CA1054821A - Granular sulfur-bentonite mixture for fertilizer - Google Patents
Granular sulfur-bentonite mixture for fertilizerInfo
- Publication number
- CA1054821A CA1054821A CA235,667A CA235667A CA1054821A CA 1054821 A CA1054821 A CA 1054821A CA 235667 A CA235667 A CA 235667A CA 1054821 A CA1054821 A CA 1054821A
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- sulphur
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- clay
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Abstract
ABSTRACT OF THE DISCLOSURE
The present specification discloses a sulphur suspension in suitable mineral clays as a source of plant nutrient, and more particularly to a water-degradable granular suspension of elemental sulphur in bentonite clay. The importance of sulphur as a soil additive, either in the form of sulphur compounds or in its elemental form, with or without a suspension medium such as a mineral clay has been widely understood in the literature for some time. This specification discloses a process for the manufacture of water-degradable granular solid suspension of elemental sulphur in bentonite clay, comprising the stop of adding 7 to 9 parts (out of 10 parts) of liquid sulfur to 1 to 3 parts of substantially dry clay dust, with continuous and thorough mixing, at an elevated temperature between 240 and 300°F., pouring the uniform mixture onto a wet stainless steel plate, and allowing to cool to a thickness of 1/4 to 2 inches, comminuting the mixture and screening and separating the granules having a particle size of minus 4/plus 14 mesh on the U.S.
Standard scale.
The present specification discloses a sulphur suspension in suitable mineral clays as a source of plant nutrient, and more particularly to a water-degradable granular suspension of elemental sulphur in bentonite clay. The importance of sulphur as a soil additive, either in the form of sulphur compounds or in its elemental form, with or without a suspension medium such as a mineral clay has been widely understood in the literature for some time. This specification discloses a process for the manufacture of water-degradable granular solid suspension of elemental sulphur in bentonite clay, comprising the stop of adding 7 to 9 parts (out of 10 parts) of liquid sulfur to 1 to 3 parts of substantially dry clay dust, with continuous and thorough mixing, at an elevated temperature between 240 and 300°F., pouring the uniform mixture onto a wet stainless steel plate, and allowing to cool to a thickness of 1/4 to 2 inches, comminuting the mixture and screening and separating the granules having a particle size of minus 4/plus 14 mesh on the U.S.
Standard scale.
Description
~05~8Z~
The present invention re~ates to sulphur suspension in suitable mineral clays as a ;ource of plant nutrient, and more particularly to a water-degradable granular suspension of elemental sulphur in bentonite clay.
Broadly stated, this invention deals with a process of procluction of an agriculturally and horticulturally useful nutrient, widely recognized in its importance, namely sulphur, _ _ in the form of a solid clay suspension.
The importance of sulphur as a soil additive, either in the form of sulphur compounds or in its elemental form, with or without a suspension medium such as a mineral clay has been widely understood in the literature for some time.
However, the present method of production of a water degrad- ~__ able granular suspenfiion of elemental sulphur in bentonite clay, and the product of the method, are new.
Among the known methods, reference is made to the following prior publications, which are listed below:
French Patent No. 1,511,002, Yves Berquin - delivered 18 December, 1967 - "Process for the manufacture of granules of sulphur"
"Development of a water-degradable granular sulphur product" Bridger et al - Sulphur Institute Final Reports 1 July, 1965 through 30 June, 1966 Canadian Patent No. 267,180 - "Fertilizer", Dedolph et al - Decernber 28, 1926 Canadian Patent No. 811,080 - "Suspension Fertili7er" -Ramaradhya, ~pril 22, 1969 "Introduction of Solid and Molten Sulfur Into Li~uid, Granular ancl Bulk-Blcndc~ Complete rertilizers~
Bridger & Bixby ~-~054~
Fertilizers, particularly of sulphur and nitrogen compounds, are usually of either liquid or solid type. Liquid mixed fertilizers are in two forms, suspension and solution types.
As taught by Ramaradhya in CP 811,080 for example, suspended or slurried fertilizers combined better than the liquid type. For maximum effect, it is desirable for the fertilizer to have a high concentration of plant nutrient.
However, such high concentration introduces the possibility of a settling-out of the solids, with many resulting problems.
It has been shown by G.L. Bridger et al in 1966 (Supra:-Part B pp. 7-8), that products could be made from molten sulphur by spraying a suspension containing 10% bentonite in molten sulphur onto a pan granulator (see process of Y. Berquin Supra). In other tests, 10% of ammonium sulphate was also used in addition to the bentonite to produce a product con-taining some soluble sulphur. It was necessary to pre-heat the bentonite somewhat above the melting point of sulphur (to about 200F.), to prevent foaming when added to the molten sulphur. The resulting products of this procedure were some-what irregular in shape, but were quite hard and quickly water-degradable.
Several earlier methods of producing a granular sulphur fertilizer product have been used with limited success. The use of attapulgite and the prilling method of granulation, for instance, in the earlier processes resulted in products which were agronomically unsuitable. Because of the unsat-isfactory nature of these earlier products, their production was eventually discontinued.
10548Z~
Thus, sulphur or its comp~)unds, in various forms, is useful for either decreasing the alkalinity of soils or, alternatively, increasing the acidity of those soils weak in that respect, by gradual oxidation, on being added to soils.
To maintain high concentration, elemental sulphur is the preferred way of adding sulphur to high-analysis fertil-zers .
It is important that the elemental sulphur, as a soiladditive, be in a finely-divided form. In this form it may be stabilized in suspensions by the use of certain mineral clays, such as pulgite or bentonite. Studies have shown, for instance, that up to 2% of attapulgite is required to produce stability of sulphur in a complete liquid fertilizer. I-lowever, as stated above, the sulphur must be finely ground, and this adds to thc cost of preparation and, up until the present, satisactory procedures for introducing less finely-ground sulphur, or molten sulphur, solid-suspension fertilizers, have ~-not been developed. -In passing, it should be mentioned that a calculation of the sulphur requirement of various soils should, of course, be made. Ilowever, means for doing this are well known in the art.
Objects of the Invention The primary object of the invention is an improved method of production of a water-degradable granular solid suspension of elemental sulphur in bentonite clay.
A further object of this invention is to manufacture a product which is a water-degradable, granular suspcnsion of elemental sulphur in bentonite clay, said product being a source of elemental sulphur, which is released slowly into the soil.
10548'~1 The objects are achieyed ~y pouring sulphur and ~entonite as a liquid mixture onto a wet thermally conductive plate, and -solidifying the mixture by allowing to cool to a planned thiekn~ss. This material is then crush~d to a finally accept-able uniform size. The resulting granules of the product are sized so that the product is acceptable in nature for fertilizing purposes.
~ nother object of this invention is to produce a granular product of the same particle size as other bulk-blend raw materials which will degrade or decompose to rather fine particles upon becoming wet from soil moisture, the granules of the product being of uniform size.
The present invention therefore provides a proccss for the manufacture of a water-degradable granular solid suspension of elemental sulphur in bentonite elay, eomprising the step of adding substantially dry clay dust to liquid sulphur, with ___ continuous and thorough mixing, at an elevated temperature between 240 and 300F., pouring the uniform mixture onto a wet thermally conductive plate, and allowing to cool to a thickness of 1/4 to 2 inches, comminuting the mixture and screening and separating the granules having a particle size of minus 4/plus 14 mesh on the U.S. Standard scale.
In a preferred aspect the present invention provides such a process whercin 1 to 3 parts (out of 10 parts) of sub-stantially dry bentonite elay dust is added, with con-tinuous and thorough mixing to 7 to 9 parts o~ liquid sulphur at an elevated tem,cerature between 240 and 300~F., pouring the uniform mixture onto a wet metal plate and allowing to cool to a thickness of 1/2 to 2 inches, com-minutinc3 the mixture to about 1/8 inch granules and scre~n-ing and separating the granules having particl~ size of minu~ plus 14 m~sh.
10548Z~
In another preferred aspect the present invention provides such a process wherein 1 to 3 parts of substantially dry bentonite clay dust is added, with continuous and thorough ;
mixing to 7 to 9 parts of li~uid sulphur at an elevated tem-perature 240 and 300F., pouring the uniform mixture onto a moving wet met~l belt and allowing the mixture to cool to a thickness of 1/4 to 1/2 an inch while moving on the belt, comminuting the mixture to about 1/8 inch granules and screening and separating the granules having a particle size of minus 4/plus 14 mesh.
mh~ metal is prcferably steel and most preferably stain-less steel.
The inventor also found that the adoption of an agingperiod of about one hour prior to crushing is desirable to obtain a better crushiny result. This probably results from a change in the crystalline structure of the sulphur rom monoclinic to rhombic as the temperature of the sulphur decreases during the aging process. (see Moeller "Inorganic Chemistry" -Wiley & Sons 1952 pages 488-489) Laboratory tests of the resulting granular products of this invention have indicated that they possess good storage properties under severe conditions of high temperature and humidity, without caking or degradation, and that they dis-integrate to fine particles, on wetting.
An example of this is shown by granules produced from ~olten sulphur containing 70-90 percent sulphur and 10-30 percent bentonite clay.
As an example of the degree of water-degradability of the granulated sulphur, samples of a granular solid product made from molten sulphur and having a particle size of -4, +14 mesh (U.S. Standard) and containing 10% of bentonite, were wet-screened after being submerged in water for 1 hour. The typical wet-screen analysis of the degraded samples was as follows:
105~8Z~
40 mesh ......................... 85% passed through 80 mesh ......................... 50% passed through This indicates that the degraded sulphur granules should be available to plants within a reasonable time.
Agronomic tests demonstrate that these granulated sulphur products show more rapid response than prilled sulphur or other solid sulphur agglomerates, since they break down to a fine .
particle size within a few minutes. The breakdown of the sulphur particles of the product of the invention is pronounced, and hence the product gives a good agronomic response.
The result of this invention is an upgrading of previous methods to produce an improved and acceptable water-degradable .
granular sulphur fertilizer, resulting in the improved yrocess --as described below.
The main difference between the prescntly described process and previous attempts to manufacture a suitable product lies in the method of preparation and mixing of the raw materials; the metllod of solidifying the mixture; and the sizing of granules of product acceptable to the fertilizer industry.
The product of the present process has unexpectedly improved characteristics. Some generalized examples of certain preferred em~odimcnts of the invention are as follows.
Into a mix-tank is added 7 to 9 parts liquid melted sulphur.
The mix-tank is heated by steam tracer lines to keep sulphur liquid at a constant 245F. 1 to 3 parts dry lattice expanding type bentonite clay "type 325" having a moisture content less than 5% is added to the liquid sulphur. The clay is added in dust form and mixed slowly, to eliminate balling up of the clay. Moisture content of the clay should be kcpt to a minimum, to eliminate boiling over in the mix-tank. The product is now continually mixed and kept at about 245F. The thoroughly mixed '-product is poured onto a wet stainless steel plate floor and allowed to cool. Pouring is accomplished in 3 separate pours, 1059~l~Z~
one on top of the other. Each pour is allowed to cool until hard be~ore the next pour is added. Each pour is approximately 1/2" thick, giving the end product on the floor an approximate thickness of 1.5".
Once cooled, hardened and aged, the product is ready for the crushing operation. Crushing may desirably be accomplished in 3 separate crushers. The product is loaded by means of a ~__ front-end loader into a jaw crusher, which reduces the product to a granular size of approximately 1/2". A second crusher reduces this product to approximately 1/4" granules. A third crusher reduces this product to approximately 1/8" granules.
The product from the third crusher is now screened to obtain a uniform sized product. All granules which are too large are returned to the third crusher for reprocessing. All granules too small are returned to the mix-tank for reprocessing.
The finished product, having particle size within range of minus -~~
4/plus 14 mesh, is now conveyed to a product tank, from which it may be bulk-loaded or bagged for shipment.
~ typical ~eneralized example of certain preferred embodiments of a continuous manu~acturin~ proccdure is as follows. Into a mix-tank is added 7 to 9 parts liquid sulphur.
The mix-tank is heated by steam tracer lines to kcep sulphur liquid at a constant 2~5F. One to three parts bentonite clay is added to thc liquid sulphur. The clay is added in dust orm and mixed slowly, to eliminate ballin~ up of the clay.
Thc thorou~hly mixed product is continuously pourcd onto a wet moving stainlcss steel belt of which the under side is coolcd by water. I~hile movin~ on the belt, the mixture product is allowcd to cool and cvcntually to solidify. Tl~c thickncss o the mixture product pourecl on thc belt is adjustcd to (7ivc a prcdctcrMincd thickness to thc solidificd l~roduct, preerably about 5/8" when it is spread onto the bclt.
10~4821 The mixed product thus solidified separates from the end of the belt in the form of thin fragments of 1/4 to 1/2 an inch q in thickness and then subjected to an aging process for about one hour.
Crushing is accomplished by means of a roller-crusher which reduces the fragments to approximately 1/8" granules. T~le product from the roller-crusher is then screened to obtain a uniform sized product. All granules too large are returned ~o the roller-crusher for reprocessing, while all granules too small are returned to the mix-tank for reprocessing. The finished product, having particle size within range of minus 4 plus 14 mesh, is then conveyed to a product tank, from which it may be bulk-loaded or bagged for shipment.
The following safety factors are desired in manu-facturing. Magnets are installed throughout the system to prevent metal items from causing sparks. The entire plant system of elevators, crushers, screens, storage tanks and dust collectors is purged with an inert gas blanket of carbon dioxide (CO ) to eliminate the chance of an explosion or fire or both. A dust collector system is also employed to prevent accumulation, and the dust is poured periodically back into the mix-tank, and in addition, a humidity of 35% or more is maintained, to prevent static sparks. All equipment should be well grounded and all motors and electrical fixtures must be explosion-proof. Steam is the basic source of heat and is also piped into the dust system to be used in case of fire. Finally, all product is moved from one step to the next step by slow-moving, non-sparking belts or bucket elevators.
Hence, the scope of the inYention is defined in the fol~
lowing claims where:
The present invention re~ates to sulphur suspension in suitable mineral clays as a ;ource of plant nutrient, and more particularly to a water-degradable granular suspension of elemental sulphur in bentonite clay.
Broadly stated, this invention deals with a process of procluction of an agriculturally and horticulturally useful nutrient, widely recognized in its importance, namely sulphur, _ _ in the form of a solid clay suspension.
The importance of sulphur as a soil additive, either in the form of sulphur compounds or in its elemental form, with or without a suspension medium such as a mineral clay has been widely understood in the literature for some time.
However, the present method of production of a water degrad- ~__ able granular suspenfiion of elemental sulphur in bentonite clay, and the product of the method, are new.
Among the known methods, reference is made to the following prior publications, which are listed below:
French Patent No. 1,511,002, Yves Berquin - delivered 18 December, 1967 - "Process for the manufacture of granules of sulphur"
"Development of a water-degradable granular sulphur product" Bridger et al - Sulphur Institute Final Reports 1 July, 1965 through 30 June, 1966 Canadian Patent No. 267,180 - "Fertilizer", Dedolph et al - Decernber 28, 1926 Canadian Patent No. 811,080 - "Suspension Fertili7er" -Ramaradhya, ~pril 22, 1969 "Introduction of Solid and Molten Sulfur Into Li~uid, Granular ancl Bulk-Blcndc~ Complete rertilizers~
Bridger & Bixby ~-~054~
Fertilizers, particularly of sulphur and nitrogen compounds, are usually of either liquid or solid type. Liquid mixed fertilizers are in two forms, suspension and solution types.
As taught by Ramaradhya in CP 811,080 for example, suspended or slurried fertilizers combined better than the liquid type. For maximum effect, it is desirable for the fertilizer to have a high concentration of plant nutrient.
However, such high concentration introduces the possibility of a settling-out of the solids, with many resulting problems.
It has been shown by G.L. Bridger et al in 1966 (Supra:-Part B pp. 7-8), that products could be made from molten sulphur by spraying a suspension containing 10% bentonite in molten sulphur onto a pan granulator (see process of Y. Berquin Supra). In other tests, 10% of ammonium sulphate was also used in addition to the bentonite to produce a product con-taining some soluble sulphur. It was necessary to pre-heat the bentonite somewhat above the melting point of sulphur (to about 200F.), to prevent foaming when added to the molten sulphur. The resulting products of this procedure were some-what irregular in shape, but were quite hard and quickly water-degradable.
Several earlier methods of producing a granular sulphur fertilizer product have been used with limited success. The use of attapulgite and the prilling method of granulation, for instance, in the earlier processes resulted in products which were agronomically unsuitable. Because of the unsat-isfactory nature of these earlier products, their production was eventually discontinued.
10548Z~
Thus, sulphur or its comp~)unds, in various forms, is useful for either decreasing the alkalinity of soils or, alternatively, increasing the acidity of those soils weak in that respect, by gradual oxidation, on being added to soils.
To maintain high concentration, elemental sulphur is the preferred way of adding sulphur to high-analysis fertil-zers .
It is important that the elemental sulphur, as a soiladditive, be in a finely-divided form. In this form it may be stabilized in suspensions by the use of certain mineral clays, such as pulgite or bentonite. Studies have shown, for instance, that up to 2% of attapulgite is required to produce stability of sulphur in a complete liquid fertilizer. I-lowever, as stated above, the sulphur must be finely ground, and this adds to thc cost of preparation and, up until the present, satisactory procedures for introducing less finely-ground sulphur, or molten sulphur, solid-suspension fertilizers, have ~-not been developed. -In passing, it should be mentioned that a calculation of the sulphur requirement of various soils should, of course, be made. Ilowever, means for doing this are well known in the art.
Objects of the Invention The primary object of the invention is an improved method of production of a water-degradable granular solid suspension of elemental sulphur in bentonite clay.
A further object of this invention is to manufacture a product which is a water-degradable, granular suspcnsion of elemental sulphur in bentonite clay, said product being a source of elemental sulphur, which is released slowly into the soil.
10548'~1 The objects are achieyed ~y pouring sulphur and ~entonite as a liquid mixture onto a wet thermally conductive plate, and -solidifying the mixture by allowing to cool to a planned thiekn~ss. This material is then crush~d to a finally accept-able uniform size. The resulting granules of the product are sized so that the product is acceptable in nature for fertilizing purposes.
~ nother object of this invention is to produce a granular product of the same particle size as other bulk-blend raw materials which will degrade or decompose to rather fine particles upon becoming wet from soil moisture, the granules of the product being of uniform size.
The present invention therefore provides a proccss for the manufacture of a water-degradable granular solid suspension of elemental sulphur in bentonite elay, eomprising the step of adding substantially dry clay dust to liquid sulphur, with ___ continuous and thorough mixing, at an elevated temperature between 240 and 300F., pouring the uniform mixture onto a wet thermally conductive plate, and allowing to cool to a thickness of 1/4 to 2 inches, comminuting the mixture and screening and separating the granules having a particle size of minus 4/plus 14 mesh on the U.S. Standard scale.
In a preferred aspect the present invention provides such a process whercin 1 to 3 parts (out of 10 parts) of sub-stantially dry bentonite elay dust is added, with con-tinuous and thorough mixing to 7 to 9 parts o~ liquid sulphur at an elevated tem,cerature between 240 and 300~F., pouring the uniform mixture onto a wet metal plate and allowing to cool to a thickness of 1/2 to 2 inches, com-minutinc3 the mixture to about 1/8 inch granules and scre~n-ing and separating the granules having particl~ size of minu~ plus 14 m~sh.
10548Z~
In another preferred aspect the present invention provides such a process wherein 1 to 3 parts of substantially dry bentonite clay dust is added, with continuous and thorough ;
mixing to 7 to 9 parts of li~uid sulphur at an elevated tem-perature 240 and 300F., pouring the uniform mixture onto a moving wet met~l belt and allowing the mixture to cool to a thickness of 1/4 to 1/2 an inch while moving on the belt, comminuting the mixture to about 1/8 inch granules and screening and separating the granules having a particle size of minus 4/plus 14 mesh.
mh~ metal is prcferably steel and most preferably stain-less steel.
The inventor also found that the adoption of an agingperiod of about one hour prior to crushing is desirable to obtain a better crushiny result. This probably results from a change in the crystalline structure of the sulphur rom monoclinic to rhombic as the temperature of the sulphur decreases during the aging process. (see Moeller "Inorganic Chemistry" -Wiley & Sons 1952 pages 488-489) Laboratory tests of the resulting granular products of this invention have indicated that they possess good storage properties under severe conditions of high temperature and humidity, without caking or degradation, and that they dis-integrate to fine particles, on wetting.
An example of this is shown by granules produced from ~olten sulphur containing 70-90 percent sulphur and 10-30 percent bentonite clay.
As an example of the degree of water-degradability of the granulated sulphur, samples of a granular solid product made from molten sulphur and having a particle size of -4, +14 mesh (U.S. Standard) and containing 10% of bentonite, were wet-screened after being submerged in water for 1 hour. The typical wet-screen analysis of the degraded samples was as follows:
105~8Z~
40 mesh ......................... 85% passed through 80 mesh ......................... 50% passed through This indicates that the degraded sulphur granules should be available to plants within a reasonable time.
Agronomic tests demonstrate that these granulated sulphur products show more rapid response than prilled sulphur or other solid sulphur agglomerates, since they break down to a fine .
particle size within a few minutes. The breakdown of the sulphur particles of the product of the invention is pronounced, and hence the product gives a good agronomic response.
The result of this invention is an upgrading of previous methods to produce an improved and acceptable water-degradable .
granular sulphur fertilizer, resulting in the improved yrocess --as described below.
The main difference between the prescntly described process and previous attempts to manufacture a suitable product lies in the method of preparation and mixing of the raw materials; the metllod of solidifying the mixture; and the sizing of granules of product acceptable to the fertilizer industry.
The product of the present process has unexpectedly improved characteristics. Some generalized examples of certain preferred em~odimcnts of the invention are as follows.
Into a mix-tank is added 7 to 9 parts liquid melted sulphur.
The mix-tank is heated by steam tracer lines to keep sulphur liquid at a constant 245F. 1 to 3 parts dry lattice expanding type bentonite clay "type 325" having a moisture content less than 5% is added to the liquid sulphur. The clay is added in dust form and mixed slowly, to eliminate balling up of the clay. Moisture content of the clay should be kcpt to a minimum, to eliminate boiling over in the mix-tank. The product is now continually mixed and kept at about 245F. The thoroughly mixed '-product is poured onto a wet stainless steel plate floor and allowed to cool. Pouring is accomplished in 3 separate pours, 1059~l~Z~
one on top of the other. Each pour is allowed to cool until hard be~ore the next pour is added. Each pour is approximately 1/2" thick, giving the end product on the floor an approximate thickness of 1.5".
Once cooled, hardened and aged, the product is ready for the crushing operation. Crushing may desirably be accomplished in 3 separate crushers. The product is loaded by means of a ~__ front-end loader into a jaw crusher, which reduces the product to a granular size of approximately 1/2". A second crusher reduces this product to approximately 1/4" granules. A third crusher reduces this product to approximately 1/8" granules.
The product from the third crusher is now screened to obtain a uniform sized product. All granules which are too large are returned to the third crusher for reprocessing. All granules too small are returned to the mix-tank for reprocessing.
The finished product, having particle size within range of minus -~~
4/plus 14 mesh, is now conveyed to a product tank, from which it may be bulk-loaded or bagged for shipment.
~ typical ~eneralized example of certain preferred embodiments of a continuous manu~acturin~ proccdure is as follows. Into a mix-tank is added 7 to 9 parts liquid sulphur.
The mix-tank is heated by steam tracer lines to kcep sulphur liquid at a constant 2~5F. One to three parts bentonite clay is added to thc liquid sulphur. The clay is added in dust orm and mixed slowly, to eliminate ballin~ up of the clay.
Thc thorou~hly mixed product is continuously pourcd onto a wet moving stainlcss steel belt of which the under side is coolcd by water. I~hile movin~ on the belt, the mixture product is allowcd to cool and cvcntually to solidify. Tl~c thickncss o the mixture product pourecl on thc belt is adjustcd to (7ivc a prcdctcrMincd thickness to thc solidificd l~roduct, preerably about 5/8" when it is spread onto the bclt.
10~4821 The mixed product thus solidified separates from the end of the belt in the form of thin fragments of 1/4 to 1/2 an inch q in thickness and then subjected to an aging process for about one hour.
Crushing is accomplished by means of a roller-crusher which reduces the fragments to approximately 1/8" granules. T~le product from the roller-crusher is then screened to obtain a uniform sized product. All granules too large are returned ~o the roller-crusher for reprocessing, while all granules too small are returned to the mix-tank for reprocessing. The finished product, having particle size within range of minus 4 plus 14 mesh, is then conveyed to a product tank, from which it may be bulk-loaded or bagged for shipment.
The following safety factors are desired in manu-facturing. Magnets are installed throughout the system to prevent metal items from causing sparks. The entire plant system of elevators, crushers, screens, storage tanks and dust collectors is purged with an inert gas blanket of carbon dioxide (CO ) to eliminate the chance of an explosion or fire or both. A dust collector system is also employed to prevent accumulation, and the dust is poured periodically back into the mix-tank, and in addition, a humidity of 35% or more is maintained, to prevent static sparks. All equipment should be well grounded and all motors and electrical fixtures must be explosion-proof. Steam is the basic source of heat and is also piped into the dust system to be used in case of fire. Finally, all product is moved from one step to the next step by slow-moving, non-sparking belts or bucket elevators.
Hence, the scope of the inYention is defined in the fol~
lowing claims where:
Claims (20)
1. A process for the manufacture of a water-degradable granular solid suspension of elemental sulphur in bentonite clay, comprising the step of adding 1 to 3 parts (out of 10 parts) of substantially dry clay dust to correspondingly 7 to 9 parts of molten sulphur, with continuous and thorough mixing, at an elevated temperature between 240 and 300°F., pouring the uniform mixture onto a wet thermally conductive metal plate, and allow-ing to cool to a thickness of 1/4 to 2 inches, comminuting the mixture and screening and separating the granules having a particle size of minus 4/plus 14 mesh on the U.S. Standard scale.
2. A process, as in claim 1, comprising pouring the uniform mixture onto a wet metal plate and allowing to cool to a thickness of 1/2 to 2 inches, comminuting the mixture to about 1/8 inch granules and screening and separating the granules having a particle size of minus 4/plus 14 mesh.
3. A process as in claim 1 or 2 wherein the metal is steel.
4. A process as in claim 2 wherein the metal is stainless steel.
5. A process as in claim 1, 2 or 4 wherein the pouring is effected in three separate pours, wherein each of the three pours is to approximately 1/2-inch thickness.
6. A process as in claim 1, 2 or 4 wherein the comminuting is effected by means of at least a jaw-crusher.
7. A process as in claim 1, 2 or 4 in which the comminution is effected in a crusher, and the screening pro-cedure used to ensure a uniform sized product comprises returning all granules which are too large to the crusher for reprocessing, returning all granules too small to the mixing step for reprocessing, and allowing the finished product of acceptable particle size to be separated and conveyed to a product tank for preparation for shipment.
8. A process, as in claim 1, wherein the mixture of bentonite clay and liquid sulphur is poured onto a moving wet metal belt and allowed to cool to a thickness of 1/4 to 1/2 an inch while moving on the belt, comminuted to about 1/8 inch granules and screened for recovery of the granules having a particle size of minus 4/plus 14 mesh.
9. A process as in claim 8 wherein the metal is steel.
10. A process as in claim 8 wherein the metal is stainless steel.
11. A process, as in claim 8, 9 or 10 wherein the pour of mixture is as thick as about 5/8" when it is spread onto the metal belt.
12. A process, as in claim 8, 9 or 10 wherein the metal belt is water-cooled.
13. A process, as in claim 8, 9 or 10 wherein the comminuting is effected by means of a roller-crusher.
14. A process, as in claim 8, 9 or 10 in which the comminuting is effected by a roller crusher, and the screening procedure used to ensure a uniform sized product comprises re-turning all granules which are too large to the crusher for reprocessing, returning all granules which are too small to the mixing step for reprocessing, and allowing the finished product of acceptable particle size to be separated and conveyed to a product tank for preparation for shipment.
15. A process, as in claim 1, 2 or 4 wherein prior to crush-ing the solidified mixture it is aged for about an hour while cooling.
16. A process, as in claim 8, 9 or 10 wherein prior to crush-ing the solidified mixture it is aged for about an hour while cooling.
17. A process, as in claim 1, 2 or 8 wherein the clay dust has a moisture content less than 5% by weight of the clay dust.
18. A process, as in claim 1, 2 or 8 wherein the raw materials are mixed at 245°F.
19. A process, as in claim 1, 2 or 8 wherein the process is carried out in an inert gas atmosphere.
20. A process, as in claim 1, 2 or 8 wherein the process is carried out in an inert gas atmosphere consisting of carbon dioxide (CO2) gas.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA235,667A CA1054821A (en) | 1975-09-17 | 1975-09-17 | Granular sulfur-bentonite mixture for fertilizer |
| NZ182031A NZ182031A (en) | 1975-09-17 | 1976-09-13 | Manufacture of granular solid suspension of sulphur in bentonite clay |
| AU17788/76A AU503623B2 (en) | 1975-09-17 | 1976-09-15 | Granular sulfur-bentonite mixture for fertilizer |
| NL7610287A NL7610287A (en) | 1975-09-17 | 1976-09-15 | Granular mixts. of sulphur and bentonite, prodn. - for use as soil improvers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA235,667A CA1054821A (en) | 1975-09-17 | 1975-09-17 | Granular sulfur-bentonite mixture for fertilizer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1054821A true CA1054821A (en) | 1979-05-22 |
Family
ID=4104073
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA235,667A Expired CA1054821A (en) | 1975-09-17 | 1975-09-17 | Granular sulfur-bentonite mixture for fertilizer |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1054821A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4394150A (en) | 1980-02-29 | 1983-07-19 | Canadian Superior Oil Ltd. | Sulphur-clay prills |
| CN104163735A (en) * | 2013-05-16 | 2014-11-26 | 世光化学工业株式会社 | soluble particle sulphur fertilizer and manufacture method for the same |
-
1975
- 1975-09-17 CA CA235,667A patent/CA1054821A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4394150A (en) | 1980-02-29 | 1983-07-19 | Canadian Superior Oil Ltd. | Sulphur-clay prills |
| CN104163735A (en) * | 2013-05-16 | 2014-11-26 | 世光化学工业株式会社 | soluble particle sulphur fertilizer and manufacture method for the same |
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