FERTILIZER COATING FOR DUST CONTROL AND/OR ANTI-CAKING

Abstract

A method of reducing dust formation and/or caking in fertilizer or other particulates. The method comprises coating the fertilizer or other particulate in a coating comprising vacuum tower asphalt extender (VTAE). The VTAE may be a non-distilled fraction of vacuum distillation of used automotive and/or industrial oil. The VTAE may not be asphalt or bitumen, although the coating may further comprise bitumen.

Claims

1. A fertilizer composite comprising: simple or complex fertilizer; and a coating at least partially covering the fertilizer, the coating comprising vacuum tower asphalt extender (VTAE), where the VTAE is bottoms from a vacuum distillation process of used automotive and/or industrial oil.

2. The fertilizer composite of claim 1 where the VTAE is not bitumen or asphalt.

3. The fertilizer composite of claim 1 where the coating further comprises bitumen and/or asphalt.

4. The fertilizer composite of claim 4 where: the bitumen is bitumen, cutback bitumen, or a combination of bitumen and cutback bitumen; the asphalt is asphalt, cutback asphalt, or a combination of asphalt and cutback asphalt; the VTAE is VTAE, cutback VTAE, or a combination of VTAE and cutback VTAE; or any combination thereof.

5. The fertilizer composite of claim 4 where the bitumen and/or asphalt is emulsified with water.

6. The fertilizer composite of claim 4 where the coating is emulsified with water.

7. The fertilizer composite of claim 1 where the VTAE is emulsified with water.

8. The fertilizer composite of claim 1 where the fertilizer is a plant nutrient selected from the group consisting of compounds of primary macronutrients (Nitrogen, Phosphorous, and Potassium), secondary macronutrients (Calcium, Sulfur, and Magnesium), and micronutrients (Boron, Chlorine, Copper, Iron, Magnesium, Molybdenum, and Zinc), or combinations thereof.

9. The fertilizer composite of claim 1 where the fertilizer is granular, crushed, compacted, crystalline, agglomerated, or prilled fertilizer or a combination thereof.

10. A coating comprising vacuum tower asphalt extender (VTAE), where the VTAE is bottoms from a vacuum distillation process of used automotive and/or industrial oil.

11. The coating of claim 10 where the coating is a dust control and/or anti-caking coating.

12. The coating of claim 10 where the VTAE is not bitumen or asphalt.

13. The coating of claim 10 where the coating further comprises bitumen and/or asphalt.

14. The coating of claim 13 where the bitumen is bitumen, cutback bitumen, or a combination of bitumen and cutback bitumen; the asphalt is asphalt, cutback asphalt, or a combination of asphalt and cutback asphalt; the VTAE is VTAE, cutback VTAE, or a combination of VTAE and cutback VTAE; or any combination thereof.

15. The coating of claim 13 where the bitumen and/or asphalt is emulsified with water.

16. The coating of claim 13 where the coating is emulsified with water.

17. The coating of claim 10 where the VTAE is emulsified with water.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a chart dust control performance on NPS fertilizer with an approximately 130 cps DCA;

[0024] FIG. 2 is a chart showing dust control performance on NPS fertilizer with an approximately 700 cps DCA;

[0025] FIG. 3 is a chart showing dust control performance on NPS fertilizer with an approximately 1200 cps DCA;

[0026] FIG. 4 is a chart showing dust control performance of Blend #1 and VTAE #1;

[0027] FIG. 5 is a chart showing dust control performance of Blend #2 and VTAE #2;

[0028] FIG. 6 is a chart showing improvement in caking resistance of coated DAP compared to uncoated DAP;

[0029] FIG. 7 is a chart showing improvement in caking resistance in coated NPS fertilizer compared to uncoated NPS fertilizer; and

[0030] FIG. 8 is a chart showing improvement in caking resistance in coated NPK compared to uncoated NPK.

[0031] Other advantages and features will be apparent from the following description and from the claims.

DETAILED DESCRIPTION OF THE INVENTION

[0032] The devices and methods discussed herein are merely illustrative of specific manners in which to make and use this invention and are not to be interpreted as limiting in scope.

[0033] While the devices and methods have been described with a certain degree of particularity, it is to be noted that many modifications may be made in the details of the construction and the arrangement of the devices and components without departing from the spirit and scope of this disclosure. It is understood that the devices and methods are not limited to the embodiments set forth herein for purposes of exemplification.

[0034] In general, in a first aspect, the invention relates to a coating composition comprising vacuum tower asphalt extender (VTAE). The composition may be used as a coating for fertilizer or other particles, such as silica dust, respirable dust, etc. The coating may control ambient dust levels, reduce dust formation, and/or reduce caking tendencies without affecting the handling characteristics of the fertilizer or other particles.

[0035] The VTAE may be derived from refined automotive and/or industrial oils. Specifically, the VTAE may be the non-distilled fraction from the vacuum tower of re-refined automotive and/or industrial oils. The VTAE may be made by recovering used oil, subjecting the recovered oil to dehydration and fuel stripping to remove fuels for industrial use, subjecting what remains to vacuum distillation, and collecting the bottoms of the vacuum distillation as VTAE. The VTAE may not be asphalt or bitumen.

[0036] The coating composition may additionally comprise bitumen, asphalt, diluent, and/or other constituents in addition to VTAE. The VTAE may be emulsified with water prior to use. If the coating composition additionally comprises bitumen, the VTAE may be emulsified prior to combining it with bitumen and/or asphalt; the bitumen and/or asphalt may be emulsified prior to combining it with VTAE; the coating may be emulsified after the VTAE and bitumen and/or asphalt are combined; or any combination thereof. The bitumen may be bitumen, cutback bitumen, or a combination thereof; the asphalt may be asphalt, cutback asphalt, or a combination thereof; and the VTAE may be VTAE, cutback VTAE, or a combination thereof. Cutters useful for compounding with the VTAE include, but are not limited to, white oil, refined mineral oils, and vegetable oils such as corn oil, canola oil, cottonseed oil, sunflower oil, soy oil, linseed oil, castor oil, and tall oil. Oils having moderate viscosity, low volatility, and high flash point may be preferred.

[0037] The coating composition may be used to coat inorganic or organic fertilizers. The fertilizer may be a plant nutrient selected from the group consisting of compounds of primary macronutrients (Nitrogen, Phosphorous, and Potassium), secondary macronutrients (Calcium, Sulfur, and Magnesium), micronutrients (Boron, Chlorine, Copper, Iron, Magnesium, Molybdenum, and Zinc), or combinations thereof, or may be any other desired fertilizer. The fertilizer may be in granular, pelletized, crushed, compacted, crystalline, agglomerated, or prilled form. The coating composition may not interfere with the fertilizer grade, the product quality, or the rate of release of the fertilizer. The coating composition may be applied to the fertilizer through spraying or through other desired techniques.

[0038] Fertilizers coated with this emulsified coating may generate less dust that those coated with current commercial products. In addition, fertilizers coated with this coating may cake less than those coated with current commercial products. This reduction in caking tendency was unexpected.

[0039] The invention can be further explained by reference to the below-described examples.

EXAMPLES

[0040] During testing, fertilizer was heated to 60 C (140 F) prior to coating. The coating agents were around 85 C (185 F) at the time of application. The coating agents were applied at dosage rates of 4 lbs./ton and 8 lbs./ton. After application, the coated fertilizer was allowed to cool to room temperature before running caking tests and dust control tests.

[0041] Dust levels were determined by using a dust tower described in U.S. Pat. No. 6,062,094 to Carlini et al. In this test, the fertilizer particles are passed through a counter current air stream and are agitated at the same time by passing through a series of grates. The dust particles are collected on a filter and the dust levels determined by measuring the changes in weight on an analytical balance. This test is believed to be accurate to within +/−50 ppm. Dust level were determined both initially after treatment with the coating formulations and again after aging for four weeks. This aging process is used to simulate the increase in dust levels normally encountered during the storage of fertilizers.

[0042] Caking levels were determined by using a compaction instrument to evaluate the strength required for breaking the caked fertilizer. In this test, the fertilizer particles were placed into the conditioning chamber where controlled temperature, humidity, and pressure conditions were used to induce caking. In particular, the fertilizer coated at a rate of 8 lbs./ton was exposed either 75% relative humidity at 35 C or 65% relative humidity at 30 C under 5 pressure for 19 hours. Caking test cells were then cooled to room temperature for an additional three hours before measurements were taken. The caked fertilizer particles were placed under a probe attached to a digital force gauge. The probe was lowered at a controlled rate into the fertilizer granules to a depth of ½ inch. The force required to break up the caked fertilizer was recorded from the force gauge and is a measurement of the extent of caking. Uncoated fertilizer was tested using the same procedure and conditions as a control.

[0043] The Examples below demonstrate improved dust control of fertilizer coated with VTAE or a coating comprising VTAE and bitumen compared to uncoated fertilizer, and comparable levels of dust control when compared to fertilizer coated in bitumen without VTAE. The Examples also demonstrate improved caking resistance of fertilizer coated with VTAE compared to both uncoated fertilizer and fertilizer coated with a bituminous coating without VTAE. Thus, coatings containing VTAE may offer increased resistance to caking without losing the dust control benefits of a bituminous coating.

Example 1

[0044] Five types of VTAE coatings, designated VTAE #1 through VTAE #5, were tested for dust control on nitrogen phosphorus sulfur (NPS) fertilizer. VTAE #1 and VTAE #2 are two types of VTAE alone, while VTAE #3, #4, and #5 are combinations of VTAE #1 and bituminous dust control agents. Uncoated fertilizer, two types of bituminous dust control agents without VTAE, designated DCA #1 through DCA #3, and two bituminous blends, designated Blend #1 and Blend #2, also without VTAE, were also tested for comparison. Such bituminous coatings are discussed in the related U.S. patent application Ser. No. 15/404,348 (“the '348 application”).

[0045] In the first dust test, uncoated NPS fertilizer had an initial dust level of 325 and a four week total of 455. The three types of dust control agents were tested at coating rates of both 4 lbs. and 8 lbs. and were each compared to a VTAE coating with a similar viscosity, also applied at 4 lbs. and 8 lbs. The results are shown in Table 1 and FIGS. 1, 2, and 3.

TABLE-US-00001 TABLE 1 1 2 4 Coating Viscosity of Coating Initial Week Weeks Weeks Totals Agent/Dose (cps, 140 F.) (ppm) (ppm) (ppm) (ppm) (ppm) Control 325 55 38 37 455 4 lbs. DCA #1 135 87 82 52 65 285 8 lbs. DCA #1 135 20 48 50 53 172 4 lbs. VTAE #3 130 62 75 57 52 245 8 lbs. VTAE #3 130 27 65 57 98 247 4 lbs. DCA #2 700 30 33 23 47 133 8 lbs. DCA #2 700 12 18 15 17 62 4 lbs. VTAE #4 702 30 37 38 58 163 8 lbs. VTAE #4 702 5 25 20 52 102 4 lbs. DCA #3 1250 32 17 17 27 92 8 lbs. DCA #3 1250 8 5 12 20 45 4 lbs. VTAE #5 1207 32 22 28 50 132 8 lbs. VTAE #5 1207 18 60 20 47 145

[0046] As shown in Table 1, all three VTAE coatings tested showed significant improvement in dust levels both initially and in total compared to uncoated fertilizer. In particular, VTAE #3 had a four week total of 245 at a 4 lbs. coating rate and 247 at an 8 lbs. coating rate; VTAE #4 had a four week total of 163 at a 4 lbs. coating rate and 102 at an 8 lbs. coating rate; and VTAE #5 had a four week total of 132 at a 4 lbs. coating rate and 145 at an 8 lbs. coating rate. All were much lower than the four week total of 455 of the uncoated fertilizer. The VTAE coatings also showed similar dust control compared to the bituminous dust control agents tested with a similar viscosity, which were shown in the '348 application to provide improved dust control compared to other commercial coatings.

[0047] In the second dust test, uncoated NPS fertilizer had an initial dust level of 197 and a four week total of 442. Two types of VTAE were tested at coating rates of both 4 lbs. and 8 lbs., along with a blend with a similar viscosity, also applied at 4 lbs. and 8 lbs. The results are shown in Table 2 and FIGS. 4 and 5.

TABLE-US-00002 TABLE 2 1 2 4 Coating Viscosity of Coating Initial Week Weeks Weeks Totals Agent/Dose (cps, 140 F.) (ppm) (ppm) (ppm) (ppm) (ppm) Control 197 78 67 65 407 4 lbs. VTAE #1 590 32 63 105 68 268 8 lbs. VTAE #1 590 22 53 103 188 367 4 lbs. Blend #1 612 38 55 83 97 273 8 lbs. Blend #1 612 8 42 73 147 270 4 lbs. VTAE #2 1602 15 42 92 115 263 8 lbs. VTAE #2 1602 7 42 78 133 260 4 lbs. Blend #2 1620 27 38 58 87 210 8 lbs. Blend #2 1620 2 40 80 83 205

[0048] As shown in Table 2, both VTAE coatings showed significant improvement in both initial and total dust levels compared to the uncoated NPS fertilizer. In particular, the totals ranged from 260 to 367, compared to 407 for the uncoated fertilizer. This was true of both 4 lbs. and 8 lbs. coating rates and a range of viscosities. In addition, the VTAE coatings also showed similar dust control compared to the bituminous blends tested with a similar viscosity, which were shown in the '348 application to provide improved dust control compared to other commercial coatings.

Example 2

[0049] Two types of VTAE coatings, designated VTAE #1 and VTAE #2, and two bituminous blends, designated Blend #1 and Blend #2, were tested for caking strength on three types of fertilizer. VTAE #1, VTAE #2, Blend #1, and Blend #2 are all the same as those used in Example 1 above. Uncoated fertilizer was also tested for comparison.

[0050] Uncoated DAP was tested three times, and showed an average caking strength of 31.423. The two types of VTAE, as well as the two types of blends with similar viscosities, were similarly tested three times and their averages compared to the caking strength of uncoated DAP. The results are shown in Table 3, with the percent improvement in caking resistance compared to uncoated DAP shown in FIG. 6.

TABLE-US-00003 TABLE 3 DAP; 8 lbs./ton; 35° C.; 75% RH Viscosity of Replicate Replicate Replicate Coating 1 2 3 Averages Sample (cps, 140 F.) (lbs.) (lbs.) (lbs.) (lbs.) Control n/a 26.64 34.06 33.57 31.42 VTAE 590 20.35 12.57 10.63 14.52 #1 Blend 612 23.62 32.93 22.78 26.45 #1 VTAE 1600 26.52 19.51 19.21 21.75 #2 Blend 1620 51.49 36.53 22.62 36.88 #2

[0051] As shown in Table 3, VTAE #1 had an average caking strength of 14.52, for an improvement over uncoated DAP of 54%. VTAE #2 had an average caking strength of 21.75, for an improvement over uncoated DAP of 22%. Blend #1, on the other hand, showed an average improvement of 16%.

[0052] Uncoated NPS fertilizer was similarly tested three times, and showed an average caking strength of 16.467. VTAE #1 and Blend #1 with a similar viscosity were similarly tested three times and their averages compared to the caking strength of uncoated NPS fertilizer. The results are shown in Table 4, with the percent improvement in caking resistance compared to uncoated NPS fertilizer shown in FIG. 7.

TABLE-US-00004 TABLE 4 NPS fertilizer; 8 lbs./ton; 35° C.; 75% RH Replicate Replicate Replicate 1 2 3 Averages Sample (lbs.) (lbs.) (lbs.) (lbs.) Control 19.68 15.46 14.25 16.47 VTAE 7.368 5.892 12.98 8.75 #1 Blend 14.23 11.42 22.85 16.17 #1

[0053] As shown in Table 4, VTAE #1 had an average caking strength of 16.47, for an improvement over uncoated NPS fertilizer of 47%.

[0054] Uncoated NPK was likewise tested three times, and showed an average caking strength of 30.51. VTAE #1 and Blend #1 with a similar viscosity were similarly tested three times and their averages compared to the caking strength of uncoated NPK. The results are shown in Table 5, with the percent improvement in caking resistance compared to uncoated NPK shown in FIG. 8.

TABLE-US-00005 TABLE 5 NPK; 8 lbs./ton; 30° C.; 65% RH Replicate Replicate Replicate 1 2 3 Averages Sample (lbs.) (lbs.) (lbs.) (lbs.) Control 30.05 34.49 26.99 30.51 VTAE 20.98 17.85 24.57 21.14 #1 Blend 24.77 34.96 33.01 30.91 #1

[0055] As shown in Table 5, VTAE #1 had an average caking strength of 21.14, for an improvement over uncoated NPK of 31%. By comparison, Blend #1 showed an average loss of 1%.

[0056] This set of tests demonstrates an improvement in caking strength of fertilizer coated with VTAE compared to uncoated fertilizer. It also shows an improvement in caking strength of fertilizer coated with VTAE compared to both blends.

[0057] Whereas, the devices and methods have been described in relation to the drawings and claims, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention.