US3063800A - Dust control in potash products - Google Patents

Description

United States Patent Ofiiice 3,063,800 Patented Nov. 13, 1952 3,063,800 DUST CONTROL IN POTASH PRODUCTS William B. Daney, Carlsbad, N. Mex., assignor to inteb national Minerals & Chemical Corporation, a corpora- The present invention relates to a method for the con More particularly,

trol of dusting in potash products. the present invention relates to the application of oil to finely divided potash products to substantially prevent dusting.

The problem of controlling dust created by the handling of finely divided potash materials has been a universal problem. When loading or unloading such materials in large quantities, the dust thus created causes poor working conditions, loss of a large portion of the product and possible contamination of surrounding areas. For example, when loading a freight car with finely divided potash material, it is frequently necessary for the operator of the loading apparatus to wear a dust mask for protection. Sometimes the dust becomes so dense during loading and unloading operations, it is necessary to temporarily cease operation until the dust has settled. This results not only in a loss of time but also an increase in operating costs.

The problem of controlling the dusting of potash material is complicated by the light color of the material and by the necessity of future processing of the material. It will be apparent that means to prevent dusting of potash material desirably will not substantially adversely affect the color of the material and will not change the characteristics of the material to substantially affect subsequent processing.

It is a primary object of this invention to control the dusting of finely divided potash material.

It is a further object of this invention to control the dusting of finely divided potash material without substantially adversely afiecting the color of the material.

It is yet a further object of this invention to control the dusting of finely divided potash material without substantially adversely affecting the quality of the material.

An additional object of the present invention is to reduce loss of a finely divided potash material through dusting.

Another object is to improve the handling conditions of a finely divided potash material.

Still another object is to provide more eflicient operating conditions when handling a finely divided potash material which creates a large amount of dust.

According to the present invention, finely divided potash material is contacted with a small amount of viscous mineral oil which conforms to critical specifications. The

potash material treated in accordance with this invention may be subjected to normal handling incident to loading Band unloading operations and the like and will not exhibit any pronounced tendency to dust. The color integrity of the material is maintained and the quality of the material is preserved.

As employed herein, potash materials embrace potassium chloride, potassium sulfate and similar salts of potassium. The term potash has attained a recognized meaning in the art.

The mineral oils which are employed in the practice of the present invention are characterized by a pour point of from about 30 F. to about 120 F., a viscosity from about 50 SSU to about 350 SSU at 100 F., a distillation temperature above about 500 F., a distillation end point below about 1000 F., a distillation residue of not more than about 15%, and an aromatic content of not more than about 60%.

Preferred mineral oils which are employed in the practice of this invention are characterized by a pour point of from about 35 F. to about 100 F., a viscosity from about 100 SSU to about 310 SSU at 100 F., a 10% distillation temperature from about 500 F. to about 700 F., a distillation end point below about 900 F., a distillation residue of not more than about 15%, and an aromatic content of not more than about 50%.

From the foregoing specifications it will be apparent that an asphalt base oil conventionally employed for dust control on highways is inapplicable, inter alia, be cause of adverse effects to the color of potash products. Crude oils of various types are too wide in boiling range and often too high in asphaltic content for optimum dust control performance. Gasoline and kerosene fractions, as well as diesel oil fractions, have too low a viscosity to prevent dusting. Only those oils which conform to the above specifications have been found suitable for this invention.

Suitable oil fractions for use in the present invention can be obtained from lubricating oil stocks in paraffin on wax distillates which result from the distillation of crude petroleum oils and the rcdistillation of cracked petroleum,

stocks and heavy petroleum distillates. These materials provide the desired results of the present invention pro refining crude petroleum oil from Eddy and Lea Coun-' ties, New Mexico. This fractionator still bottoms is available from the Malco Refinery, Artesia, New Mexico.

In obtaining such a material, crude oil is first distilled at reduced pressure until an overhead vapor temperature of about 700 F. is obtained. The overhead fraction obtained by vacuum distillation at about 700 F. is termed vacuum gas oil. This stock oil is fed to a catalytic cracking unit from which fractionator bottoms, a

preferred petroleum fraction for dust control, is obtained.

Table I below identifies five representative oils which conform to the specifications set forth above and which provide excellent dust control for potash materials. Oil A represents the fractionator still bottoms discussed above. It will be apparent that the oils embraced by this invention contain a substantial paraflinic hydrocarbon content.

TABLE I Oil A B G D E Distillation range:

Initial boiling pt., F 265 585 648 580 600 End point, F 875 975 1, 000 1, 000 1, 000 Distillation recovery, percent 85 97. 5 85 85 85 Viscosity:

F., SSU 310 300 150 61 290 F, SSU--- 153 148 78 46 132 210 F, SSU 51 40 34 49 Pour point, F 80-90 90-100 Retroactive index 1. 543 1. 520 1. 530 1. 470 1. 512 API gravity 18.5 21.2 17.8 35.5 22.5 Specific gravity 60/60 F .9433 9267 9478 8473 9188 Ash, percent 0 0 Molecular weight 302 355 255 275 322 Gonradson 0, percent 2-4 0.3 Sulfur, percent 1. 93 0. 80 1. 34 0 2. 20 Paraffin and naphthene 50. 3 56.0 40 86 52 Aromatic 49. 5 44. 0 60 14 48' Unsulfonatable material..- 60 70 It will be apparent that blends of oils may be employed in the present invention provided that the characteristics of the blend conform to the specifications of this invention. For example, a blend of a light lubricating oil stock and a crude oil fractionator bottom in a volumetric ratio ofabout 1 to about 4 may be employed to provide a desirable dust control. In such a blend it is advantageous to employ a distillate fraction in conjunction with a fractionator bottom fraction. In this manner it is possible to maintain a maximum viscosity yet maintain a minimum proportion of color forming bodies in the mineral oil. The precise choice of stocks and the proportions in which they are employed is readily within the skill of the art.

In the event that the mineral oil exhibits an undesirable odor, a small amount of another oil such as pine oil can be admixed with the mineral oil. Proportions of about 1 gallon of pine oil per 1,000 gallons of mineral oil effectively overcomes any undesirable odor of the mineral oil without adversely afiecting either the quality or color of the potash material.

The mineral oil is applied in amounts from about 0.25 to about 5 gallons per ton of potash material to be treated. Somewhat higher proportions may be employed but adverse effects to the color and quality of the product may result. Conversely, a somewhat lower proportion may reduce dusting but will not substantially prevent dusting. The mineral oil preferably is employed in amounts from about 0.5 to about 1.5 gallons per ton of potash material.

Mixing of mineral oil with the potash materials may be accomplished in any manner which will provide a substantially even distribution of the oil throughout the potash materials. Commercial spray apparatus including paint spray apparatus advantageously can be employed. A thin layer of potash on a moving belt can be contacted with an oil spray to achieve the oil coating of this invention. It will be apparent that other means also can be employed to provide the coated product of this invention. No subsequent heat treatment or the like is required or desirable.

In one desirable method of admixing materials, potassium sulfate which is to be loaded for shipping in large quantities is admixed with a mineral oil as hereinabove described by spraying the potash with the mineral oil at the discharge end of a conventional pan heater used in standard loading operations. The oil-treated potassium sulfate on the way to a receiving car subsequently is passed through a screw conveyor wherein additional mixing is accomplished.

The following specific embodiments are included for purposes of exemplification only and in no way are intended to limit the scope of this invention.

Example I I Forty tons of potassium sulfate were sprayed with 47 gallons of the above described oil A. The sprays were located on the discharge end of a pan feeder in a loading operation. The oil-treated material was subsequently passed through a screw conveyor in such a manner that the mixing of the potassium sulfate and the fractionator bottoms was completed.

The treated material, as well as an equal quantity of untreated potassium sulfate, was loaded and shipped to a distant point. The treated material created essentially no dust in both the loading and subsequent unloading operations, Whereas the untreated material dusted to such an extent that about 6% of the product was lost.

Representative samples amounting to 300 pounds of the treated potassium sulfate and 300 pounds of untreated potassium sulfate were subjected to a screen analysis, the results of which appear in Table 11 below.

TABLE Regular Oiled KzSO; K2304 i6 mesh 3 i 8-..- 5 -|l0 l0 7 +14 12 9 +20 17 13 +28 25 21 +35 38 34 +48. 47 44 +05 59 57 +100 75 72 --l00 25 28 Example 11 TABLE III Percent increase in calrlng tendency of treated potassium sulfate Ratio 1 K20:

Although these figures show a negligible increase in caking tendencies of the treated product, the lumps formed were approximately half as hard as those formed by the untreated sulfate material. Accordingly, the slight increase in caking of potassium sulfate-superphosphate mixture was not significant.

Example III Granulation tests were carried out by formulating the potassium sulfate treated with oil A into a 5-10-15 (N, P, K) fertilizer. The formula for this grade was as follows:

81 lbs. 60/60 B. H 271 lbs. 37% nitrogen UAL-C solution 1,025 lbs. 19.5% superphosphate I 590 lbs. sulfate of potash 193 lbs. dolamite filler Water The granulating test consisted of granulating the above formula using various amounts of Water to effect different degrees of granulation. The use of sufiicient water or liquid medium provided acceptable granulation.

The mineral oil treatment of the potassium sulfate did not change the instantaneous solubility nor the wetability of the material to any measurable degree. Instantaneous solubility was found to be exactly the same for both the untreated and treated materials. The oil treatment also did not change the analysis, as both the treated and untreated potassium sulfate showed an analysis of 50.32% K 50 Since obvious modifications of this invention will be apparent to those skilled in the art, it is intended that this invention be limited only by the scope of the appended claims.

I claim:

1. The method of controlling dusting of finely-divided potash which consists essentially of intimately admixing finely-divided potash with from about 0.25 to about 5 gallons of mineral oil per ton of potash to substantially coat said potash with said mineral oil, said mineral oil being characterized by a pour point of from about 30 F. to about 120 'F., a viscosity of from about 50 SS to about 350 SSU at 100 F., a distillation temperature above about 500 F., a distillation end point below about 1000 F a distillation residue of not more than about and an aromatic content of not more than about 60%.

2. The method of claim 1 in which the mineral oil is employed in amounts from about 0.5 to about 1.5 gallons per ton of potash.

3. The method of claim 1 wherein the mineral oil is a petroleum oil.

4. The method of controlling dusting of finely-divided potash which consists essentially of intimately admixing finely-divided potash Withfrom about "0.25 to about 5 gallons of mineral oil per ton of potash to substantially coat said potash with said mineral oil, said mineral oil being characterized by a pour point of from about 35 F. to about 100 F., a viscosity of from about 100 SSU to about 310 SSU at 100 F, a 10% distillation temperature from about 500 F., to about 700 F., a distillation end point below about 900 F, a distillation residue of not more than about 15% and an aromatic content of not more than about 50%.

5. The method of claim 4 wherein the mineral oil is employed in amounts from about 0.5 to about 1.5 gallons per ton of potash.

6. The method of claim 4 wherein the mineral oil is a petroleum oil fraction.

7. The method of claim 4 wherein the mineral oil contains a small amount of pine oil.

8. The method of controlling dusting of finely-divided potash which consists essentially of intimately admixing finely-divided potash with from about 0.25 to about 5 gallons of mineral oil per ton of potash to substantially coat said potash with said mineral oil, said mineral oil being a petroleum fractionator still bottoms characterized by a pour point of from about 80 to 90 F., a viscosity of about 310 SSU at 100 F., a 10% distillation temperature of about 510 F., a distillation end point of about 875 F., a distillation residue of about 15 and an aromatic content of less than about 5 0%.

*9. The method of claim 8 wherein the mineral oil is employed in amounts of from about 0.5 to about 1.5 gallons per ton of potash.

10. The method of claim 8 wherein the mineral oil contains a small amount of pine oil.

11. A nondusting potash material which consists essentially of finely-divided potash substantially coated with from about 0.25 to about 5 gallons per ton of potash of a mineral oil characterized by a pour point of from about 30 F. to about 120 F., a viscosity of from about SSU to about 350 SSU at 100 F., a 10% distillation temperature above about 500 F, a distillation end point below about 1000 F., a distillation residue of not more than about 15% and an aromatic content of not more than about 12. The finely-divided potash of claim 11 containing from about 0.5 to about 1.5 gallons of mineral oil per ton of potash.

13. A nondusting potash material which consists essentially of finely-divided potash substantially coated with from about 0.25 to about 5 gallons per ton of potash of a mineral oil characterized by a pour point of from about 35 F. to about F., a viscosity of from about 100 SSU to about 310 SSU at 100 F., a 10% distillation temperature from about 500 F. to about 700 F, a distillation end point below about 900 F, a distillation residue of not more than about 15% and an aromatic content or" not more than about 50%.

14. The finely-divided potash of claim 13 containing from about 0.5 to about 1.5 gallons of mineral oil per ton of potash.

References titted in the tile of this patent UNITED STATES PATENTS 1,946,863 Koenders Feb. 13, 1934 2,164,089 Shumaker June 27, 1939 2,390,406 WegSt et a1. Dec. 4, 1945 2,413,491 Fajans Dec. 31, 1946 2,734,002 Schoeld et al. Feb. 7, 1956

Claims (1)

1. THE METHOD OF CONTROLLING DUSTING OF FINELY-DIVIDED POTASH WHICH CONSISTS ESSENTIALLY OF INTIMATELY ADMIXING FINELY-DIVIDED POTASH WITH FROM ABOUT 0.25 TO ABOUT 5 GALLONS OF MINERAL OIL PER TON OF POTASH TO SUBSTANTIALLY COAT SAID POTASH WITH SAID MINERAL OIL, SAID MINERAL OIL BEING CHARACTERIZED BY A POUR POINT OF FROM ABOUT 30* F. TO ABOUT 120*F., A VISCOSITY OF FROM ABOUT 50 SSU TO ABOUT 350 SSU AT 100*F., A 10% DISTILLATION END POINT BEPERATURE ABOVE ABOUT 500*F., A DISTILLATION END POINT BELOW ABOUT 1000*F., A DISTILLATION RESIDUE OF NOT MORE THAN ABOUT 15% AND AN AROMATIC CONTENT OF NOT MORE THAN ABOUT 60%.