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Патент USA US2134055

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Patented Oct. 25, 1938
2,134,055
* UNITED STATES PATENT * oFFicE 7
V
’
2,134,055
,
METHOD or MAKING CADMIUM RED
Walter F. Meister, Elizabeth,‘ \N. ~J., assignor, by
mesne assignments, to Interchemical Corpora
tion, New York, N. Y., a‘corporation of Ohio
No Drawing. Application January 31, 1938,
’
. "Serial N0. 187,398
10 Claims.
This invention relates to a method of making
5
-
(Cl; 134-58) ‘
without leaving any excess of cadmium oxide in
cadmium red, and aims to, provide an improved
the ?nal product.
product at a reduced cost of manufacture.v ~
cess cadmium oxide in the ?nal product dele
teriously aifects the color of the'pigment.
This application is a continuation in part of
my co-pending application Serial No. 89,772,
?ledvJuly 9, 1936.
.
This is important since -ex-,
' . InHthe practical carrying out of my process,
it is often desirable to use somewhat less cad
“Cadmium red” is used herein to indicate any
mium-oxide than the’ speci?ed molecular propor
one vof the series of pigments varying in color
tions in order to avoidthe possibility of any un
from bright orange‘ to dark red and having the
composition :rCdS/yCdSe. “Cadmium thiosele
nide” is used herein to identify the dull, brown
ish material containing cadmium, sulphur and
selenium which has heretofore been formulated
CdSSeX.
My own researches indicate that this
15 substance is not an inde?nite compound as indi
cated by the formula CdSSeX, but rather an in
de?nite mixture of two ‘de?nite compounds,
which should be formulated xCds-l-ycdssez.
In accordance with my invention, cadmium
20 red is obtained by calcining cadmium thiosele
nide in the presenceof cadmium oxide. To carry
out the method, cadmium thioselenide is mixed,
reacted cadmiumoxide in the ?nal product, and
it’ is’ important that the calcination be carried
outina neutral atmosphere in order to avoid
the formation of any additional cadmium oxide
during the calcination. I ?nd it most desirable
10
in practice to make the number of molecules of
cadmium‘, oxide or of the compound decompos 15
able into. cadmium oxide only approximately
equal to one-half the number ‘of; atoms ofsele
nium, that is, a few per cent. less than required
by the speci?ed molecular proportion. It ‘should
be noted that the use of any cadmium oxide re 20
sults in reduced loss of selenium, so that the ad
vantage _of my process can be obtained to some
prior to calcination, with cadmium oxide or with
extent by. the use of any amount of, cadmium
oxide less than, that required by the speci?ed
25 the hydroxide, which is decomposable into cad» molecular proportion, and to the greatest, extent 25
mium oxide by the heat of calcination. I prefer
by an amount approximately equal to that re
ably include in the mixture which ‘is to be cal
quired by the speci?ed molecular proportion.
a cadmium compound, such as the carbonate or
3
cined a quantity of cadmium sulphide su?icient
to produce the sulphur-to-selenium ratio in the
?nal product required to give the color desired.
If an extended pigment is desired, barium sul
phate is also included in the mixture to be cal
cined.
For best theoretical results, the amount of
35 cadmium oxide or of the compound decompos
able into cadmium oxide bears a proportion to
the amount of cadmium thioselenide which
makes the number of molecules of cadmium
oxide equal to one-half the number of atoms
40 of selenium.
My process diifers from prior processes in
which cadmium red has been produced by cal
cining cadmium thioselenide either alone or with
cadmium sulphide or with cadmium “sulphide
45 and barium sulphate, in that the loss of selenium
which has occurred in prior processes may be
substantially reduced and even entirely elim
inated by my process. Besides effecting a sub
stantial economy by eliminating loss of selenium,
50 my process produces a pigmentwhich is cleaner
and brighter than those of prior processes.
I believe that the reaction which occurs in my
process may be indicated as follows:
55
The cadmium thioselenide used in my process’
may be made by known methods, as, forexam
ple, by precipitating a solution of selenium in a
water solution of barium or sodium sulphide 30
with cadmium sulphate; but so far as my process
is concerned, it is immaterial how the cadmium
thioselenide is made, since it constitutes one of
the starting‘materials in my process. The cad
35
mium oxide or the compound decomposable into
cadmium oxide may be mixed with a cadmium
thioselenide after the cadmium thioselenide has
been made, or, if preferred, may be mixed with
the reagents used in making the cadmium thio 40
selenide. In some instances, the compound de
composable into cadmium oxide may consist of
an excess of one of the reagents used in making
the cadmium thioselenide. The calcination is
effected at a temperature of from 1200° F. to
45
1500° F. in a closed furnace in which a neutral
atmosphere, such as an atmosphere of carbon
dioxide, is maintained in order to avoid the
formation of cadmium oxide which would con
taminate the pigment. For the same reason the 50
calcined pigment is quenched in water without
contact with the air.
What I claim is:
'
1. The process of making cadmium red which
comprises calcining in a neutral atmosphere 55
cadmium thioselenide in admixture with a num
This formulation indicates that when the
molecular proportions above speci?ed are used,
60 the loss of selenium may be entirely eliminated
ber of molecules of cadmium oxide less than one
half the number of atoms of selenium contained
in the cadmium thioselenide.
2. The processof making cadmium red which 60
2,184,055
of cadmium oxide less than one-half the number.
comprises calcining cadmium thioselenide in ad
of atoms of selenium contained in the cadmium
mixture with a number of molecules of cadmium
thioselenide.
oxide approximately. equal to one-half, thenum‘;
7. The process of making cadmium red which
ber of atoms of selenium contained in the cad
mium thioselenide.
, comprises calcining cadmium thioselenide and
; V p
cadmium sulphide in admixture with cadmium
oxide, th'e'number of molecules of cadmium oxide
selenide and a cadmium compound selected from being approximately equal to one-half the num
the class consisting of cadmium oxide'and'cadl ' b’e'r of_atoms of selenium.
8;.The. process of making extended cadmium 10
10 mium compounds decomposable ,by .heat into
cadmium oxide, the proportions of the mixture ‘red-which comprises calcining cadmium thic
being such that the number of molecules of cad V. selenide,- cadmium‘sulphide and barium sulphate
mium oxide is less than one-half the number in" admixture with cadmium oxide, the number
of atoms of selenium so that, while the cadmium‘ of molecules of cadmium oxide being approxi
oxide__reduces the loss of ‘selenium, no excess of mately equal to one-half the number of atoms
of: s‘e‘léniiimx
' _
.,
I
cadmiuml oxide‘ remains'in‘ the‘ product, and cal
9: The process: or making: extended cadmium
cining‘ the mixture- in- a‘ neutral atmosphere to
avoid the formation‘ of‘ additional cadmium red which comprises making a- mixture of cad
mium- thios'elenide' and barium sulphate with a
51". The processo'f makingcadmium" red? which cadmium- compound selected from the class con
sisting of cadmium oxide and? cadmium com
comprises making a mixture'wof cadmium thio
3. The process of making cadmium ‘red which
comprises making a mixture of-cadmiunithio- >
oxideywr"
_
h
__
selenide and a ‘cadmium compound’ selected from
the class ‘consisting of‘cadmium oxide’ and cad
mium compounds decomposable by heat intocad‘
pounds" decomposable by heat into' cadmium ox
ide, the proportions‘ of the mixture being such
that‘ the number of molecules of cadmium oxide
mium oxide, theproportions‘ of the mixture be
ing" such that the number of molecules of" cad
mium ox‘id‘ei's‘ approximately equal' to one-half
is less» than one-half the’ number of atoms of
seremum. so that‘while the cadmium oxide re
the number of atoms of selenium, and calcining
oxide remains in the product, and‘ calcining the
mixture in a. neutral atmosphere to avoid the 30
formationof additionzavL-l-v cadmium oxide. '
10.. The process-of making‘ cadmium red which
the mixture.
‘
_>
A
_ 5. The processiof" making cadmium red which
comprises calcining in'va‘ neutral ‘ atmosphere ‘cad
mi'um-thiosélé'nide and‘ cadmium sulphide in?ad-f
mixture with'a number of molecules of cadmium
oxide less than one-half the number of atoms
35 of selenium contained in the cadmium thio
selenide.
I
_
'
‘
‘
6_'. The process of making extended cadmium
red’ which comprises calcining in a; neutral- at
mosphere cadmium‘ thioselenide and barium sul
phate in admixture with a'number of molecules
duces the loss‘ of selenium no excess of cadmium
comprises making a mixture of the material pre
cipitated by cadmium sulphate from a solution of
selenium in: barium sulphide with a cadmium
compound selected from the class consisting of
cadmium oxide and-cadmium compounds decom
posable into cadmium oxide by heat, and calcin-v
ing the mixture;
-
WALTER F. MEISTER.
310
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