A New or Improved Method of Treating the Glass Oullet 66 known as Blacks
Year: 1886

page_text: Date of Application, 17th Dec., 1886.
Complete Left, 18th Aug., 1887.
Complete Accepted, 20th Sept., 1887.
RESERV
PROVISIONAL SPECIFICATION.
A New or Improved Method of Treating the Glass Oullet
66
known as Blacks."
I JOHN NORTHWOOD of Kingswinford in the County of Stafford Manager of Glass
Works do hereby declare the nature of this invention to be as follows:-
In the manufacture of articles of glass that portion of the glass which is attached
to the iron blow pipe or punty or pontil takes with it when removed from the blow
pipe or punty a quantity of scale consisting mainly of oxide of iron. This glass when
detached from the blow pipe or punty is known as "blacks" and can only be
employed in the manufacture of coloured glass or inferior qualities of uncoloured
glass in consequence of the colour which the oxide of iron communicates to any glass
with which the said "blacks" are melted.
My invention has for its object to remove from the said blacks the scale referred
and to render the cullet freed from the said scale suitable for melting and mixing
with the finest qualities of colourless glass.
My said invention consists of the following method of treating the said "blacks."
I steep the said blacks in one of the mineral acids that is in hydrochloric sulphuric or
nitric acid but preferably in hydrochloric acid until the whole or nearly whole of the
attached scale has been dissolved. The hydrochloric acid I employ is of commercial
strength and the "blacks" are steeped in it two or three days. It frequently happens
that a small portion of the scale remains attached to the glass after prolonged steeping
in the acid.
In this case after removing the partially treated “blacks" from the hydrochloric
acid and washing I immerse them from five minutes to a quarter of an hour in a
mixture of about one part by volume of the hydrofluoric acid of commerce at about
ten parts by volume of water. If the acid employed is below the average commercial
strength the quantity of water must be varied accordingly. By this treatment the
last trace of scale is removed and after washing in water the cullet is fit for use in the
manufacture of the finest qualities of colourless glass.
Dated this Savanteeth day of December 1886
W. T. WHITEMAN,
Agent for the Applicant.

page_text: A New or Improved Method of Treating the Glass Cullet
66
known as Blacks."
I JOHN NORTHWOOD of Kingswinford in the County of Stafford, Manager of Glass
Works, do hereby declare the nature of-my-invention- and in what manner the same
is to be performed to be particularly described and ascertained in and by the following
statement :-
In the manufacture of articles of glass that portion of the glass which is attached to
the iron blow pipe or punty or pontil takes with it when removed from the blow pipe
or punty a quantity of scale consisting mainly of oxide of iron. This glass when
detached from the blowpipe or punty is known as "blacks" and can only be employed
in the manufacture of coloured glass or inferior qualities of uncoloured glass in
consequence of the colour which the oxide of iron communicates to any glass with
which the said blacks are melted.
My invention has for its object to remove from the said blacks the scale referred to
and to render the cullet (as broken glass is commonly called) when freed from the
said scale suitable for melting with the materials from which the finest qualities of
colourless glass are produced.
My said invention consists of the following method of treating the said "blacks."
I steep the said blacks in one of the mineral acids, that is, in hydrochloric or muriatic
acid, sulphuric acid or nitric acid, but preferably in hydrochloric or muriatic acid,
until the whole or nearly the whole of the attached scale has been dissolved. The
hydrochloric acid I employ is of commercial strength and the " "blacks are steeped
in it two or three days at ordinary temperatures, that is, without the application of
heat. It frequently happens that a small portion of the scale remains attached to the
glass after prolonged steeping in the acid.
وو
In this case after removing the partially treated "blacks" from the hydrochloric
acid and washing in water I immerse them from five minutes to a quarter of an hour
in a mixture of about one part by volume of the hydrofluoric acid of commerce to
about ten parts by volume of water. If the acid employed is below the average
commercial strength the quantity of water must be diminished accordingly.
By the treatment with dilute hydrofluoric acid the last trace of scale is removed
from the glass and after washing in water the cullet is fit for use in the manufacture
of the finest qualities of colourless glass.
Although I have described my invention as carried into effect by the use of strong
hydrochloric acid followed by the use of dilute hydrofluoric acid and have found the
treatment of blacks by these acids to answer well in practice yet I do not limit myself
thereto as instead of hydrochloric acid nitric acid or sulphuric acid may be employed
or a mixture of nitric acid with hydrochloric acid or sulphuric acid may be employed.
When nitric acid is added to hydrochloric or sulphuric acid the removal of the scale
is much expedited but as nitric acid is costly and as hydrochloric acid answers

page_text: without the addition of nitric acid I prefer the use of hydrochloric acid as hereinbefore
described.
"
Where the heated glass has been in contact with the blowing iron or punty only a
short time the blacks produced are sufficiently cleared of the attached scale by the use
of hydrochloric, nitric or sulphuric acid or mixtures of these acids in which case the
treatment with hydrofluoric acid is not resorted to.
Having now particularly described and ascertained the nature of my Invention and
the manner in which the same is to be performed I declare that I claim as my
invention :-
The method hereinbefore described of treating the "blacks" produced in the glass
manufacture that is to say, steeping the said blacks in hydrochloric or muriatic acid
or in nitric acid or in sulphuric acid or in a mixture of these acids, whereby the
adhereing scale is either wholly or for the most part removed from the glass and when
the scale is not wholly removed by the action of the said acids or mixture of acids
treating the partially cleaned blacks with dilute hydrofluoric acid whereby the last
traces of the scale are removed and the cullet or broken glass thus treated rendered
suitable for addition to the materials from which the finest quality of glass is
produced.
TAL: Th