A NEW OR IMPROVED PROCESS FOR TREATING GALVANIZED IRON OR STEEL
Year: 1885

page_text: .I HARRY GRIMSHAW of Clayton near Manchester in the County of Lancaster
Manufacturing Chemist do hereby declare the nature of my invention for A NEW
OR IMPROVED PROCESS FOR TREATING GALVANIZED IRON OR STEEL to be as
follows:-
This invention relates to a process of treating galvanized iron (that is iron or
steel coated with metallic zinc) in order to separate and utilize the iron and zinc..
My process consists in treating the galvanized iron or steel either with sulphuric,
hydrochloric or nitric acid or mixtures of them, together with water. Or instead
of employing the above named acids I may treat the galvanized iron or steel with
a solution of chloride of zinc in water, or with a solution of sulphate of zinc in
water, or with a mixture of sulphate or chloride of zinc and either or all of the
above named acids and water.
By either of these means the zinc becomes dissolved and the iron or steel is left'
free from zinc.
The iron or steel is then of considerably greater value and can be used in the
same way as iron or steel which has not been galvanized, and the solution con-
taining, the zinc can be used as such or purified and treated as may be desirable
for obtaining other compounds of zinc.

page_text: A New or Improved Process for Treating Galvanized Iron
or Steel.
"
I HARRY GRIMSHAW of Clayton near Manchester in the County of Lancaster
Manufacturing Chemist do hereby declare the nature of my invention for "A NEW
OR IMPROVED PROCESS FOR TREATING GALVANIZED IRON OR STEEL and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:—
This invention relates to a process intended principally for treating scrap or
waste "galvanized" sheet iron or steel (that is sheet iron or steel coated with
metallic zinc) in order to separate and utilize the iron or steel and the zinc.
Hitherto it has been the custom simply to burn the zinc off from the iron or
steel in the furnace so as to recover the latter alone and the zinc has thereby been
either entirely wasted by volatilization or has become incorporated with the iron or
steel thereby deteriorating the quality and making it what is known as "short"
but by my improved process the whole of the zinc and the iron or steel is recovered
and can be utilized without any loss whatever and the iron or steel is not
deteriorated. It will however be evident that this process is not only applicable
to waste or scrap galvanized sheet iron or steel, but may also be employed for old
galvanized wire netting or in any case where it is desirable to separate metallic
zinc from iron or steel so as to utilize the same.
My improved process consists in treating the galvanized iron or steel either with
sulphuric, hydrochloric or nitric acid, (or a mixture of any two or more of such
acids) with water so as to dissolve away the zinc, leaving the iron or steel
undissolved.
I do not desire to confine myself to any particular strength of dilute acid to be
employed for this purpose but a mixture which I have found to answer the purpose
well is as follows:-namely:-One part by weight of acid of ordinary commercial
strength to three parts of water. Or, instead of using the above named dilute acids,
or any one or more of them for the purpose of dissolving away the metallic zine
I may treat the galvanized iron or steel with a solution of chloride of zinc in
water, or with a solution of sulphate of zinc in water, or with a mixture of sulphate
and chloride of zinc and water and either with, or without the addition of any or
all of the above named acids.
The following is a solution which I have found to answer the purpose satis-
factorily namely:-
About one part by weight of anhydrous sulphate or chloride of zinc to two parts
of water and I prefer to use this solution at a temperature about equal to that of
boiling water, Although I do not wish to limit myself to this particular mixture
as before stated.

page_text: Having now particularly described and ascertained the nature and object of my
said invention and in what manner the same is to be performed I declare that
what I claim is
The new or improved process for treating "galvanized" iron or steel by
dissolving away the metallic zine by means of dilute acids or by solutions of
chloride or of sulphate of zinc (or both) in water either with or without the
addition of acids so as to separate and utilize the zinc and the iron or steel
substantially as hereinbefore set forth and described.
GEORGE DAVIES,
Agent for the Applicant.