Smokeless sulfur-free firework propellant powder and preparation method thereof

Abstract

The invention belongs to the technical field of energetic materials, and provides a smokeless sulfur-free firework propellant and a preparation method thereof. The invention provides a preparation method of smokeless sulfur-free firework propellant powder. According to the invention, the first cotton nitrocellulose and / or the second cotton nitrocellulose are / is used as nitrocellulose, so that the finally obtained firework propellant powder is smoke-free and sulfur-free, and has an excellent gunpowder force value. The preparation method provided by the invention is simple and easy to operate. The nitrogen content of the smokeless sulfur-free firework propellant provided by the invention is 6.813 to 12.6 percent, the viscosity of the smokeless sulfur-free firework propellant is 3.24 to 4.9 DEG C, the apparent density of the smokeless sulfur-free firework propellant is 0.82 to 0.89 g / cm < 3 >, the gunpowder force of the smokeless sulfur-free firework propellant is 842.6 to 897.6 kj / kg, the specific heat ratio of the smokeless sulfur-free firework propellant is 1.1023 to 1.2588, the flame temperature of the smokeless sulfur-free firework propellant is 1435 to 2042 K, and the residual capacity of the smokeless sulfur-free firework propellant is 776 to 1067 cm < 3 > / kg.

Description

Technical Field

[0001] The invention relates to the technical field of energetic materials, and in particular to a smokeless and sulfur-free fireworks propellant and a preparation method thereof. Background Art

[0002] As people's environmental awareness increases, they are paying more and more attention to the smoke and dust produced by fireworks. Since most of the current fireworks propellants cannot be smokeless, many cities have banned fireworks in order to prevent air pollution. In order to solve the above dilemma, the fireworks industry has shifted its research and development focus to the research and development of new types of fireworks propellants. The related technology discloses a fireworks propellant, including potassium nitrate, sulfur, plant carbon powder and adhesive. However, the above fireworks propellant still produces smoke. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a smokeless and sulfur-free fireworks propellant and a preparation method thereof. The preparation method provided by the present invention is simple, and the obtained fireworks propellant is smokeless and sulfur-free.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing smokeless and sulfur-free fireworks propellant, comprising the following steps:

[0006] The nitrocellulose is successively finely chopped and dehydrated to obtain nitrocellulose powder;

[0007] The nitrocellulose powder and the stabilizer are mixed, and the obtained mixture is plasticized to obtain plasticized nitrocellulose;

[0008] Granulating the plasticized nitrocellulose to obtain drug granules;

[0009] The powder particles are sequentially subjected to boiling, washing, rinsing, dehydrating, drying and gloss treatment to obtain the smokeless and sulfur-free fireworks propellant;

[0010] The nitrocellulose includes a first cotton nitrocellulose and / or a second cotton nitrocellulose;

[0011] The first cotton nitrocellulose has a nitration degree of 211 to 218 cc / g and a viscosity of 3.8 to 4.2 degrees Engel;

[0012] The second cotton nitrocellulose has a nitration degree of 180 to 195 cc / g and a viscosity of 2.0 to 2.6 degrees Engelhard.

[0013] Preferably, the median diameter of the nitrocellulose powder obtained by the fine cutting is 10 to 40 μm.

[0014] Preferably, the dehydration comprises centrifugal dehydration and anhydrous ethanol dehydration in sequence, the time of the centrifugal dehydration is 25 minutes to 40 minutes; the time of the anhydrous ethanol dehydration is 30 minutes.

[0015] Preferably, the stabilizer is dicyandiamide, melamine or diphenylamine; the mass ratio of the stabilizer to nitrocellulose is 3 to 6:200;

[0016] The stabilizer is used in the form of a stabilizer solution, and the solvent of the stabilizer solution is one or more of ethanol, acetone and ethyl acetate.

[0017] Preferably, the mixed material further comprises nanocellulose and / or nitrated corn flour;

[0018] When the mixed material includes nanocellulose, the added amount of the nanocellulose is 10 to 100% of the mass of nitrocellulose;

[0019] When the mixed material includes nitrated corn powder, the added amount of the nitrated corn powder is 20-100% of the mass of the nitrocellulose.

[0020] Preferably, the plasticizing treatment includes sequentially performing a first kneading, a first plasticizing, a second kneading, a second plasticizing and a third kneading.

[0021] Preferably, the first kneading time is 2 to 5 minutes, the first plasticizing time is 60 to 120 minutes, the second kneading time is 2 to 6 minutes, the second plasticizing time is 60 to 240 minutes, and the third kneading time is 2 to 6 hours.

[0022] Preferably, the granulation method is thread rolling granulation or roller granulation; the particle size of the granules is 0.8 to 1.5 mm.

[0023] Preferably, the mass ratio of water to medicine particles used in the boiling and washing is 5 to 15:1, the boiling and washing temperature is 65 to 95°C, and the time is 2 to 6 hours;

[0024] The reagent used for rinsing is tap water, the rinsing temperature is 15-25°C, and the time is 10-20h;

[0025] The drying temperature is 40-50°C, the pressure is 600-650 mmHg, and the time is 2-6 hours;

[0026] The reagent used for the gloss treatment is colloidal graphite powder, the addition amount of the colloidal graphite powder is 0.02-0.3% of the mass of the medicine particles, and the gloss treatment time is 30-60 minutes.

[0027] The present invention also provides smokeless and sulfur-free fireworks propellant obtained by the preparation method described in the above technical solution, wherein the smokeless and sulfur-free fireworks propellant has a nitrogen content of 6.813-12.6%, a viscosity of 3.24-4.9 degrees Ener, and a bulk density of 0.82-0.89 g / cm 3 , the gunpowder force is 842.6~897.6kj / kg, the specific heat ratio is 1.1023~1.2588, the flame temperature is 1435K~2042K, and the residual volume is 776~1067cm 3 / kg.

[0028] The invention provides a method for preparing smokeless and sulfur-free fireworks propellant.

[0029] The present invention uses the first cotton nitrocellulose and / or the second cotton nitrocellulose as nitrocellulose, and obtains smokeless and sulfur-free fireworks propellant through fine cutting, dehydration, plasticization treatment, granulation and gloss treatment. The data of Example 1 show that the nitrogen content of the smokeless and sulfur-free fireworks propellant is 6.813-12.6%, the viscosity is 3.24-4.9 degrees Ener, and the bulk density is 0.82-0.89 g / cm 3 , the gunpowder force is 842.6~897.6kj / kg, the specific heat ratio is 1.1023~1.2588, the flame temperature is 1435K~2042K, and the residual volume is 776~1067cm 3 / kg. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a real photo of the thread rolling granulator;

[0031] Figure 2 This is a real photo of the three-roller machine;

[0032] Figure 3 This is a real photo of the double-roll granulator;

[0033] Figure 4 This is a real photo of the gloss machine. DETAILED DESCRIPTION

[0034] The present invention provides a method for preparing smokeless and sulfur-free fireworks propellant, comprising the following steps:

[0035] The nitrocellulose is successively finely chopped and dehydrated to obtain nitrocellulose powder;

[0036] The nitrocellulose powder and the stabilizer are mixed, and the obtained mixture is plasticized to obtain plasticized nitrocellulose;

[0037] Granulating the plasticized nitrocellulose to obtain drug granules;

[0038] The powder particles are sequentially subjected to boiling, washing, rinsing, dehydrating, drying and gloss treatment to obtain the smokeless and sulfur-free fireworks propellant;

[0039] The nitrocellulose includes a first cotton nitrocellulose and / or a second cotton nitrocellulose;

[0040] The first cotton nitrocellulose has a nitration degree of 211 to 218 cc / g and a viscosity of 3.8 to 4.2 degrees Engel;

[0041] The second cotton nitrocellulose has a nitration degree of 180 to 195 cc / g and a viscosity of 2.0 to 2.6 degrees Engelhard.

[0042] In the present invention, unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0043] The invention sequentially performs fine cutting and dehydration on nitrocellulose to obtain nitrocellulose powder.

[0044] In the present invention, the nitrocellulose includes a first cotton nitrocellulose and / or a second cotton nitrocellulose. In the present invention, the nitration degree of the first cotton nitrocellulose is 211-218cc / g, specifically 211cc / g, 212cc / g, 213cc / g, 214cc / g, 215cc / g, 216cc / g, 217cc / g or 218cc / g; the viscosity is 3.8-4.2 degrees Englert, specifically 3.8 degrees Englert, 3.85 degrees Englert, 3.9 degrees Englert, 3.95 degrees Englert, 4.0 degrees Englert, 4.05 degrees Englert, 4.1 degrees Englert, 4.15 degrees Englert or 4.2 degrees Englert. In the present invention, the moisture content of the first cotton nitrocellulose is preferably 20-25%.

[0045] In the present invention, the nitration degree of the second cotton nitrocellulose is 180-195cc / g, specifically 180cc / g, 181cc / g, 182cc / g, 183cc / g, 184cc / g, 185cc / g, 186cc / g, 187cc / g, 188cc / g, 189cc / g, 190cc / g, 191cc / g, 192cc / g g, 193cc / g, 194cc / g or 195cc / g; the viscosity is 2.0 to 2.6 degrees Enr, specifically 2.0 degrees Enr, 2.05 degrees Enr, 2.1 degrees Enr, 2.15 degrees Enr, 2.2 degrees Enr, 2.25 degrees Enr, 2.3 degrees Enr, 2.35 degrees Enr, 2.4 degrees Enr, 2.45 degrees Enr, 2.5 degrees Enr, 2.55 degrees Enr or 2.6 degrees Enr. In the present invention, the moisture content of the second cotton nitrocellulose is preferably 20 to 25%.

[0046] In the present invention, when the nitrocellulose includes a first cotton nitrocellulose and a second cotton nitrocellulose, the mass ratio of the first cotton nitrocellulose and the second cotton nitrocellulose is preferably 3:2.

[0047] In the present invention, the fine breaking is preferably carried out in a fine breaking machine. In the present invention, the fine breaking is preferably carried out under the action of water flow, and the flow rate of the water flow is preferably 16 to 35 kg / min, specifically 16 kg / min, 18 kg / min, 20 kg / min, 25 kg / min, 30 kg / min or 35 kg / min.

[0048] In the present invention, the median diameter of the nitrocellulose powder obtained by the fine cutting is preferably 10 to 40 μm, specifically 10 μm, 20 μm, 22 μm, 26 μm, 30 μm, 35 μm or 40 μm.

[0049] In the present invention, the dehydration preferably includes centrifugal dehydration and anhydrous ethanol dehydration in sequence. In the present invention, the time of the centrifugal dehydration is preferably 25min to 40min, specifically 25min, 30min, 35min or 40min. In the present invention, the centrifugal dehydration is preferably carried out in a W-800 type closed explosion-proof centrifuge. In the present invention, the mass ratio of the nitrocellulose to anhydrous ethanol is preferably 4:3 to 4:5; the time of the anhydrous ethanol dehydration is preferably 30min.

[0050] In the present invention, the nitrocellulose powder contains anhydrous ethanol, and the mass content of the anhydrous ethanol in the nitrocellulose powder is 10%.

[0051] After obtaining the nitrocellulose powder, the present invention mixes the nitrocellulose powder with a stabilizer, and plasticizes the obtained mixture to obtain plasticized nitrocellulose.

[0052] In the present invention, the stabilizer is preferably dicyandiamide, melamine or diphenylamine, and more preferably diphenylamine. In the present invention, the mass ratio of the stabilizer to nitrocellulose is preferably 3 to 6:200. In the present invention, the stabilizer is preferably used in the form of a stabilizer solution, and the solvent of the stabilizer solution is preferably one or more of ethanol, acetone and ethyl acetate, and more preferably acetone and ethyl acetate. In the present invention, the mass ratio of acetone to nitrocellulose is preferably 1 to 2:10, and the mass ratio of ethyl acetate to nitrocellulose is preferably 1 to 2:10.

[0053] In the present invention, the mixed material preferably also includes nanocellulose and / or nitrated corn flour. In the present invention, the preparation method of the nitrated corn flour preferably includes the following steps: a pressure-resistant four-mouth reaction device with a volume of 2000mL and 420g of 70% nitric acid is half-immersed in a -5°C high-precision low-temperature constant temperature reactor, 600g of 98% sulfuric acid is added to the nitric acid, stirring is started at a rate of 550rpm, and when the sulfuric acid is completely dissolved in the nitric acid and mixed evenly, 60g of ammonium nitrate is added to the mixed solution, the temperature is raised to 5°C, and after keeping warm for 2h, a nitrating agent is obtained. 220g of corn flour with a moisture content of less than 5%, a particle size of 0.2 to 25μm, and dried at 80°C for 10h is slowly added to the nitrating agent, and stirring is started at a rate of 180rpm. The reaction temperature is controlled at 10°C during the stirring process. After the corn flour is added, stir for 30min, then seal the reaction device, replace the air in the reaction device with nitrogen, after replacement 3 times, raise the temperature to 25°C, continue the reaction for 35min, filter with a centrifuge to remove a large amount of acid, wash the filter residue 3 times with 400g of water each time, and dehydrate to obtain 293.6g of crude nitrated corn flour. A pressure-resistant four-necked flask device with a volume of 2000 mL and filled with 400 g of deionized water was half immersed in a high-precision constant temperature reactor, wherein the pressure-resistant four-necked device was equipped with a reflux condenser, 293.6 g of crude nitrated corn flour was added to the deionized water, stirring was started at a rate of 70 rpm, and the high-precision constant temperature reactor was heated to 101° C. After keeping warm for 30 minutes, 55 g of a sodium carbonate solution with a mass fraction of 4.5% was added thereto, and after keeping warm and stirring for 60 minutes, it was filtered, and the filter residue was washed 3 times with 400 mL of water each time. After dehydration, it was dried at 60° C. and a vacuum degree of 490 mmHg for 8 hours to obtain 273.6 g of nitrated corn flour with a nitrogen content of 10.42%, and the yield was 124.36% (97.4% of the theoretical yield).

[0054] In the present invention, when the mixed material includes nanocellulose, the added amount of the nanocellulose is preferably 10-100% of the mass of nitrocellulose, specifically 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%.

[0055] In the present invention, when the mixed material includes nitrated corn flour, the added amount of the nitrated corn flour is preferably 20-100% of the mass of nitrocellulose, specifically 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%.

[0056] In the present invention, the plasticizing treatment preferably includes sequentially performing a first kneading, a first plasticizing, a second kneading, a second plasticizing and a third kneading.

[0057] In the present invention, the first kneading time is preferably 2 to 5 minutes, specifically preferably 2 minutes or 4 minutes; the first kneading is specifically preferably 2 minutes of forward rotation and 2 minutes of reverse rotation. In the present invention, the first plasticization time is preferably 60 to 120 minutes, specifically 60 minutes, 90 minutes or 120 minutes; the first plasticization method is preferably to stop kneading and let it stand. In the present invention, the second kneading time is preferably 2 to 6 minutes, specifically 2 minutes, 3 minutes, 4 minutes, 5 minutes or 6 minutes. In the present invention, the second plasticization time is preferably 60 to 240 minutes, specifically 60 minutes, 120 minutes, 180 minutes or 240 minutes, and the second plasticization method is preferably to stop kneading and let it stand. In the present invention, the third kneading time is preferably 2 to 6 hours, specifically 2 hours, 3 hours, 4 hours, 5 hours or 6 hours. In the present invention, the plasticization treatment is preferably carried out in a kneader.

[0058] After obtaining the plasticized nitrocellulose, the present invention granulates the plasticized nitrocellulose to obtain medicinal granules.

[0059] In the present invention, the granulation method is preferably thread rolling granulation or roller granulation. In the present invention, the thread rolling granulation is preferably carried out under a nitrogen atmosphere, the thread rolling granulation is preferably carried out in a thread rolling granulator, and during the thread rolling granulation, the rotation speed of the thread rolling granulator is preferably 26r / min. In the present invention, the actual photo of the thread rolling granulator is as follows Figure 1 shown.

[0060] In the present invention, before the double-roll granulation, it is preferred to further include sheeting, and the thickness of the sheet obtained by the sheeting is preferably 1.5 mm. In the present invention, the sheeting is preferably carried out on a three-roller machine, and the actual photo of the three-roller machine is as follows: Figure 2 As shown. In the present invention, the double-roll granulation is preferably carried out on a double-roll granulator, and the double-roll granulator preferably has a pore of 1.2 mm. In the present invention, the double-roll granulation is preferably carried out under nitrogen protection, and during the double-roll granulation, the rotation speed of the double-roll granulator is preferably 8r / min. In the present invention, the actual photo of the double-roll granulator is as shown Figure 3 shown.

[0061] In the present invention, the particle size of the drug particles is preferably 0.8 to 1.5 mm.

[0062] After obtaining the medicine particles, the present invention sequentially performs boiling, washing, rinsing, dehydration, drying and gloss treatment on the medicine particles to obtain the smokeless and sulfur-free fireworks propellant.

[0063] In the present invention, the mass ratio of water and medicine particles used in the boiling and washing is preferably 5-15:1, specifically 5:1, 10:1, 12:1 or 15:1; the water is preferably deionized water. In the present invention, the boiling and washing temperature is preferably 65-95°C, specifically 65°C, 70°C, 75°C, 80°C, 85°C, 90°C or 95°C; the time is preferably 2-6h, specifically 2h, 3h, 4h, 5h or 6h.

[0064] In the present invention, the reagent used for rinsing is preferably tap water, and the rinsing temperature is preferably 15-25°C, specifically 15°C, 20°C or 25°C; the rinsing time is preferably 10-20h, specifically 10h, 15h, 16h, 17h, 18h, 19h or 20h.

[0065] In the present invention, the dehydration is preferably fish-out dehydration.

[0066] In the present invention, the drying temperature is preferably 40-50°C, specifically 40°C, 45°C or 50°C; the pressure is preferably 600-650 mmHg, specifically 600 mmHg, 610 mmHg, 620 mmHg, 630 mmHg, 640 mmHg or 650 mmHg; the time is preferably 2-6 h, specifically 2 h, 3 h, 4 h, 5 h or 6 h.

[0067] In the present invention, the agent used for the gloss treatment is preferably colloidal graphite powder, and the amount of the colloidal graphite powder added is preferably 0.02-0.3% of the mass of the drug particles, specifically 0.02%, 0.03%, 0.035%, 0.05%, 0.10%, 0.15%, 0.2%, 0.25% or 0.3%. In the present invention, the gloss treatment time is preferably 30-60 minutes. In the present invention, the gloss treatment is preferably carried out in a gloss machine, and the actual photo of the gloss machine is as shown in FIG. Figure 4 shown.

[0068] The present invention also provides smokeless and sulfur-free fireworks propellant obtained by the preparation method described in the above technical solution, wherein the smokeless and sulfur-free fireworks propellant has a nitrogen content of 6.813-12.6%, a viscosity of 3.24-4.9 degrees Ener, and a bulk density of 0.82-0.89 g / cm 3 , the gunpowder force is 842.6~897.6kj / kg, the specific heat ratio is 1.1023~1.2588, the flame temperature is 1435K~2042K, and the residual volume is 776~1067cm 3 / kg.

[0069] The smokeless and sulfur-free fireworks propellant and the preparation method thereof provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0070] Example 1

[0071] S1. 120 kg of cotton nitrocellulose (water content 20%) with a nitration degree of 213 cc / g (N-13.3%) and a viscosity of 3.86 degrees Ener and 80 kg of cotton nitrocellulose (water content 20%) with a nitration degree of 185 cc / g (N-11.56%) and a viscosity of 2.3 degrees Ener are mixed and fed into a special fine chopper. At a water flow rate of 25 kg / min, the nitrocellulose powder is finely chopped into nitrocellulose powder with a medium particle size of 26 μm. The powder is collected in a cotton bag, dehydrated in a W-800 closed explosion-proof centrifuge for 25 min, and dehydrated successively with 150 kg of anhydrous ethanol for 30 min to obtain nitrocellulose powder containing 10 wt% anhydrous ethanol.

[0072] S2. Add the nitrocellulose powder obtained in S1 into a kneader; mix 20 kg of acetone and 20 kg of ethyl acetate evenly, add 3000 g of diphenylamine, stir until completely dissolved, filter, and add all the filtrate into the kneader containing the nitrocellulose powder. The obtained mixture is plasticized in the kneader. The specific process is: first start the kneader for 2 minutes in the forward direction and 2 minutes in the reverse direction, then stop the machine to plasticize the nitrocellulose for 90 minutes, then start the kneader for 5 minutes, then stop the machine for plasticization for 180 minutes, and then rotate the kneader for 3 hours of kneading. The raw materials are kneaded into a dough like steamed buns.

[0073] S3, placing the nitrocellulose kneaded into dough on a three-roller machine ( Figure 2 The flexible dough belt is placed on a roller granulator with a pore size of 1.2 mm ( Figure 3 As shown), inert gas is introduced into the system during roller pressing, the roller granulator is started, and the speed is adjusted to 8r / min. The roller-pressed granules automatically fall into the material tray with a certain amount of water under the roller machine for collection.

[0074] S4. The collected medicine particles (particle size of 1.2 mm) were washed with deionized water at a mass ratio of 1:12, the washing temperature was controlled to be 85°C, the washing time was 3 h, after washing, they were rinsed with tap water at 15°C for 15 h, removed and dehydrated, and dried at 40°C and 600 mmHg for 3 h; then put into a gloss machine ( Figure 4 As shown), add 0.035% colloidal graphite by weight of the powder particles, start the gloss machine, adjust the forward and reverse rotation ratio, and take out the gloss after 60 minutes to obtain a smokeless and sulfur-free fireworks propellant with excellent antistatic properties and good fluidity.

[0075] Result analysis: Nitrogen content is 12.6%, viscosity is 3.24 degrees, and bulk density is 0.87g / cm 3 , the gunpowder force is 897.6 kj / kg, the specific heat ratio is 1.2588, the flame temperature is 2042 K, and the residual volume is 1067 cm 3 / kg.

[0076] Example 2

[0077] S1. 80 kg of cotton nitrocellulose with a nitration degree of 218 cc / g (N-13.625%) and a viscosity of 4.0 degrees Ener are mixed and fed into a special fine chopper. At a water flow rate of 18 kg / min, the nitrocellulose powder is finely chopped into a median diameter of 22 μm. The powder is collected in a cotton bag, dehydrated in a W-800 closed explosion-proof centrifuge for 30 minutes, and dehydrated with 100 kg of anhydrous ethanol for 30 minutes to obtain a nitrocellulose powder containing 10% anhydrous ethanol.

[0078] S2. Add the nitrocellulose powder obtained in S1 into a kneading machine, and add 80 kg of nitrated corn flour (nitrogen content is 10.42%) at the same time; mix 12 kg of acetone and 12 kg of ethyl acetate evenly, add 2400 g of dicyandiamide, stir until completely dissolved, filter, and add all the filtrate into the kneading machine containing nitrocellulose powder and nitrated corn flour, first start the kneading machine for 2 minutes, reverse for 2 minutes, stop the machine, plasticize the nitrocellulose for 90 minutes, start the kneading machine for 5 minutes, stop the machine for plasticization for 180 minutes, and then rotate the kneading machine for 3 hours of kneading. The raw materials are kneaded into a dough like steamed bread.

[0079] S3, kneading the dough into a mixture of nitrocellulose and nitrated corn flour (the preparation method of which is the same as that of Example 3) into a feed port of a thread rolling granulator ( Figure 1 During the thread rolling granulation, inert gas is introduced into the system, the thread rolling granulator is started, and the speed is adjusted to 26r / min. The thread rolling granulation particles automatically fall into the receiving tray for collection.

[0080] S4. The collected granules (particle size of 1.2 mm) were washed with deionized water at a ratio of 1:10, the washing temperature was controlled to be 90°C, the washing time was 2 h, after washing, they were rinsed with tap water at 15°C for 10 h, removed and dehydrated, and dried at 45°C and 610 mmHg for 5 h; then put into a gloss machine ( Figure 4 As shown), add 0.030% of colloidal graphite by weight of the powder particles, start the gloss machine, adjust the forward and reverse rotation ratio, and take out the gloss after 60 minutes to obtain smokeless, smokeless and sulfur-free fireworks propellant with excellent antistatic properties and good fluidity.

[0081] Wherein, the preparation method of nitrated corn flour comprises the following steps:

[0082] A pressure-resistant four-mouth reaction device with a volume of 2000 mL and filled with 420 g of 70% nitric acid was half immersed in a -5°C high-precision low-temperature constant temperature reactor, 600 g of 98% sulfuric acid was added to the nitric acid, and stirring was started at a rate of 550 rpm. When the sulfuric acid was completely dissolved in the nitric acid and mixed evenly, 60 g of ammonium nitrate was added to the mixed solution, the temperature was raised to 5°C, and after keeping warm for 2 hours, a nitrating agent was obtained.

[0083] 220g of corn flour with a moisture content of less than 5%, a particle size of 0.2 to 25μm, and dried at 80°C for 10h is slowly added to the nitrating agent, and stirring is started at a rate of 180rpm. The reaction temperature is controlled at 10°C during the stirring process. After the corn flour is added, stir for 30min, then seal the reaction device, replace the air in the reaction device with nitrogen, after replacement 3 times, raise the temperature to 25°C, continue the reaction for 35min, filter with a centrifuge to remove a large amount of acid, wash the filter residue 3 times with 400g of water each time, and dehydrate to obtain 293.6g of crude nitrated corn flour.

[0084] A pressure-resistant four-necked flask device with a volume of 2000 mL and filled with 400 g of deionized water was half immersed in a high-precision constant temperature reactor, wherein the pressure-resistant four-necked device was equipped with a reflux condenser, 293.6 g of crude nitrated corn flour was added to the deionized water, stirring was started at a rate of 70 rpm, and the high-precision constant temperature reactor was heated to 101° C. After keeping warm for 30 minutes, 55 g of a sodium carbonate solution with a mass fraction of 4.5% was added thereto, and after keeping warm and stirring for 60 minutes, it was filtered, and the filter residue was washed 3 times with 400 mL of water each time. After dehydration, it was dried at 60° C. and a vacuum degree of 490 mmHg for 8 hours to obtain 273.6 g of nitrated corn flour with a nitrogen content of 10.42%, and the yield was 124.36% (97.4% of the theoretical yield).

[0085] Result analysis: Nitrogen content is 11.84%, viscosity is 3.87 degrees, and bulk density is 0.89g / cm 3 , the gunpowder force is 874.2 kj / kg, the specific heat ratio is 1.2236, the flame temperature is 1985 K, and the residual volume is 997 cm 3 / kg.

[0086] Example 3

[0087] S1. 80 kg of cotton nitrocellulose with a nitration degree of 218 cc / g (N-13.625%) and a viscosity of 4.0 degrees Ener are mixed and fed into a special fine chopper. At a water flow rate of 18 kg / min, the nitrocellulose powder is finely chopped into a median diameter of 22 μm. The powder is collected in a cotton bag, dehydrated in a W-800 closed explosion-proof centrifuge for 30 minutes, and dehydrated with 100 kg of anhydrous ethanol for 30 minutes to obtain a nitrocellulose powder containing 10% anhydrous ethanol.

[0088] S2. Add the nitrocellulose powder obtained in S1 into a kneading machine, and add 80 kg of nanocellulose at the same time; mix 15 kg of acetone and 15 kg of ethyl acetate evenly, add 2400 g of melamine, stir until completely dissolved, filter, and add all the filtrate into the kneading machine containing nitrocellulose powder and nanocellulose, first start the kneading machine for 2 minutes, reverse for 2 minutes, stop the machine, plasticize the nitrocellulose powder and nanocellulose mixture for 90 minutes, start the kneading machine for 5 minutes, stop the machine for plasticization for 180 minutes, and then rotate the kneading machine for 3 hours to knead the raw materials until they are kneaded into a dough like steamed buns.

[0089] S3, placing the mixture of nitrocellulose and nanocellulose kneaded into dough at the feed port of the thread rolling granulator ( Figure 1 During the thread rolling granulation, inert gas is introduced into the system, the thread rolling granulator is started, and the speed is adjusted to 26r / min. The thread rolling granulation particles automatically fall into the receiving tray for collection.

[0090] S4. The collected granules (particle size of 1.2 mm) were washed with deionized water at a ratio of 1:10, the washing temperature was controlled to be 90°C, the washing time was 2 h, after washing, they were rinsed with tap water at 15°C for 10 h, removed and dehydrated, and dried at 50°C and 630 mmHg for 5 h; then put into a gloss machine ( Figure 4 As shown), add 0.030% of colloidal graphite by weight of the powder particles, start the gloss machine, adjust the forward and reverse rotation ratio, and take it out after glossing for 60 minutes to obtain a smokeless and sulfur-free fireworks propellant with excellent antistatic properties and good fluidity.

[0091] Result analysis: Nitrogen content is 6.813%, viscosity is 4.9 degrees, and bulk density is 0.82g / cm 3 , the gunpowder force is 842.6 kj / kg, the specific heat ratio is 1.1023, the flame temperature is 1435 K, and the residual volume is 776 cm 3 / kg, there is smoke when burning and 10% dust is produced after burning.

[0092] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing smokeless and sulfur-free fireworks propellant, comprising the following steps: The nitrocellulose is successively finely chopped and dehydrated to obtain nitrocellulose powder; The nitrocellulose powder and the stabilizer are mixed, and the obtained mixture is plasticized to obtain plasticized nitrocellulose; Granulating the plasticized nitrocellulose to obtain drug granules; The powder particles are sequentially subjected to boiling, washing, rinsing, dehydrating, drying and gloss treatment to obtain the smokeless and sulfur-free fireworks propellant; The nitrocellulose includes a first cotton nitrocellulose and / or a second cotton nitrocellulose; The first cotton nitrocellulose has a nitration degree of 211 to 218 cc / g and a viscosity of 3.8 to 4.2 degrees Engel; The second cotton nitrocellulose has a nitration degree of 180 to 195 cc / g and a viscosity of 2.0 to 2.6 degrees Engelhard.

2. The preparation method according to claim 1, characterized in that: The median diameter of the nitrocellulose powder obtained by the fine cutting is 10 to 40 μm.

3. The preparation method according to claim 1, characterized in that: The dehydration includes centrifugal dehydration and anhydrous ethanol dehydration in sequence, the time of the centrifugal dehydration is 25 minutes to 40 minutes; the time of the anhydrous ethanol dehydration is 30 minutes.

4. The preparation method according to claim 1, characterized in that: The stabilizer is dicyandiamide, melamine or diphenylamine; the mass ratio of the stabilizer to nitrocellulose is 3 to 6:200; The stabilizer is used in the form of a stabilizer solution, and the solvent of the stabilizer solution is one or more of ethanol, acetone and ethyl acetate.

5. The preparation method according to claim 1, characterized in that: The mixed material also includes nanocellulose and / or nitrated corn flour; When the mixed material includes nanocellulose, the added amount of the nanocellulose is 10 to 100% of the mass of nitrocellulose; When the mixed material includes nitrated corn powder, the added amount of the nitrated corn powder is 20-100% of the mass of the nitrocellulose.

6. The preparation method according to claim 1, characterized in that: The plasticizing treatment includes sequentially performing a first kneading, a first plasticizing, a second kneading, a second plasticizing and a third kneading.

7. The preparation method according to claim 6, characterized in that: The first kneading time is 2 to 5 minutes, the first plasticizing time is 60 to 120 minutes, the second kneading time is 2 to 6 minutes, the second plasticizing time is 60 to 240 minutes, and the third kneading time is 2 to 6 hours.

8. The preparation method according to claim 1, characterized in that: The granulation method is thread rolling granulation or roller granulation; the particle size of the granules is 0.8-1.5 mm.

9. The preparation method according to claim 1, characterized in that: The mass ratio of water to medicine particles used in the boiling and washing is 5 to 15:1, the boiling and washing temperature is 65 to 95°C, and the time is 2 to 6 hours; The reagent used for rinsing is tap water, the rinsing temperature is 15-25°C, and the time is 10-20h; The drying temperature is 40-50°C, the pressure is 600-650 mmHg, and the time is 2-6 hours; The reagent used for the gloss treatment is colloidal graphite powder, the addition amount of the colloidal graphite powder is 0.02-0.3% of the mass of the medicine particles, and the gloss treatment time is 30-60 minutes.

10. The smokeless and sulfur-free fireworks propellant obtained by the preparation method according to any one of claims 1 to 9, characterized in that: The smokeless and sulfur-free fireworks propellant has a nitrogen content of 6.813-12.6%, a viscosity of 3.24-4.9 degrees En, and a bulk density of 0.82-0.89 g / cm 3 , the gunpowder force is 842.6~897.6kj / kg, the specific heat ratio is 1.1023~1.2588, the flame temperature is 1435K~2042K, and the residual volume is 776~1067cm 3 / kg.

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