A New Compound to be used in Paint or Pigment.
Year: 1889

page_text: Date of Application, 2nd Aug., 1889
Complete Specification Left, 30th Apr., 1890-Accepted; 31st May, 1890
PROVISIONAL SPECIFICATION.
A New Compound to be used in Paint or Pigment.
I RICHARD CONDY of 6 Duke Street, Adelphi W.C. in the County of Middlesex,
Chemist do hereby declare the nature of this invention to be as follows:-
This invention has for its object the treatment of sulphate of lead when intended
for a pigment in such a way that when ground in oil it shall be found to possess the
properties of quickly drying and having a good body and consists in adding oxide of
lead by preference hydrated protoxide of lead to sulphate of lead. The proportions that
I prefer to employ are one equivalent of oxide to two of sulphate of lead though I do
not limit myself to these exact proportions. This compound may be produced by
various methods two of the most important of which are:-
1. The precipitation of sulphate of lead in conjunction with hydrated oxide from
solution of lead salts.
2. By preparing hydrated oxide of lead and grinding or mixing it intimately with
sulphate of lead independently produced already existing or obtained from any other
source.
The method by which to obtain this compound is to precipitate from lead salts in
solution two thirds of the lead therein contained by means of sulphuric acid or soluble
sulphates and one third of the lead in the form of hydrated protoxide and the
soluble lead salts which I prefer to employ are basic acitates or nitrates.
The most suitable salt for illustration of the method of procedure is sesqui basic
acetate of lead which contains two equivalents of acetic acid and three of protoxide
of lead.
After
To 438 parts of dehydrated sesqui basic acetate of lead using sufficient water to
dissolve it I add 142 parts of anhydrous sulphate of soda (or its equivalent 322 parts
of crystallised sulphate of soda containing 10 equivalents of water).
intimately mixing these two substancs neaerly the whole of the lead is precipitated
as a dense white powder consisting as nearly as possible of two equivalents of
sulphate of lead and one equivalent of hydrated oxide. In using tribasic acetate
of lead I use 396 parts of the crystallised salts containing one equivalent of water
to 161 parts of crystallised, sulphate of soda and 49 parts of concentrated sulphuric
acid S.G. 185. After intimately mixing these three substances the precipitate will
resemble approximately the compound derived from the last described mode of
procedure.
After filtering,. pressing or washing either of these precipitates they should be
stirred up in water containing a small quantity of alkaline carbonate but added in
sufficient quantity to indicate slight excuss of the latter after which the pricipitate
must be collected and dried at a low temperature, say 200 to 212 degrees
Fahrenheit..
The original liquor from which the precipitate has been derived should be
rendered, alkaline by, the addition of carbonate of soda in slight excess and can then
be evaporated and crystallised for the recovery for the acetate of soda contained
in it.,
If any other, salts of lead are used the proportion of sulphuric acid sulphate of
soda, or of both combined must be determined by the operator after ascertaining
by analysis or, otherwise the amount of lead contained in the salt. or solution he is
employing.
In cases in which it may be desirable to deal with sulphate of lead separately or
independently made or existing with a view of producing a compound which is the
subject of this invention the hydrated oxide of lead separately prepared can be ground

page_text: or ultimately mixed with the sulphate of lead in the proportion of 121 parts of the
former to 304 parts of the latter though I do not confine myself as before stated to
those exact proportions.
בד
HERBERT & Co.,
Agents to Applicant.
COMPLETE SPECIFICATION.
A New Compound to be used in Paint or Pigment.
1 RICHARD CONDY of 6 Duke Street, Adelphi in the County of Middlesex,
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:-
This invention has for its object the treatment of sulphate of lead when intended
for a pigment in such a way that when ground in oil it shall be found to possess the
properties of quickly drying and having a good body and consists in adding hydrated
protoxide of lead to sulphate of lead.
The proportions that I prefer to employ are one equivalent of oxide to two of
sulphate of lead though I do not limit myself to those exact proportions. This com-
pound may be produced by various methods two of the most important of which are
firstly the precipitation of sulphate of lead in conjunction with hydrated oxide from
solution of load salts and secondly by preparing hydrated oxide of lead and grinding
or mixing it intimately with sulphate of lead independently produced already existing
or obtained from any other source.
The method by which to obtain this compound is to precipitate from lead salts in
solution, two thirds of the lead therein contained by means of sulphuric acid or
solable sulphates and one third of the lead in the form of hydrated protoxide, and the
soluble lead salts which I prefer to employ are basic acetates or nitrates. The most
suitable salt for illustration of the method of procedure is sesqui basic acetate of lead
which contains two equivalents of acetic acid and three of protoxide of lead.
To 438 parts of dehydrated sesqui basic acetate of lead using sufficient water to
dissolvo it I add 142 parts of anhydrous sulphate of soda (or its equivalent 322 parts
of crystallized sulphate of soda containing 10 equivalents of water).
After intimately mixing these two substances nearly the whole of the lead is pre-
cipitated as a dense white powder consisting as nearly as possible of two equivalents
of sulphate of lead and one equivalent of hydrated oxide. In using tribasic acetate
of lead I use 396 parts of the crystallised salt containing one equivalent of water to
161 parts of crystallized sulphate of soda and 49 parts of concentrated sulphuric acid
S.G. 1.85. After intimately mixing these three substances the precipitate will
resemble approximately the compound derived from the last described mode of
procedure.
After filtering, pressing or washing either of those precipitates they should be stirred
up in water containing a small quantity of alkaline carbonate but added in sufficient
quantity to indicate slight excess of the latter, after which the precipitate must be
collected and dried at a low temperature say 200 to 212 degrees Fahrenheit.
The original liquor from which the precipitato has been derived should be rendered
alkaline by the addition of carbonate of soda in slight excess and can then be
evaporated and crystallized for the recovery of the acetate of soda contained in it.
If any other salts of lead are used, the proportion of sulphuric acid, sulphate of soda
or of both combined must be determined by the operator after ascertaining by
analysis or otherwise the amount of lead and of acid contained in the salt or solution
he is employing
In cases in which it may be desirable to deal with sulphate of lead separately or
independently made or existing with a view of producing the compound which is the
subject of this invention, the hydrated oxide of lead separately prepared can be ground

page_text: or intimately mixed with the sulphate of lead in the proportion of 121 parts of the
former to 304 parts of the latter. I do not confine myself as before stated to these
exact proportions but I find them to be the most eligible for the purposes of this
invention.
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 :-
The compound to be used in paint or pigment consisting of a mixture of sulphate
of lead and hydrated oxide of lead substantially as herein described.
Dated this 30th day of April 1890.
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.