Patented Mar.

2, 1954
2,671,058 '

‘ UNITED STATES PATENT osmos

‘ 2,671,058
PIbOCESSv FOR PREPARATION OF ACID
ACTIVATED CLAY
Grant A. Mickelson, AltadenaiCaliL, assignor to
TFiltrol Corporation, Los Angeles, Calif., a cor
poration of Delaware
No Drawing‘. Application July 21, 1951,
Serial No. 238,021
10 Claims. , (01.252-4570)
This invention relates to acid activation of sub
bentonite clay. More particularly, it-relates to proper ?ow rates through the reactor whereby
thelacid treatment ofsub-bentonite clay to pro optimum cracking conditions will obtain. _ ,
duce activated clay material especially suitable In the ?uid catalytic cracking process, thesolid
for use in thermofor catalytic cracking processes CR catalyst is handled 'as a ?ne powder and is sus
and also in ?uid catalytic cracking processes, and pended in a stream of the hydrocarbon vapors
for use incidentally as an adsorbent in the de which are to be contacted. The solid material
colorization of vegetable and mineral oils. is maintained in a. freely-?owing condition at all
It is~well known» that certain natural clays. times and can thus be handled in much the same
particularly the sub-bentonites, can be treated Way as a ?uid. The?uidizing properties of the
with mineral acids, particularly sulfuric acid, to solid catalyst, or the, ability to besuspendedin
produce ef?cient bleaching earths and active cat thegas stream, dependsupon the size and density
alytlc materials. - > r - of the particles and distribution of particle size
Sub-bentonites are a group of the bentonite for any velocity and density of gas stream. ' The
clays, the chief mineral constituent of which is 15 larger particles must be ?ne enough to be, easily
montmorillonite. . The sub-bentonites are rela suspended in a moving stream of gas. Although
tively non~swe1ling in water as distinguished from the upper limit may bevaried to a considerable
the Wyoming type 'bentonite which is the swell extent,_ depending upon the velocity andden‘sity
ing type. Moreover, the sub-bentonites are acid of the gas stream,_practical, operating conditions
activatable to produce decolorizing material and 20 have shown that the maximum size limit‘should
cracking catalysts, and have predominately mag not exceedabout 150 microns, in equivalent diam
nesium and calcium base exchangeable ions,~as eter for activated clay ?uid catalyst. ‘On the
distinguished from the Wyoming type bentonite other hand, the catalyst should not contain par
having sodium as the predominant base exchange ticles that are'too ?ne._ Catalyst particles en
ion. , - ~ trained in the e?luentvapors from the contact‘
25 ing zone are separated from the gases in cyclone
, In many of the operations involving the use
of such activated clay'the particle size and hard separators andelectrical precipitators, suchvas
ness of the material plays an important role. Cottrell ,precipitators. ‘These separating devices
This is especially true when the activatedclay is are able to‘e?ectivelyjremove particles ‘greater
used as a catalyst in the thermofor and the ?uid thanabout 10 to 20 microns inequivalent diam
catalytic cracking processes for cracking petrole 30 eter, and considerablequantities of, material ?ner
um hydrocarbons to make gasoline. - » than this, are lost from the system. :Practical
The thermofor catalytic cracking (TCC) proc considerations have shown that a ?uid catalyst
ess is characterized by continuous movement of shouldhave all, of its particles substantially ?ner
solid catalyst through the reaction zone. The 35 than 150v microns, and not more than 20%__of its
catalyst moves slowly through the reactor by weight made up of particles ?ner than 20 microns.
gravitation and at a rate such as to give the eiTect Moreover, the solid catalyst particles should be
of static bed operation, but at the same time su?iciently hardto withstand breakdown and
catalyst is continuously being replenished. Va excessive attritionlosses duringr use in the ?uid
cracking units. , .
porized feed stock is passed through they reactor
In conventional acid activation processes, raw
either in countercurr‘ent or concurrent ?ow rela-' clay, is extruded with the proper moisture con
tion. . Spent catalyst gravitating to the bottom of tent for extrusion (about 30-40% V. M.) through
the reactor is transferred by suitable elevators a die and the extruded strands, are cut oifto form
?rst to the regenerator. and, after being regen small cylinders or pellets about 1A, .to 1A; .inchin
erated, to the top of the reaction zones for'an 45 diameter and about 1A to % inch in length. The
other pass therethrough. ‘In, this process the clay extruded clay pellets are thencontactedj with
catalyst is in the form of granules having ‘a size ' sulfuric, acid, so that theconcentration of the
within the range of from about 4 .to 10 mesh, and treat exceeds about 30%, sulfuric acid, and heated
is of su?icient hardness towithstand the normal fromabout 200 to 250 degrees F. until theacid
handling to which it is subjected in tfherrocess 50 is substantially consumed, after which the excess
without substantial attrition. This particle size acid and salts are removedrby washing and ?lter
ing, and the product ‘?nally, dried. . v
range is lmportantto elimination of entrainment
,ofucatalyst material the effluentvapors from .Althoug. the originalpellets of raw clay are
the vr1ontactilie zones’ and. to the _:maintenance of 55
within the preferred size range of .TCC catalyst,
when contactedowith acid; during. activation the
 2,671,058 4
3 acid required for activation of the clay, and the
pellets break down or slake to produce a large water content of the clay is adjusted so that the
quantity of activated material of ?uid catalyst resulting mixture is of a suitable consistency
size and ?ner. The dried material thus is too (about 30 to 40% V. M.) for compaction in hard,
?ne for use in the TCC process. It is necessary, stable particles of desired shape and size. The
therefore, to grind the dry activated material and mixture is extruded or otherwise compacted pref
then separate particles of ?uid catalyst size from erably into hard ‘pellets or nodules of a size within
the ?nes. The ?nes, which are smaller than the range for TCC catalyst, that is, from about 4
about 20 microns, are mixed with the proper to 10 mesh. The compacted pellets or nodules
amount of water for extrusion, and are again are then contacted with the residual portion of
extruded through a die and out 01f to form TCC the acid and heated at 200 to 250 degrees F. for
catalyst pellets. one to several hours, or until the acid is substan
In addition to the requirement of extrusion of tially consumed, after which the excess acid and
the acid activated clay ?nes to produce catalyst salts are removed simply by decantation or an
particles within the range required for thermo'f-or equivalent procedure. Ordinarily the total acid
catalytic cracking, known processes of this type dosage for activation, that is, the per cent sul
for producing activated clay catalyst material rune acid based on the volatile free (to constant
have the additional disadvantage of producing-a weight at L700 degrees F.) raw clay, exceeds 40%
large quantity of ?nely dispersed material, some and is ‘preferably about {i5 to 60%, and the con
of which is lost in the washing and separating centration of the acid. solution exceeds 30 %, and
steps. preferably is from '35 to 40%. The activated
One object of this invention is to provide a product ?nally is dried ‘and separated to speci?
process for acid activation of clay, which will cations. A large proportion of the product is of
obviate the foregoing difficulties. TCC ‘size, with a small quantity of fluid catalyst
Another object of the invention is to provide size or ?ner; however, the relatively large TCC
such a process wherein raw clay is extruded or material may be ground to produce ?uid catalyst
otherwise ‘formed into the proper size pellets or or decolorizing material, if desired.
nodules for use in the TCC process, and which By this'process the ‘above enumerated advan
pellets or nodules may be subjected to acid treat tages are obtained and, at the same time, the
ment, washing, and drying with substantially no 3 C: resulting vproduct ‘will ‘have an activity or ef
slaking, thereby to produce ‘active catalyst ma ?ciency ‘at least as ‘good as similar commercial
terialor' TCC size without additional extrusion or materials produced by "conventional activation
forming operations. procedures.
A further object is to provide a clay activation ‘The invention will be more readily understood
process in ‘which the quantity of ?nes produced from the following ‘detailed ‘description.
and lost during the ‘acid treating and washing ln-one embodiment of ‘the invention, clay as it
steps ‘are reduced to a'minimum. comes from the "mine is crushed and ground, and
Other objects and features of the present in then ‘worked ‘in a pug ‘mill with from 5 to '30
vention will be apparent from the ‘description dosage sulfuric acid to provide a uniform mix;
which follows‘: _ ' 40 ture, the sulfuric acid preferably being contained
I have discovered that if, in conjunction with a in ‘an acid solution having ‘a concentration of}
process for the acid activation of Sub-bentcnite about 35 'to 40%. 'It is then extruded under pres
clay to make decolorizing material or ‘cracking ‘sure to ‘form compact and stable pellets. The
catalyst, especially for thermofor catalytic crack moisture content of the mixture should be ad
ing, the raw clay is mixed with a portion of the justed to a fairly narrow range for eifectiv'e
address-lied for “activation and "then compressed ‘ operation of the extrusion apparatus andin order
into "forms or shapes, preferably substantially uni to 'obtainv'pellet's of the desired density and sta-r
form in size and shape, for the ‘acid treatment, bility. The moisture ‘range ‘for e'ifective opera
the compacted ‘clay pellets of nodules containing tion ‘during pelleting may vary with the extru
acid will retain the "same ‘form throughout the 50 sion apparatus and the particular v'sub-‘bentoe
activation period ‘and during washing, whereby nitecla'y dep'ositbu't usually will be found to be
certain ‘distinct advantages are obtained. The in the range of'abouit 30 to 40% 'V’. M. V. M. is
principal advantage lies in the surprising discov de?ned as the “total percentage of material re
‘er‘y that thepellets ‘remain hard and compact moved ‘from the clay mixture by heating to con;
during ‘the whole of the subsequent "acid contact, 'stant weight at 1,700 degree's'F. '
washing, and drying steps, and by initially com The clay-‘acid mixture preferably is ‘forced
pressing the clay-acid mixture into pellets of through 'a die 'plate under high pressure and the
nodules of the proper size, active catalytic crack; extruded strands out to form compacted ‘pellets
i‘n'g material "for use in TCC processes can be about 1/8 to 1/4 inch in diameter ‘and about 1/4 to
produced without the further forming or ‘extru 60 ‘1% inch in length. Although somewhat larger
sion operations required by known activation pellets also "w'll perform ‘satisfactorily, pellets as
processes. Another advantage is that the amount large ‘as ‘1/2 inch in diameter and about 1 to-"Z
of ‘fines lost during acid treating, ‘washing, ‘and inches in length have a tendency to slake and,
drying is materially less ‘than in customary proc therefore, pellets of lesser dimensions should be
esse's. In additionwashing of ‘the activated ma; 05 used. Ingeneral, the compression into forms as
terial can be accomplished simply by ‘decant'ation, by v.pelleting should preferably increase the den
or draining, or similar "procedure, thus eliminat sity from a particle density to the density of the
ing' expensive thickening ‘and ?ltering ‘operations compressed io'rms, where each density is meas
involved in heretofore known activation processes. ‘ured at the 'V. of the compacted or extruded
Another distinct advantage is that contact of ‘the ‘material, at least about 7% and better ‘results
‘clay in the pellet or nodule with the acid mixed ‘ ‘are ‘obtained‘at ‘above ‘about '12 %. Ordinarily, it
therewith during compaction results in moreuni 'will not be vfound practicable to increase the
form activation ‘of the ‘product. ' density more than about ‘25%.
In accordance with the present invention, raw ‘Clay ‘pellets ‘formed with about 5 to '3'0, and
sub-bentonite clay, vafter being ‘dried and ground, "preferably-b I110325, dosage of sulfuric Pacidre'main
‘if ‘desired, is mixed with a speci?c portion of "the
 r.
5,671,058
substantially " whole throughout the entire acti
vation process, ' including the acid contacting, typical analysis of‘the clay from such deposit,‘
washing, and drying steps. -~ However, a'harder on a volatile free basis,is as followsr .l
?nal product is obtained by use of 10 to 20 dosage ‘ . Percent
sulfuric acid, with excellent results being ob Silica (sio2>_’______. _________ _;_~ ____ __-____- 69.0
tained with 15 dosage; therefore, such dosage is Aluminum oxide (A1203) ______ g. ________ _‘_.20.3
preferred. If higher dosages are employed, such, Ferric oxide (F9203) ____________________ __ 1.8
for example, as 40%, the pellets break down or Magnesium oxide (MgO) ____________ __-___'_ 6.9
slake promptly upon contact with the activating Calcium oxide (Ca-O)___<_‘_____' _________ __-;f ‘2.6
acid solution. ‘Similarly, pellets formed with 10 . EXAMPLE 1 . "
less than about 5 dosage sulfuric acid readily
slake during activation. --A sample of sub-bentonite from the Cheto de
'- The extruded pellets may be immediately con posit was thoroughly mixed with su?icient water
tacted with the remaining portion of the acid or to. provide a uniform mixture having a V. M. con
they may be permitted to stand or’ age before tent of 42.5%. The mixture was then extruded
acid contact for a period of time up to about 24 throughv a Tag-inch die ori?ce and cut off into
‘ hours. However, maximum hardness of the ?nal pellets of about 133' to 14 inch in length. ‘The '
'
product, other factors remaining the same, is compacted, pellets were then treated with 50 (1082:
realized Where the pellets have been permitted to age sulfuric acid, the overall-concentration"being
age for about 4 hours before acid contact or acti 20 35%, at a ‘temperature of 220 degrees F..for three
vation. Approximately the same hardness ofthe hours With‘a minimum ofagitation. Following
product is obtained where the pellets areaged 24 this, the-mixture was diluted with an equal V01?
hours as results when the clay pellets are imme ume of water, ?ltered, and washed. Finally, the
diatelycontacted with acid. ' mat'eriallwasdried in a steam chest‘at 180 de
grees F. ' .
lviineral acids and certain organic acids such 25,
as formic may be used in the process of this in The pellets were completely disintegrated,>and
vention, but sulfuric acid is preferred. the. dried material contained a large amount. of
very ?ne particles. . V - 1 -
>~The acid impregnated pellets immersed and
activated in sulfuric acid acid solutions about 30 EXAMPLE II
or 40% or stronger surprisingly remain substan 30
tially whole throughout the activation process . A sample of the same sub-bentoniteas usedlin
and, consequently, can be washed free of salts Example I, afterbeing dried to a,_V. M. content
and excess acid quickly and easily by a variety of 26%, was thoroughly mixed with 15 dosage
of methods such as decantation, percolation, or sulfuric acid and su?icient water to yield a mix,
?ltering. Therefore, it is preferable to use a ture having a V. M. content-of 42.5%., The mix
moderately-concentrated to concentrated solu ture was extruded in thesame manner as de
tion of sulfuric acid in the treat for activating scribed in Example I. ‘The ‘compacted pellets
compacted pellets. were then treated with 35 dosage of sulfuric acid,
Following washing, the product may be dried, the tota1 acid dosage (acid in pellets plus acid
preferably at a temperature of about 150 to 250 40 added) being the same (50%) as in Example I,
degrees F., although higher or lower temperatures and the overall acid concentration being 35%, at
may be employed, to a suitable moisture content. a temperature of 220 degrees F. for three hours
In practice, the pellets usually are dried at a with a minimum of agitationr After acid'treat-'
temperature of 220 degrees F. to a V. M. content ment, the material was subjected to the same
of about‘ 10 to 25%. operations as described in Example I.
Since the acid impregnated pellets remain hard In this case, the pellets remained hard and
and stable throughout the process, by proper se stable and substantially the same size and shape
lection of original pellet shape and size a ?nal as ‘extruded. Practically no ?nes were present
in the product. " I ,
product may be obtained without additional
‘forming or extrusion of a size suitable for use in 50 In order to evaluate the catalytic activity, a
‘the TCC process. sample of the product was submitted for CAT-A
If desired, however, such prod evaluation. The conditions 'under which the
uct may be selectively ground by any suitable
grinder or crusher to ?uid catalyst or decoloriz product was prepared, together with the results
ing ‘size. ‘ of the CAT-A test, are set forth in Table 1. '
While in the foregoing it has been pointed out 55 ‘In evaluating the catalytic activity of product
‘that the acid mixed with the clay to form pellets produced in this and other accompanying ex
comprises a portion of the total acid requirements amples, there was employed a modi?cation of the
for activation, it is to be understood that the CAT-A method as described by J. Alexander and
concentrations of the two acid portions may H.‘G. Sharp in their article entitled “Laboratory
Methods for Determining the Activity of Crack
differ, provided, however, that each solution is 60 ing
above about 10% and preferably about 30%, with Catalyst,” on page R537, National Petroleum
best results being obtained using concentrations News, Technical Section, August 2.1944. In this
between about 30 and 40%, or higher. » test, a. standard light East Texas gas oil is
‘charged at a
The process of the present invention and also rate of 5 cc. per minute for 10
minutes over 200 cc. of catalyst pellets held at
the bene?ts obtained thereby over known proc 65 800 degrees F. and which have preferably been
esses of activation which involve pelleting of the calcined under bone dry air at 1,050 degrees F.
raw clay in the absence of acid are illustrated by ‘for 5 hours. The liquid product from the crack
means of the following examples. It will be un mg test is collected .at a temperature of 60 de
derstood that the invention is not limited to those . grees F. Catalytic activity is measured in terms
speci?c embodiments and particular data given 70 of the volume per cent yield of gasoline on the
since the examples are given primarily for pur no-loss basis (so-called N. L. B. gasoline yield)
poses of illustration. which is'the volume of 410 degrees F. endpoint
In these examples, the sub-bentonite was ob- ' gasoline distilled from the liquid’ cracked prod
tamed from the Chet?’ were FQPPSW; A uct expressed as a percentage of the volume of
gas oil charged corrected for 100% recovery in
 -'I‘he foregoing examples and the results set
the test. The weight per cent conversion is also forth in Table 1 show that acid-containing pellets
determined. This value is obtained ‘by-subtract retain their shape and size throughout actuation,
ing from 100 the quantity, weight of liquid prod whereas acid-free pellets slake and break down
not after removal of 410 degrees endpoint badly, and further that the product .irom acid
gasoline multiplied by 100 divided by the weight containing pellets is of high catalytic activity
of gas oil feed. The amount of coke deposited and within the range for commercial catalyst
on the catalyst and the amount of gaseous prod—
not produced, both expressed as weight per cent material.
For the purpose of demonstrating more accu
or‘ gas oil charged, are determined as is also the 10 rately thedegree of breakdown or slaking during
density of the gaseous product. According to activation and washing of acid-containing clay
the standard ‘CAT-A procedure a isu?icient num pellets formed in accordance with this invention,
ber "of cracking cycles are run until the gasoline as compared with acid-free clay pellets, the fol
yield of three different cycles check within 1.5 %., lowing four examples were run and in all of them
weight ‘per cent, coke yields check'within 3%., the clay pellets were subjected to the same acid
and weight per cent gas values check within 1%. contact and washing techniques, the tota acid
This standard procedure was modi?ed in that (acid in clay pellets, if any, plus acid added in
only 2 cycles are run and ‘the results from the treat) in each case being 50 dosage.
second cycle only are used for evaluation of the
catalyst since .it has been found from long :ex EXAMPLE V
peri'e'nce with the-CAT-A test that the results of A sample of sub-bentonite from the Cheto de
the second cycle are comparable to the average posit was thoroughly mixed with sufficient water
of the three check cycles. to provide a uniform ‘mixture having a V. M. con
Commercially acceptable catalysts should show tent of 31.5%. The mixture was then extruded
catalytic activity ratings of about 35% N. L. B. through a gig-inch die orifice and cut oli into
gasoline yield or higher by the CAT-A method. '~' pellets of about 1% to 1/4 inch in length. The
The coke deposition should not exceed a certain compacted pellets were then treated with 50
amount in order to avoid di?ieulties in burning dosage and 35% concentration of sulfuric acid
off such coke during regeneration. In general, at a temperature of 226 degrees F. for 90 min
the ratio of N. L. B. gasoline yield to coke yield 3 (l utes. Following this, the material was ?ltered
should exceed ‘about 9/1 ‘to 10/1. The gas vden and ‘washed. The product was submitted for wet
‘sity ‘values are also indicative to ‘the character screen analysis to determine the degree of pellet
istics of the catalyst. A high gas density is de slaking or breakdown. Results of the screen
sirable and generally the gas produced during analysis are given in Table 2.
cracking should have 1a density of 1.2 and higher.
EXAMPLE VI
EXAMPLE III
A sample of sub-.bentonite from the Cheto de
A sample of the same s'ub-bentonite as used in posit, pro-dried to a V. M. content of 22.’? %, was
Example II was pro-dried to 15% V. M. and then mixed with water to form a uniform mixture
mixed with 5 dosage sulfuric acid and sufficient 40 having a 32.1 V. M. content and the mixture was
water to yield a mixture having a V. M. content extruded into pellets of the same size as in Ex
of 42.5%. The uniform mixture was extruded ample V. Following extrusion, the compacted
into pellets which were treated with 45 dosage pellets were subjected to the same operations as
sulfuric acid and activated, washed and dried in described in Example V. The results of the screen
the same manner as the sample of Example II.
The pellets, like those of Example II, remained analysis are given in Table 2.
hard and stable throughout the entire activation VII
process and practically no ?nes were present in A sample of the same pre-dried sub-bentonite
the product. The CAT-A test results on this as used in Example VI was pugged with 15 dosage
product are given in Table 1. 50 sulfuric acid and suf?cient water to yield a, uni
EXAMPLE IV form mixture having a V. M. content of 35.9%.
The pugged mixture was then subjected to the
-A sample of the same pro-dried sub-bentonite same extrusion, activation and other operations
as used in Example III was mixed with 25 dosage as the clay of Examples V and VI except that the
sulfuric acid and sufficient water to yield a mix ' pellets were contacted only with 35 dosage sul
ture having a V. M. content of 42.5. The mix furic acid (acid in pellets plus added acid, total
ture was extruded, contacted with 25 dosage sul ing 50 dosage) and that the activation time was
furic acid, and activated, washed and dried in only 66 minutes. The results of the screen anal
the same manner as the samples of Examples
ysis are given in Table 2. '
11 and III.
Again, the pellets remained hard and stable EXAI/[PLE VIII
and substantially of the same size and shape as A sample of the same ‘pro-dried sub-bentonite
extruded. Practically n0 fines were present in as employed in Examples VI and VII was mixed
the product. rl‘he CAT-A test results on this or pugged with 15 dosage sulfuric acid and su?‘i
product are given in Table 1.
, TABLE 1
Summary of preparation conditions and activities of products
. I ’ 1 ‘Initial W't. Wt. Wt. Ratio
. M.0fACld-\ DAG“
Total v. usage Acid
T9?‘ Acid. N. L. B. Percent
, Percent Gas -Percent
_ l\, . L. ‘.B.
may Pellets in Pellets Dosage Cone. G330‘ Conv. Gas Density Coke Gas/Coke

Example II—42.5_ _ _
Percent15 Percent50 ‘ Percent35 42. 3 __________________ -_ 1.43 ____________________ __
Example III-42.5," v5 50 as 43.4 43.1 5.4 1.33 4.3 10.1
Example Iii-42.5-- 25 50 35 44.6 48.4 4.7 1.45 4.4 11.0
 2,671,058 I

cient'water to yield aunlform mixture'havlng a

V. M. content of 37.2%. The pugged mixture was ' causes the mixture to be compressed into balls or
."extruded into pellets about 1/2 inch in diameter nodules. The amount of water that is sprayed
and..1 inch in length. The compacted pellets then , onto the clay controls the size of the balls; the
were subjected to the same activation with 35
dosage sulfuric acid, and other operations, as the
iclay'in Example VII except that the activation
period was 75 minutes. In Table 2 are given the ‘continued, but the nodules are rolled for an addi
results of the screen analysis on the product. - ~ tional period of about an hour or more to further
compact the clay into hard, stable nodules.
TABLE ,2 10
' This embodiment of the invention in which the
Size distribution of activated and washed pellets clay-acid mixture is compacted into nodules by
use of a revolving cylinder or tumbler, and the
Examples
15 same manner, but acid-free, are
VI ’ VII VIII further illustrated by means of the following
examples.
, +3 mesh ________ __
?3 and +5 mesh_ _ EXAMPLE VIII(a)
—5 and +8 mesh. _ _
+8 and +12 mesh. _ A sample of sub-p-bentonite from the Cheto de
—l2 and +20 mesh 20 posit, dried to a V. M. content of about 20%, was
—20 and +32 mesh.
. -32 and+80 mesh. pugged with 15 dosage and 35% concentration of
_ #80 mesh '
sulfuric‘acid for about 30 minutes. The acid
clay mixture was then placed in a continuously
I. The results. presented in Table 2 show the e?ect revolving tumbler and water was atomized onto
of 'pelleting clay with acid upon maintaining 25 the batch of the mixture until nodules of about
.- pellets in their original hard and stable condition SmeshWere formed. The water spray was, at
throughout the activation process. ~ Although that time, discontinued, but the nodules were
4 ' acid-containing
pellets of a relatively large size, tumbled for an additional period of one hour to
as_,.for example, 1%; inchin diameter, have some compact the nodules into hard; stable balls. The
tendency to slake during acid contacting or wash 30 nodules had a V. M. content of 39.2%. Then the
'ing,_acid~free pellets even as small as 1% inch in compacted nodules were treated with an acid
diameter 's'lake much worse and yield a large solution containing an additional quantity (35
quantity of material less'than 12 mesh. Acid dosage) of sulfuric acid, su?icient to make a total
containing pellets about 1% inch in diameter have acid dosage (acid dosage contained in compacted
substantially no tendency to‘ slake and yield a nodules plus added in treat)‘ of 50%, at a tem
_perature of 220 degrees F. for 3 hours. Follow
product containing less than 3% of material of
a‘size ?ner than 8 mesh, as compared with acid ing acid treatment,» the-nodules were washed by
- free pellets of similar size which yield a product decantation using several batches of water, the
containing as much as 55% of material less than water being adequate to reduce the acidity of the
8 mesh. Also, it will be noted that a relatively nodules to between_5,_and 10 mg. KOH. per gram
20% V. M. product. - . I
great amount of material ?ner than 80 mesh is
contained in the product from acid-free pellets The activated nodules remained hard and stable
as compared with the product from acid-con? and substantially of the same size as formed.
taining pellets. Practically no slaking of the nodules was ob
In another embodiment of this invention, the served. In order to evaluate the catalytic activity
clay-acid mixture is compacted by tumbling ‘or of the activated nodules, a sample of the product
rolling the mixture in a continuously revolving was submitted for CAT-A evaluation. The results
cylinder or tumbler whereby the mixture is of the CAT-A test are set forth in Table 3.
formed into balls or nodules of a desired diam v EXAMPLE IX '
' eter..
.The‘ compacted acid-containing nodules 50 ‘

are then subjected to acid-treatment, washing, A sample of the same predried sub-bentonite
. and drying in the manner disclosed hereinbefore as in Example VIII was pugged with 20 dosage and
- in connection with extruded pellets.
The amount 35 %v concentration of sulfuric acid for about 30
of acid added to the clay in the formation of the ~ minutes and the mixture was compacted into
compacted nodules, the amount of acid with nodules, and activated with 30 dosage of sulfuric
which the nodules are contacted during activation acid (total dosage of sulfuric acid of 50%), and
-, (and consequently the total acid dosage); the washed in the same manner as in Example VIII.
‘time and temperature for activation, and the re The nodules, like those of Example VIII,
remained
quired washing are essentially the same as for hard and stable throughout the entire process,
extruded acid-containing pellets. _ 60 and practically no slaking was observed. The
In accordance with this invention, nodules or CAT-A test resultson this product are given in
Table 3. . -
---balls_ of clay containing from 5 to 30, and pref~
erably 5 to 25, dosage sulfuric acid are formed
by pugging or thoroughly mixing the sub-ben
tonite clay with the desired amount of acid for 65 . A sample of the Cheto sub-bentonite dried to a
avtiinev su?icient to product a uniform mixture. V. M. content of about 20% was pugged with 15
.Usually 30 minutes pugging will be su?icient. dosage sulfuric, acid, formed into nodules or balls
The clay-acid mixture is placed in a revolving by tumbling, acid contacted with 35 dosage sul
.cylinder or tumbler wherein the mixture rolls furic acid (total acid dosage of 50%)‘, and washed
over and over. The clay-‘acid mixture is sprayed 70 in the same manner and under the same condi-
with a ?nely atomized water spray as the tumbler tions as described in Example VIII, except the
iscontinuously ‘revolved. The water spray mois activation time (period, during which the com
tens the clay mixture, and the, rolling action, to pacted. nodules were contacted with the second
‘gather with the compaction force. exerted on ma portion of the acid) was 150 minutes, instead of
terial as iti‘alls during the revolving of thedrum, 7 3~hours,, . ,.. _~ .

“Again the“ nodules remainedhard andrstable

 ‘ 2,671,058
12
11 scribed herein, it will be understood that various
‘during activation and washing; The results of Ymodi?cations and adaptations thereof may be
the CAT-A test‘ on the product are given in made without departing from the spirit and
scope of the invention as set forth in the ap
Tablev 3. 5 pended claims. For example, other methods,
EXAMPLE XI
Another‘ sample of the pro-dried sub-bentonite such as briquetting, may be employed for‘ cum
from the Cheto deposit was‘ Bugged with 15 pasting the clay-acid mixture into hard, stable
‘dosage sulfuric acid, formed into nodules by penets 01- 1101111195 of the desired size;
tumbling, acid contacted with 35 dosage sulfuric I claim;
acid, and Washed by the Same Procedure» and 10 1. In a process for acid activating an acid
‘under the same conditions as: in Example VIII, activatable clay in which raw uncalcined clay in
-6X0Bpt here the activation time was only one the form of pellets of substantially uniform size
‘hour. and shape is treated with a mineral acid and
There was Substantially n0 breakdown of the thereafter is washed to remove soluble salts and
nodules during the entire DI'OCBSS- T11e CATrA is excess acid and dried, the improvement of hard
test Was made on the Product and the results ening the pellets su?icient to prevent breakdown
thereof are presented in Table 3. of the pellets during acid activation of the clay
, with the mineral acid and also during washing
EXAMPLE XII of the activated clay which comprises mixing
In order to compare the stability of. acid- 20 with the raw unpelleted clay 5 to 30 weight per
impregnated. compacted nodules with similar cent or’ mineral. acid based on the volatile» free
nodules produced in the same manner but con- weight of the clay, pelleting the clay-acid mix
taining no acid,fa sample of the same pre-dried ture, and treating the pelleted uncalcined clay
sub-bentonit-e as used in. Examples VIII to XI acid mixture with an additional amount of min
was pugged with water only, placed in the re- 25 eral acid sufficient to‘ bring about acid activation
volving tumbler and water was atomized thereon of the pelleted clay;
until nodules of about:5 mesh were formed. The 2. In a process for acid activating an acid
spray was then discontinued but, as in the other activatable clay in which raw uncalcined _ clay
examples, the nodrles were tumbled for an addi- in the form of pellets of substantially" uniform
tional period of one hour.. The compacted‘sn size and shape is treated with a, mineral. acid
nodules, having a- V. M. content of 35.3%, then and thereafter is washed to remove soluble salts
were treated with 50 dosage and 35% concentra- and excess acid and dried, the improvement of
tion of sulfuric acid at a temperature of 220 de- hardening the pellets suflicient to prevent break
grecs. F. for 3 hours, Thereafter the nodules down of the pellets during acid activation of‘ the
were washed and filtered, g5 clay with the mineral acid and also during wash
Thenodules badly slaked and broke down into ing of the activated clay which comprises mix
very ?ne particles. ing, with they raw unpelleted clay l0‘to 20 weight
TABLE 3

. n I Total Initial ' _ Weight Weight Weight

what?“ an as. with Parr

Percent. Percent '
nmmpnvm-imm- 50 35 42.6 49.6 i as 1,50 4.?
Example ix’—2o%._l.l 50 as 42.1 51.0 9.7 1.442 4 5.5
'Emmple x-15%_ _. 5o 35.. 39,6 44. 2 s. 4 1. 51 s. 4
Example xr~1s%. . _ ._ so 35 4313 47. 2 4. s, 1. 42 4.0
Example XII—-0%_._._ 5O 35 __l______-__ .-__..._-. ............................. ._

_ From an examination oi Table 3, it will be seen .-,n per cent of mineral acid based on the volatile
that the activated‘ clay pellets produced in ac- n” vfree weight of the clay, pelleting the clay-acid
'cordance with the present, invention by activat- mixture, and treating the pelleted uncalcined
ingjraw clay pellets hardened by the incorpora- clay-acid mixture with an additional amount of
tion therein of. a portion of the acid required mineral acid su?icient to bring about acid ac
to activate the clay had a catalytic activity well ,r_ "tivation of the pelleted clay.
within the range for commercial operations. "“’ 3. In a process for acid activating an acid
Speci?cally, the activated clay pellets produced; in activatable clay in which raw uncalcined clay in
accordance with the invention as describe-i in the form of’pellets of substantially uniform size
the examples whenrtested by the modi?ed CAT-A and shape is treated with a mineral acid and
method showeda N. LB. gasoline of at least 39.6 M thereafter is washed to remove soluble salts and
and a weight per cent conversion of at least 44.2. ""’ excess acid and dried, the improvement oi‘hard
The results of the above experiments show ening the pellets sui?cient to prevent breakdown
that hard, stable nodules: which will not slake or of the pellets during acid activation of the clay
brealc down. during acid activation and washing with the mineral acid and also during washing
may be prepared by tumbling a clay mixture hav- _ of the activated clay which comprises mixing
ing between 5 and 30 dosage acid, as well as by with the raw unpelleted clay 5 to 30 weight per
extrusion. It is further shown that mere com- cent of mineral acid based on the volatile free
paction without the inclusion of acid in the clay weight of the, clay, extruding the clay-acid mix
is not sufficient and such acid-free nodules badly ture, and treating the extruded uncalcined clay
slake and break down during activation and r acid mixture with an additional amount of min
washing. Moreover, the acid-containing nodules ‘0 er-al‘ acid suiflcient to bring about acid'activation
upon activation yield catalyst of high catalytic oi the extruded clay.
activity and well within the activity range for 4. In, a process for acid activating an acid
commercial catalyst. activatable clay in which raw uncalcined clay
While particular embodiments and examples 75 in the form of pellets of substantially uniiorm
size and shape is treated with a; mineral acid
of this invention have been set forth and‘ de
 2,671,058
13
and thereafter is washed to remove soluble salts l4
and excess acid and dried, the improvement of ture is capable of being extruded into hard stable
hardening the pellets sufficient to prevent break pellets, pelleting the mixture, and treating the
down of the pellets during acid activation of the pelleted uncalcined clay-acid mixture with an
clay with the mineral acid and also during wash additional amount of mineral acid suf?cient to
Q:
ing of the activated clay which comprises mix bring about acid activation of the pelleted clay.
ing with the raw unpelleted clay 5 to 30 weight
per cent of concentrated mineral acid based on
the volatile free weight of the clay, adjusting in the form of pellets of substantially uniform
the moisture content of the clay-acid mixture size and shape is treated with a mineral acid
so as to produce a consistency suitable for pellet and thereafter is washed to remove soluble salts
ing of the mixture into hard stable pellets, pellet and excess acid and dried, the improvement of
ing the mixture, and treating the pelleted un hardening the pellets su?icient to prevent break
calcined clay-acid mixture with an additional down of the pellets during acid activation of the
amount of mineral acid su?icient to bring about 15 clay with the mineral acid and also during wash—
acid activation of the pelleted clay.‘ ing of the activated clay which comprises mix
5. In a process for acid activating an acid ing with the raw unpelleted clay 5 to 30 Weight
activatable clay in which raw uncalcined clay per cent of mineral acid based on the volatile
in the form of pellets of substantially uniform free weight of the clay, pelleting the clay-acid
size and shape is treated with a mineral acid 20 mixture, aging the mixture for a period of from
and thereafter is washed to remove soluble salts 1 to 24 hours, and treating the pelleted un
and excess acid and dried, the improvement of calcined clay-acid mixture with an additional
hardening the pellets sumcient to prevent break amount of mineral acid sufficient to bring about
pellets during acid activation of acid activation of the pelleted clay.
9. In a process for acid activating an acid
washing of the activated clay which comprises 25
mixing with the raw unpelleted clay 10 to 20
weight per cent- of concentrated mineral acid
based on the volatile free weight of the clay, ad thereafter is washed to remove soluble salts and
justing the moisture content of the clay-acid excess acid and dried, the improvement of
mixture so as to produce a consistency suitable hardening the pellets su?icient to prevent break
down of the pellets during acid activation of the
pelleted uncalcined clay-acid mixture with an
additional amount of mineral acid su?icient to <
bring about acid activation of the pelleted clay.
6. In a process for acid activating an acid
activatable clay in which raw uncalcined clay
in the form of pellets of substantially uniform
size and shape is treated with a mineral acid and
thereafter is washed to remove soluble salts and
excess acid and dried, the improvement of
hardening the pellets su?‘icient to prevent break
down of the pellets during acid activation of the
clay with the mineral acid and also during wash- .
ing of the activated clay which comprises mix
ing with the raw unpelleted clay 5 to 30 weight
per cent of mineral acid in an aqueous solution
containing su?icient water such that the mix
ture is capable of being extruded into hard stable
pellets, pelleting the mixture, and treating the 50
pelleted uncalcined clay-acid mixture with an
additional amount of mineral acid sufficient to
bring about acid activation of the pelleted clay.
7. In a process for acid activating an acid- H
activatable clay in which raw uncalcined clay
in the form of pellets of substantially uniform
size and shape is treated with a mineral acid and an additional
thereafter is washed to remove soluble salts and amount of mineral acid sufficient to bring about
excess acid and dried, the improvement of hard acid activation of the extruded clay.
_ ening the pellets sufficient to prevent breakdown GRANT A. MICKEL-SON.
of the pellets during acid activation of the clay
with the mineral acid and also during washing References Cited in the ?le of this patent
of the activated clay which comprises mixing UNITED STATES PATENTS
with the raw unpelleted clay 10 to 20 weight Number Name Date
per cent of mineral acid in an aqueous solution U5
2,551,580 Bond _____________ __ May 8, 1951
containing su?'icient water such that the mix 2,582,956 Bond ____________ __ Jan. 22, 1952