Egg-tented July 179 i934 ‘ 3.9569947 . barren STATES PATEN'I‘Q OFFICE

_ 1,966,947 I NONCAKING ivnxnn mn'mrznn can Eyer, Ludwigshafcn-on-the-Rhine, Gottwald Baetz, Oggersheim, and August Herterich, _Gerthc, Germany, assignors to I. G. Farben industrie Aktiengcsellschaft, Frankfort-on-the- ‘ . Main, Germany No Drawing. Application October 19, 1931, Serial No. 569,834. In Germany October 20, 1930 9 Claims. (01. 71-9) - 'The present invention relates to non-caking ,insu?icient for the complete conversion into ‘fer mixed fertilizers containing ammonium nitrate ric salts. V _ and a process for their production. ‘ It is not necessary to employ the additional Ammonium nitrate and many mixed fertilizers salts in a completely or partially dehydrated 55 containing ammonium nitrate have the objec-' state, but good results are also obtained by the tionable property of'hardening more or less employment of the completely hydrated salts, rapidly and strongly when stored, thereby losing provided a drying operation is applied after the 65 their capacity for being scattered. In order to addition of the iron or aluminium salts. obviate this objection it has already been pro-, . It is immaterial at which stage of the process it» posed to .add to the mixed. fertilizers small or in which form the said salts are added; for amounts of salts capable of combining with example they may be added in a dissolved or water of crystallization as for example mag solid form to the dissolved or fused fertilizers or 70 nesium salts or sodium salts; these additional mixed in the wholly or partly dehydrated form substances certainly prevent the hardening of with the ?nishedfertilizers. The additional salts ' ‘it the salts to a certain extent when stored, but may also be sprayed onto the fertilizers“ in the they have the objedtion that they increase the form of concentrated solutions. In this case the hygroscopicity of thesalts to a greater or less sprayed product is subjected to a subsequent 75 extent. treatment by drying at elevated temperature. We have now found that fertilizers having a theThe present iron orinvention aluminium prevent salts usedhardening according of the to go substantially better capacity for storage than the products obtained with the said additional mixed fertilizers much more eillciently than other substances are obtained-by adding to or incor salts which have previously been suggested for 80 porating with the mixed fertilizers containing this purpose, as for example magnesium salts. ammonium nitrate salts of aluminium or of iron This is evident from a series ‘of comparative tests '25 which in the anhydrous state have the property in which samples of ammonium sulphate nitrate of being capable of taking up water as water of with diiferent additions were examined for the crystallization. The salts of iron or aluminium same time under exactly the same conditions as 85 ' which are capable of taking up water as water regards temperature, atmospheric moisture and of crystallization need not be added as such, but pressure load. Thereby the samples hardened ‘ 39 may also be formed by the interaction of an iron to some extent so that a certain pressure was or aluminium compound with a component of the necessary to break down the hardened massesf. This breaking pressure is a direct measure for mixed fertilizer. It is preferable to select sul 90 phates as the additional substances because these the degree of hardening, the ‘pressure being the have a particularly strong capacity for combin higher the more the mass hadvhardened during ing with water. In the presence of ammonium storage. The results of such comparative ex sulphate the said metal salts form double salts; periments are given in the following table,the breaking pressure of the sample with magnesium thus aluminium ammonium alum or iron ammo 95 . nium alum is formed when aluminium sulphate sulphate being calculated as 100 relative units. or ferric sulphate respectively are used in the __ Relative ‘so presence of ammonium sulphate, and ferrous Added substance Amount breaking ammonium sulphate (Mohr’s salt) is formed added pressure when ferrous sulphate is used. These double‘ ' 100 salts may also be added to the fertilizers from . the start instead of the single sulphates and other 45 double salts containing aluminium or iron, as for example potassium aluminium sulphate (KAKSOOa) or sodium iron sulphate 105 . (‘Na-RG04) a) or sodium aluminium sulphate exert a similar action. Such sulphates may also be “formed in the mixed fertilizers by the inter ac_ion of sulphates for example those of am monium, potassium, sodium,_divalent iron, zinc 110 , or manganese, with the chlorides or nitrates of 55 aluminium or iron or also with the liquid rich in ferric hydroxide hydrosol which is obtained by

adding to ferrous sulphate containing water of ' - 15 crystallization an amount of nitric acid which is The amounts of iron or aluminium salts added :1 2 1,966,947 according to the present invention need not be to remove any water still remaining, as for ex very great. They vary as a rule between 1 and ample in a drying drum at about 100° C. 10 per cent, and preferably between 3 and 6 Example 6 per cent, by weight of the dry mixed fertilizers. The following examples will further illustrate 67 parts of commercial ferric chloride are in 80 how this invention may be carried out in prac troduced into 1000 parts of an ammonium ni tice, but the invention is not restricted to these trate melt of 97 per cent strength. After the fer examples. The parts are by weight. ric chloride has been dissolved, the mass is mixed Example 1 with a mixture of 1100 parts of crude potassium 10 chloride containing 80 per cent of KCl and 75 85 45 kilograms of wholly or partly dehydrated parts of ammonium sulphate. The mixture is pulverized aluminium sulphate are introduced then allowed to cool while being comminuted. while stirring well, into 720 kilograms of a hot Example 7 ammonium nitrate melt of about 96 per cent 15 strength. 1000 kilograms of ammonium sul 1000 kilograms of commercial ferrous sulphate phate are added to this mixture in an endless are mixed with 480 kilograms of ammonium sul screw, whereby the mass solidi?es rapidly. The phate and 510 kilograms of nitric acid of 50 per aluminium sulphate may also be mixed with a cent strength are added. - Nitric oxide is evolved part of the necessary ammonium sulphate, the and a solution of ferric ammonium alum and am 20 mixture introduced into the ammonium nitrate monium nitrate is obtained, which is evaporated 95 melt and the remainder of the ammonium sul until it has a syrupy consistency. 4 parts of this phate then added. concentrated solution are added to 45 parts of an In both cases a product having only a slight ammonium nitrate melt of 97 per cent strength hygroscopicity and an excellent capacity for and then 51 parts of ammonium sulphate are in 25 storage is obtained. troduced while mixing well, whereupon the mass Example 2 is allowed to cool. Instead of the aforesaid concentrated iron so 60 kilograms of ferrous sulphate (FGSO4.7H2O) lution, use may be made of the liquid which is in the form of a very concentrated solution and obtained by the action of 150 kilograms of nitric 30 1000 kilograms of ammonium sulphate are added acid of 62 per cent strength on 1000 kilograms of 105 to ‘750 kilograms of a hot ammonium nitrate ferrous sulphate FeSOa‘lHzO. . melt of about 92 per cent strength in an endless What we claim is:— _ . screw. The mixing of the ferrous sulphate with 1. As a new article of manufacture, mixed fer the hot ammonium nitrate alone should be avoid tilizers comprising ammonium nitrate, contain ed, since decomposition of the ammonium nitrate ing a sulphate of a metal selected from the group 110 might take place. The product is subsequently consisting of aluminium and iron, said sulphate dried and comminuted. Instead of ferrous sul being capable of taking up water as water of phate, ferrous ammonium sulphate or ferric sul crystallization, said mixed fertilizers being sub phate may be employed. stantially. as readily soluble in water as the same 40 The ferrous sulphate may also ?rst be mixed mixed fertilizers when free from said salt capable 115 in the solid form with a part of the ammonium of taking up water. sulphate, this mixture introduced into the am 2. As a new article of manufacture, mixed fer monium nitrate melt and the remainder of the tilizers comprising ammonium nitrate, containing ammonium sulphate then added. a double sulphate of a metal selected from the 45 group consisting of aluminium and iron, said 120 Example 3 sulphate being capable of taking up water as A concentrated ferric nitrate solution is pre water of crystallization, said mixed fertilizers pared by dissolving iron scraps in nitric acid. being substantially as readily soluble in water Ammonium nitrate is added in such an amount as the same mixed fertilizers when free from 50 to the solution, ?ltered if necessary, that there said salt capable of taking up water. 125 are 700 kilograms of ammonium nitrate to each 3. As a new article of manufacture, ammonium 20 to 30 kilograms of anhydrous ferric nitrate. sulphate nitrate, containing a sulphate of a The resulting mixture is worked up into ammon metal selected from the group consisting of alu ium sulphate nitrate with 1000 kilograms of am minium and iron, said sulphate being capable of monium sulphate. The resulting product is dried taking up water as water of crystallization, said 130 at about 100° C. product being substantially as readily soluble in Example 4 water ‘as ammonium sulphate nitrate itself. 4. As a new article of manufacture, ammo 1000 kilograms of ammonium sulphate nitrate nium sulphate nitrate, containing an iron sul 60 are mixed with from 30 to 40 kilograms of partly phate capable of taking up water as water of 135 or wholly dehydrated sodium aluminium sulphate crystallization, said product being substantially (NaAl(SO4)2). In order to ensure a uniform and as readily soluble in water as ammonium sulphate intimate mixing, the alum is employed in a very nitrate itself. ' ?nely divided form. This product also has a good 5. As a new article of manufacture, ammo 65 capacity for storage. nium sulphate nitrate, containing an iron dou~ 140 ble sulphate capable of taking up water as water Example 5 of crystallization, said product being substantially A hot saturated solution of magnesium alu as readily soluble in water as ammonium sulphate minium sulphate ((MgA1)2(SO4)5) is sprayed in nitrate itself. 70 the form of a ?ne mist by means of a nozzle onto 6. As a new article of manufacture, mixed 145 dry ammonium sulphate nitrate or another mixed fertilizers comprising ammonium nitrate, con fertilizer containing ammonium nitrate, prefer taining a salt of a metal selected from the group ably while the fertilizer is still hot so that the consisting of aluminium and iron, said-salt be water contained in the concentrated solution is ing capable of taking up water as water of crys to a great extent evaporated. It is advantageous tallization, said mixed fertilizers being substan 1,968,947 3 tially as readily soluble in- water as the same or aluminium and iron, said salt being capable mixed iertil'izers when free from said salt capable of taking up water as water of crystallization, of taking up water. , ‘ said mixed‘i‘ertilizers being substantially as read 7. As a new article of manufacture, mixed fer ily soluble inwater as the same mixed ferti tilizers comprising ammonium nitrate, containing lizers when tree from said salt capable of tak 80 between 1 and 10 per cent by weight, of ai-salt ing up water.‘ _ ' ' of a metal selected from'the group consisting of 9. As a new article of manufacture, ammo‘ aluminium and iron, said salt being capable oi’ nium sulphate nitrate, containing a salt of a taking up water as water of crystallization, said metal selected from the group consisting of alu- ' 10 mixed fertilizers being substantially as readily minium and iron, said salt being capable of tak-, soluble in water as the same mixed fertilizers ing up water as water of crystallization, said prod when free from said salt capable of taking up not being substantially as readily soluble in wa— ' water. ' ' ' tar as ammonium sulphate nitrate itself. 8. As a new article 01' manufacture, mixed fer tiliz‘ers comprising ammonium nitrate, contain CARL EYER. . is ing between 3 and 6 per cent by weight, of a salt GOTTWALD BAETZ. of a metalselected from the: group consisting ' ‘AUGUST HERTERICHQ >

20 95

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120

130

135

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