Year: 1887

page_text: Date of Application, 2nd Dec., 1887
Complete Specification Left, 3rd Sept., 1888
Complete Specification Accepted, 9th Nov., 1888
I, ALEXANDER SYDNEY RAMAGE of 16, Derwent Road Liverpool in the County of
Lancaster, Manufacturing Chemist, do hereby declare the nature of this invention to be
as follows:-
The material to be operated upon is the scrap tin plate formed by tinned goods
manufacturers, and all waste material such as old tinned boxes etcetera and tin
refuse.
The scrap tin plate is placed in a vat, made of wood, soaked in paraffin, earthenware
or other material capable of withstanding acid, or other suitable vat, fitted with a
false perforated bottom, and commercial hydrochloric acid is added. It is then heated.
with steam, till the tin is nearly all, or all dissolved, and then the liquor run off from
below the false bottom into another vat similar to first vat, and filled with scrap tin
plate. It is then heated as before till the tin is dissolved. A series of these vats can
be used, and the liquor when the acid is nearly neutralized by the tin is run into a
settler and settled. The clear liquor is then run into a vat, and scrap zinc or scrap
galvanised iron or both are added in sufficient quantity to precipitate all the tin,
which is assisted by heating. When the tin is all precipitated and allowed to settle,
the clear liquor is then run off and the zinc precipitated with milk of lime while being
kept hot, until the slight greenish precipitate of ferrous hydrate is perceived. A
little acid or fresh zinc liquor is added to redissolve the ferrous hydrate, and the zine
oxide, or hydrate is then run off into a vacuum filter or other suitable filter and well
washed. It can then be sold to alkali manufacturers, or in a dry state as Zinc
Oxide."
The tin precipitated by the zinc, can have more strong liquor run on it, till all the
zine is dissolved, which can conveniently be done by using two precipitation vats, and
then well washed and dried, and then if not sold in that state for tin crystal manu-
facture, is melted and cast in ingots. The scrap iron which is left in the first vats

page_text: (dissolving vats) is the best charcoal iron, and can when washed with a little water,
which washings run into a tank in which some zinc is kept to precipitate any tin
still in solution, be sold to precipitate copper in copper extraction works.
If the scrap iron is wanted free from tin, it can be placed in a solution of soda
caustic, or even the hydrochloric acid to be used in a subsequent operation.
In my experiments, I found that about 25 lbs. of scrap tin plate will produce 1 lb.
of tin and of a pound of zinc is required to precipitate it, of which about 90 per
cent. can be recovered in the form of oxide.
In place of using a series of vats with the liquor transferred from one to the other,
the scrap can be placed in cages in the vats and the entire cages removed from vat
to vat. In this case, if desirable, the tin scrap can be washed with dilute acid or water
in transit from vat to vat.
D
1
1002

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to the Chemical Treatment or Utilisa-
tion of Scrap Tin or Terne Plates, Scrap Zinc, Galvanised Iron,
and the like.
I, ALEXANDER SYDNEY RAMAGE, of 16, Derwent Road, Liverpool, in the County
of Lancaster, Manufacturing Chemist, 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 :-
Hitherto tin has been separated from the tin scrap either by means of caustic soda
by which stannate of soda is formed; by mercury by which an amalgam of tin is
formed; or by steeping in acids, and then precipitating by means of zine or with lime
as tin paste.
My invention is for improvements on the latter process, whereby instead of getting,
as has heretofore been done, a very impure tin, and an iron not free from tin, so that
it is useless in copper manufacture, and a large amount of zinc chloride or sulphate
wasted, I get the whole of the tin and lead separate from each other, the whole of
the zine as zinc oxide, and the whole of the iron, either as iron oxide or as good
charcoal iron, useful for copper precipitation. The accompanying sheet of drawings
shows a plan of plant suitable for carrying out the operations hereinafter described.
1 collect the tinned scrap in cages, each fitting a truck, though there can be two,
four, or any other number of cages arranged so that they shall entirely fill the truck.
The truck being run into the works, the cages are lifted by means of an overhead
travelling crane A of ordinary description, and are lowered into troughs of enamelled
iron, wood steeped in paraffin or other tanks of material not acted upon by acid.
These troughs are not shown in the drawing. The cages are also preferably made of
wood well steeped in paraffin. The acid used is hydrochloric acid.
In order to separate the arsenic therefrom, a little stannus chloride (the liquor from
the first vat B hereafter described) is added, just sufficient to throw down all the
arsenic as arsenite of tin, the exact amount required being found on testing a sample.
This separates out in the course of a day, and settles down as a brownish black powder,
leaving the acid perfectly colourless.
This acid is now run into an empty vat B and a cage full of tinned scrap is let
down into said vat. If desired, a rising and falling motion can be given to the cage,
so as to oblige the acid to circulate. This vat B, as also the other vats B' D & D¹ are
heated by means of steam coils a² connected by a pipe a with the boiler a¹.
When the tin is partially or nearly removed from the iron, the cage is lifted up and
lowered into another vat B' of acid, and allowed to steep further, and this operation
can be done several times, if desirable, the fresh acid being put in the further tanks,

page_text: and the fresh tin into those tanks, the acid of which is nearly exhausted. In the
drawings have only shown two steeping tanks but a greater number might be used.
After passing the last tank, the iron now freed from the tin is well washed in a tank
of water B. The liquor is then run into a large settler C, and a little milk of lime
added to take up the large excess of acid, but not to make it quite neutral. This lime
may conveniently be placed in a tank F placed in a central position. The mixture is
then allowed to settle, and any lead in solution will precipitate out. When settled, the
clear liquor is run into another vat D, and scrap zine is added and the whole heated
with steam. The zinc precipitates the tin, forming tin and zinc chloride thus:
In this last reaction, galvanized iron may be used instead of zinc, as the zine on the
iron is thus utilized. The tin, as a rule being spongy comes to the surface.
The contents of the precipitating vat are then run through a centrifugal machine,
or other suitable filter E driven by a small engine e which is in connection with the
boiler a¹. The filtrate is then run into another vat D¹. The tin is treated as after-
wards given. To the filtrate, milk of lime is run in, (and the whole well boiled),
until a slight greenish precipitate is seen (Ferrous hydrate). The precipitate is
stopped just before all the zinc is thrown. The reaction is as follows:-
(Zn Cl, Fe C₁₂) + Ca (OH)₁ = Zn (OH), + (Ca Cl₂ + Fe Cl₂)
liquor Milk of)
Zine
(Ca Cl₂+ Fe C₁₁) + Ca (OH)₂ = Fe (OH)2 + 2 Ca Cl₂
liquor
Milk of Ferrous
lime S Hydrate
=
+ Lime chloride.
The contents are run through a centrifugal machine, or other suitable filter E, and
the hydrate well washed. It is then thrown on iron plates heated by a slow fire,
and dried, with occasional stirring the oven for this operation is shown at G ; the
water goes off and the ferrous hydrate oxidises into ferric oxide, thus

page_text: The tin from the centrifugal machine can be dried and sold in that state. If it is
wanted, as metal ingots, it can be melted in several ways. The difficulty is that on
being heated it ignites, and oxidises with the air, being in such a fine powder. The
best way is to place the wet tin in a small force press and strongly press it. The
ingots afterwards are melted into solid ringing metal.
It can also be melted in an air-tight retort or crucible, or else in a crucible covered
with coal dust, such as H, so that the air cannot enter.
The iron after the tin is taken from it, is best charcoal iron, or steel, and can be
washed, dried, and strongly pressed into bales, and sold to chemical works for pre-
cipitating copper, which cannot be done with the ordinary loose scrap, thus making it
merchantable, or to forgemen for re-rolling, or to puddlers for mixing with the fused
iron on puddling.
Suitable baling presses such as shown at I, 1, may be placed in a convenient position
under the traveller A.
The arsenite of tin in time collects to be a considerable item, and can be sold in that
state, or else furnaced and sold as tin oxide, and arsenic collected.
If the lead is present in large quantities in the liquor, through terne plate clippings
being used, it is as well to precipitate it slightly with a little vitriol or sulphuric acid
before adding the lime.
The hydrochloric acid may be stored for use in tanks such as J, which are filled by
means of a pipe J' from adjacent acid works, or other source.
A steam injector K is provided to force the acid into the tanks B, B'.
All parts of the plant which require steam are connected to the boiler a' by
pipes a.
A branch line L from a railway may with advantage pass under the traveller A, to
ensure an easy access to the material.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I am well aware that tin scrap
has long ago been treated with hydrochloric acid, and the tin precipitated therefrom
by means of metallic zine, and that this tin has been washed, dried, melted, and run
out into bars also that the iron nearly freed from tin by the crude processes hitherto
adopted has been suggested for use in copper works, forges, et cetera, but I believe
it has always been found so insufficiently purified from in or alloy of tin and iron,
as not to be utilizable, and consequently, the suggestion has been of no practicable
value hitherto, and I make no claim for this aforesaid crude process or for the
use of the resulting imperfectly treated iron for this purpose, but that what I claim
as new is :-
1. The processes for utilizing tin scrap and obtaining pure products therefrom,
substantially as above described and subject to the disclaiming notes.
2. Also the following steps in the manufacture, each substantially as and for the
purposes specified.
(a) Packing the tin scrap in cages, and giving them a rising and falling motion
in successive baths of acid, beginning with the nearly saturated acid and ending
with the nearly fresh acid, whereby the alloy of tin and iron beneath the tin is
extracted, and yet the acid is eventually nearly saturated.
() Using the chloride of tin (formed by treating the tin scrap with hydro-
chloric acid) to precipitate the arsenic from the acid before applying it to
the tin scrap, and separating the precipitate, whereby arsenite of tin is
obtained and forms a valuable article of commerce, and the tin afterwards
precipitated is nearly pure tough metal, instead of being brittle through
contamination with arsenic.
(c) Dissolving off the tin and lead coating of the iron, by means of hydrochloric
acid, running off the acid solution, and adding to the latter milk of lime
till the solution is nearly neutral, then allowing it to settle whereby the lead
is separated from the tin solution.

page_text: (d) Pressing the flocculent tin precipitate separated from the aforesaid solution,
into hard cakes, and then melting it whereby the mother liquid is removed and
the tin melted without oxidation.
(e) Precipitating the zinc oxide and iron oxide successively by means of milk of
lime, obtaining them thus separated from each other, and utilizing them sub-
stantially as described.
3. The plant substantially as and for the purposes herein described and illustrated in
the accompanying drawings.