CN102580711B - Production method for synthesizing melamine catalyst by urea with gas phase method - Google Patents
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Abstract
The invention belongs to a catalyst preparation technology, and particularly discloses a production method for synthesizing a melamine catalyst by using urea as a raw material with a gas phase method. The method comprises the following steps: (1), preparation of original gum, namely performing the reaction on sodium silicate and aluminium sulfate to prepare the original gum, wherein the concentration of the sodium silicate is controlled into the range of 21 percent to 26 percent, the concentration of the aluminium sulfate is controlled into the range of 20 percent to 30 percent and the pH value at the end point of the neutralization reaction of the sodium silicate and the aluminium sulfate is controlled into the range of 5 to 6; (2), washing; (3), mixing and beating; (4), soda boiling and chambering; (5), washing; (6), acid soaking; and (7), calcination. The catalyst produced with the method has high strength and low consumption in a fluidized bed reactor, namely, averagely, 0.1 to 1kg of the catalyst is consumed by each ton of melamine; the catalyst has high activity, namely, averagely, each kilogram of catalyst can bear 150 to 400 grams of urea per hour; the catalyst has strong poison resistance and does not need to be activated in the production process; and the catalyst has good fluidization effect and has no bad phenomena of channeling, bubbling and the like in the fluidized bed reactor.
Description
Technical field
The invention belongs to catalyst preparation technology, be specially the production method of synthesizing melamine catalyst by urea with gas phase method.
Background technology
Melamine [(NH
2)
3C
3N
3] that is melamine, be a kind of broad-spectrum Organic Chemicals.Mainly for the manufacture of melamine-formaldehyde resin (MF); Can be used for making daily utensil, environment-friendly type decoration thick china, fabric finishing agent etc., also can coordinate with ether and make paper treating agent, can be used as in addition coating crosslinking agent and flame retardant chemical treatment agent etc.
Early stage melamine production raw material is dicyandiamide, and after nineteen sixties, the suitability for industrialized production melamine begins take urea as raw material, carries out following reaction under uniform temperature and certain pressure effect:
6(NH
2)
2CO?→?C
3H
6N
6?+?6NH
3?+?3CO
2
Above-mentioned synthesis technique is divided into two kinds of high pressure liquid phase on-catalytic synthetic method (abbreviation high-pressure liquid phase method) and low-pressure vapor phase catalysis synthesis process (being called for short the low-pressure vapor phase method) according to the difference of chemical reaction condition.High-pressure liquid phase method adopts tower reactor, reaction pressure 7-15MPa, and reaction temperature 380-450 ℃, molten state urea is converted into melamine under the HTHP effect.The low-pressure vapor phase fado adopts fluidized-bed reactor, reaction pressure 0.05-2.5MPa, and reaction temperature 370-420 ℃, urea gasifies rapidly and is converted into melamine under the acting in conjunction of high-temperature low-pressure and catalyst.Low-pressure vapor phase method technique is compared with high-pressure liquid phase method technique, have that flow process is short, equipment is few, corrosive medium is little, the advantage such as reduced investment, construction period are short, so obtained paying close attention to widely and using, show as low-pressure vapor phase method technique in the recent decade the development comparatively swift and violent, approximately accounted for 70% of global melamine total output, and this trend is also continuing development.
Although the low-pressure vapor phase method technique of melamine is widely applied, but be subject to for a long time supporting without corresponding special efficient catalyst, make the production capacity of the single cover of low-pressure vapor phase method melamine device be difficult to be greatly enhanced, device ubiquity catalyst consumption is high, the melamine quality is unstable, raw material material and the problem such as the energy resource consumption advantage is not obvious.
In the melamine low-pressure vapor phase method process units of China, the catalyst that present stage adopts is mainly gross porosity microsphere silica gel, activated alumina microballoon and Alusil microballoon.
The gross porosity microsphere silica gel is as catalyst or catalyst carrier, just be widely applied petrochemical industry is produced from nineteen sixties, but it uses as catalyst in the melamine production device, and effect is unsatisfactory.The ubiquity catalytic activity is low, and the urea of silica gel feeds intake load generally lower than 75g/kg.h; Wear away highly, melamine per ton need consume 8～15 kilograms, silica gel; Easily poisoning, every two weeks all need activate once even weekly, each 4～8 hours consuming time; Fluidized-bed reactor fluidization quality is poor, is embodied in fluid bed and air pocket easily occurs, and the bed vibrations are large.The activated alumina microballoon is as the melamine catalyst, and is high than gross porosity microsphere silica gel catalytic activity, and urea feeds intake to load and can reach 80～130g/kg.h; Wear away also lowly than the gross porosity microsphere silica gel, melamine per ton consumes 3～5 kilograms of activated alumina microballoons; Also be difficult for poisoning; Fluid effect is also good than the gross porosity microsphere silica gel; But it exists critical defect to be: the accessory substance that its catalysis generates is sticking filter bag especially easily, makes the filter bag pressure reduction rising of melamine device very fast, two weeks of life of bag filter less than.The filter bag consumption is large, and labor strength is large, and the maintenance of equipment environment is poor, finally causes device to be produced hard to carry on.By the experiment of a large amount of production practices and lab scale, find that the Alusil microballoon is best suited for the melamine production catalyst, but the problem such as common si-al catalyst microspheres also exists intensity undesirable in the market, and catalyst activity is not good enough.
Summary of the invention
The present invention just is being based on above technical problem, provides that a kind of intensity is good, catalytic activity is high, selectively good; China's low-pressure vapor phase method melamine production device single line production capacity is enough maximized; The production method of the efficient melamine catalyst that the production cycle is long.
Technical scheme of the present invention is:
The production method of synthesizing melamine catalyst by urea with gas phase method comprises following steps:
(1) virgin rubber processed: by flower bulb alkali and reacting aluminum sulfate glue, the concentration of flower bulb alkali is controlled at 21%--26%, and the concentration of aluminum sulfate is controlled at 20%--30%, and the control of reaction end point of flower bulb alkali and aluminum sulfate neutralization reaction is 5-6 at pH value;
(2) washing: the stirring of the reaction solution in step () is stopped postprecipitation, take out upper water, then add deionized water, after stirring, parked and precipitation, wash 4-6 time, repeatedly to remove the sodium sulphate that produces in course of reaction;
(3) mix making beating: add aluminium hydroxide and nitric acid mixing making beating after the washing colloid, beating time is 10-24 hour;
(4) mist projection granulating: controlling EAT is 400 ℃-420 ℃, and leaving air temp is 110 ℃-120 ℃;
(5) soda boiling reaming: add the NaOH of 10%--30%, temperature is controlled at 90 ℃-100 ℃, and the soda boiling time is 1-2 hour;
(6) washing: repeatedly wash with deionized water, washing times is at least twice, with centrifuge, water is removed and dries, except sodium metasilicate, the sodium aluminate that dereaction generates, the water-solubility impurity of unreacted NaOH;
(7) acid soak: add phosphoric acid to flooding material, immersion is the acid site for the fortifying catalytic agent, strengthens catalyst activity;
(8) calcining: calcine under 600 ℃-650 ℃, calcination time is 1-3 hour;
(9) packing: adopt air to carry out hybrid refrigeration, be 0.2-0.5 hour cool time, is packaged as finished product.
The production method of synthesizing melamine catalyst by urea with gas phase method need add aluminium hydroxide when mixing making beating, aluminium hydroxide is Powdered, calculates by mass percentage, and the aluminium hydroxide amount that adds is the 20%-50% of aluminum sulfate amount.
Adding in the production method of synthesizing melamine catalyst by urea with gas phase method and need adding concentration after aluminium hydrate powder is 30%, calculates by percentage to the quality, and the amount that adds nitric acid is 15% of aluminium hydroxide amount, then mixes making beating.
Adopting the concentration of NaOH in soda boiling in step in the production method of synthesizing melamine catalyst by urea with gas phase method (seven) is 10%-30%.
The acid that acid soak in step in the production method of synthesizing melamine catalyst by urea with gas phase method (seven) adopts is phosphoric acid, and the concentration of phosphoric acid is 5%--10%, and soak time is 2-5 hour.
Virgin rubber refers to Alusil, with flower bulb alkali and the reaction of aluminum sulfate acid-base neutralization.The concentration of flower bulb alkali is controlled at 21%--26%, and the concentration of aluminum sulfate is controlled at 20%--30%.Two kinds of raw material all need be used high-class product, to reduce bringing into of impurity, affect product quality.Control of reaction end point is that 5-6 is advisable at pH value.
Hydro-oxidation aluminium powder and nitric acid mixing making beating in step (three), aluminium hydrate powder plays the double action of filler and bonding agent, and nitric acid is to make it have bond effect for the molten aluminium hydrate powder of acid.In addition, the addition of controlling aluminium hydrate powder can be regulated the silica alumina ratio of catalyst, thereby controls the activity of catalyst.
Mist projection granulating is to make the granularity of catalyst be controlled in the suitable scope of fluid bed by operating parameters such as the frequency of controlling atomizer, EAT, inlet amounies.
The soda boiling reaming is because the holes of products that magma is produced is many but the hole is thin, is unfavorable for the parsing of catalyst, and this is easily poisoning main cause of silica gel.By adding the NaOH of 10%--30%, temperature is controlled at 90 ℃-100 ℃, and the time is 1-2 hours, but average pore size enlarges 30%-50%.
Washing in step (six) is sodium metasilicate, the sodium aluminate that generates for except dereaction, the impurity such as unreacted NaOH.
The purpose of soaking in acid soak is the acid site for the fortifying catalytic agent, strengthens catalyst activity.
Calcining, calcining one under 600 ℃-650 ℃ is for the curing catalysts structure, increases its intensity, the 2nd, in order to change the unreacted crystalline structure of aluminium hydrate powder completely, make it change activated alumina into, increase the catalytic efficiency of product.
Sodium metasilicate (Na
2SiO
3) have another name called flower bulb alkali, waterglass.
The catalyst basic index that the present invention produces is as follows:
| Chemical property | Unit | Be not less than | Be not more than | Remarks |
| Burning decrement | % by weight | —— | 4 | In calcining more than 800 ℃ |
| Gama-alumina | % by weight | 10 | 30 | ? |
| Sulphur | ppm | —— | 500 | ? |
| Fe 2O 3 | % by weight | —— | 0.15 | ? |
| Chlorine | ppm | —— | 50 | ? |
| Na 2O | % by weight | —— | 0.2 | ? |
| Physical property | ? | |||
| Specific surface | Meters squared per gram | 120 | —— | ? |
| Pore volume | Ml/g | 0.2 | 0.5 | ? |
| Bulk density | Grams per milliliter | 0.8 | 0.95 | ? |
| Abrasion index | % by weight | —— | 4 | ? |
| Granularity (laser mensuration) | ? | |||
| ＞425 microns | % by weight | —— | 2 | ? |
| 125～425 microns | % by weight | 85 | —— | ? |
| ＜125 microns | % by weight | —— | 13 | ? |
Compared with prior art, beneficial effect of the present invention is:
(1), that the catalyst produced with this method has intensity is high, consumes low characteristics in fluid bed, on average produces 0.1 to 1 kilogram of melamine spent catalyst per ton;
(2), the product catalytic efficiency is high, average per kilogram per hour can catalyzing urea 150-400 gram.
(3), mithridatism is strong, need not activate in production process.
(4), fluid effect is good, and the bad phenomenon such as channel, air pocket do not occur in fluidized-bed reactor.
Description of drawings:
Fig. 1 is production technological process of the present invention.
The specific embodiment
The present invention is described in further detail below in conjunction with the specific embodiment.
But this should be interpreted as that the scope of the above-mentioned theme of the present invention only limits to following embodiment.
Embodiment 1:
Be that 20% aluminum sulfate 50kg is placed in the 300L stainless steel cauldron with the concentration that configures, start stirring, take the speed of 5L/min, the concentration that configures is added reactor as 22% sodium silicate solution, controlling reaction end ph value is 5.Stop after reaction is reached home stirring, quiescent setting is drained upper water with vacuum machine.Add deionized water 150L in reactor, start and stirred 20 minutes, quiescent setting is drained upper water with vacuum machine, so repeatedly washes 4 times.Add aluminium hydrate powder 3kg, 30% nitric acid 0.45kg, deionized water 120L start to stir and mix making beating 24 hours.Add the water deionized water according to the denseness of slurries and regulated, so that centrifugal spray drying.Controlling EAT is 400 ℃, and leaving air temp is 110 ℃ and carries out spray granulating and drying.Drying product out is reinstalled in stainless steel cauldron, adds the liquid caustic soda of 10% concentration to flooding material 20cm, start and stir and electrical heating, temperature is risen to more than 90 ℃ soda boiling 1 hour.Alkali is emitted, repeatedly wash 5 times with deionized water, with centrifuge, water deviate from and dried.To dry the product stainless steel cauldron of packing into, and add the phosphoric acid of 5% concentration to soak 2 hours to flooding material 10cm.With the 610 ℃ of calcinings of stainless steel rotary calcining kiln temperature control 1 hour of packing into after the material taking-up, discharging is packaged into finished product after screening in cooling 5 hours in air.
Embodiment 2:
Be that 25% aluminum sulfate 50kg is placed in the 300L stainless steel cauldron with the concentration that configures, start stirring, take the speed of 5L/min, the concentration that configures is added reactor as 26% sodium silicate solution, controlling reaction end ph value is 6.Stop after reaction is reached home stirring, quiescent setting is drained upper water with vacuum machine.Add deionized water 150L in reactor, start and stirred 20 minutes, quiescent setting is drained upper water with vacuum machine, so repeatedly washes 4 times.Add aluminium hydrate powder 3kg, 30% nitric acid 0.45kg, deionized water 120L start to stir and mix making beating 24 hours.Add the water deionized water according to the denseness of slurries and regulated, so that centrifugal spray drying.Controlling EAT is 410 ℃, and leaving air temp is 120 ℃ and carries out spray granulating and drying.Drying product out is reinstalled in stainless steel cauldron, adds the liquid caustic soda of 20% concentration to flooding material 20cm, start and stir and electrical heating, temperature is risen to more than 90 ℃ soda boiling 1 hour.Alkali is emitted, repeatedly wash 5 times with deionized water, with centrifuge, water deviate from and dried.To dry the product stainless steel cauldron of packing into, and add the phosphoric acid of 10% concentration to soak 2 hours to flooding material 10cm.With the 620 ℃ of calcinings of stainless steel rotary calcining kiln temperature control 1 hour of packing into after the material taking-up, discharging is packaged into finished product after screening in cooling 5 hours in air.
Embodiment 3:
Be that 20% aluminum sulfate 50kg is placed in the 300L stainless steel cauldron with the concentration that configures, start stirring, take the speed of 5L/min, the concentration that configures is added reactor as 21% sodium silicate solution, the control reaction end is ph5.Stop after reaction is reached home stirring, quiescent setting is drained upper water with vacuum machine.Add deionized water 150L in reactor, start and stirred 20 minutes, quiescent setting is drained upper water with vacuum machine, so repeatedly washes 4 times.Add aluminium hydrate powder 5kg, 30% nitric acid 0.75kg, deionized water 120L start to stir and mix making beating 24 hours.Add the water deionized water according to the denseness of slurries and regulated, so that centrifugal spray drying.Controlling EAT is 420 ℃, and leaving air temp is 120 ℃ and carries out spray granulating and drying.Drying product out is reinstalled in stainless steel cauldron, adds the liquid caustic soda of 10% concentration to flooding material 20cm, start and stir and electrical heating, temperature is risen to more than 90 ℃ soda boiling 1 hour.Alkali is emitted, repeatedly wash 5 times with deionized water, with centrifuge, water deviate from and dried.To dry the product stainless steel cauldron of packing into, and add the phosphoric acid of 5% concentration to soak 2 hours to flooding material 10cm.With the 630 ℃ of calcinings of stainless steel rotary calcining kiln temperature control 1 hour of packing into after the material taking-up, discharging is packaged into finished product after screening in cooling 5 hours in air.
Embodiment 4:
Be that 20% aluminum sulfate 50kg is placed in the 300L stainless steel cauldron with the concentration that configures, start stirring, take the speed of 5L/min, the concentration that configures is added reactor as 22% sodium silicate solution, the control reaction end is ph5-6.Stop after reaction is reached home stirring, quiescent setting is drained upper water with vacuum machine.Add deionized water 150L in reactor, start and stirred 20 minutes, quiescent setting is drained upper water with vacuum machine, so repeatedly washes 4 times.Add aluminium hydrate powder 5kg, 30% nitric acid 0.75kg, deionized water 150L start to stir and mix making beating 24 hours.Add the water deionized water according to the denseness of slurries and regulated, so that centrifugal spray drying.Controlling EAT is 420 ℃, and leaving air temp is 120 ℃ and carries out spray granulating and drying.Drying product out is reinstalled in stainless steel cauldron, adds the liquid caustic soda of 20% concentration to flooding material 20cm, start and stir and electrical heating, temperature is risen to more than 90 ℃ soda boiling 1.5 hours.Alkali is emitted, repeatedly wash 5 times with deionized water, with centrifuge, water deviate from and dried.To dry the product stainless steel cauldron of packing into, and add the phosphoric acid of 10% concentration to soak 2 hours to flooding material 10cm.With the 650 ℃ of calcinings of stainless steel rotary calcining kiln temperature control 1 hour of packing into after the material taking-up, discharging is packaged into finished product after screening in cooling 5 hours in air.
Embodiment 5:
Be that 30% aluminum sulfate 50kg is placed in the 300L stainless steel cauldron with the concentration that configures, start stirring, take the speed of 5L/min, the concentration that configures is added reactor as 22% sodium silicate solution, controlling reaction end ph value is 5.5.Stop after reaction is reached home stirring, quiescent setting is drained upper water with vacuum machine.Add deionized water 150L in reactor, start and stirred 20 minutes, quiescent setting is drained upper water with vacuum machine, so repeatedly washes 4 times.Add aluminium hydrate powder 5kg, 30% nitric acid 0.75kg, deionized water 150L start to stir and mix making beating 24 hours.Add the water deionized water according to the denseness of slurries and regulated, so that centrifugal spray drying.Controlling EAT is 420 ℃, and leaving air temp is 110 ℃ and carries out spray granulating and drying.Drying product out is reinstalled in stainless steel cauldron, adds the liquid caustic soda of 30% concentration to flooding material 20cm, start and stir and electrical heating, temperature is risen to more than 90 ℃ soda boiling 2 hours.Alkali is emitted, repeatedly wash 5 times with deionized water, with centrifuge, water deviate from and dried.To dry the product stainless steel cauldron of packing into, and add the phosphoric acid of 10% concentration to soak 2 hours to flooding material 10cm.With the 640 ℃ of calcinings of stainless steel rotary calcining kiln temperature control 1 hour of packing into after the material taking-up, discharging is packaged into finished product after screening in cooling 5 hours in air.
Embodiment 6:
Be that 30% aluminum sulfate 50kg is placed in the 300L stainless steel cauldron with the concentration that configures, start stirring, take the speed of 5L/min, the concentration that configures is added reactor as 26% sodium silicate solution, the control reaction end is ph6.Stop after reaction is reached home stirring, quiescent setting is drained upper water with vacuum machine.Add deionized water 150L in reactor, start and stirred 20 minutes, quiescent setting is drained upper water with vacuum machine, so repeatedly washes 4 times.Add aluminium hydrate powder 7.5kg, 30% nitric acid 1.2kg, deionized water 150L start to stir and mix making beating 24 hours.Add the water deionized water according to the denseness of slurries and regulated, so that centrifugal spray drying.Controlling EAT is 420 ℃, and leaving air temp is 110 ℃ and carries out spray granulating and drying.Drying product out is reinstalled in stainless steel cauldron, adds the liquid caustic soda of 10% concentration to flooding material 20cm, start and stir and electrical heating, temperature is risen to more than 90 ℃ soda boiling 1 hour.Alkali is emitted, repeatedly wash 5 times with deionized water, with centrifuge, water deviate from and dried.To dry the product stainless steel cauldron of packing into, and add the phosphoric acid of 5% concentration to soak 2 hours to flooding material 10cm.With the 630 ℃ of calcinings of stainless steel rotary calcining kiln temperature control 1 hour of packing into after the material taking-up, discharging is packaged into finished product after screening in cooling 5 hours in air.
Embodiment 7:
Be that 30% aluminum sulfate 50kg is placed in the 300L stainless steel cauldron with the concentration that configures, start stirring, take the speed of 5L/min, the concentration that configures is added reactor as 26% sodium silicate solution, controlling reaction end ph value is 5.Stop after reaction is reached home stirring, quiescent setting is drained upper water with vacuum machine.Add deionized water 150L in reactor, start and stirred 20 minutes, quiescent setting is drained upper water with vacuum machine, so repeatedly washes 4 times.Add aluminium hydrate powder 7.5kg, 30% nitric acid 1.2kg, deionized water 150L start to stir and mix making beating 24 hours.Add the water deionized water according to the denseness of slurries and regulated, so that centrifugal spray drying.Controlling EAT is 400 ℃, and leaving air temp is 110 ℃ and carries out spray granulating and drying.Drying product out is reinstalled in stainless steel cauldron, adds the liquid caustic soda of 20% concentration to flooding material 20cm, start and stir and electrical heating, temperature is risen to more than 90 ℃ soda boiling 1 hour.Alkali is emitted, repeatedly wash 5 times with deionized water, with centrifuge, water deviate from and dried.To dry the product stainless steel cauldron of packing into, and add the phosphoric acid of 10% concentration to soak 2 hours to flooding material 10cm.With the 650 ℃ of calcinings of stainless steel rotary calcining kiln temperature control 1 hour of packing into after the material taking-up, discharging is packaged into finished product after screening in cooling 5 hours in air.
Embodiment 8:
Be that 30% aluminum sulfate 50kg is placed in the 300L stainless steel cauldron with the concentration that configures, start stirring, take the speed of 5L/min, the concentration that configures is added reactor as 26% sodium silicate solution, controlling reaction end ph value is 5.Stop after reaction is reached home stirring, quiescent setting is drained upper water with vacuum machine.Add deionized water 150L in reactor, start and stirred 20 minutes, quiescent setting is drained upper water with vacuum machine, so repeatedly washes 4 times.Add aluminium hydrate powder 7.5kg, 30% nitric acid 1.2kg, deionized water 120L start to stir and mix making beating 24 hours.Add the water deionized water according to the denseness of slurries and regulated, so that centrifugal spray drying.Controlling EAT is 420 ℃, and leaving air temp is 120 ℃ and carries out spray granulating and drying.Drying product out is reinstalled in stainless steel cauldron, adds the liquid caustic soda of 30% concentration to flooding material 20cm, start and stir and electrical heating, temperature is risen to more than 90 ℃ soda boiling 2 hours.Alkali is emitted, repeatedly wash 5 times with deionized water, with centrifuge, water deviate from and dried.To dry the product stainless steel cauldron of packing into, and add the phosphoric acid of 10% concentration to soak 2 hours to flooding material 10cm.With the 650 ℃ of calcinings of stainless steel rotary calcining kiln temperature control 1 hour of packing into after the material taking-up, discharging is packaged into finished product after screening in cooling 5 hours in air.
Catalyst effect embodiment: to carrying out the effect comparative experiments in order to the standby catalyst of top legal system and silica gel and aluminium oxide catalyst, experiment minute intensity and catalytic efficiency two parts carry out.
Embodiment 9: intensity experiment
10 grams are put into drier by the microballoon of above method preparation after respectively at oven dry in 200 ℃ of baking ovens and be cooled to the tubular type air-flow abrasion instrument of packing into after normal temperature, with 1500ml/min air-flow velocity boiling 60 minutes, record its abrasion loss and be respectively 1.2%, 1.7%, 1.6%, 1.5%, 1.3%, 1.2%, 1.4%, 1.8%.
Embodiment 11: intensity experiment
The microballoon of 10 gram silica gel, aluminum oxide micro-sphere and this method preparation is put into drier after respectively at oven dry in 200 ℃ of baking ovens and be cooled to the tubular type air-flow abrasion instrument of packing into after normal temperature, with 1500ml/min air-flow velocity boiling 60 minutes, record its abrasion loss and be respectively silica gel 6%, aluminium oxide 3.8%, the catalyst microspheres of this method preparation is 1.4%.
Embodiment 12: the catalytic efficiency experiment
Under following operating mode, with the yield of melamine, the catalytic efficiency of catalyst is assessed.
Carrier gas: ammonia
Carrier gas flux: 1500ml/min
Reaction temperature: 395 ± 1 ℃
Liquid material flow: 50 grams/h
Loaded catalyst: 250 grams
The result of reaction is that silica gel melamine yield is 3.62g/h, and the melamine yield of aluminum oxide micro-sphere is 6.45g/t, and the catalyst melamine yield made from the embodiment of the present invention 1 to 8 is 9.67g/t-12.09g/h.
Claims (4)
1. the production method of synthesizing melamine catalyst by urea with gas phase method is characterized in that comprising following steps:
(1) virgin rubber processed: by flower bulb alkali and reacting aluminum sulfate glue, the concentration of flower bulb alkali is controlled at 21%--26%, and the concentration of aluminum sulfate is controlled at 20%--30%, and the control of reaction end point of flower bulb alkali and aluminum sulfate neutralization reaction is 5-6 at pH value;
(2) washing: the stirring of the reaction solution in step () is stopped postprecipitation, take out upper water, then add deionized water, after stirring, parked and precipitation, wash 4-6 time, repeatedly to remove the sodium sulphate that produces in course of reaction;
(3) mix making beating: add aluminium hydroxide and nitric acid mixing making beating after the washing colloid, beating time is 10-24 hour;
(4) mist projection granulating: controlling EAT is 400 ℃-420 ℃, and leaving air temp is 110 ℃-120 ℃;
(5) soda boiling reaming: adding concentration is the NaOH of 10%--30%, and temperature is controlled at 90 ℃-100 ℃, and the soda boiling time is 1-2 hour;
(6) washing: repeatedly wash with deionized water, washing times is at least twice, with centrifuge, water is removed and dries, except sodium metasilicate, the sodium aluminate that dereaction generates, the water-solubility impurity of unreacted NaOH;
(7) acid soak: add phosphoric acid to flooding material, immersion is the acid site for the fortifying catalytic agent, strengthens catalyst activity;
(8) calcining: calcine under 600 ℃-650 ℃, calcination time is 1-3 hour;
(9) packing: adopt air to carry out hybrid refrigeration, be 0.2-0.5 hour cool time, is packaged as finished product.
2. the production method of synthesizing melamine catalyst by urea with gas phase method according to claim 1, it is characterized in that: need add aluminium hydroxide when mixing making beating, aluminium hydroxide is Powdered, calculates by mass percentage, and the aluminium hydroxide amount that adds is the 20%-50% of aluminum sulfate amount.
3. the production method of synthesizing melamine catalyst by urea with gas phase method according to claim 2, it is characterized in that: adding and need adding concentration after aluminium hydrate powder is 30% nitric acid, calculate by percentage to the quality, adding concentration is that the amount of 30% nitric acid is 15% of aluminium hydroxide amount, then mixes making beating.
4. the production method of synthesizing melamine catalyst by urea with gas phase method according to claim 1, it is characterized in that: the acid that the acid soak in described step (seven) adopts is phosphoric acid, and the concentration of phosphoric acid is 5%--10%, and soak time is 2-5 hour.
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| CN113694912A (en) * | 2021-09-16 | 2021-11-26 | 四川金象赛瑞化工股份有限公司 | Catalyst for melamine production and preparation method thereof |
| CN113694911A (en) * | 2021-09-16 | 2021-11-26 | 四川金象赛瑞化工股份有限公司 | Catalyst for synthesizing melamine and preparation method thereof |
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| CN1257754A (en) * | 1999-12-23 | 2000-06-28 | 化学工业部天津化工研究设计院 | Process for preparing Si-Al catalyst carrier |
| CN1493565A (en) * | 2003-09-17 | 2004-05-05 | 丁泽华 | Trimeric cyanamide joint production method using one step method |
| CN101024171A (en) * | 2007-03-28 | 2007-08-29 | 德清县三龙催化剂有限公司 | Catalyst for synthesizing melamine and preparing method |
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2012
- 2012-02-01 CN CN 201210022119 patent/CN102580711B/en active Active
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1545648A1 (en) * | 1965-12-24 | 1969-08-07 | Bergwerksverband Gmbh | Process and plant for the production of melamine |
| CN1257754A (en) * | 1999-12-23 | 2000-06-28 | 化学工业部天津化工研究设计院 | Process for preparing Si-Al catalyst carrier |
| CN1493565A (en) * | 2003-09-17 | 2004-05-05 | 丁泽华 | Trimeric cyanamide joint production method using one step method |
| CN101024171A (en) * | 2007-03-28 | 2007-08-29 | 德清县三龙催化剂有限公司 | Catalyst for synthesizing melamine and preparing method |
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