Improvements in Pigments having a Lead Basis.
Year: 1891

page_text: Date of Application, 2nd Apr., 1891
Complete Specification Left, 1st Jan., 1892-Accepted, 6th Feb., 1892
Improvements in Pigments having a Lead Basis.
I CHARLES ANTHONY BURGHARDT of 35 Fountain Street Manchester in the
County of Lancaster Analytical Chemist do hereby declare the nature of this
invention to be as follows:
My invention relates to the class of pigments produced by causing oxide of lead
to take up analine or other suitable colouring matters. Previously to my invention
it has been necessary when producing such pigments to prepare litharge or lead
oxide by a long process of levigation and decantation in order to obtain the oxide
in a finely comminuated condition so that it should be in a suitable state to take up
the colouring matter. This process has been used principally or wholly in the
production of imitation vermillion by causing the levigated lead oxide to take up
rosine. The object of my invention is to dispense with the necessity for wet
grinding or levigation and to obtain a more regular and superior product at a lower
cost. I use hydrated lead oxide prepared by the re-action of aqueous solutions
which will cause the said oxide to be thrown out as a fine precipitate.
When so prepared the oxide is in a very fine state of division and is also in a
more regular condition than can be obtained by grinding for ordinary periods of
time so that it is not necessary to eliminate coarser particles by subsidence and
decantation. In the carrying into effect of my invention I prefer to prepare the
hydrated lead oxide in accordance with the directions contained in the Specification
of a former invention for which I have made application for Letters Patent
Number 5442 of the year 1890.
When so prepared the ammonium nitrate resulting from the process being in
itself a valuable product greatly reduces the cost of production of the lead oxide.
I take the wet freshly prepared hydrated lead oxide in a thick creamy state of
consistency and I add to the oxide the analine or other colouring matter which is
to be taken' up.
I generally prepare the creamy paste of oxide in one vessel and
dissolve the colouring matter in another vessel in a small quantity of water and I
then add the dissolved colouring matter to the lead oxide and mix the two
thoroughly. I then allow the mixture to remain at rest for some time until the
colouring matter has been taken up by the lead oxide wholly or to the required
extent or I agitate at intervals and permit the mixture to rest between the periods
of agitation. The result can be tested by drying a sample and comparing it with
the master sample which is to be matched in shade. If too light more colouring
matter may be added. If too dark more lead oxide may be added and the agitation
be repeated or the product may be washed with water until the required reduction
in shade is obtained.
In some cases the operation is aided by heating the mixture.
When it is considered that the right shade will result the excess of moisture is
removed by filtration and the paste is carefully dried in a steam heated stove or
room and when dry may be ground or disintegrated and will then be ready for sale
or use. For some purposes and especially when the pigment is required for early
use the drying may be dispensed with. In cases wherein the colouring matter
would withstand the action of the chemicals it might be added to one of the solutions
ised in the preparation of the lead oxide and be carried down by the precipitated
oxide. The hydrated lead oxide being in an exceedingly fine and even state is in
he best possible.condition to combine with the colouring matters and being more
ure than the ordinary litharge or lead oxide, finer and more regular shades can be

page_text: obtained and also I believe that tints can be obtained which could not be produced
by the ordinary processes.
DUTTON & FULTON,
1, St. James' Square, Manchester, Agents.
COMPLETE SPECIFICATION.
Improvements in Pigments having a Lead Basis.
I CHARLES ANTHONY BURGHARDT of 35 Fountain Street, Manchester, in the
County of Lancaster, Analytical 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, that is to say :-
My invention relates to the class of pigments produced by causing oxide of lead
to take up analine or other suitable colouring matter.
.
Previously to my invention it has been necessary when producing such pigments
to prepare litharge or lead oxide by a long process of levigation and decantation in
order to obtain the oxide in a finely comminuated condition so that it should be in
a suitable state to take up the colouring matter. This process has been used
principally or wholly in the production of imitation vermillion by causing the
levigated lead oxide to take up rosine. The object of my invention is to dispense
with the necessity for wet grinding or levigation and to obtain a more regular and
superior product at a lower cost. I use hydrated lead oxide prepared by the
re-action of aqueous solutions which will cause the said oxide to be thrown out as a
fine precipitate. When so prepared the oxide is in a very fine state of division
and is also in a more regular condition than can be obtained by grinding for
ordinary periods of time so that it is not necessary to eliminate coarser particles by
subsidence and decantation. In the carrying into effect of my invention I prefer
to prepare the hydrated lead oxide in accordance with the directions contained in
the Specification of a former invention for which Letters Patent Number 5442 of
the year 1890 have been granted to me.
up.
When so prepared the ammonium nitrate resulting from the process being in
itself a valuable product greatly reduces the cost of production of the lead oxide.
I take the wet freshly prepared hydrated lead oxide in a creamy state of consistency
and I add to the oxide the analine or other colouring matter which is to be taken
I generally prepare the creamy paste of oxide in one vessel and dissolve the
colouring matter in another vessel in a suitable quantity of water and I then add the
dissolved colouring matter to the lead oxide and mix the two thoroughly. I then
allow the mixture to remain at rest for some time until the colouring matter has been
taken up by the lead oxide wholly or to the required extent or I agitate at intervals
and permit the mixture to rest between the periods of agitation. In some cases I
may diffuse the oxide or a quantity of the creamy paste of the oxide in a quantity
of water and add thereto the selected colouring matter mixing all well together
and allowing the precipitate to settle. The result can be tested by drying a sample
and comparing it with the master sample which is to be matched in shade. If too
light more colouring matter nay be added. If too dark more lead oxide may be
added and the agitation be repeated or the product may be washed with water
until the required reduction in shade is obtained.
In some cases the operation is aided by heating the mixture.
When it is considered that the right shade will result, the excess of moisture is
removed by filtration and the paste is carefully dried in a steam heated stove or
room and when dry may be ground or disintegrated and will then be ready for sale
For some purposes and especially when the pigment is required for early
use the drying may be dispensed with.
or use.
In cases wherein the colouring matter would withstand the action of the
chemicals it might be added to one of the solutions used in the preparation of the

page_text: lead oxide and be carried down by the precipitated oxide. The hydrated lead
oxide being in an exceedingly fine and even state is in the best possible condition
to combine with the colouring matters and being more pure than the ordinary
litharge or lead oxide finer and more regular shades can be obtained and also I
believe that tints can be obtained which could not be produced by the ordinary
process.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The production of pigments by mixing hydrated lead oxide obtained as a
precipitate from solutions with analine or other selected colouring matter in
company with water.
2. The production of pigments by adding to water precipitated hydrated lead
oxide and analine or other suitable colouring matter mixing intimately and allowing
the coloured oxide to settle as set forth.
3. The production of pigments by adding colouring matter of a suitable nature
to a solution of lead nitrate and treating the liquid to throw down a tinted
precipitate of hydrated lead oxide as set forth and indicated.
4. In the preparation of pigments having a lead basis preparing hydrated lead
oxide by precipitation from an aqueous solution of lead salt and adding a suitable
dyeing or colouring matter at a stage in the process so as to obtain hydrated lead
oxide tinted by reason of having taken up or combined with such dye or colouring
matter.
Dated this 31st day of December 1891
DUTTON & FULTON,
1, St. James' Square, Manchester, Agents.