Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
  • B01J2/30—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic using agents to prevent the granules sticking together; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
  • C01C1/00—Ammonia; Compounds thereof
  • C01C1/18—Nitrates of ammonium
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B23/00—Compositions characterised by non-explosive or non-thermic constituents
  • C06B23/009—Wetting agents, hydrophobing agents, dehydrating agents, antistatic additives, viscosity improvers, antiagglomerating agents, grinding agents and other additives for working up

Definitions

• ABSTRACT A p rilled ammonium nitrate composition ha ving and wherein R and R each represent alkyl groups having 10 to 20 carbon atoms and R is an alkylene group having one to two carbon atoms, which composition is characterized by improved anti-caking and anti-scattering properties,
• the present invention relates to a prilled ammonium nitrate composition having improved anti-caking and anti-scattering properties and to a method of making the same.
• Ammonium nitrate is known to exist in several different crystalline structures, depending upon tempera- 'ture. Each of these structures are characterized by a different water solubility, specific volume and degree of hygroscopicity. As the ammonium nitrate is subjected to cycling across the crystal structure transition temperature, therefore, it experiences variations in solubilities, specific volume and hygroscopicity. If the ammonium nitrate is in the form of prills or small, spherical, usually hollow, particles, as are commonly used for various commercial and agricultural purposes, the prills tend to absorb increasing amounts of moisture from the air, and tend to cake into a non-flowable mass.
• Another object of the present invention is to provide a method of making the prilled ammonium nitrate composition having such improved anti-caking and antiscattering properties.
• At least one anti-caking agent selected from the group consisting of:
• R] and R ⁇ each represent alkyl groups having to carbon atoms and R represents an alkylene group having one to two carbon atoms.
• Another object of this invention is accomplished by aaaiiirg *iafinezr'airrate'aasrammg Tie l0 pr'cnt'by weight of water, at a temperature of 40 to C., adding a drying aid, drying at a temperature higher than said aerating temperature and blending the obtained granular ammonium nitrate with:
• At least one anti-caking agent selected from the group consisting of:
• R R and R are as defined above.
• a particular petroleum hydrocarbon and anti-caking agent are blended with prilled ammonium nitrate.
• the petroleum hydrocarbon used herein should have a bom ng point of greafer thanm c farid a r neitirfg point of less than 20C., preferably less than 0C.
• Suitable hydrocarbons include the distillates having average boiling points of 200 to 300C. obtained by atmospheric distillation of crude oil; the liquid paraffins pre pared by dewaxing a wax containing fraction obtained by vacuum distillation of paraffinic crude oil; the processing oils, such as cutting oil, quenching oil, etc.; the light lube oils, such as spindle oil, refrigerating oil, turbine oil, etc., and mixtures thereof.
• Petroleum hydroc afbons having melting points of more than 20C. are
• the quantity of the petroleum hydrocarbon used is too small, the quantity of anti-caking agent adhering to the prilled ammonium nitrate will be too low and the anti-scattering effect of the agent will be too small.
• the quantity of additive is too large, the prilled ammonium nitrate admixed with the additive will be so wet that handling can become difficult. Therefore, it is desirable to use the petroleum hydrocafbo n in amounts of from 0.05 to 1.0 percent 52155 on the weight of the prilled ammonium nitrate.
• the anti-caking agent used in the present invention may be selected from at least one of:
• Suitable salts of group (a) include magnesium stearate, barium stearate, zinc oleate, copper palmitate, aluminum stearate, cadmium oleate, calcium stearate, magnesium oleate, etc.
• Magnesium stearate is most preferred.
• the metallic salts of fatty acids having carton contents of less than six carbon atoms, or melting points of below 40C., are not desired since their anticaking effects are low and/or they tend to melt due to the rising of temperature during storage so that caking of the prilled ammonium nitrate can occur.
• Suitable compounds of group (c) include, for example, methylene bispalmitylamide, methylene bisstearoamide, ethylene bis-stearoamide, a formaldehyde condensate of palmitic acid amide and stearic acid amide, etc. or mixtures thereof.
• the quantity of anti-caking agent blended therewith is too small, sufficient anti-caking effects cannot be obtained. If excess amounts are used, no significant improvements in anti-caking effects and antiscattering effects can be expected.
• prilled ammonium nitrate as a raw material for producing such explosive compounds as ANFO, a large excess of anticaking agent is actually detrimental, since it can result in reductions in explosive efficiency.
• the petroleum hydrocarbon is first dsitributed and homogeneously mixed withe the prilled ammonium nitrate in an available mixer, such as a rotary drum, and subsequently the anti-caking agent is distributed and mixed thereto in the same manner;
• the petroleum hydrocarbon and anti-caking agent are simultaneously distributed and mixed homogeneously with the granular or prilled ammonium nitrate.
• the prilled ammonium nitrate used in the present invention may be either high density or low density prilled ammonium nitrate. However, the latter is more preferable when the prills are being used as raw materials in the preparation of such explosive compounds as ANFO. The lower the water content, the greater will be the anti-caking properties of the prilled ammonium nitrate.
• the prills are obtained by spraying a molten ammonium nitrate containing, for example, 2 to 10 percent, by weight, of water from the top of a prilling tower of several tens meters in height. The prills are then dried at a temperature of 80-l20C. to
• One method of efficiently drying the prills is, for example, to aerate the prills in an atmosphere of an inert gas, for example air, at a temperature of 40to 90C. and then, if necessary, adding a drying agent and subjecting the prills to an aging treatment. Good results are attainable if the aeration is carried out at a temperature of 40 to C., preferably 60 to 90C. If the temperature is lower than 40C. drying of the granulate will not be sufficiently complete. If higher temperatures are used, no significantly better results will be expected and it will merely be economically disadvantageous from the viewpoint of energy consumption. Aeration usually requires more than 5 minutes, and preferably between about 10 to 30 minutes.
• One method of effecti r ig the above aeration is for example, to place the ammonium nitrate onto a perforated plate, and fluidize it by air blasts from an aperture.
• Another suitable method is to pass the ammonium nitrate on a moving belt through an aeration room.
• Still another method is to pass air into a rotating rotary containing the prills.
• Suitable inert gases which can be used in this treatment include air, nitrogen, carbon dioxide, etc., although it is generally sufficient to use air.
• the required rate of inert gas is commonly greater than 10 cm/sec., and preferably within the range of to 300 cm/sec.
• the relative humidity of the inert gas the better it is, the relative humidity need only be below the critical humidity of the prilled ammonium nitrate.
• the favorable effect of aeration treatment is believed to be due to the fact that a relatively large size (10 to 20p.) aperture is formed on the surface layer of the ammonium nitrate particles due to the contact with inert gas.
• the permeation of the drying aid into the interior of the ammonium nitrate particle therefore, is quite easy.
• the aerated prill is preferably subsequently admixed with the drying aid.
• Suitable drying aids used herein include, for example,
• R represents a saturated or unsaturated chain y sa adiwlbavins eiehttq ..8..qetbq at m or its derivative, or, forms an inorganic or organic salt of said amines, preferably an amine nitrate;
• R R and R each represent methyl or ethyl, and X represents chlorine or bromine, and R is as defined above;
• n is an integer of one to 20;
• R is an alkyl group having eight to nine carbon atoms
• Prilled ammonium nitrate is prevented from partially powdering during the drying step by using one of these drying a ids. i a rticuiarly good results are attained with alkylamine orits saltsfshown in (1) The result is that prilled ammonium nitrate having improved antiscattering property is obtained, in good yields.
• drying agents include dodecylamine or its nitrate, octadecyiamine or its nitrate, lauryltrimethylammonium-chloride, poiyoxyethylenestearylether, polyoxyethyleneoctylether, polyoxyethylene nonyiether, polyoxyethylene sorbitane monooleate, laurylpicolinium chloride, sodium iaurylsulfate, sodium octylsulfate, polyoxyethylene octylamide, polyoxyethylene stearylamide, oleic acid amide, sodium sulfonate, polyethyleneglycoi monostearate, sorbitan monostearate, poiyoxyethylene octadecylamine, laurylbetain, acetylpyridium chloride, etc.
• drying agents may be used in any concentration in a solution, such as, for example, an aqueous solution, alcohol solution, or benzene solution, they are desirable used as a solution in amounts of l to percent, by weight, in concentration, in order to be uniformly distributed over the ammonium nitrate.
• the amount of drying aid should be added in amounts of from 0.01 to 1.0 percent and preferably 0.02 to 0.06 percent based on the weight of the prilled ammonium nitrate. If one of the above alkylamines or salts thereof are used, it is used in amounts of 0.2 to 0.5 percent, by weight.
• the drying aid may be introduced by being sprayed onto the particle surface of the prilled ammonium nitrate. This is accomplished, generally in a suitable mixer, such as a rotary drum, or the like. This spray adding may be carried out stepwise, once, twice,
• the addition of the drying agent may be done either immediately after the aeration treatment, i.e., while the particles are still at elevated temperatures, or after the particles are cooled to room temperatures.
• the aging treatment is to permeate the drying agent from the surface of the ammonium nitrate prill sufficiently into the interior thereof.
• Aging is preferably effected by stirring or mixing the pai'ireias'w i'th the drying aid, using, for instance, a rotating vessel or the like in the absence of air.
• the aging treatment is preferably carried out at tempera tures of to 80C. for about 5 to 30 minute s.
• the prilled ammonium nitrate which has been admixed with the drying agent and, if necessary, has been aging treated is subjected to further drying.
• This drying treatment is preferably eminent at ternpe ratu rs of froin to 100C., or higher than that in the above aeration treatment, for 10 to 30 minutes.
• This step should preferably be carried out by fluidizing the particles in an atmosphere of inert gas, such as air, nitrogen, or carbon dioxide.
• the veiocity ofthe gas shouldbe g r eater than 10 cm/sec., and, preferably, between 100 and 300 cm/sec.
• EXAMPLE 1 One Kg of prilled ammonium nitrate'Icontamirig 312 percent by weight, of water was aerated at C., and 5% %H, in a velocity of 1.5 m/sec. for 20 minutes. An aqueous solution of 3%, by weight, of drying agent as shown in Table i was added thereto by spraying under mixing in a pan type pelletizer. Next, the mixture was dried by fluidized treatment under the same conditions 55in the above aeration for 20 minutes and then was fluidized in a stream of dehydrated air at 15C. for 10 45 minutes where it was cooled at room temperature. To
• EXAMPLE 2 Prilled ammonium nitrate containing 3.4 percent, by weight, of water was aerated at thetemperature and time as shown ir Table, and then 20 cc. of an aqueous solution of 3 percent, by weight, of octadecylamine nitrate (Sample Nos. l to 6) or dodecylamine nitrate (Sample NOS. 7 to were added thereto by spraying while mixing in pan type pelletizer. After fluid drying with air of 1.5 m/sec. at a velocity under the conditions as shown in Table ii, the mixture was fluidized in a stream of dehydrated air at about mifiiii' to effect cooling at room temperature. To the dried,
• magnesium stearate by weight, of magnesium stearate and 0.1
• Anti-scattering percentage of fine powder I Five hundred g. of sample prepared in each eggarnple are allowed to naturally fall from a height of 0.5 meter onto a screen of 3 mm. and the scattering state of fine powder was rated by the following five grades:
• Anti-caking percentage into a highly rigid polyvinyl chloride vessel (qb 10 X h 10 cm) and, after placing a load of 0.2 Kglcm was sealed by a polyethylene bag.
• the sample was sub- Fee to a thermal e me t s idavs, the tasti temperature being raised from 20 to 45C. over a period of half a day and then reduced again to 20C. over another one-half day.
• the sample was broken by means of a Tensilon (UTM-lll type made by Toyo Sokki Co.). Anti-caking percentage is indicated by the destructive load required percent when load Kglcrn 55:1'0 553cm when 5 st 3.
• Adhering percentage gS ample prepared in each example is sifted through a 0.42 mm screen.
• the adhered amount of anti-caking agent is measured on the sample of the above screen by Three hundred g. of sample prepared are introduced atomic absorption analysis, and then the proportion of the amount to that of charged anti-caking is given with percentage.
• a prilled ammonium nitrate composition having improved anti-caking and anti-scattering properties which comprises a blend of prilled ammonium nitrate 5 with (l) a petroleum hydrocarbon having a boiling point of greater than 150 C and a melting point of less than C and (2) at least one anti-caking agent selected from the group consisting of:

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Glanulating (AREA)
• Fertilizers (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Catalysts (AREA)

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• 1971
  • 1971-09-27 JP JP46075330A patent/JPS5140554B2/ja not_active Expired
• 1972
  • 1972-09-13 GB GB4253072A patent/GB1365782A/en not_active Expired
  • 1972-09-15 US US00289729A patent/US3779821A/en not_active Expired - Lifetime
  • 1972-09-15 AU AU46720/72A patent/AU459485B2/en not_active Expired
  • 1972-09-25 FR FR7233891A patent/FR2154571B1/fr not_active Expired
  • 1972-09-26 DE DE19722247171 patent/DE2247171A1/de not_active Ceased

Patent Citations (12)

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