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Патент USA US2131557

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Patented Sept. 27, 1938
‘ 2,131.55")
‘Jeremiah F. Goggin, Davenport, Iowa
No Drawing. Application March 30, 1936,
Serial No. 71,794
1 Claim. (Cl. 134-47)
The present invention pertains to the produc
inafter, and added to the mixture of 1 hydrated
tion of a luminous composition of matter and the '
lime and barium hydroxide. ,
product resulting from the practicing of the proc
ess herein described. Among the objects of this
The solutions mentioned are best kept in con-_
tainers provided" with means whereby the solu
tions may be readily drawn from the containers
5 invention are the production of a highly luminous
product; the economical production of a product
of the nature indicated; an improved method of
producing a luminous composition of matter with
the object in‘ view of having a highly luminous.
10 product; and such further objects, advantages,
. Y
as desired. The bismuth nitrate crystals are'dis
solved in water to make a solution having‘ a con
centration approximately equivalent to twenty
and capabilities as will hereafter appear and as
?ve milligrams (25 mg.) of the nitrate to one
cubic centimeter (1 cc.) of solution. Of course, in‘ 10
preparing the solution, one would not want to
are inherent in the process and product herein
use these quantities, but they are given merely
as illustrative of the proportions used. In pree
Phosphorescent products and various methods
of producing them are already known but I have,
by diligent investigation, discovered a new method
of producing such products which results in a
.more highly luminous substance and one which
holds its luminescence for a longer period of time.
20 Broadly speaking, my invention comprises com
bining in proper proportions and under proper
conditions vhydrated lime or alkali earth hy
droxide or carbonate; 9, liquid solution of lithium
paring the solution, a quantity of the crystals in
excess of the amount needed should be powdered
and then the requisite amount should be weighted
out. ' Twenty-?ve grams (25 g.) of the powder is,
then dissolved in about twenty cubic centimeters '
(20 cc.) of dilute nitric acid (1:6) and several.
hundred cubic centimeters of water.
If a white
precipitate isproduced, additional acid must be
added to clear up this precipitate, as it is neces
sary to use sufficient acid to prevent the bismuth
salts, such as nitrate; a liquid solution of bismuth ' nitrate from hydro-lyzing and precipitating as the ‘ I
salts, such as chloride; a liquid solution of
chromium, molybdenum, uranium, or tungsten
salt and sulphur, or their equivalents. The pro
portions of these substances may vary consider
ably and the luminescence will likewise vary.
process of combining‘ these substances is
more critical than the amounts thereof .
After complete solution, enough
(1 kg.) of sugar is dissolved in. about one and,
?ve-tenths (1.5) liters of water, the water being‘,
warmed if necessary. 'When the sugar is‘ com;
00 O
‘from the substances named above willbe stated
pletely dissolved, wateris added to make a total '
. hereinafter, the present statement being intend—
of ‘two (2) liters of solution, and. then this is
placed in another container'for storage until,
' ed merely as illustrative.
water is added to-make one liter,vand this solution
is then stored in one of the containers.‘
In making the sugar solution, one kilogram
The following is given as illustrative of the ma
terials used in producing one form of the sub
stance herein referred to:
The lithium nitrate solution is prepared by dis~ .
solving two hundred ?fty grams (250 g.) of the
Hydrated ?nishing lime containing about ten , powdered nitrate in about eight hundred cubic
per cent (10%) of volatile matter.
Bismuth nitrate, ‘Bi(NO3)3.5I-I2O, the‘ regular
crystalline bismuth nitrate obtainable from any
chemical supply house.
centimeters (800 cc.) of water, and then, when
Barium hydroxide, Ba(OH) 2.8H2O, generally ~ completely‘, dissolved, suf?cient water is added to 40
produce a total of one liter. This will give ap-l *
secured in the form of pure crystals.
, - _
Ordinary granulated sugar.
tion of the lithium nitrate. This is then stored
in one of the three containers-provided for this
Ordinary lithium nitrate as secured from a
chemical supply house.
proximately a twenty-?ve per cent. (25%) solu- '
Commercial powdered sulphur, either ?owers
or roll; however, the ?owers of sulphur is prefer
50 able because it must be used in powdered form in
order to be satisfactory.
The amount of iron content in the above.
chemicals must be small.
The hydrated lime and barium hydroxide may.
be and preferably are used in the powdered form,
Since the purity of the sulphur is unimportant,
any commercial powdered sulphur may-be used.
Y The proportions of the materials used‘ in pre
paring six pounds (6 lb.) of this luminous sub? ‘
stance are preferably approximately as follows:
Calcium oxide (hydrated)'____, ______ _____‘ 2,0716, '
Barium hydroxide ____________________ __ 1,088
Bismuth nitrate ____ __96 cc. of solution__ 1
Sugar"; __________ “320 cc. of solution__
while the bismuth nitrate, , sugar, and lithium
Lithium nitrate_'_____16'l cc. of solution__
' 41,8
nitrate are dissolved in water, as set forth here
Sulphur ______ __' ______________ ___ _____ __
2,131, 557
If these amounts were to be expressed in per
cent of the entire weight of materials used, the
amounts would be approximately as follows:
Bismuth nitrate
________ nfn'urunfn
__________ “'- ____ __-_“"
sulphur being thoroughly mixed in. Since the
mixture is not ?nely ground to start with and the
sulphur is, there is a tendency for the sulphur to
leave the grinder ?rst. This makes it necessary
that‘ the miXture be thoroughly stirred after
______________________ "
the grinding operation 15 completed.
Emmi-511E}; “““““““““““““““““ "
powder is stirredthoroughly in order to assure the
1-08.; procedure is to add the sulphur in small quan
"“““:::'::“_::::: l6izlewtities as the grinding proceeds.
' ‘The powder-{produced as above set forth, is 10
This ?gures up to a little more. than one hum.. now placed in, a suitable container to be heated
dred per cent (100%) but the percentages given . to a high temperature. This container‘ is pref
are only approximate and this slight variation'is‘ erably a graphite crucible. The No. 8 size will
not enough that it need disturblahyone. .
e I
‘holdi-alittl‘e over two pounds (2 lbs.) of the pow
The approximate limits for the typical example ‘ der and is probably the most satisfactory as it 15
given above are about as follows:
. g
CaO __ ___________ _,____,_,.____.__,_,_- 49.
Ba(OH)‘2.8HzO_‘_' _____ __>;__'__‘____‘ 25.6
4:5 ,
s ______________________
c c
This producesa blue‘colorg.v
443-5 1
LiNO3___ _______________ __, _____ -l
larger size. The process is more or less critical
in "the ‘matter'of heating ‘as a variation intem
' permits'a more uniform heating than would a
the ‘period-of heating is more or less critical.
This description is’ ‘given with reference to the
perature in excess of twenty degrees (20°). above
or ‘below the proper‘ amount is ‘likely to cause
partial or complete failure of the process. Also,‘
pyromet‘er' at ' Saint ‘Ambrose College, Davenport,
Iowa‘, and ‘any other pyrometer, in order to‘ give 25
The predetermined.- quantities! of calcium ~, oxide ‘accurate ‘results, should be calibrated with'this
and-barium oxide,.in accordancewith the propor
tions given in theabove-tablesyare mixed-in a
dry state until thoroughlyintermingled. Water
is then addedland the mixturestirredlthoroughly
. to form a thin-paste... Abetter mixture» may be
produced by bringingthe liquid toa boil and stir
ring. for several minutes.‘ This is :bestdone in a
,. container having. a glazed surfacasuchas a gran—.
iteware pan. To thispaste is added, slowly and
with. constant. stirring, ninety-six cubic. centi
' meters (96%.) ofthe bismuthnitrate solution.
It is important that this be added. slowly and that.
it ‘be stirred- constantly until a‘ complete and
40 thorough mixing has been accomplished.
~ ;
7 It is immaterial whethenthesugar or the lith
ium'v nitrate isjaddedl next but. we willrassume the
addition'e¢sugar.- This requires. the addition
of, three hundredtwenty cubic centimeters (320
cc.) of the sugarfsolution, if the product is being
prepared-in accordance'with the ?rst table given
above. This sugar. solution shouldbe added. slow
ly_and,stirred in well. in-orde'r..torproduce auntform ‘mixtures After this," ~the.lithium. nitrate
solution ,may be. added,» ‘slowly and .with .constant
stirring, ‘in’ order to prevent the formation. .of.
‘ 2the hydroxide which wouldbe precipitated and
would prevent the formationeof-ea uniform mix-,.
the‘ usual accuracy. "
Before‘the'mixture‘is placed in‘ the‘ furnace,
the temperature of ‘the'furnace should‘be'brought’
to nine‘hundred'degrees"(900°) , an'd‘it should be
maintained within not to exceed twenty degrees‘
(20°) of this point during the‘ time of heating.
Any'suitable heating means may be used, pro!
vided" a reducing ‘ atmosphere? is maintained in‘
the'heating chamber. For two pounds (2"‘lbs.)
of mixture in a'No. 8 crucible, the heating period 40
is from two and one-fourth (2%) to 'two'and one—
half (2%‘) hours." Larger crucibles will require
experimentation'to"determine the exact period
of heating requi'redtto produce the'best ‘results.
If'a" No. 5 crucible; contain'in’ga smaller amount
of'the mixture, is‘used, thetime'may‘be reduced
to from*'forty-?ve”'(45)'to‘ sixty’ (60) minutes.
The degree of ?neness‘of'the material is also a
determining factor'in the ‘length of time required.“
TSince' graphite ‘crucibles are fragile, it" is neces- '
sary that they be handled‘c'arefully'. ' lfiproperly 50
handled‘, 'they'williwithstanda great number of
heats but thegrajphite is‘ gradually. oxidized" and
ture. The foregoing accoun'tsiOrv everything but. only the ?reclay base remains.‘ For this reason,
the sulphur, and this isto'be added at alaterstage they crucibles become'brown'after oneior two heats. 55
After the heating-“has been’ completed, the‘
in theprocess. .
should‘ be ‘removedi'frorn the furnace
The mixture produced,‘ as above described, is.
now placed in a suitable container, preferably: and covered with apiece of asbestos to-‘prevent
glazed, such as a granite pan, and‘evaporated to: oxi'datiom of the material. ‘.They should then ‘be.
dryness. In doing this, it is necessary that the
7 mixture be stirred to prevent spattering and to:
assure homogeneity of the mixture. Sinceit is
very di?icult to completely Vcleana container~in
which a quantity. ofithe-‘mixture has been dried}
65 it‘is preferable that the ‘mixing and drying be
_ done in different containers in order to keep one.‘
' cleanzfor the. mixing operation. As the‘dryne'ss'
progresses, the paste becomes stiff and lumpy.
The lumps should be brokenupv asmuch as.possi-.
one todetermine changes in temperature read
ings‘ne‘eded to 'secure’the best results. The read
ings'of this pyrometer are correct according to
ordinary methods of calibration, and it possesses
ble to fabiIitate the drying.
When the. mixture’ is dry," the required amount’
3 of .sulphurisladded and the mixture- is ground to
a very ?ne powder. The ?ner and moreuniform
themixture, the more uniform will'be the result?
75 ing phosphorescent material. After grinding, the"
set in as=cool a place as’ possible and‘ allowed to 60
remain undisturbed until cool:v This may require
one or two hours, depending‘upon the method of
cooling? When : the coolingihasi been completed,
the top layer of oxidized matter" isjtobe ‘scraped’ -
away-until the surface-exposed is a- uniform yellow
color.-- The phosphorescence ~of=the exposedsur~~
face isthento-be tested;- ~If it-shows a‘ uniform
bright blue color, the heating’temperature and
time‘havej-proba'bl-ir bveen?correct. However, be—
fore turning out the sulphides,~~the~upper-three; 70
fourts: inch '(f/t' in~.-)* should lee-removed and the
new.~~surface-~'again'tested: If ‘it appearsto con-' :"
sist‘of two layers with the‘inner .cor-e'luminescing
only poorly;v the heating-time rhas¢been too short. a
The outer layer may be recovered by cautiously 75
separating it from theinner' layer. This is'notl' nitrate is'ilSbd- as "any activator‘.'5 As substitutes
difficult as the two layer'sjtend to _'cohere quite
for this, inwhole' or in part, equivalent quantities
well.’ Re-heating of the center portion‘ is of no ' of’; basic substances: such ‘as copper- nitrate
value, and this must be regarded as wast'e'm'al'
terial. If it is the outer layer? which is poor in
(Cu(NOs)z)',' manganese-chloride. (MnClz), ru
bidium Tnitrate (RbNOa), vcaesium sulphate 5
(Cs2SO4), and chromium chloride (CrCh); may
be 'used. xAlso',-,acidic substances may be used, l
such as sodium chromate (NazCrOi) , potassium
luminescence, it is an indication of’ too high- a
temperature or too long a period of heating. It
is for this reason that the temperature and time
of heating must be so closelyrwatch‘ed throughout
this entire period of heating.
(K2M004) ,- and sodium tungstate
While still hot,‘ the sulphides will luminesce"
The lithium nitrate, in the typical example
with a green color which becomes blue as they
given above, was used as a ?ux.‘ vOther ?uxes,
cool. Various procedures have been followed in
an effort to determine what is the'most desirable
practice for the production of the best results.
such as mo-lybdates, carbonates, nitrates, borates,
phosphates, ohromates, tungstates, chlorides, and
sulphates of alkali metals and alkali earth metals 15
Several of these have had to be'discarded as’
may be'subs'titutedin'equivalent'amountsfor the"
worthless or even harmful.
As an illustration;
5 -'
' ‘q ‘
the barium and calcium hydroxides were' pre-'
heated atatemperature varying-from six'hundr'ed
In the typical example, the sugar'servesias a
binder '~ and. as a reducing agent; Equivalent
to eight hundred degrees ‘(600°-800°) but this
yielded a less satisfactory result-V Also, covering"
quantities of such c'arbohydratesas cellulose-and 20
glucose maylbe-used,"as' may alsoan? equivalent
with aor
the ?tting
excess ?reclay
and prethe ' quantity
The sulphur
of ground.
‘ in
~ whole
r _ or
" iin
result is not so good. If the sulphur is mixed
with the Wet paste. before drying, it is readily
part, by equivalent quantities of selenium (Se)
and tellurium (Te). The resulting product will 25.
vtaken up to form polysulphides which are decom-
‘ be a luminous selenide'or telluride instead of a
posed when heated to the temperature required
- sulphide.
by this method. This gives a perfectly uniform
distribution of the sulphur but for some reason
30 the same results are not attained as by following
the method described above. There is no advantaee in using this procedure and it. in fact,
as for blue: Strontium hydrate, bismuth nitrate,
It has been indicated above that the materials
35 used may be Varied» When the materials are
It is believed, however, that
Sodium tungstate, lithium nitrate, andsulphun ;
The percentage limits of these substances and for 35
varied, it necessitates corresponding changes in
anything like satisfactory results appear to. be‘
about as ‘follows;
for a satisfactory product, the maximum temp-
By a proper choice of materials and operating
conditions, blue, red, and colors intermediate be
tween b1ue and red have been produced. For ‘30
example, the color green has been produced by
the use of the following mixture and proceeding
yielded a poorer product.
the temperature.
erature is approximately one thousand degrees
centrigrade (l,000° 0.). Similarly, the lower
gggggnf'smo """"""""""" “ 9(1) 25 9g 29
Nazwogég'?'é““““ “,"'".""f“" 0'34'1 0'381 40
limit for satisfactory results appears to be approximately seven hundred degrees centigrade
LiNO ' 2 “““““““““ "f""“’ 0' 341 0' 381
3 “““““““““““““““““ ""1, 5'
I 8‘
(700° 0.).
However, it is possible that mixtures
not yet tried might prove that these limits should
45 be altered. The degree of ?neness of the mixture
""""""""" "' “““““““““““““ "
The following table repeats the two typical ex
amples given and indicates vthe substitutions 4;,
to be heated will alter both the time and the
which may be made for the substances given in
temperature of heating.
the typical examples.
Blue____ 0210.
I Fluxes
Carbohydrate. LiNOa.
Green__ Sl'(OH)2.8HzO.
Carbohydrate. LiNOa.
j ‘
Oxides, hydrox-
Carbohydrates Molybdates, carbonates, ni-
ides, carbonates
such as sug-
trates, borates, phosphates, To. ‘ '
ars and cellu-
chromates, tungstates,
‘ loses.
chlorides, sulphates-of a1
kali metals and alkali
earth metals.
In the variation of materials referred to above,
the calcium and barium compounds may be re-
In this speci?cation and the appended claim,
the expression “Luminescent formers” is used as
placed in whole or in part by equivalent amounts ‘the equivalent of “Lu-minaphores” and the‘ word
of such materials as the basic oxides, hydroxides,
70 and carbonates of strontium, zinc, and cadmium.
As there would be Variations in the quantities
of the materials given in the typical example, so
also, there would be corresponding variations in
these materials.
In the typical example given above, bismuth
“Reducers” is used as the equivalent of “Reducin , ' _
I have by no means named all of the substances.
which have been tried and found to work, nor
is it possible to give, within reasonable limits, all
of the operating conditions for all of the combi
nations of substances which may be combined
to; produce a satisfactory product. I; I have; how-: to ?fty-three (49»to~;_53) parts of the former to
ever, indicated a typical example andln-inidic'ated twenty-?ve and six-,tenths-‘to twenty-nine and
how variations of substances, temperaturea-?nee six-tenths (25.6'to 297.6) parts of the latter, add
ness of powder, and time of heating may modify
the results which are evidenced by a product ‘hav
ing a greater or less phosphorescence. In view of
the number of variables and-the amount of vari-'
ation which may occur, I do not wish to be lim-v
ing water and stirring-to form a thin paste; adding
to the paste, slowlyand with constant stirring, a
ited to any particular proportions of the sub
to four and ?ve-tenths" (3.5 to 4.5) parts of sugar
stances used, since these may vary _ with the
in solution; adding to the mixture, slowly and 10’
substances chosen. Also, as indicated above, the
temperatureand time of heatingmust vary with
the substances used and the proportions thereof.
with constant stirring, a solution of ‘one to two
(1 to 2 parts'of lithium nitrate; evaporating the
mixture to approximate dryness, the mixture
It is of course understood that the speci?c dis
15 closure given above may be departed from with
out departing from the spirit of this invention as
set forth in this speci?cation and in-the‘ appended
Having now disclosedby invention, I claim:
The method of producingphosphorescent maa
terial-which comprisesmixing dry hydratedxcahy
cium oxide and dry barium hydroxide, both in
powdered form, in the proportion'of'iorty-nine
solution of, ?ve-hundredths to seven-hundredths
(.05 to .07) ‘parts of bismuth nitrate; adding to
the mixture, while stirring, three and ?ve-tenths
being stirredvwhiledrying; reducing the dry mix
ture to a powder; adding to~the dry mixture four 15
teen‘to eighteen (14 to 18) parts of sulphur in
powdered form; grinding and mixing the mix->
ture; and ‘heating the mixturein a reducing at
mosphere at a "temperature of approximately
nine hundred degrees centigrade (900° C.) for‘ 20%
approximately three (3) ‘hours.
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