IMPROVEMENTS IN TREATING AND UTILIZING REFUSE TINNED IRON AND OTHER COMBINED METALS
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by William Clark at the Office of
the Commissioners of Patents, with his Petition, on the 3rd March
1864. A communication from abroad by Nicolas Oscar André, junior,
Law Student, of 29, Boulevart St. Martin, Paris.
I, WILLIAM CLARK, of 58, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN TREATING AND UTILIZING REFUSE TINNED IRON AND
OTHER COMBINED METALS," to be as follows:-
This Invention relates to an improved method of utilizing new or old
refuse or cuttings of iron when coated with tin, lead, zinc, or alloys of these
metals by subjecting them to the action of nitrous or nitric vapours, or any
other gaseous acids or mixtures of same with a view to the re-employ-
ment of said metals and especially of tin, such scraps forming the refuse
of various existing manufactures or products. In the following descrip-
tion I will only give one example of the methed of operating, although
I reserve the use of any other tending to the same result. The metal refuse
is first poured into a vertical column from five to ten yards in height and of
a size proportionate to the amount of products to be treated. This column is
divided into compartments of about fifteen inches in depth by means of wood
divisions moving in a horizontal plane. The metal is put in at the top of the
column, care being taken to introduce the wood divisions above each com-
partment when filled, so that the total weight of the metal shall not rest on the
bottom but be divided into as many fractional parts as there are compartments.
The acid vapours are then introduced at the lower part of the column (nitrous

page_text: vapours for example), and on the other hand steam is introduced at the same
point, which becoming partially condensed renders humid the substances con-
tained in the column. The gaseous acids oxidize the surfaces of the refuse
metal and ultimately attack the iron, and this action is allowed to continue in
order to ensure the oxidation of all the foreign metals, and when the operation
has sufficiently advanced the bottom compartment of the chamber is emptied,
and the divisions above mentioned successively withdrawn from the bottom
upwards, so as to empty the contents of each compartment into the next below
it which has become vacant, while the upper one is charged with a fresh
quantity of materials. The operation after once commencing continues
indefinitely, the materials being withdrawn at the bottom and fresh introduced
at the top of the column, while the substances are displaced in successive
gradations, which by renewing the surfaces enables the vapours to act on the
whole of the materials. The refuse which is now covered with a pasty oxide
is washed in several waters and sorted, while if there be any oxide still adhering
it is again washed in acidulated water and then rinsed. The sorting is effected
with greater or less care according to the purpose for which these cleaned iron
scraps are intended. The acids are reduced and melted in a crucible enveloped
in charcoal in the ordinary manner. In order to obtain the tin in a perfectly
pure state the oxide is washed in nitric or acetic acids. If the metal scraps
have been treated by means of the vapours of hydrochloric acid with a view to
obtain the whole or part of the tin in the state of protochloride or bichloride it
may be precipitated, in a metallic state by means of zinc. The iron scraps or
solder which may have been imperfectly deprived of the tin or other metal are
introduced a second time into the column, or they may be employed in chemical
operations where the presence of small quantities of lead or tin is not
prejudicial.