is then firmly pressed down. To accelerato the
running off of the liquor from this filter I arrange at any convenient
place between the bottom of the tank and the lower false bottom a tube
which when once filled with the liquor tends like the column of mercury
in a barometer to create a vacuum underneath the filter, thus effecting
a rapid separation of the precipitate and liquor.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Gustav Bischof in the Great Seal Patent Office
on the 9th March 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GUSTAV
BISCHOF, junior, of 14, Toppelsdorfer Allée, Bonn, in the Kingdom
of Prussia, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of September, in the year
of our Lord One thousand cight hundred and sixty-cight, in the thirty-
second ycar of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Gustav Bischof, Her special licence that
I, the said Gustav Bischof, my executors, administrators, and assigns,
or such others as I, the said Gustav Bischof, my executors, adminis-
trators, and assigns, should at any time agree with, and no others,

page_text: 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 "IMPROVEMENTS IN THE
PRECIPITATION AND SEPARATION OF COPPER FROM ITS SOLUTIONS," upon the
condition (amongst others) that I, the said Gustav Bischof, mỹ
executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, 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 Gustav Bischof, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by
the following statement thereof, that is to say:-
When precipitating solutions containing copper with spongy iron by the
means hitherto known the latter is liable to cake together and to form
cakes or small lumps only externally coated with copper, the interior
still containing a large proportion of metallic iron. To obviate this I
effect the precipitation in apparatus consisting of a large wooden cask
suspended horizontally on axes supported in bearings on suitable
standards. The cask has in its interior four or other number of longi-
tudinal partitions extending radially from the circumference towards
the centre. Spongy iron and cupreous liquor having been introduced
into the cask an intimate mixture is effected without any caking of
the contents by turning the cask slowly on its axes.
And in order that this part of my Invention may be fully understood
and readily carried into effect, I will proceed to describe more fully the
manner in which I prefer to conduct the process and I have also shown
a drawing of the form in which I prefer to construct the apparatus.
Figure 1 of the accompanying engraving represents a longitudinal
section of the apparatus; Figure 2, a section of the same through
line A, B, of Figure 1. The same letters refer to the same parts in both
Figures.
a, a, are the axes upon which the cask is supported; b, b, are partitions
extending to about one foot from its circumference towards the centre;
c is a so-called man-hole; d, an opening in the circumference of the

page_text: cask; e is a valve for the escape of any gases generated during the
precipitation. As will be seen from Figure 2 this valve is closed by
the wooden wedge f pressing against the arm g of the valve and opened
at every turn of the cask by the pressing of against the rod h, h,
Figure 1; i, i, Figure 1, is a wheel which being brought in communi-
cation with any convenient motive-power sets the cask in motion. The
cask is charged with spongy iron or cupreous liquor through the opening
d, the cask being for this purpose in such a position that d is uppermost.
After finishing the precipitation of copper, the so-called spent liquor is
run off from the cask through taps which at intervals of about one foot
are inserted at the side k, k, Figure 1, and which are not represented
in the Drawing. They are successively opened when running off the
spent liquor, the uppermost tap first; and to prevent a splashing of
the spent liquor india-rubber tubes leading into the filter herein-after
described may be connected with the mouth of such taps. The precipi-
tated copper is raked out through the opening d which then is at the
bottom, a rake being introduced for this purpose through the man-
hole c, through which latter finally a boy may pass into the interior of
the cask in order to scrape out such precipitate as cannot be reached by
the rako.
To effect the precipitation of copper in the apparatus hercin-before
described the spongy iron need only be crushed so finely that it passes
through a sieve of 3 holes on the inch. However when riddling the
spongy iron I employ a double sieve, the upper one having as stated
3 holes, the lower one 40 holes on the inch. The finest parts which
thus pass through both sieves are kept separate for use as herein-after
described. According to the size of the cask, say one ton of the coarser
parts of riddled spongy iron is introduced into the cask; the latter is
then filled up to about 6 inches with cuprcous liquor and turned round
once every minute. All the copper will be precipitated in about 20
minutes according to the strength of the liquor. Then some 5 minutes
are allowed for the solid particles in the cask to settle down, and the
spent liquor is run off from the cask through the taps which are inserted
in the cask. Instead of taps one can attach to the cask short leaden
mouth-pieces, draw over them a piece of india-rubber tubing, and close
the latter with wooden plugs. The spent liquor is let run through the
inoss filter herein-after described. Again cuprcous liquor is added and
this repcated over and over again until the metallic iron is used up and

page_text: the copper not wholly precipitated from the cuprcous liquor which has
been added last after it has been turned in the cask for one hour. At
this stage a few per cent. of. the finest spongy iron which has passed
through the finer sieve are added, and if they are not sufficient to
precipitate the rest of the copper from the above liquor after some 15
minutes turning a few per cent. more are added. A small excess of iron
is desirable when precipitating the chloride of copper, as it prevents the
formation of oxychloride, and even reduces any oxychloride which may
have been formed to the metallic state, a great excess must however be
avoided. The quantity of the fine spongy iron requisito at the last
stage of the precipitation will by a little practice soon be estimated
with accuracy by dipping a clean piece of iron into the liquor for a
certain length of time, say half a minute, and then observing the thick-
ness of the film of copper precipitated on the iron. After finishing the
precipitation the spent liquor is run off and the precipitated copper
which is all in the state of powder is raked on to the filter hercin-after
described, where it should be repeatedly washed with clean waters. It
is then ready for drying and smelting. The precipitated copper thus
produced can be obtained, practically speaking, free from metallic iron
and oxychloride of copper.
Another advantage of the new method is the saving of motive power,
as the spongy iron need not be ground to fine powder, which hitherto
was customary, and as the slow motion of the cask requires less motive
power than the stirrer or rake hitherto in use. To make sure that no
particles of the fine precipitate are carried away in running off the
spent liquor, and at the same time to accelerate the separation of the
precipitate from the liquor, I pass the latter through a filter of the
following construction :-I take a tank of appropriate size, having about
six inches above its bottom a perforated false bottom. On the latter I
put a bottom of wickerwork; then I spread uniformly on the top of
the latter such a quantity of moss as when firmly compressed forms a
layer of from two to three inches thick. The moss should be fibrous and
washed clean from earthy parts after being separated from the roots.
Over this there comes again a bottom of wickerwork, and finally another
perforated false bottom, which latter is then firmly pressed down. To
accelerate the running off of the liquor from this filter I arrange at
any convenient place between the bottom of the tank and the lower
false bottom a tube which when once filled with the liquor tends like

page_text: the column of mercury in a barometer to create a vacuum underneath
the filter, thus effecting a rapid separation of the precipitate and
liquor.
In witness whereof, I, the said Gustav Bischof, have hereunto
set my hand and seal, this the Sixth day of March in the 5
year of our Lord One thousand eight hundred and sixty-nine.
GUSTAV BISCHOF, JR. (L.S.)