US2363876A - Improved fuller's earth and preparation thereof - Google Patents

Description

'N \28,-1944- 1 w. A. LA LANDE, JR 2,363,87

IMPROVED FULLERS EARTH AND PREPARATION THEREOF Filed March 28, 1942 .2 Roll Crusher 7 6 "Qatari #Hlkaliue Agent Pug Mm Inventor fittest William H. LaLande Jr.

By f/ K fliiorney Patented Nov. 28, 1944 UNITED STATES PATENT orrlcrz mmovsn man's mam AND mamm- TION 'rnaaaor William A. La Lande, In, Upper Darby, 1a., assignor to Attapulgus Clay Company, Philadelphia, 2a., a corporation of Delaware Application March 28, 1942, Serial No. 436,630

9 Claims.

The present invention relates to a process for increasing the adsorptive capacity, and particularly the decolorizing or bleaching efllciency of argillaceous substances such as fuller's earth of the Georgia-Floridatype.

This application is a continuation-in-part of my application Serial No. 298,563, filed October 9, 1939, and entitled Substance Preparation.

In the production of granular fullers earth for use in the treatment of petroleum products, and especially for decolorization of lubricating oils and waxes, it has been conventional practiceto dry the raw fuller's earth, crush the dried earth, screen the crushed material to obtain granular particles of the desired size, for example, 30-60 mesh, and thereafter heat or calcine the granular particles at temperatures of the order of from 900 F. to 1200 F., prior to utilizing the earth as a decolorizer. Fuller's earth produced in this manner, and employed in large quantities for decolorizing hydrocarbon oils and waxes, has an average volatile content (mostly water) of the order of from 3.5% to 4% by weight, a volume weight of the order of from 30 to 33 lbs. per cu. ft., and a decolorizing efllciency arbitrarily designated at 100% on both the weight and volume basis.

The decolorizing efficiency of some types of fullers earths may be improved by a process wherein the fullers earth containing suflicient water to render it plastic is subjected to a grinding, kneading and mixing action under substane tial pressure, for example, of the order oi from 400 to 1200 pounds per square inch, and then extruded through a die-plate provided witha plurality of orifices. The earth is then dried. ground, screened and calcined to produce, for example, a granularearth of 3060 mesh, which has improved decolorizing properties for mineral oils. Tests upon numerous samples of fullers earths which respond to increase in decolorizing efiiciency when processed in the manner last above referred to, indicates that the decolorizin efflciency upon a weight bas s is markedly improved. that the decolorizing efilciency upon a volume basis is also improved, but to a lesser degree than upon the weight basis, and that the volume wei ht of theprocessed earth (e. g. pounds per cubic foot) is substantially lower than that of samples of the respective iullers earths not so p ocessed. Typical of the properties of a fullers earth before and after so processingrare the following:

Before After In accordance with the present invention, I

have found that the adsorptive capacity, and particularly the decolorizlng efficiency of fullers earths for hydrocarbon oils may be markedly increased in a relatively simple and inexpensive manner. More specifically, in accordance with my invention, I have been able to increase the decolorizlng efllciency of fullers earth upon the volume basis to a very substantial extent, and usually at the same time increase the decolorizing eiliciency upon the weight basis. Furthermore, I have been able to effect an advantageous-increase in volume weight (lbs/cu. It.) of the iullers earth treated-in accordance with my process. By thus increasing the volume weight, the decolorizing capacity of a filter of given volume may be increased, for example, by 20 to My invention is particularly applicable to the treatment of those fullers earths, which, upon being subjected to grinding, kneading, mixing and extrusion under substantial pressure in water-moist or plastic conditiomand thereafter being dried, screened and calcined, will exhibit a decrease in volume weight andan increase in decolorizing efiiciency. Such behav or is characteristic of the majority of the fullers earths of the Georgia-Florida type, for example. those obtained from Decatur County, Georgia, and Gadsden County, Florida. However, materials such as clays from Nagodoches, Texas, and clays from Creede, Colorado, do not behave'in this manner, and are unsuitable for my purpose.

In accordance with my invention, Georgia- Florida type fullers earth, in moist condition, is intimately admixed with a chemical agent which reacts alkaline in aqueous solution, the mixture is extruded at elevated pressure in a suitable extrusion machine. The extruded material is dried and then reduced to granular particles of desired size by crushing and screening, and the granular particles are finally heated or calcined at temperatures of the order of from 200 F. to 1400 F., and preferably at temperatures of from 800 F. to l200 prior to use as a decolorizing medium for hydrocarbon oils. The quantity of alkaline agent employed may range from 0.1% to about 1.75% by weight, based u on volatile-free fullers earth. and is preferably of the order of from 1.00 to 1.50% by wei ht. Since the volatile content of fullers earth varies consi erably with the source of the material, the quantity of water to be used in making up the alkaline solution to be admixed with the earth likewisemust bevaried, in order that the total volatile content of the earth be kept within the desired limits, i. e., to by weight, during the mixing and extrusion operation. In general, the concentration of alkaline agent in the aqueoussolution to be mixed with the fullers earth is of the order of from 1% to- 6% by weight. By volatile conten or "volatile matter" is meant those constituents of fullers earth which are volatilizcd or driven off by heating the'earth for a period of 20 minutes at a temperature of substantially 1800" F. The

mixing operation may be accomplished in any' and in all cases must be sufficient to permit a thorough incorporation of the alkaline solution.-

in the fullers earth. Periods of the order of from 10 to 15 minutes or longer may be employed. The temperature at which mixing and extrusion is carried out may range from atmospheric to about 200 F., and is preferably of the order of from 70 F. to 100 F. While it is preferred to employ raw fullers earth containing natural moisture as the starting material, earths which have been dried and rewetted may also be utilized. .When employing a continuous extrusion press to obtain a mixing, grinding and shearing action under elevated pressure, one may prepare the charge for the press in the following manner. The raw fullers earth, in the form of lumps, may be subjected to a preliminary crushing to reduce the lumps, and the reduced earth may be mixed directly with the solution of alkaline agent, for example, in a pug mill, care being taken to adjust the concentration of the solution so that the water content thereof plus the natural water content of the earth will give a plastic material having a volatile content between 45% and 60% by weight.

Among the chemical agents reacting alkaline in aqueous solution which may be employed in accordance with my invention are the hydroxides, oxides, peroxides, carbonates, bicarbonates, secondary and tertiary phosphates, silicates, sulfltes and sulfides of Na, K, Li, and NH4 which are soluble in water to substantial extent. Because of their avaliability, effectiveness, and non-corrosive properties, the alkali metal hydroxides, and particularly sodium hydroxide are preferred. Other alkaline reacting substances which may be employed are the alkoxides and phenolates of strong bases; alkali metal hydrosulfides and polysuliides; calcium and barium hydrosulfides and polysulfides; soluble magnesium, calcium, and barium salts of the weak acids; alkali metal aluminates, zincates, plumbites, arsenites, arsenates, antimonites, stannites, stannates, chromites, manganates, phosphites, hypoohosphites, hydrosulfites, thiosulfates, hypochlorites, hydrogen sulfltes; amides of metals forming soluble strong bases; quaternary bases such as tetraalkyl ammonium hydroxides, tetra-aryl ammonium hydroxides, and

mixed alkylaryl ammonium hydroxides; hydrazine, hydroxylamine, urea; and other organic bases. While, in general, it is desirable to employ aqueous solutions of alkaline agents. ad-

vantageous results may be obtained by utilizing aqueous alcoholic solutions, or solutions containing small amounts of wetting agents such as fatty acid soaps, water-soluble sulfonic acid soaps, sulfonated alcohols, and the like, in addition to the alkaline agent.

My invention may be further illustrated with reference to the accompanying drawing. which shows diagrammatically a system suitable for carrying out my process.

Raw fuller's earth or "clay of the type obtained from the Georgia-Florida fullers earth deposits and containing natural moisture (45% to 55%) is passed from storage vessel l to the roll crusher 2 wherein the lumpy earth is reduced to relatively flat fragments which may be readily handled in the pug mill 3. The pug mill 3 consists of a housing and a longitudinal shaft 4 having a plurality of spirally disposed paddles 5 adapted to intimately mix the earth while advancing it toward the discharge end of the housing. The shaft may be rotated at a suitable speed by a motor or other source of power not shown. In the pug mill the earth is intimately admixed with the alkaline agent introduced in solution through line 6, the quantity of agent being of the order of 0.1% to 1.75% by weight, based on the volatile-free earth, and preferably about 1% by weight. Depending upon the initial moisture'of the raw earth, the concentration of the alkaline solution introduced through line 6 is adjusted to give a total volatile content in the earth of the order of from 45% to 60% by weight, and preferably of the order of from 50% to 55% by weight. If necessary, water may be added to the earth in the pug mill by means of line 1.

Upon discharge from the pug mill 3, the plastic earth of proper moisture content and containing,

for example, 1% of alkaline agent thoroughly dis-- persed therein, is introduced into an apparatus capable of exerting a mixing, grinding, and shearing action thereupon, preferably under elevated pressure. The apparatus, in the present instance, is shown as an auger-type, continuous extrusion press comprising a housing or barrel 8 provided with a rotatable screw 9 and a die plate l0 at the discharge end of the housing. The die plate It is provided with a plurality of orifices of suitable size and shape, such orifices generally having a diameter of from about one-eighth to about seven-eighths of an inch. The plastic earth containing the alkaline agent introduced into the housing 8 is subjected therein to an intensive mixing, grinding, and shearing action by means of the screw 9, and is finally extruded through the orifices of the die plate I!) at elevated pressures of the order of from 400 to 1200 lbs/sq. in., or higher. The moist, extruded earth discharged through the orifices of the die plate I0 is then passed through a drier II wherein it is dried, preferably at temperatures of from 250 F. to 300 F., to the desired volatile content, for example, 15% by weight. The heated earth from the drier II is cooled in tank l2 and passed to the roller mill l3, wherein the dried earth is reduced to granular particles. The granular material from mill I3 is thereafter screened in screen l4, and that portion having the desired particle size, for example, 30 to 60 mesh, is either passed to storage or calcined at elevated temperatures of the order of from 200 F. to 1400 F., and preferably at temperatures of from 800 F. to 1200 F. Dust or fines, resulting fromthe milling and screening operations (designated as reject), may be returned to the pug mill 3 or to the extrusion press for further processing. Or, such fines, being of themselves of improved adsorptive efiiciency, may

be employed in various processes, such as contact decolorization of hydrocarbon oils, or as catalysts or catalyst carriers, and the like. Oversize particles from screen I 4 may be returned to the roller mill I 3 and reduced to particles predominantly of the desired size, and

above described.

In order to further illustrate my invention and to show the advantages of my process over those thereafter screened as 3 volume of filtrate of 6 N. P. A.-color thus obtained. .when compared with the volume of filtrate of the same color obtained by filtration through commercial fullers earth. is indicative of the decoloremployed heretofore, the following examples are I 5 izlng emciency of the treated earth.

Pugging Extrusion Product Eiiiciency Example i i 3 Time, Y Ampere Thruput, v. M. v01. wt.

who min. can load (on/min.) (burned) (burned) wt VOL 1 per cent per cent 1 Commercial iuller's earth. 3. 5 31. 7 100. 100.0 2 Raw Iullers earth 53. 53. 5 3. 5 34. 6 3. 4 29. 6 121. 2 114. 3 3 Raw fullers earch +0.25% Na0H. 53. 6 15 53. 6 3. 5 33. 5 3. 8 32. l 125. 0 125. 7 4) Raw fullers earth-+0.50? NaOH &. 8 I5 53. 8 3. 5 32. 8 i 3. 5 32. 8 123. 4 126. 4 5) Raw fuller's earth+0.75 o NaOH. 54. 0 15 54.0 3. 5 33. 3 3. 7 32. 8 124. 7 123. 2 5) Raw lullers earth+1.0 o N aOH. 53. 4 15 53. 4 3. 5 32. 3 3. 7 33.8 124. 2 131. 7 (7) Raw iuller's earth 1.25% NaO 54. 2 15 a 54. 2 3. 5 38.8 3.4, 34. 3 127. 3 137.0 8) Raw iuller's earth 1 50%Na0H 54. 3 l5 54.3 3. 5 38.6 3.5 35.4 124. 2 137.9 9) Raw fuller: earth-+1.75% Na0H 53.4 15 53.4 3. 5 32. 7 3. 7 36. 3 120. 5 137. 0 10) Raw fuller's earth-+% NaOH 53. 5 15 53. 5 3. 5 31. 5 4. 0 l 36. 2 116. 2 132. 2 11) Raw iullers earth+1.0% NBzCOz. 53.7 15 53. 7 3. 5 36. 6 3.8 32. 5 122. 5 125.2 12) Raw iullers earth-+10% LiOH... 53.5 15 53. 5 3. 5 34.8 3.0 33. 1 123. 2 128. 4 13) Raw iuller's earth+l.0% NH H 53.7 15 53. 7 3. 5 14. 3 4.0 30. 2 127.0 120. 7 14; Raw fuller's earth+1.0% NaHCO 3. 53.8 15 53.8 3.0 18.9 3. 9 30. 7 128. 2 123. 8 15 Raw fuller's earth-+10% NazHPO. 53.8 15 53.8 2. 5 33.5 3. 2 31.3 123.0 120. 7 (16) Raw fullers earth-+10% Na3PO 53.8 15 53.8 3.5 36.4 4.0 31.2 128.4 125.4 (17) Raw fullets earth-H.075 NazSiOu.-. 53. 7 15 53. 7 3. 5 31. 6 3. 5 31.0 128. 8 125.2 (18) Raw fullers earth-14.0% NazS J... 53. 4 15 53. 4 2. 5 10.9 3.9 32. 7 125.1 127. 4 (19) Raw iullers earth+l.0% Na:S03.... 53.2 15 53.2 2. 5 7.4 4.3 31.4 124. 2 122.0

presented. It is to he understood that such examples are merely illustrative and are not to be It will be seen from Examples 3 to 9 and10 to 19 that treatment of fullers earth with chemical considered as limiting the scope of my invention. an I agents reacting alkaline in aqueous solution re- In the table are'shown the results obtained by sults in a marked increase in decolorizing efiltreating raw fullers earth from the Attapulgus, ciency, both on a weight and volume basis, as Georgia, fullers earth deposits, in the presence well as an increase in volume weight in the maand in the absence of added chemical agents. jority of the samples treated. Pugging raw full- For purposes of comparison there are included an ers earth with less than about 2% by weight of examples of commercial Georgia-Florida fullers an alkaline agent, followed by extrusion (Examearth, and Georgia-Florida fullers earth pugged ples 3 to 9 and 10 to 19), produces a substantial in the presence and in the absence of chemical increase in volume weight as well as a great imagents and then extruded. provement in decolorizing efliciency (particularly Commercial fullers earth (Example 1) was pro- 40 on a volume basis), as compared with commercial duced by drying raw fullers earth (V. M. --43%), fullers earth (Example 1), or raw fullers earth grinding the dried material, screening same to which has simply been pugged with water and 30 to 60 mesh, and calcining or burning the 30 then extruded (Example 2). It will be noted to 60 mesh earth at 900 F. for 20 minutes. 4? that the weight efllciency of the treated earth in In theexamples involving intimate grinding, Example 10, using 2% NaOH, has fallen below kneading, mixing and extrusion in addition to that of the water-extruded earth (Example 2). pugging (Examples 2 to 19), the puggedearth Such decrease is substantial and undesirable, and was passed through a twin screw extrusion press it is therefore evident that the quantity of alkahaving 2" diameter screws or augers' approxiline agent should be maintained below 2%, and mately 14" in length, and a die plate 1" thick preferably not higher than about 1.75%, in order provided with aplurality of A" orifices. The exto maintain the weight eiliciency at least equal trusion press was operated at substantially conto and the volume efliciency greater than the stant load, i. e., about 3.5 amperes, the thruput of corresponding efllciencies of water-extruded full earth varying with volatile content thereof and ers earth. v with the effect of the chemical agent upon the To further compare the efliciencies, on both earth. In all cases, the earth resulting from the weight and volume basis, of water-extruded the pugging and extrusion operations was dried, fullers earth and earth containing different ground and screened to 30 to mesh, calcined quantities of an alkaline reagent, 1. e., NaOI-I, or burned at 900 F., for 20 minutes, and then the following examples are presented. The proc tested for volatile matter (V. M.), volume weight 60 essing and testing methods were identical with (lbs/cu. ft.), and decolorizing efliciency on both those described with reference to the examples weight and volume basis. The decolorizing efligiven hereinbefore, with the exception that the ciency was determined by solution filtration of raw Georgia-Florida type fullers earth was taken Pennsylvania "A cylinder stock through a given from a different batch than that employed in the weight of earth at 135 F. to 6 N. P. A. color. The previous examples.

Commer- Water 1% 2% 3% 10 45% M armed are. eat. eat.

Extrusion: Volatile matter. .wt. pereent 54.2 .8 53.4 54 0 53.5 54.0 Product (calcined 900 F.):

Volatile matter wt. percent-. 2. 4 2. l l. 7 2. 3 2. 4 1. 9 Volume weight 1bs./cu. m. 31. 7 29. a a2. 0 as. 1 35.1 41. 3 72. 5 Deoolorizing efficiency:

Weight, percent efficiency 126 126 104 28 None Volume, percent eflieiency 100 117 128 114 42 None From the above examples, it is apparent that extrusion of the earth containing 1% NaOH produced a substantial increase in volume efliciency over that of the water-extruded earth, but that with earths containing 2% or more of NaOH, the efliciencies decreased.

The argillaceous substances of the fullers earth type produced in accordance with my invention and having substantially improved adsorptive properties may be employed in the decolorization of hydrocarbon oils, petrolatum, and hydrocarbon wax. Such improved argillaceous substances may also be utilized in the treatment of petroleum distillates for the removal of sulfur compounds, gum, and color-forming constituents, as well as catalysts or catalyst carriers in the cracking, reforming, polymerization, oxidation, hydrogenation, and dehydrogenation of hydrocarbon oils, waxes and gases.

While, herein, reference has been made to the production of granular particles particularly of 30-60 mesh size, it is to be understood that the production of particles of any desired size is within the scope of this invention. Depending upon the use to which my improved argillaceous substances are to be put, the particle size may vary to a considerable extent. For example, the particles may be of the following mesh sizes-180- 300, 100-200, 60-90, 50-180, 30-60, 15-60, 15-30, 12-30, -30, 8-20, 4-8, and larger. The finer particle sizes, i. e., 100-200 or 180-300, are particularly adapted, for example, to contact decolorization, neutralization or adsorption, whereas the larger particle sizes, i. e., -30 r 30-60 are especially useful in percolation decolorization or other treatments. Y

I claim:

1. A process for improving the adsorptive and bleaching efiiciency of Georgia-Florida type fullers earth, which comprises extruding at elevated pressure a plastic fullers earth of the Georgia-Florida type intimately admixed with from 0.1% to 1.75% by weight, based upon volatile-free earth, of a substantially water-soluble alkaline agent.

2. A process for improving the adsorptive and bleaching efiiciency of Georgia-Florida type fullers earth, which comprises extruding at elevated pressure a plastic fullers earth of the Georgia-Florida type intimately admixed with from 0.1% to 1.75% by weight, based upon volatile-free earth, of a substantially water-soluble alkaline agent, and drying the extruded earth. 5

3. A process for improving the adsorptive and bleaching efflciency of Georgia-Florida type fullers earth, which comprises extruding at elevated pressure a plastic fullers earth or the Georgia-Florida type intimately admixed with from 0.1% to 1.75% by weight, based upon volatile-free earth, of a substantially water-soluble alkaline agent, drying the extruded earth, and reducing the dried earth to granular particles.

4. A process for improving the adsorptive and bleaching efficiency of Georgia-Florida type fullers earth, which comprises extruding at elevated pressure a plastic fullers earth of the Georgia-Florida type intimately admixed with from 0.1% to 1.75% by weight, based upon volatile-free earth, of sodium hydroxide.

5. A process for improving the adsorptive and bleaching efiiciency of Georgia-Florida type fullers earth, which comprises forming a plastic mixture of said earth with from 0.1%, to 1.75% by weight, based upon volatile-free earth, of a substantially water-soluble alkaline agent, and extruding said plastic mixture at elevated pressure.

6. A process for improving the adsorptive and bleaching efllciency of Georgia-Florida type fullers earth, which comprises forming a plastic mixture of said earth with from 0.1% to 1.75% by weight, based upon volatile-free earth, of a substantially water-soluble alkaline agent, extruding said plastic mixture at elevated pressure, and drying the extruded earth.

7. A process for improving the adsorptive and bleaching. efliciency of Georgia-Florida type fullers earth, which comprises forming a plastic mixture of said earth with from 0.1% to 1.75% by weight, based upon volatile-free earth, of a substantially water-soluble alkaline agent, extruding said plastic mixture'at elevated pressure, drying the extruded earth, and reducing the dried earth to granular particles.

8. Fuller's earth of the Georgia-Florida type impregnated with from 0.1% to 1.75% by weight of a substantially water-soluble alkaline agent.

9. Fuller's earth of the Georgia-Florida type impregnated with from 0.1% to 1.75% by weight of sodium hydroxide.

WILLIAM A. LANDE, JR.

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