CA1109051A - Process for making a synthetic liquid absorbent and products resulting therefrom - Google Patents
Process for making a synthetic liquid absorbent and products resulting therefromInfo
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- CA1109051A CA1109051A CA291,923A CA291923A CA1109051A CA 1109051 A CA1109051 A CA 1109051A CA 291923 A CA291923 A CA 291923A CA 1109051 A CA1109051 A CA 1109051A
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Abstract
ABSTRACT OF THE DISCLOSURE
A method for producing synthetic liquid absorbent granules to serve the same purposes as granules made from naturally occurring sorptive minerals such as absorbent clays. Water is mixed with powdered gypsum plaster in mixing apparatus and a paste or slurry condition results, with the volume of water relative to the plaster being varied to vary the bulk density and the absorption capacity characteristics of the ultimate granular product from each mix. The mix is taken from the apparatus and is allowed to set and harden in a form to be readily handled for crushing and sizing into desired screen mesh size granules, or the mix can be directly formed into pellets or granules so as to be allowed to set and harden and be cor-respondingly sized as the commercial product. Additives can be included in the mixing to vary the density and the absorption characteristics of the final absorbent granules. The fines recovered from screening and sizing the material can usually be introduced into the mix with the plaster and the water, whereby the otherewise unuseable fines have a useful function in the method and in the product manufactured thereby.
A method for producing synthetic liquid absorbent granules to serve the same purposes as granules made from naturally occurring sorptive minerals such as absorbent clays. Water is mixed with powdered gypsum plaster in mixing apparatus and a paste or slurry condition results, with the volume of water relative to the plaster being varied to vary the bulk density and the absorption capacity characteristics of the ultimate granular product from each mix. The mix is taken from the apparatus and is allowed to set and harden in a form to be readily handled for crushing and sizing into desired screen mesh size granules, or the mix can be directly formed into pellets or granules so as to be allowed to set and harden and be cor-respondingly sized as the commercial product. Additives can be included in the mixing to vary the density and the absorption characteristics of the final absorbent granules. The fines recovered from screening and sizing the material can usually be introduced into the mix with the plaster and the water, whereby the otherewise unuseable fines have a useful function in the method and in the product manufactured thereby.
Description
~.'lV9QS~
B~CKGROUND OF THE INyENTION
(1) Field of the Invention The present invention relates to the field of absor-bent granules produced from naturally occurring sorptive minerals, and in the past have consisted almost entirely of absorbent clay granules. The granules have various industrial and household uses such as the absorption of oil and grease and the like on floors and elsewhere where these materials repre-;~'1 ~
~)9CSl sent a safety hazard, they are used in an animal toilet appli-cation as a cat box absorbent, they are used as a carrier for c]lcmicals such as pcsticides, herbicidcs and the li~e in various agricultuTal and horticultural applications, and thcy are used as ground cover in their natural color. The inven-tion comprises a method for utilizing hydrated gypsum plaster.
Gypsum as a naturally occurring mineral, or the powdered plaster therefrom, are not suitable as a moisture absorbent material such as is absorbent clay, but by controlled pro-cessing absorbent granules can be made with properties sub-stantially equivalent to those of the absorbent clay granules.
More particularly, the present invention relates to a process utilizing standard commercially available plaster, or plaster of Paris as such plaster is often called, in po~dered form made from gypsum. The plaster is mixed with water, or water and other materials, according to predetcr-mined specifications for a mix. ~ariations in the specifica-tions for the synthetic absorbent produce variations in the characteristics of the final absorbent granules produced thereby with respect to bulk density, moisture absorption, hardness, and stability in water OT other liquid.
The absorbent gTanule product of this invention is con-sistent from mix to mix with respect to the specifications provided for the process, depending upon the plaster being the same from mix to mix, for it is known that plaster can vary in constituency. The characteristics of a plaster can be determined in advance of starting a production run so that adjustments can be made to compcnsate for undesired variations.
~ 5 1 Such consistency of product cannot be obtained in the manu-facture of absorbent granules from the naturally occurring sorptive minerals such as the absorbent clays.
B~CKGROUND OF THE INyENTION
(1) Field of the Invention The present invention relates to the field of absor-bent granules produced from naturally occurring sorptive minerals, and in the past have consisted almost entirely of absorbent clay granules. The granules have various industrial and household uses such as the absorption of oil and grease and the like on floors and elsewhere where these materials repre-;~'1 ~
~)9CSl sent a safety hazard, they are used in an animal toilet appli-cation as a cat box absorbent, they are used as a carrier for c]lcmicals such as pcsticides, herbicidcs and the li~e in various agricultuTal and horticultural applications, and thcy are used as ground cover in their natural color. The inven-tion comprises a method for utilizing hydrated gypsum plaster.
Gypsum as a naturally occurring mineral, or the powdered plaster therefrom, are not suitable as a moisture absorbent material such as is absorbent clay, but by controlled pro-cessing absorbent granules can be made with properties sub-stantially equivalent to those of the absorbent clay granules.
More particularly, the present invention relates to a process utilizing standard commercially available plaster, or plaster of Paris as such plaster is often called, in po~dered form made from gypsum. The plaster is mixed with water, or water and other materials, according to predetcr-mined specifications for a mix. ~ariations in the specifica-tions for the synthetic absorbent produce variations in the characteristics of the final absorbent granules produced thereby with respect to bulk density, moisture absorption, hardness, and stability in water OT other liquid.
The absorbent gTanule product of this invention is con-sistent from mix to mix with respect to the specifications provided for the process, depending upon the plaster being the same from mix to mix, for it is known that plaster can vary in constituency. The characteristics of a plaster can be determined in advance of starting a production run so that adjustments can be made to compcnsate for undesired variations.
~ 5 1 Such consistency of product cannot be obtained in the manu-facture of absorbent granules from the naturally occurring sorptive minerals such as the absorbent clays.
(2) Description of the Prior Art Beginning in the late 1930's and early 1940's, naturally occurring sorptive minerals, such as the clay which is known as fuller's earth, and having a natural porous structure, were first used a`s absorbents for oils, greases, water and other undesirable substances on the floors of factories and shops, filling stations, and the like. Prior to that, the major use of fuller's earth had been in the refining of oils.
Because of the low bulk density of such material, in the range of 25 to 55 pounds per cubic foot, and because of its porosity and its absorbent propeTties, other uses were developed. Granules of fuller's earth found a large market as a use in pet animal toilet boxes, particularly cat boxes, and as a carrier for chemicals for agricultural purposes, as mentioned above. This density range represents what is con-sidered to be a light weight material.
More specifically, as to the naturally occurring absor-bent or sorptive mineral clays, these are mined, dried or calcined, crushed, and screened to a size determined by the particular use for which the material is intended.
For example, the usual size is 6 x 60 screen mesh for oil and grease absorbent, and for cat box absorbent. However, granules for each purpose can be of many different sizes, and 10 x 60 mesh, 6 x 16 mesh, and 6 x 24 mesh sizes have been mar~eted. A special size such as a very coarse 4 x 1~ mesh has been used for either one of the above two purposes. For ~9~51 oil and greasc absorbents, it is also desirable that the granules be resistant to crushing and to sticking to the floor when wal~ed on, or travelled over by plant e~uipment such as lift trucXs.
l~ith respect to screen mesh sizes, the sizes for the tl~O above discussed granules can vary ~uite l~idely, and larger size granules ~hich are approximately 1 to 2 inches in diam-eter or in the cross dimension have been used for decorative ground cover.
For sorptive mineral clay granules when used as carriers for insecticides, or pesticides, or herbicides, the specifica-tions are tight. Sizes which are commonly specified are 8 x 16, 16 x 30, 30 x 60, and 2~ x 48, and each size has specified tolerances sùch as screen size, and bul~ density.
A representative specification for one such product is that the bulk density must be measured by the well known Ohaus Loose Bulk Density method, and such bulk density can be 31 to 35 lbs. per cu. ft. The screen size tolerance is that a maximum of 2% by weight of the granules can be larger than 20 mesh, and none larger than ln mesh. There must not be any more than 1-1/2% to 2~ smaller by ~eight than 60 mesh for the granules. These mesh sizes are Tyler standards. In addition, it has been specified that there must be betl~een 5 and 8 million particles or granules per pound of absorbent product.
For such chemical carriers, lack of dust in th~ product is important. It is also important that the specified proper-ties of the absoTbent clay granules be consistent from ship-ment to shipment since the distribution of the different 9~b5~L
chemicals by means of the granules is a carefully controlled operation.
From the above specific characteristics which are gener-ally reo,uired, it is clear ~chat a substantial degree of con-trol should be maintained in processing the naturally occur-ring minerals such as absorbent clays in order to satisfy each of the numerous uses discussed for the granules, Howe~rer, such control is not possible except by careful selection of the clay to be processed. Size can be varied by crushing and sizing, and the hardness and stability in water of the granules can be varied by calcining the sorptive mineral, but that is substantially the limit in the controlled variation of properties or characteristics of the absorbent granules made from naturally occurring minerals such as clay. There is no practical way to cl:ange the bulk density or the absorp-tion capacity of such clays.
The lack of uniformity in bulk density in the clays at various mining and processing operations creates a problem in packaging. If the bulk density is high relative to the norm for a particular package size of granules, a predeter-mined amount such as 5 or 5n pounds will only partially fill a package or bag of a predetermined size. If the bul~ density is too low or the clay is very light in weight relative to a norm, the package or bag will not accommodate the required weight of granules.
The usefulness and effectiveness of the absorbent clay granules for the purposes discussed above also vary ~ith respect to the different mines in different locations from which the cIay is obtained.
9~Sl.
In addition to the preceding problems, absorbent clay as the principal sor~tive mineral suitable for the purposes described is found only in limited areas in the United Statcs and in some other countries of thc world, and is not found at all in most industrial areas in the ~orld. As a result, the cost of transportaLion overall from the sources of such clay to all the markets of the ~orld is a substantial part of the total selling price. In fact, for the United States and per-haps even more so in Europe, the absorbent clay with the desired characteristics and suitable for the purposes des-cribed is found in such limited areas that a substantial per-centage of the delivered cost of this bulky product is in its transportation cost.
With ever expanding use for the absorbent granules such as clay granules, and with the limited areas where such clay has been available, extensive searches for new sources of such raw materials have been undertaXen by the industry. How-ever, no substantial new deposits of sorptive r.linerals have been found which serve the same purposes as the absorbent clays, and no equivalent naturally occurring absorbent materials have been found which can be economically produced and marketed. Consideration has been given to synthetic sub-stitutes, but until the product made by the process of the present invention was discovered, none has been found which has acceptable properties and characteristics, is competitive in cost, and for ~.hich the sources of supply are so located as to minimize the cost of transportation.
Considering that the need for such absorbents is world--wide, and the grcatest need is in industrial, agricultural ~ 9~,c and urban areas, most of which are far removcd from the sources of sorptive minerals such as absorbent clay, it is clear that the o~erall problems with this naturally occurring product have created hurdles for some time that the industry must surmount.
. SU~ARY OF TH~ I~'VENTION
It i5 an o~ject of the present inventiDn to provide an essentially inorganic synthetic absorbent as a substitute for the naturally occurring sorptive minerals which can be granu-lated to a desired size for (1) use in absorbing liquids on the floors of factories, shops, and the like where water, oil, and grease accumulate and represent a safety hazard, (2) use as an absorbent in a cat box or other animal box, (3) use as an absorbent for carrying and distributing chemicals for agricultural applications, (4) use as a soil conditioner, and (5) use for light weight decorative ground cover to be colored with color pigments as desired.
It is also an object of my invention to provide a process : ;
to produce a granulated absorbent which can be practiced with materials which are available in many areas throughout the world so as to provide a ready source of supply of the granu-lated synthetic absorbent material relatively near the market for the same so that the cost of transportation of the manu-factured product is materially reduced as compared to that cost for presently used absorbent granules.
A further object of my invention is to provide a process for ma~ing such an absorbent granule wherein the character-istics and the granule size of the ultimate product can be controlled to relatively tig}lt specifications not only to ~9~Sl insurc that the product ~.ill serve the purposes for l.rhich it is intendecl, but that such characteristics of the product will be consistent from batch to batch made by the process.
A still further object is to providc a manufactured or synthetic absorbent as contrasted with the natural occurring absorbent that can be produced and marketcd at a cost com-petitive ~iith the natural product in a given locati~n.
The principal feature of my invention is the provision of an absorbent granule product and a process for making the same, which product has the same purposes and is adapted for the same applications served by the absorbent granules made from naturally occurring sorptive minerals, and yet is plenti-ful in many areas throughout the world. The synthetic ab-sorbent granule can be processed to controlled specifications on an economical basis, and the cost of transportation for many markets is reduced in comparison with that for the granules produced from naturally occurTing sorptive mineTals. ~ -Plaster, or plaster of Paris as it is also called, from which the product of my in~ention is made, in tuTn, is manu-factured from mined or quarried gypsum that is described chemically as calcium sulfate dihydrate (CaS04 2H20). In ma~ing the plaster, the raw gypsum is heated and loses water to form calcium sulphate hemihydrate (CaS04 1/2H2n), or plaster. The manufacture of such plaster is well-known, and plants for such manufacture exist at many locations through- -out the world.
J~y invention ta~es the plaster or calcium sulphate hemi-hydrate through steps which includc mixing the plaster with water in predetermined quantities to form a slurry or a paste depending upon the amount of water used relative to the volume of plaster.
The result of such step is that in time the plaster substantially reverts to gy~sum (CaS04-2~l20).
The slurry or paste is put into a form or forms for setting and hardening. After setting and hardening and drying the material is ground or crushed, and then screened to granules of the desired size. Or, as an alternative, the material is formed into predetermined configurations as granules. Such a mix is placed in a pelletizer or extruder or a similar device from which granules are prepared directly for the ultimate desired size.
The process can be practiced by readily available equipment for mixing and crushing and sizing, and as a result the process can be put into commercial practice in any location with a minimum of delay and at a mini-mum cost for a new manufacturing operation.
More specifically, my invention relates to a method for manufac-turing synthetic liquid absorbent granules from gypsum plaster in which the granules so produced are to be used for any one of different liquid absorp-tion purposes including that for oil and grease and the like on floors, that in toilet boxes for the use of household pets, that as a carrier for a chemical to be used in agriculture as an insecticide, or as a herbicide, or a fungicide, that as a colored ground cover with color pigment therein, and that for introduction into the soil as a soil conditioner. This method includes ~he steps of ~a) providing plaster and water to a mixing apparatus in predetermined proportions, and in a range of substantially 15% water and 85% plaster to substantially 50% water and 50% plaster for mixing a batch of the same. The batch of water and plastar is (b) mixed in a mixing apparatus to provide a wet mix material in a condition wherein the batch material is spreadable for setting, hardening, and drying, and is then (c) spread into a form to set and harden and dry such that it can be prepared for crushing.
The spread batch material is (d) permitted to set and harden and dry, and 9~
(e) broken into pieces of a size to be accommodated in a crusher. The broken pieces are ~f) crushed into granule size, and the granules are (g) sized by screen means to provide granules of a predetermined size related to the screen means, whereby the granules are ready for packaging to be ultimately used as liquid absorbent granules.
The product of this invention is a synthetic liquid absorbent material in a granule form with the granules being adapted to be used for any one of different liquid absorption purposes including that as an oil and grease absorbent on floors or the like, that as an absorbent in toilet boxes for household pets, that as an absorbent to carry a chemical to be used as an insecticide, or herbicide, or fungicide for agriculture pur-poses, and that as a ground cover or a conditioner. The material comprising granules are manufactured from a combination of materials including gypsum plaster and water; such combination of materials being provided in a hardened granule condition with the granules of a size within the general range of granule sizes which will pass through a 6 mesh screen and will be retained in a 60 mesh screen.
The ultimate absorbent granules are iight in weight, have porous spaces therein for absorption of liquids, they maintain a satisfactory physical granular form in use, and they are chemically stable in those uses.
BRIEF DESCRIPTION OF DRAWINGS AND
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings:
Fig. 1 is a diagrammatic illustration of the steps in the process of my invention.
In practicing the process of the invention, commercially available plaster is placed in a mixer. Water is added to the powder in sufficient quantity to bring it to a paste or slurry condition during the mixing. The nature of the slurry -9a-or paste condition, in turn, is ~lcter?ninativc of the ultimate densit~ desired for thc finished product.
A mi~ which is in slurry condition is normal]y poured into forms f~r setting and hardening. The mix in paste con-dition is either spread into a sheet-like form, or processed by machinery into pellets as cylinders or cu~es, or into balls. The particular form of the material as processed from the paste condition is of a size and configuration to permit ready subse~uent handling including crushing by equipment available for that purpose.
It is also noted that in the case of a pellet configur-ation for cat box absorbent, as one example of the use of such pellets, the paste can be processed so as to be formed into granules of the desired size which are ultimately used for the marketed product without any crushing.
The material is permitted to set and harden, and the timing to set and harden is affected by the use in the mixing step of known special plasters, retarders, or accelerators.
With the material in whatever form or configuration and size it is prepared for the setting and hardening step, it is allowed to set and harden, and is thereafter allowed to dry. Alternatively, it can be dried in a dryer, ta~ing care, in any event, that the temperature in the dryer or in the environment in which it is dried does not exceed the dehydra-tion temperature of the gypsum, which is approximately 250F-300F. After the drying step, the material is then crushed, and thereafter screened to the desired granule size for the ultimate use of the product.
For some drying equipment, such as a fluid bed dryer, it may be desirable to first crush, then dry the granules, and thereafter screen the dried granules. This is not illus-trated in Figure 1.
As noted in Figure 1, the purpose of the screening is to separate out those synthetic absorbent granules of the desired size for packaging and then marketing. The oversize granules are crushed or granulated again, and then run through the screens. The undersize particles are "fines" according to the sizing for that operation, and fines up to 30% by weight of the plaster in the mix are fed back into the mixing apparatus - during the mixing step. The plaster and fines are mixed with ;~ water to a slurry or paste condition depending upon the amount of water used in the mix, and the succeeding steps as shown are carried out.
This use of the fines occurring in the practice of the present process is one of the advantages of this invention.
There is no way to prevent fines from being formed in the crushing step, but here they can be used at little added cost and a resulting overall saving.
In the crushing and sizing operation of the natural mineral absorbent, such as absorbent clay, the members of the industry usually cannot recycle the fines or dust generated in such crushing and sizing. However, the assignee of the present application has pelletized such fines by a pelletizing operation disclosed in United States Patent 4,036,928 of Rudolph C. Valenta, filed originally on August 9, 1971, and assigned to such assignee. The alternative has been simply to dump or otherwise disposed of the clay fines.
~9~51 In the above dcscribed preferred embodiment, the two characteristics of bulk dcnsity and moisturc absorbency of the finished product of tl~is present invention are controlled by varying the l~!ater content relative to the plaster. It is also possible to control such characteristics by including various additives in various amounts. The water content is varied in conjunction with the additive. SUC]I additives are light weight naturally absorptive materials, as for example, paper pulp, or finely divided paper, or wood dust, peat dust, or light weight clay dust. Normally suc~l additives are introduced into the mixing in the proportion of 1% to 20% of the weight of the plaster.
EXAMPLES
In practicing the preferred embodiment in Holland, ,he relative quantities of plaster and water were varied for the following representative batches, and the characteristics noted were obtained. The plaster utilized in all batches was identified as SBA lOFM, and it was obtained as a commercial product in Amsterdam, Holland.
Batch No. 1 2 3 4 5 6 Percent Plaster 85 82 78 75 73 70 Percent ~Yatcr 15 18 22 25 27 30 Bulk Density tlbs/cu.ft.) 50.5 51.8 48.3 41.1 38.8 38.7 Water Absorption (Percent) 22 19 24.7 27.4 34 - 33 Set Time 8 8 11 13 14 14 (Min.) ~09~5~L
Batch No. 7 8 9 10 11 12 Percent Plaster 68 66 63 62 60 58 Percent Water 32 34 37 38 40 42 Bul~ Density 34.3 33.1 31.4 29.9 28.6 26.4 (lbs/cu.ft.) l~ater Absorption 39.6 47 54.7 61.3 69.6 78 (Percent) Set Time 15 17 20 23 27 34 (Min.) Such twelve batches varied in total weight from one pound to one and a half pounds, made up in plaster and water in the percentages by weight noted in the above table. Each batch was made by hand in a bowl and was removed from the bowl in which it was mixed and spread on a plastic sheet to a thickness of approximately one-quarter inch thic~. After setting, the set piece was stable enough to be placed in a vertical position for air-drying. After such drying approxi-mately one third of each set piece was broken into granules which were approximately .2 inch in size, and the granules were heated to 230F in hot air as the final drying step.
LARGE VOLUME BATC~I EXA~PLE IN HOLLAND
Batch Number 7 appeared optimum for general use as ulti-mate absorbent granules from tests which were made for density and for water absorption, and the specification for that batch was selected for testing in a large volume. A total of one hundred ten pounds of the plaster described above and water were mixed in a commercial concrete mixer for 1~ minutes.
The proportion of this batch was 68~ by weight of plaster and 32~ by weight of water. The mix was poured from the mixer in the form of a layer approximately 1.2" thic~;, and after setting for approximately 3 hours, the material was ~ 9~ 5 1 hard and had a moistur~ content of 2.3~. The sheet was bro~en into small granules approximately 4 x l0 mesh screén in size.
~ pproximately 6.6 pounds of the small granules were spread on a greasy concrete floor to determine the capability or capacity of the granules as an oil and grease absorbent.
After a peTiod of approximately two hours, the oil and grease was absorbed by the granules, and on the followin~ day these granules were removed simply by sweeping with a broom. Thé
floor was dry and clean. The absorbent action was as good or better as that with the naturally occurring absorbent clay~
used for the same purp~se.
Samples of 22 pounds each were used over a period of time in different cat toilet boxes, or cat boxes, as they are called, and the granules absorbed moisture and reduced odoT in the respective boxes as satisfactorily as do the absorbent clay granules in a presently commercially available product.
EXA~PLES OF BATCHES MIXED IN THE UNITED STATES
Plaster and water batches were also mixed in the United States with U.S. Gypsum No. l Moulding Plaster obtained in Chicago, Illinois, and each batch was made by putting the plaster and water into a commercially available electric kitchen mixer and bowl. Each mix was l to l-l/2 pounds in total weight. After mixing, the material was placed or poured, depending on the consistency of the material as mixed, onto a plastic sheet and allowed to set and harden for one hour. Each sheet was then broken into pieces and placed in front of a blower of hot air at 100F and dried for three hours.
~ 5 ~
The bro]~en pieces were then granulated in a hand operated grinder and the granules were sized by screening with a 6 mesh screen, and ~ith a 16 mesh screen. The granules which passed through the 6 mesh screen l.ere then placed on a 16 mesh screcn for passing through that screen or being retained on the screen. Three sizes ~ere obtained by this sizing, (1) those that did not pass through the 6 mesh screen, (2) those that passed through the 16 mesh screen, and (3) those that passed through the 6 mesh but were retained on the 16 mesh slze screen.
Those that did not pass through the 6 mesh screen (No.
1 above) were recrushed to a size so that they would pass .
through the 6 mesh screen. After this crushing, the granu-lated material was 6 x 16 mesh sizes, and that smaller than 16 mesh was classified as "fines" and was not further tested.
In other words, as is the practice in the liquid absorbent granule industry, those granules passing through the finest screen size used in the operation which are not destined for marketing in that particular manufacturing ope~ation at a particular time are called "fines".
The 6 x 16 mesh material (this passed the 6 mesh screen but did not pass through the 16 mesh screen) ~as tested for bulX density, for liquid absorption, and for oil absorption.
The tests for determining the absorption characteristics of the granules are those specified in Bulletin P-A-1056, Federal Specification, Absorbent r~aterial, Oil and Water (For Floors and Decks), to be obtained from General Services Administra-tion. The batches, and the results of the testing are summarized:
Sl Batch No. 13 14 15 1~l 17 Percent Plaster 7~ 62 59 56 50 Percent l~'ater 30 38 41 44 50 Bul~ Densit~ lbs/cu.ft. 4~ 38.6 38 35.5 33 Percent l~ater Absorption 52 5Q 6~ 70 88 Percent Oil ~bsorption 34 50 5~ 66 74 Note 1 - Batch No. 1 was in paste form; all others were in slurry form.
The above data shows these batches to be well within the range of characteristics for commercially accepted granulated clay absorbents now in use, which are as follows: ' Commercial Range or Size From Range The Above Batches 13 To 17 Inclusive Bul~ Density 20-55 lbs/cu.ft. 33-48 Oil and Water Absorption 20-110~ 30-8g%
Mesh Size 6 x 60 6 x 16 EX~lPLE OF BATC~IES WITH ADDITIVE TO THE ~IX
~ ixes were also made in Holland with the plaster pur-chased in Amsterdam under 'the identification SBA 10FM, and with used newspaper as an additive to the mixture to aid in varying the bul~ density and absorption capacity character-istics of the ultimate synthetic absorbent granules. The used newspaper was reduced to a sludge or pulp by,mixing with water in a high speed electric mixer. Excess water was pressed out of the mix so the paper water ratio was 1:15 when ready to be mixed with the plaster and water.
The used ne--spaper treated as above was mixed with the plaster and water in ~roportions shown in the following table with the density and water absorption characteristics of each ~ 9~5 ~
of the 5iX batches OT mixes. Each batch was approximately 1 pound to 1.5 pounds, and was mixed by hand, and removed, set and hardened, dried, and then granulated in the same manner as described above for the t~elve batches made in Holland.
Batch No. 18 19 20 21 22 23 Percent Plaster 69.fi ~6.7 64.5 64 61.5 59.3 Percent Paper .9 1.7 1.6 2.4 3.1 3.7 Percent l~ater 24.5 31.6 33.9 33.6 35.4 37.0 Density (lbs/cu.ft.) 33.7 32.6 29.5 2~.1 25.7 24.
Percent l~rater Absorption 44.6 51.2 58 73 81 111 -Setting Time (Min.) 16 19 20 24 30 31 Note: Percentage of paper is measured on basis of the weight of dry paper.
Samples of 22 pounds each from the formulation o~ -batches 20 and 21 were tested in cat boxes over a period of time, and the synthetic absorbent granules from each batch served their purpose very satisfactorily.
TESTING TO DETERMINE PLASTER CHARACTERISTICS
FOR PRODUCTION OF SYNTHETIC ABSORBENT GRANULES
Plaster characteristics may vary for numerous reasons including the location and nature of the gypsum mined, as well as the actual manufacturing specifications for the plaster. In order to determine the synthetic absorbent granule characteristics foT a given plaster, simple tests can be made corresponding to the formulations and the procedures for any one or more of Batches 1 to 17 inclusive above.
~ ~ 9~'5~
Thc ~ter content for a test batch will detcrmine the bulk density and ab~orption charactcristics for that batch. l~hen the desired characteristics are obtained, that is the water content to use for production of granules using that particu-lar plaster. The various examplcs indicate that a simple test will determine in advance the water content to be used ~ith any plaster in order to meet a particular specification for the granules.
If additives, such as paper pulp or other light weight naturally absorptive materials are to be used, the examples in Batches 18 to 23 inclusive illustrate corresponding test methods for chec~ing the combination of plaster and each such absorptive material to obtain the desired characteristics for the final granules to be used for absorbing purposes.
If it is desired to have synthetic colored granules in accordance with the present invention, pigment of the desired colo~ is mixed with the material in the mixing appaTatus in-cluding plaster and water. The entire batch of the desired color is then processed through the remaining steps described herein, and crushed and granulated to the desired screen mesh size.
Accordingly, the process of the present invention shows that liquid absorbent granules can be synthesized to pTovide equivalent or improved characteristics relative to the gran-ules made from naturally occurring liquid absorbent minerals such as fuller's earth, and such characteristics can be con-trolled to a predetermincd formulation for a particular purpose in a manner and to a degree not possible with the natural product.
Because of the low bulk density of such material, in the range of 25 to 55 pounds per cubic foot, and because of its porosity and its absorbent propeTties, other uses were developed. Granules of fuller's earth found a large market as a use in pet animal toilet boxes, particularly cat boxes, and as a carrier for chemicals for agricultural purposes, as mentioned above. This density range represents what is con-sidered to be a light weight material.
More specifically, as to the naturally occurring absor-bent or sorptive mineral clays, these are mined, dried or calcined, crushed, and screened to a size determined by the particular use for which the material is intended.
For example, the usual size is 6 x 60 screen mesh for oil and grease absorbent, and for cat box absorbent. However, granules for each purpose can be of many different sizes, and 10 x 60 mesh, 6 x 16 mesh, and 6 x 24 mesh sizes have been mar~eted. A special size such as a very coarse 4 x 1~ mesh has been used for either one of the above two purposes. For ~9~51 oil and greasc absorbents, it is also desirable that the granules be resistant to crushing and to sticking to the floor when wal~ed on, or travelled over by plant e~uipment such as lift trucXs.
l~ith respect to screen mesh sizes, the sizes for the tl~O above discussed granules can vary ~uite l~idely, and larger size granules ~hich are approximately 1 to 2 inches in diam-eter or in the cross dimension have been used for decorative ground cover.
For sorptive mineral clay granules when used as carriers for insecticides, or pesticides, or herbicides, the specifica-tions are tight. Sizes which are commonly specified are 8 x 16, 16 x 30, 30 x 60, and 2~ x 48, and each size has specified tolerances sùch as screen size, and bul~ density.
A representative specification for one such product is that the bulk density must be measured by the well known Ohaus Loose Bulk Density method, and such bulk density can be 31 to 35 lbs. per cu. ft. The screen size tolerance is that a maximum of 2% by weight of the granules can be larger than 20 mesh, and none larger than ln mesh. There must not be any more than 1-1/2% to 2~ smaller by ~eight than 60 mesh for the granules. These mesh sizes are Tyler standards. In addition, it has been specified that there must be betl~een 5 and 8 million particles or granules per pound of absorbent product.
For such chemical carriers, lack of dust in th~ product is important. It is also important that the specified proper-ties of the absoTbent clay granules be consistent from ship-ment to shipment since the distribution of the different 9~b5~L
chemicals by means of the granules is a carefully controlled operation.
From the above specific characteristics which are gener-ally reo,uired, it is clear ~chat a substantial degree of con-trol should be maintained in processing the naturally occur-ring minerals such as absorbent clays in order to satisfy each of the numerous uses discussed for the granules, Howe~rer, such control is not possible except by careful selection of the clay to be processed. Size can be varied by crushing and sizing, and the hardness and stability in water of the granules can be varied by calcining the sorptive mineral, but that is substantially the limit in the controlled variation of properties or characteristics of the absorbent granules made from naturally occurring minerals such as clay. There is no practical way to cl:ange the bulk density or the absorp-tion capacity of such clays.
The lack of uniformity in bulk density in the clays at various mining and processing operations creates a problem in packaging. If the bulk density is high relative to the norm for a particular package size of granules, a predeter-mined amount such as 5 or 5n pounds will only partially fill a package or bag of a predetermined size. If the bul~ density is too low or the clay is very light in weight relative to a norm, the package or bag will not accommodate the required weight of granules.
The usefulness and effectiveness of the absorbent clay granules for the purposes discussed above also vary ~ith respect to the different mines in different locations from which the cIay is obtained.
9~Sl.
In addition to the preceding problems, absorbent clay as the principal sor~tive mineral suitable for the purposes described is found only in limited areas in the United Statcs and in some other countries of thc world, and is not found at all in most industrial areas in the ~orld. As a result, the cost of transportaLion overall from the sources of such clay to all the markets of the ~orld is a substantial part of the total selling price. In fact, for the United States and per-haps even more so in Europe, the absorbent clay with the desired characteristics and suitable for the purposes des-cribed is found in such limited areas that a substantial per-centage of the delivered cost of this bulky product is in its transportation cost.
With ever expanding use for the absorbent granules such as clay granules, and with the limited areas where such clay has been available, extensive searches for new sources of such raw materials have been undertaXen by the industry. How-ever, no substantial new deposits of sorptive r.linerals have been found which serve the same purposes as the absorbent clays, and no equivalent naturally occurring absorbent materials have been found which can be economically produced and marketed. Consideration has been given to synthetic sub-stitutes, but until the product made by the process of the present invention was discovered, none has been found which has acceptable properties and characteristics, is competitive in cost, and for ~.hich the sources of supply are so located as to minimize the cost of transportation.
Considering that the need for such absorbents is world--wide, and the grcatest need is in industrial, agricultural ~ 9~,c and urban areas, most of which are far removcd from the sources of sorptive minerals such as absorbent clay, it is clear that the o~erall problems with this naturally occurring product have created hurdles for some time that the industry must surmount.
. SU~ARY OF TH~ I~'VENTION
It i5 an o~ject of the present inventiDn to provide an essentially inorganic synthetic absorbent as a substitute for the naturally occurring sorptive minerals which can be granu-lated to a desired size for (1) use in absorbing liquids on the floors of factories, shops, and the like where water, oil, and grease accumulate and represent a safety hazard, (2) use as an absorbent in a cat box or other animal box, (3) use as an absorbent for carrying and distributing chemicals for agricultural applications, (4) use as a soil conditioner, and (5) use for light weight decorative ground cover to be colored with color pigments as desired.
It is also an object of my invention to provide a process : ;
to produce a granulated absorbent which can be practiced with materials which are available in many areas throughout the world so as to provide a ready source of supply of the granu-lated synthetic absorbent material relatively near the market for the same so that the cost of transportation of the manu-factured product is materially reduced as compared to that cost for presently used absorbent granules.
A further object of my invention is to provide a process for ma~ing such an absorbent granule wherein the character-istics and the granule size of the ultimate product can be controlled to relatively tig}lt specifications not only to ~9~Sl insurc that the product ~.ill serve the purposes for l.rhich it is intendecl, but that such characteristics of the product will be consistent from batch to batch made by the process.
A still further object is to providc a manufactured or synthetic absorbent as contrasted with the natural occurring absorbent that can be produced and marketcd at a cost com-petitive ~iith the natural product in a given locati~n.
The principal feature of my invention is the provision of an absorbent granule product and a process for making the same, which product has the same purposes and is adapted for the same applications served by the absorbent granules made from naturally occurring sorptive minerals, and yet is plenti-ful in many areas throughout the world. The synthetic ab-sorbent granule can be processed to controlled specifications on an economical basis, and the cost of transportation for many markets is reduced in comparison with that for the granules produced from naturally occurTing sorptive mineTals. ~ -Plaster, or plaster of Paris as it is also called, from which the product of my in~ention is made, in tuTn, is manu-factured from mined or quarried gypsum that is described chemically as calcium sulfate dihydrate (CaS04 2H20). In ma~ing the plaster, the raw gypsum is heated and loses water to form calcium sulphate hemihydrate (CaS04 1/2H2n), or plaster. The manufacture of such plaster is well-known, and plants for such manufacture exist at many locations through- -out the world.
J~y invention ta~es the plaster or calcium sulphate hemi-hydrate through steps which includc mixing the plaster with water in predetermined quantities to form a slurry or a paste depending upon the amount of water used relative to the volume of plaster.
The result of such step is that in time the plaster substantially reverts to gy~sum (CaS04-2~l20).
The slurry or paste is put into a form or forms for setting and hardening. After setting and hardening and drying the material is ground or crushed, and then screened to granules of the desired size. Or, as an alternative, the material is formed into predetermined configurations as granules. Such a mix is placed in a pelletizer or extruder or a similar device from which granules are prepared directly for the ultimate desired size.
The process can be practiced by readily available equipment for mixing and crushing and sizing, and as a result the process can be put into commercial practice in any location with a minimum of delay and at a mini-mum cost for a new manufacturing operation.
More specifically, my invention relates to a method for manufac-turing synthetic liquid absorbent granules from gypsum plaster in which the granules so produced are to be used for any one of different liquid absorp-tion purposes including that for oil and grease and the like on floors, that in toilet boxes for the use of household pets, that as a carrier for a chemical to be used in agriculture as an insecticide, or as a herbicide, or a fungicide, that as a colored ground cover with color pigment therein, and that for introduction into the soil as a soil conditioner. This method includes ~he steps of ~a) providing plaster and water to a mixing apparatus in predetermined proportions, and in a range of substantially 15% water and 85% plaster to substantially 50% water and 50% plaster for mixing a batch of the same. The batch of water and plastar is (b) mixed in a mixing apparatus to provide a wet mix material in a condition wherein the batch material is spreadable for setting, hardening, and drying, and is then (c) spread into a form to set and harden and dry such that it can be prepared for crushing.
The spread batch material is (d) permitted to set and harden and dry, and 9~
(e) broken into pieces of a size to be accommodated in a crusher. The broken pieces are ~f) crushed into granule size, and the granules are (g) sized by screen means to provide granules of a predetermined size related to the screen means, whereby the granules are ready for packaging to be ultimately used as liquid absorbent granules.
The product of this invention is a synthetic liquid absorbent material in a granule form with the granules being adapted to be used for any one of different liquid absorption purposes including that as an oil and grease absorbent on floors or the like, that as an absorbent in toilet boxes for household pets, that as an absorbent to carry a chemical to be used as an insecticide, or herbicide, or fungicide for agriculture pur-poses, and that as a ground cover or a conditioner. The material comprising granules are manufactured from a combination of materials including gypsum plaster and water; such combination of materials being provided in a hardened granule condition with the granules of a size within the general range of granule sizes which will pass through a 6 mesh screen and will be retained in a 60 mesh screen.
The ultimate absorbent granules are iight in weight, have porous spaces therein for absorption of liquids, they maintain a satisfactory physical granular form in use, and they are chemically stable in those uses.
BRIEF DESCRIPTION OF DRAWINGS AND
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings:
Fig. 1 is a diagrammatic illustration of the steps in the process of my invention.
In practicing the process of the invention, commercially available plaster is placed in a mixer. Water is added to the powder in sufficient quantity to bring it to a paste or slurry condition during the mixing. The nature of the slurry -9a-or paste condition, in turn, is ~lcter?ninativc of the ultimate densit~ desired for thc finished product.
A mi~ which is in slurry condition is normal]y poured into forms f~r setting and hardening. The mix in paste con-dition is either spread into a sheet-like form, or processed by machinery into pellets as cylinders or cu~es, or into balls. The particular form of the material as processed from the paste condition is of a size and configuration to permit ready subse~uent handling including crushing by equipment available for that purpose.
It is also noted that in the case of a pellet configur-ation for cat box absorbent, as one example of the use of such pellets, the paste can be processed so as to be formed into granules of the desired size which are ultimately used for the marketed product without any crushing.
The material is permitted to set and harden, and the timing to set and harden is affected by the use in the mixing step of known special plasters, retarders, or accelerators.
With the material in whatever form or configuration and size it is prepared for the setting and hardening step, it is allowed to set and harden, and is thereafter allowed to dry. Alternatively, it can be dried in a dryer, ta~ing care, in any event, that the temperature in the dryer or in the environment in which it is dried does not exceed the dehydra-tion temperature of the gypsum, which is approximately 250F-300F. After the drying step, the material is then crushed, and thereafter screened to the desired granule size for the ultimate use of the product.
For some drying equipment, such as a fluid bed dryer, it may be desirable to first crush, then dry the granules, and thereafter screen the dried granules. This is not illus-trated in Figure 1.
As noted in Figure 1, the purpose of the screening is to separate out those synthetic absorbent granules of the desired size for packaging and then marketing. The oversize granules are crushed or granulated again, and then run through the screens. The undersize particles are "fines" according to the sizing for that operation, and fines up to 30% by weight of the plaster in the mix are fed back into the mixing apparatus - during the mixing step. The plaster and fines are mixed with ;~ water to a slurry or paste condition depending upon the amount of water used in the mix, and the succeeding steps as shown are carried out.
This use of the fines occurring in the practice of the present process is one of the advantages of this invention.
There is no way to prevent fines from being formed in the crushing step, but here they can be used at little added cost and a resulting overall saving.
In the crushing and sizing operation of the natural mineral absorbent, such as absorbent clay, the members of the industry usually cannot recycle the fines or dust generated in such crushing and sizing. However, the assignee of the present application has pelletized such fines by a pelletizing operation disclosed in United States Patent 4,036,928 of Rudolph C. Valenta, filed originally on August 9, 1971, and assigned to such assignee. The alternative has been simply to dump or otherwise disposed of the clay fines.
~9~51 In the above dcscribed preferred embodiment, the two characteristics of bulk dcnsity and moisturc absorbency of the finished product of tl~is present invention are controlled by varying the l~!ater content relative to the plaster. It is also possible to control such characteristics by including various additives in various amounts. The water content is varied in conjunction with the additive. SUC]I additives are light weight naturally absorptive materials, as for example, paper pulp, or finely divided paper, or wood dust, peat dust, or light weight clay dust. Normally suc~l additives are introduced into the mixing in the proportion of 1% to 20% of the weight of the plaster.
EXAMPLES
In practicing the preferred embodiment in Holland, ,he relative quantities of plaster and water were varied for the following representative batches, and the characteristics noted were obtained. The plaster utilized in all batches was identified as SBA lOFM, and it was obtained as a commercial product in Amsterdam, Holland.
Batch No. 1 2 3 4 5 6 Percent Plaster 85 82 78 75 73 70 Percent ~Yatcr 15 18 22 25 27 30 Bulk Density tlbs/cu.ft.) 50.5 51.8 48.3 41.1 38.8 38.7 Water Absorption (Percent) 22 19 24.7 27.4 34 - 33 Set Time 8 8 11 13 14 14 (Min.) ~09~5~L
Batch No. 7 8 9 10 11 12 Percent Plaster 68 66 63 62 60 58 Percent Water 32 34 37 38 40 42 Bul~ Density 34.3 33.1 31.4 29.9 28.6 26.4 (lbs/cu.ft.) l~ater Absorption 39.6 47 54.7 61.3 69.6 78 (Percent) Set Time 15 17 20 23 27 34 (Min.) Such twelve batches varied in total weight from one pound to one and a half pounds, made up in plaster and water in the percentages by weight noted in the above table. Each batch was made by hand in a bowl and was removed from the bowl in which it was mixed and spread on a plastic sheet to a thickness of approximately one-quarter inch thic~. After setting, the set piece was stable enough to be placed in a vertical position for air-drying. After such drying approxi-mately one third of each set piece was broken into granules which were approximately .2 inch in size, and the granules were heated to 230F in hot air as the final drying step.
LARGE VOLUME BATC~I EXA~PLE IN HOLLAND
Batch Number 7 appeared optimum for general use as ulti-mate absorbent granules from tests which were made for density and for water absorption, and the specification for that batch was selected for testing in a large volume. A total of one hundred ten pounds of the plaster described above and water were mixed in a commercial concrete mixer for 1~ minutes.
The proportion of this batch was 68~ by weight of plaster and 32~ by weight of water. The mix was poured from the mixer in the form of a layer approximately 1.2" thic~;, and after setting for approximately 3 hours, the material was ~ 9~ 5 1 hard and had a moistur~ content of 2.3~. The sheet was bro~en into small granules approximately 4 x l0 mesh screén in size.
~ pproximately 6.6 pounds of the small granules were spread on a greasy concrete floor to determine the capability or capacity of the granules as an oil and grease absorbent.
After a peTiod of approximately two hours, the oil and grease was absorbed by the granules, and on the followin~ day these granules were removed simply by sweeping with a broom. Thé
floor was dry and clean. The absorbent action was as good or better as that with the naturally occurring absorbent clay~
used for the same purp~se.
Samples of 22 pounds each were used over a period of time in different cat toilet boxes, or cat boxes, as they are called, and the granules absorbed moisture and reduced odoT in the respective boxes as satisfactorily as do the absorbent clay granules in a presently commercially available product.
EXA~PLES OF BATCHES MIXED IN THE UNITED STATES
Plaster and water batches were also mixed in the United States with U.S. Gypsum No. l Moulding Plaster obtained in Chicago, Illinois, and each batch was made by putting the plaster and water into a commercially available electric kitchen mixer and bowl. Each mix was l to l-l/2 pounds in total weight. After mixing, the material was placed or poured, depending on the consistency of the material as mixed, onto a plastic sheet and allowed to set and harden for one hour. Each sheet was then broken into pieces and placed in front of a blower of hot air at 100F and dried for three hours.
~ 5 ~
The bro]~en pieces were then granulated in a hand operated grinder and the granules were sized by screening with a 6 mesh screen, and ~ith a 16 mesh screen. The granules which passed through the 6 mesh screen l.ere then placed on a 16 mesh screcn for passing through that screen or being retained on the screen. Three sizes ~ere obtained by this sizing, (1) those that did not pass through the 6 mesh screen, (2) those that passed through the 16 mesh screen, and (3) those that passed through the 6 mesh but were retained on the 16 mesh slze screen.
Those that did not pass through the 6 mesh screen (No.
1 above) were recrushed to a size so that they would pass .
through the 6 mesh screen. After this crushing, the granu-lated material was 6 x 16 mesh sizes, and that smaller than 16 mesh was classified as "fines" and was not further tested.
In other words, as is the practice in the liquid absorbent granule industry, those granules passing through the finest screen size used in the operation which are not destined for marketing in that particular manufacturing ope~ation at a particular time are called "fines".
The 6 x 16 mesh material (this passed the 6 mesh screen but did not pass through the 16 mesh screen) ~as tested for bulX density, for liquid absorption, and for oil absorption.
The tests for determining the absorption characteristics of the granules are those specified in Bulletin P-A-1056, Federal Specification, Absorbent r~aterial, Oil and Water (For Floors and Decks), to be obtained from General Services Administra-tion. The batches, and the results of the testing are summarized:
Sl Batch No. 13 14 15 1~l 17 Percent Plaster 7~ 62 59 56 50 Percent l~'ater 30 38 41 44 50 Bul~ Densit~ lbs/cu.ft. 4~ 38.6 38 35.5 33 Percent l~ater Absorption 52 5Q 6~ 70 88 Percent Oil ~bsorption 34 50 5~ 66 74 Note 1 - Batch No. 1 was in paste form; all others were in slurry form.
The above data shows these batches to be well within the range of characteristics for commercially accepted granulated clay absorbents now in use, which are as follows: ' Commercial Range or Size From Range The Above Batches 13 To 17 Inclusive Bul~ Density 20-55 lbs/cu.ft. 33-48 Oil and Water Absorption 20-110~ 30-8g%
Mesh Size 6 x 60 6 x 16 EX~lPLE OF BATC~IES WITH ADDITIVE TO THE ~IX
~ ixes were also made in Holland with the plaster pur-chased in Amsterdam under 'the identification SBA 10FM, and with used newspaper as an additive to the mixture to aid in varying the bul~ density and absorption capacity character-istics of the ultimate synthetic absorbent granules. The used newspaper was reduced to a sludge or pulp by,mixing with water in a high speed electric mixer. Excess water was pressed out of the mix so the paper water ratio was 1:15 when ready to be mixed with the plaster and water.
The used ne--spaper treated as above was mixed with the plaster and water in ~roportions shown in the following table with the density and water absorption characteristics of each ~ 9~5 ~
of the 5iX batches OT mixes. Each batch was approximately 1 pound to 1.5 pounds, and was mixed by hand, and removed, set and hardened, dried, and then granulated in the same manner as described above for the t~elve batches made in Holland.
Batch No. 18 19 20 21 22 23 Percent Plaster 69.fi ~6.7 64.5 64 61.5 59.3 Percent Paper .9 1.7 1.6 2.4 3.1 3.7 Percent l~ater 24.5 31.6 33.9 33.6 35.4 37.0 Density (lbs/cu.ft.) 33.7 32.6 29.5 2~.1 25.7 24.
Percent l~rater Absorption 44.6 51.2 58 73 81 111 -Setting Time (Min.) 16 19 20 24 30 31 Note: Percentage of paper is measured on basis of the weight of dry paper.
Samples of 22 pounds each from the formulation o~ -batches 20 and 21 were tested in cat boxes over a period of time, and the synthetic absorbent granules from each batch served their purpose very satisfactorily.
TESTING TO DETERMINE PLASTER CHARACTERISTICS
FOR PRODUCTION OF SYNTHETIC ABSORBENT GRANULES
Plaster characteristics may vary for numerous reasons including the location and nature of the gypsum mined, as well as the actual manufacturing specifications for the plaster. In order to determine the synthetic absorbent granule characteristics foT a given plaster, simple tests can be made corresponding to the formulations and the procedures for any one or more of Batches 1 to 17 inclusive above.
~ ~ 9~'5~
Thc ~ter content for a test batch will detcrmine the bulk density and ab~orption charactcristics for that batch. l~hen the desired characteristics are obtained, that is the water content to use for production of granules using that particu-lar plaster. The various examplcs indicate that a simple test will determine in advance the water content to be used ~ith any plaster in order to meet a particular specification for the granules.
If additives, such as paper pulp or other light weight naturally absorptive materials are to be used, the examples in Batches 18 to 23 inclusive illustrate corresponding test methods for chec~ing the combination of plaster and each such absorptive material to obtain the desired characteristics for the final granules to be used for absorbing purposes.
If it is desired to have synthetic colored granules in accordance with the present invention, pigment of the desired colo~ is mixed with the material in the mixing appaTatus in-cluding plaster and water. The entire batch of the desired color is then processed through the remaining steps described herein, and crushed and granulated to the desired screen mesh size.
Accordingly, the process of the present invention shows that liquid absorbent granules can be synthesized to pTovide equivalent or improved characteristics relative to the gran-ules made from naturally occurring liquid absorbent minerals such as fuller's earth, and such characteristics can be con-trolled to a predetermincd formulation for a particular purpose in a manner and to a degree not possible with the natural product.
Claims (14)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for manufacturing synthetic liquid absorbent granules from gypsum plaster, which said granules are to be used for any one of different liquid absorption purposes including that for oil and grease and the like on floors, that in toilet boxes for the use of household pets, that as a carrier for a chemical to be used in agriculture as an insecticide, or as a herbicide, or a fungicide, that as a colored ground cover with color pigment therein, and that for introduction into the soil as a soil conditioner, such a method comprising:
(a) providing plaster and water to mixing apparatus in predetermined proportions in a range of substantially 15% water and 85% plaster to substantially 50% water and 50% plaster for mixing a batch of the same, (b) mixing said batch of water and plaster in mixing apparatus to provide a wet mix material in a condition wherein said batch material is spreadable for setting, hardening, and drying, (c) spreading said batch material into a form to set and harden and dry such that it can be prepared for crushing, (d) permitting said batch material to set and harden and dry, (e) breaking said set and hardened and dried material of a batch into pieces of a size to be accommodated in a crusher, (f) crushing said pieces into granule size, and (g) sizing said granules by screen means to provide granules of a predetermined size related to said screen means, whereby said granules are ready for packaging to be ultimately-used as liquid absorbent granules.
(a) providing plaster and water to mixing apparatus in predetermined proportions in a range of substantially 15% water and 85% plaster to substantially 50% water and 50% plaster for mixing a batch of the same, (b) mixing said batch of water and plaster in mixing apparatus to provide a wet mix material in a condition wherein said batch material is spreadable for setting, hardening, and drying, (c) spreading said batch material into a form to set and harden and dry such that it can be prepared for crushing, (d) permitting said batch material to set and harden and dry, (e) breaking said set and hardened and dried material of a batch into pieces of a size to be accommodated in a crusher, (f) crushing said pieces into granule size, and (g) sizing said granules by screen means to provide granules of a predetermined size related to said screen means, whereby said granules are ready for packaging to be ultimately-used as liquid absorbent granules.
2. In the method of claim 1, providing said plaster and water to said mixing apparatus in a selected proportion for a batch which is in a range that varies from substantially 15% water and 85% plaster to a proportion of substantially 50% water and 50% plaster.
3. In the method of claim 1, crushing said set and hardened and dried material of a batch to granules which include a predetermined size for a predetermined purpose, said size being selected out of a range from screen size 4 to screen size 60.
4. In the method of claim 1, crushing said set and hardened and dried material of a batch to granules which include a predetermined screen size, sizing said crushed material to identify oversize granules that do not go through the screen of the predetermined size, said method including the step of taking said oversized granules and recrushing the same, and resizing said recrushed material to select additional granules of said predetermined screen size.
5. In the method of claim 1, mixing said combination of plaster and water to a mix in a pourable pasty condition, spreading said mix into a substantially flat sheet-like form for setting and hardening and drying of the same for the purpose of thereafter being broken up and crushed.
6. In the method of claim 1 wherein fines are produced in the crushing of said pieces of a batch into granule size and said fines are unuseable as synthetic liquid absorbent granules, the mixing of said fines with said water and plaster in a proportion up to substantially 30 percent relative to the plaster content for a batch.
7. In the method of claim 1, wherein an addive of a light weight naturally absorptive material is utilized in the manufacture of said synthe-tic liquid absorbent granules, the step of mixing such an additive, said plaster, and said water as a batch in said mixing apparatus to a condition such that it can be spreadable for setting, hardening and drying.
8. In the method of claim 7, wherein said additive is one of a group including paper pulp, finely divided paper, wood dust, peat dust, and light weight clay dust.
9. In the method of claim 7, wherein said additive is used-news-paper, and converting said used-newspaper to a sludge or pulp condition, by mixing with water so that such additive in said condition can be mixed with said plaster and water.
10. In a method of making a product for distributing chemicals, said method utilizing the synthetic granules manufactured in accordance with said method of claim 1, the step of mixing said granules with a chemical of the group consisting of insecticides, herbicides, and fungicides for the purpose of applying said mix to agricultural products to improve the same.
11. Synthetic liquid absorbent material in a granule form with said granules adapted to be used for any one of different liquid absorption pur-poses including that as an oil and grease absorbent on floors or the like, that as an absorbent in toilet boxes for household pets, that as an absor-bent to carry a chemical to be used as an insecticide, or herbicide, or fungicide for agriculture purposes, and that as a ground cover or a con-ditioner, said material comprising granules manufactured from a combination of materials including gypsum plaster and water and such combination of materials being provided in a hardened granule condition with the granules of a size within the general range of granule sizes which will pass through a 6 mesh screen and will be retained in a 60 mesh screen.
12. A synthetic liquid absorbent material in a granule form as defined in claim 11 which includes an additive therein of a light weight naturally absorptive material that affects the bulk density of the granules.
13. A synthetic liquid absorbent material as defined in claim 12, wherein the light weigth naturally absorptive material is used-newspaper.
14. A method utilizing dry powdered calcium sulfate hemihydrate to produce calcium sulfate dihydrate granules to be used for various moisture absorption purposes such as oil and grease absorption, refuse in animal toi-let boxes, and as carriers for agricultural chemicals, which method comprises, (a) providing calcium sulfate hemihydrate material in dry powdered form and in a predetermined amount to mixing apparatus, (b) providing water in a predetermined amount to said material in said mixing apparatus, (c) mixing said material and said water to provide a mixture contain-ing from about 15 percent water and about 85 percent calcium sulfate hemi-hydrate to about 50 percent water and about 50 percent calcium sulfate hemi-hydrate and effecting hydration of said material while it is being mixed so as to provide a calcium sulfate dihydrate product, (d) drying said product, (e) providing said product in granular form to be sized by screen means, and (f) providing screen means, and screening said product in granular form by said screen means to segregate the same into different screen-size groups whereby each group is marketed and used in granular form for said various moisture absorption purposes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA291,923A CA1109051A (en) | 1977-11-29 | 1977-11-29 | Process for making a synthetic liquid absorbent and products resulting therefrom |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA291,923A CA1109051A (en) | 1977-11-29 | 1977-11-29 | Process for making a synthetic liquid absorbent and products resulting therefrom |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1109051A true CA1109051A (en) | 1981-09-15 |
Family
ID=4110165
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA291,923A Expired CA1109051A (en) | 1977-11-29 | 1977-11-29 | Process for making a synthetic liquid absorbent and products resulting therefrom |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1109051A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4950692A (en) * | 1988-12-19 | 1990-08-21 | Nalco Chemical Company | Method for reconstituting superabsorbent polymer fines |
| US4970267A (en) * | 1990-03-08 | 1990-11-13 | Nalco Chemical Company | Reconstitution of superabsorbent polymer fines using persulfate salts |
| CN111517335A (en) * | 2020-06-04 | 2020-08-11 | 复星生态环境治理有限公司 | Preparation facilities of natural water dephosphorization preparation |
-
1977
- 1977-11-29 CA CA291,923A patent/CA1109051A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4950692A (en) * | 1988-12-19 | 1990-08-21 | Nalco Chemical Company | Method for reconstituting superabsorbent polymer fines |
| US4970267A (en) * | 1990-03-08 | 1990-11-13 | Nalco Chemical Company | Reconstitution of superabsorbent polymer fines using persulfate salts |
| CN111517335A (en) * | 2020-06-04 | 2020-08-11 | 复星生态环境治理有限公司 | Preparation facilities of natural water dephosphorization preparation |
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