Aug. 17, 1971 J., F

Aug. 17, 1971 J., F. ROUNSAVILLE 3,600,153 NH4NO-KHSO4. FERTILIZER COMPOSITION Filed Aug. 19, 1968 OO 23O WEST PERCENT NH4NO3 25 O 2O 3O LIQUID QUID O PLUS NH4NO3 PLUS KHSO4. 90 25 5O 75 OO WEIGHT PERCENT KHSO4. F/G. / MOLTEN NH4NO3 PRODUCT O INVENTOR. JAMES F ROUNSA VILLE BY Cu/ &c. we (c. vil Aieze & Av. PATENT ATTORNEY 3,600,153 United States Patent Office Patented Aug. 17, 1971 2 and percent S=23.5y. The two-component mixture can be 3,600,153 NHNOKHSO, FERTILIZER COMPOSITION ammoniated, as will be further explained later herein, James F. Rounsaville, Ponca City, Okla., assignor to and in the event of such ammoniation in stoichiometric Continental Oil Company, Ponca City, Okla. amount, the nutrient values will be: Filed Aug. 19, 1968, Ser. No. 753,349 percent N= (35-24.8y)/(1--0.124y) int, C. C05c 1/00 U.S. C. 71-59 3 Claims percent K2O=34.7y/(1--0.124y) and percent S=23.5y/(1.0124y) ABSTRACT OF THE DISCLOSURE O Other salts of fertilizer value, such as potassium sulfate, Melt fertilizer comprising potassium bisulfate and am potassium nitrate, monopotassium phosphate, monoam monium nitrate is prepared by acidulating KC1 or K2SO4, monium phosphate, ammonium bisulfate, and ammonium removing by-product HCl if formed, admixing the result polyphosphate, can be dissolved or suspended in the ing potassium bisulfate with ammonium nitrate in the binary melt, and subsequently processed into suitable molten state to obtain a eutectic mixture of NH4NO3 and 15 fertilizer form, although of course the equations just given KHSO4, which is cooled to the solid product. While in for nutrient value content will not be valid in such the molten state, the eutectic mixture may be ammoniated instances. and/or granulated. Likewise other salts may be added to Attention is now directed to FIG. 2, which illustrates the molten mixture prior to its solidifying. schematically an integrated fertilizer process of the pres 20 ent invention. According to the invention, a potassium salt capable of being digested with a mineral acid provides the DISCLOSURE potassium source of the fertilizer product. The preferred This invention relates to a novel fertilizer composition, salts, because of their availability, are potassium chloride and to a method for manufacturing same. 25 and potassium sulfate. This salt is introduced via conduit It is well recognized that potassium is one of the basic 1 to a reactor 2. The main product desired from reactor nutrients for a fertilizer or plant food, in addition to phos 2 is potassium bisulfate, KHSO4, along with other salts phorus and nitrogen. Further, sulfur is becoming recog soluble in molten ammonium nitrate if desired. Acid is nized as a fourth essential element of plant food. Potas introduced by way of conduit 3, and either the acid or the sium occurs widely in nature, primarily in the forms of 30 potassium salt must include sulfate ion to form the de chloride and sulfate. However, many plants are sensitive sired KHSO4. Thus, although sulfuric acid is preferred, it to chloride, and thus naturally occurring potassium chlo can be used in admixture with other acids, and in the ride is generally subjected to some treatment prior to its event of using K2SO4 as the potassium salt, sulfuric acid use in fertilizer. need not be used at all, other suitable acids for converting It is an object of this invention to provide a novel 35 KSO. to KHSO including nitric and phosphoric. Potas fertilizer composition containing at least the nutrients sium salt by way of conduit 1 and acid by way of conduit N, K and S. Another object of the invention is to provide 3 should be used in about the proper stoichiometric a method for preparing a fertilizer having high nutrient amounts to yield the desired KHSO4 by way of conduit 4. analysis, good physical characteristics, and a flexibility Certain reactants, for example potassium chloride and of grade. 40 sulfuric acid, yield also a gaseous by-product, in this Other aspects, objects, and the several advantages of instance hydrogen chloride, which is removed from re the invention will become apparent upon study of this actor 2 by way of conduit 5. Reactor 2 can preferably disclosure, the appended claims, and the drawing, in comprise simply a vessel containing one or more agitators. which: From reactor 2, the KHSO4 is passed by way of con FIG. 1 represents the phase diagram for the binary 45 duit 4 to a blending zone 6, wherein it is mixed with the system KHSO-NH4NO3, and desired amount of ammonium nitrate introduced by way FIG. 2 represents a schematic flow diagram of the of conduit 7. The ammonium nitrate can be introduced method of the present invention. in the solid state, but it is preferably introduced as a melt. According to the invention, it has been discovered that Blender 6 can comprise a vessel with one or more agita potassium bisulfate, KHSO4, and ammonium nitrate in 50 tors, or other suitable blending equipment such as a pug molten state form a simple eutectic system, the eutectic mill. Minor amounts of other fertilizer salts, such as being at about 52 weight percent KHSO4 and melting at monoammonium phosphate, monopotassium phosphate, only about 101° C. The molten mixtures are reasonably or phosphoric acid, can be added to the melt in blender 6 stable. It has further been discovered that fertilizers based . by way of conduit 8. on such molten mixtures can be formulated using a com 55 The melt produced in blender 6 is then passed by way mon potassium salt as a starting material and, in the case of conduit 9 to a finishing operation, which can comprise of using potassium chloride as a starting material, that the a granulator or a prilling operation 10. If a granulator is resulting fertilizer is relatively chloride-free. used, the product can be ammoniated therein, which Referring now to the drawing, FIG. 1 illustrates the process is known in the art, with ammonia introduced by phase diagram for the system KHSOA-NH4NO3. As can 60 way of conduit 11. Cooling of the melt to the solid state be seen, the eutectic mixture at about 52 weight percent also occurs in vessel 10. KHSO melts at about 101° C. The melting point of pure Product removed by way of conduit 12 is of high ammonium nitrate is about 169.6. C., and that of pure analysis, can be tailored over a wide range of grades, and KHSO about 210° C. Two-component compositions of has good physical characteristics including intimate ad the desired concentration can be prepared by simply heat 65 mixture of the components. A chloride-free fertilizer can ing a mixture of the two solids, in appropriate amounts, to be made without the use of water during granulation. above the melting point, and then cooling to below 101 The invention will now be further illustrated by refer C.; the molten mixture can be prilled, granulated, or ence to the following examples. otherwise treated prior to cooling. Such a two-component Example 1 mixture will contain the following nutrient values, as 70 suming pure food components, where y is the weight frac One hundred and forty-four parts of KHSOA are added tion of KHSO4: percent N=35-35y, percent K2O=34.6y, to 100 parts of molten NH4NO3. The temperature is 3,600,153 3 4. allowed to fall to 120° C. as the KHSO4 dissolves. The moniator-granulator to give a solid with grade 22-17-11. melt is granulated in an ammoniator-granulator to give a The solid has the N, P, and K uniformly distributed in solid product which has a grade of 19-0-19. The resulting each hard granule. solid is relatively hard and less deliquescent than am In order to demonstrate the solubility of various other monium nitrate. fertilizer salts in the melt, a melt of 50 weight percent Example 2 KHSO4 and 50 weight percent NH4NO at 170° C. was Thirty-seven parts of KHSO are added to 100 parts of made up. For comparison, solubilities of the salts in pure molten NH4NO3. The temperature is allowed to fall to NH4NO3 is also included. 140° C. as the KHSO dissolves. The melt is granulated O Solubility in in an ammoniator-granulator to give a solid product with NH4NO3- Solubility in a grade of 27-0-9. KHSO4 wt. NH4NO3, wt. Example 3 Salt, percent percent K2SO4------ 15 O Seventy-four parts of KCl are added to 100 parts of KNO3. - 10 6 KHPO - 10 21 97% sulfuric acid. The mixture is heated until all of the 5 KC------ (1) 6 HCl and most of the water have been driven off. Twenty NEHH2PO4- - - - 50 50 eight parts of NH4NO are added to the resulting melt NH4HSO4---------------------- (2) (2) of KHSO4. The melt is cooled to 170° C. and granulated Annonium polyphosphate 3----------- (2) (2) to give a solid product. Reacts to evolve gas. Completely miscible. Example 4 20 3 TWA's 16.0-61.6-0 from furnace acid. Two hundred parts of KHSO and 112 parts of Except for K2SO4 the solubility of potassium salts is re NHHPO are added to 100 parts of molten NH4NO3. duced upon addition of KHSO to NH4NO3. However, The temperature is kept about 150° C. The resultant melt addition of KHSO4 to NH4NO appears to increase the is granulated in an ammoniator-granulator to give a solid solubility of ammonium salts. The large solubility of product with a grade of 15.8-15.8-15.8.

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