CN104418332A - Preparation method of silicon dioxide - Google Patents
Preparation method of silicon dioxide Download PDFInfo
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- CN104418332A CN104418332A CN201310374157.6A CN201310374157A CN104418332A CN 104418332 A CN104418332 A CN 104418332A CN 201310374157 A CN201310374157 A CN 201310374157A CN 104418332 A CN104418332 A CN 104418332A
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Abstract
The invention provides a preparation method of silicon dioxide, namely, method for preparing the silicon dioxide by carbon dioxide method, and the method comprises the following steps: process gas bubbles with uniform diameter are dispersed into a sodium silicon solution for reaction of the sodium silicon solution and carbon dioxide to produce silicon dioxide slurry, wherein the process gas contains carbon dioxide; the silicon dioxide slurry is filtered to obtain filtrate; the filtrate is pulpified to obtain silicon dioxide pulp liquid; and the silicon dioxide pulp liquid is dried. Silicon dioxide particles prepared by the method are proper in particle size and uniform in particle size distribution, the number of large aggregates is decreased significantly and the content of fine powder is greatly reduced. In addition, initial gas containing carbon dioxide is purified to obtain the process gas with high concentration of carbon dioxide, the process gas with high concentration of carbon dioxide is used as a reaction raw material, the production cost is reduced, and the production efficiency is improved.
Description
Technical field
The present invention relates to chemical production technical field, in particular to a kind of preparation method of silicon-dioxide.
Background technology
Hydrated SiO 2 is commonly called as white carbon black, and molecular formula is SiO
2nH
2o, mode of appearance is powdery, microballon, particulate state, and white carbon black is the widely used material of reinforcing rubber, in general, because white carbon black (ultra-fine, surface-treated exception) reinforcing effect is good no more than carbon black, therefore belongs to half reinforcement and filler material.Therefore to determine according to use occasion the percentage ratio replacing carbon black.Precipitated silica is used for the Tire & Tube that rubber item has automobile, dump truck, truck, tractor, fork truck, bike etc., industrial belt, sebific duct, liner, offset plate, grain processing shelling rubber roll, and to white carbon black be used all more or less in the various technical rubber goods such as rubber overshoes.The work-ing life that a certain amount of white carbon black can improve tire is added in conventional tyre.Test-results shows according to the study, joins 10 ~ 20 parts of white carbon blacks and just can improve cementing property and tear strength, tread life is improved if can increase, and can also strengthen the gripping power of tire road pavement simultaneously, be beneficial to safe driving.Due to the requirement of energy-saving and emission-reduction and environmental protection, increasing white carbon black is applied to rubber for tire industry.Using white carbon black as filler and natural gum and synthetical glue mixing, being applied to tire can reduce rolling resistance, improves wet and slippery performance, thus make automobile oil consumption low, reduce exhaust gas emission.
At present, the main production process of white carbon black mainly contains the intermediate processing in vapor phase process and liquid phase method.The former makes application limited because cost is high.The year production and consumption of China's precipitated silica is more than 700,000 tons, but traditional precipitated silica adopts acid precipitation method to be main, sulfuric acid and water glass are the main raw materials that production precipitated silica is commonly called as white carbon black, current one ton of white carbon black needs to consume about 1.2 tons of water glass, consume in general production process to be concentration be 25 ~ 35% liquid sodium silicate.Different according to the concentration of used sulfuric acid, the precipitator method can be produced silicon-dioxide and be divided into concentrated acid method and diluted acid method.In addition, in traditional precipitator method, the reactor producing silicon-dioxide is generally batch tank reactor, is liquid liquid phase reaction, is mixed by reactant by agitator between sulfuric acid and water glass.But this reaction there will be the superacidulated phenomenon of high local concentrations, be easy to silicon dioxide granule is assembled at liquid liquid interface place for larger aggregate, make the size distribution of silicon dioxide granule uneven simultaneously, thus affect the final quality product of silicon-dioxide.
In recent years, developed and a kind ofly reacted by carbonic acid gas and water glass the method preparing silicon-dioxide at ambient pressure.Wherein, Chinese invention patent CN92106890.5 discloses a kind of carbonic acid gas in stack gases and water glass of utilizing and reacts the method for producing silicon-dioxide, and the processing sequence of the concrete enforcement of the method comprises: stack gases → washing groove → carbonization (adding sodium silicate solution) → press filtration → washing → drying → pulverizing.But, in the process, gas concentration lwevel in stack gas used is not high, in addition, carbon dioxide is skewness in sodium silicate solution, these not only reduce react the speed of carrying out and the silicon dioxide granule particle diameter excessive (large aggregate) making generation or too small (fine powder), size distribution is uneven.
Summary of the invention
For in prior art, the problem that the silicon dioxide granule particle diameter produced excessive (large aggregate) or too small (fine powder), size distribution are uneven, the present invention proposes a kind of method preparing silicon-dioxide, this method comprises:
A () is reacted: by the air bubbles dispersion of the process gas of uniform diameter in sodium silicate solution, to make sodium silicate solution and carbonic acid gas react, and generate silica slurry, wherein, process gas contains carbonic acid gas;
B () filters: filtered silica slip also obtains much filtrate;
(c) pulp: pulp is carried out to much filtrate, obtains silica slurry; And
D () is dry: dried silica slurries.
Specifically, aforesaid method is implemented in the following manner:
Before reactions steps of the present invention, can utilize carbon dioxide purifying device that the initial gas containing carbonic acid gas is purified to the process gas containing carbonic acid gas, wherein, the gas concentration lwevel in initial gas is greater than the gas concentration lwevel in process gas; Carbon dioxide purifying device comprises pressure-swing absorption apparatus, embrane method purification devices, low-temperature fractionation device and/or their combination; With volume fraction, the gas concentration lwevel in initial gas is between 8% and 12%, and the gas concentration lwevel in process gas is more than 30%.Initial gas can be hotblast stove tail gas or other waste gas with above-mentioned gas composition, and it may further include nitrogen, oxygen, sulfurous gas, oxynitride and/or their combination, wherein, the volume fraction of sulfurous gas is less than 0.02%, and the volume fraction of oxynitride is less than 0.05%.Replace containing the process gas of carbonic acid gas the vitriol oil that uses in traditional precipitator method in the application of the invention, saved the consumption of concentrated acid and decreased the discharge of carbon dioxide, there is certain economic benefit.In addition, use the carbon dioxide (volume percent of carbonic acid gas is more than 30%) of the higher concentration after purifying can accelerate speed of reaction as reactant gases, enhance productivity thus make maximization of economic benefit.
In reactions steps, in gas liquid phase reactor, implement the reaction of sodium silicate solution and carbonic acid gas.First evenly spread in sodium silicate solution by air-distributor by bubble, the diameter of bubble, between 1mm and 2mm, meanwhile, utilizes the stir shaft of gas liquid phase reactor inside to drive agitating vane to stir sodium silicate solution.Then, in gas liquid phase reactor, make sodium silicate solution and carbonic acid gas react, gas liquid phase reactor can be loop reactor or stirred-tank reactor; Air-distributor is arranged in gas liquid phase reactor, first process gas containing carbonic acid gas boosts to 60kpa by roots blower, then entered by a gas feed of air-distributor and evenly spread in sodium silicate solution by multiple pores of air-distributor with the form of bubble, the total flux of the pore of air-distributor is between 150L/s and 200L/s, the diameter of pore is between 1mm and 1.5mm, and the gas speed of pore is between 15m/s and 20m/s.The process gas containing carbonic acid gas can be enable to be dispersed in uniformly in sodium silicate solution by using the air-distributor arranged in above-mentioned reactor, it is enable fully to mix with sodium silicate solution, thus to avoid in reaction process, because reactant can not Homogeneous phase mixing and the problem brought completely, also accelerating speed of reaction simultaneously.In addition, due to introducing air sparger, by control the hole diameter of air-distributor between 1mm and 1.5mm and gas speed between 15m/s and 20m/s, and pass through pressure shearing and the mixing effect of agitator flabellum, the distribution of process gas in sodium silicate solution not only can be made often to put all uniformities, realize the really desirable even air feed of entirety, but also bubble diameter can be made to control between 1mm and 2mm (namely, obtain the bubble of the process gas containing carbonic acid gas of uniform diameter), thus increase gas, the contact gear ratio surface-area of liquid two-phase, improve molten gas efficiency and molten tolerance, facilitate gas-liquid mass transfer, shorten the mixing time of gas-liquid two-phase, accelerate reaction process, improve production efficiency.And, compared with traditional reactive liquid solution, in gas liquid reaction of the present invention, the mixing homogeneity of reactant is improved significantly, and eliminates the peracid phenomenon in reaction process, and the dispersiveness of product improves, large aggregate obviously reduces, and dispersiveness significantly improves.Product particle degree improves, and fine powder content greatly reduces.
In reactions steps, in gas liquid phase reactor, add sodium silicate solution and water according to the first mass ratio, wherein, the first mass ratio between 1:0.8 and 1:2.5, preferably between 1:1 and 1:2; The temperature of water is between 50 DEG C and 70 DEG C;
Pressure be greater than 0.3Mpa water vapour heating, stir speed (S.S.) is between 60rpm and 90rmp, under condition preferably between 70rpm and 90rpm, add mol ratio between 0.7:1 and 1.4:1, the carbonic acid gas preferably between 0.9:1 and 1.2:1 and sodium silicate solution are to react; Wherein, the reaction times between 20 minutes and 40 minutes, preferably between 25 minutes and 38 minutes; Temperature of reaction between 74 DEG C and 82 DEG C, preferably between 76 DEG C and 80 DEG C;
Pressure be greater than 0.3Mpa water vapour heating, stir speed (S.S.) is between 60rpm and 90rmp, preferably under the condition of 70rpm and 90rpm, make carbonic acid gas and sodium silicate solution carry out reacting and the pH value controlling sodium silicate solution between 7.6 and 9.0, preferably between 7.8 and 8.6; Wherein, the reaction times between 15 minutes and 30 minutes, preferably between 20 minutes and 28 minutes; Temperature of reaction between 84 DEG C and 94 DEG C, preferably between 86 DEG C and 92 DEG C;
In stir speed (S.S.) between 60rpm and 90rmp, preferably under the condition of 70rpm and 90rpm, add mol ratio between 0.7:1 and 1.4:1, the carbonic acid gas preferably between 0.9:1 and 1.2:1 and sodium silicate solution are to react simultaneously; Between duration of the reaction 15 minutes and 30 minutes, time preferably between 20 minutes and 28 minutes, reaction terminating;
After reaction terminating, the pH value dripping sulfuric acid adjustment silica slurry is between 4.0 and 6.0, between 4.4 and 5.4; Wherein, concentration >=98% of sulfuric acid; Flow≤the 0.8L/h of sulfuric acid.In this reactions steps, by continuous stirring, and stir speed (S.S.) is controlled between 60rpm and 90rpm, effectively can add the speed that fast response carries out.The suitable silica dioxide granule of size can be generated by controlling carbonic acid gas and the mol ratio (between 0.7:1 to 1.4:1) of sodium silicate solution and the concentration of sodium silicate solution.Reaction can be enable to carry out completely by the mixed solution in reactor being adjusted to acidity; By temperature of reaction being controlled between 74 DEG C and 94 DEG C, not only the nucleus formation speed of silicon-dioxide is fast but also quantity is many, thus forms the suitable crystal of size, in addition, can also accelerate speed of reaction.
In filtration step, use pressure filter to implement filtration step, setting pressure is between 0.3Mpa and 0.8Mpa, and preferred value is between 0.4Mpa and 0.6Mpa, the time of implementing to filter, preferred value was between 12 minutes and 17 minutes between 10 minutes and 20 minutes.Filtration step comprises washing step further, uses pressure filter to implement washing step.In washing step, setting pressure is between 0.5Mpa and 0.8Mpa, and preferred value is between 0.6Mpa and 0.8Mpa.Repeat washing step, until the washing electrical conductivity of water < 1000 μ s/cm after washing, to remove impurity Na wherein
2sO
4.After filtration and washing step, form much filtrate, content≤3.0% of vitriol in much filtrate; And the solid content of much filtrate is between 15.0% and 30.0%, preferred value is between 20.0% and 25.0%.
In slurry step, use belt conveyor to be sent in hollander by the much filtrate formed in filtration step, much filtrate, between 150rpm and 250rpm, is slurried into the paste liquid (silica slurry) of mobility by the shearing rate controlling hollander impeller.The viscosity of the silica slurry generated is between 100cp and 1000cp, and preferred value is between 400cp and 800cp, and further preferred value is between 600cp and 800cp.In this step, the viscosity by controlling silica slurry can make the suitable and good dispersity of the silicon-dioxide size of generation at below 1000cp.
In drying step, the silica slurry water pump obtained in above-mentioned slurry step is delivered in drying tower and carries out spraying dry, preferred pressure formula drying plant, control the inlet temperature of drying tower between 400 DEG C and 700 DEG C simultaneously, temperature out, between 80 DEG C and 150 DEG C, obtains silicon-dioxide.By controlling the inlet temperature of drying tower between 400 DEG C and 700 DEG C, temperature out can make the hole between the silica dioxide granule of generation larger between 80 DEG C and 150 DEG C, be not easy to generate large aggregate, and then make the dispersing property of silicon-dioxide better.
In method of the present invention, before reactions steps, dissolving step and set-up procedure can also be comprised.In dissolving step, in static pressure kettle, place sodium silicate solid (Na
2onSiO
2) and water, and pass into water vapour, form sodium silicate solution within a certain period of time, after using pressure filter to leach throw out (impurity), obtain transparent pure water glass strong solution.In dissolving step, SiO in sodium silicate solid
2with Na
2the mass ratio of O is between 2 and 4, and preferred value is between 3.0 and 3.7.The quality of sodium silicate solid and the mass ratio of water are between 2:1 and 3:1, and preferred value is 2:1.Pass into the pressure > 0.3Mpa of water vapour.Dissolution time is between 1.5 hours and 3 hours, and preferred value is between 1.5 hours and 2.5 hours.The density of the water glass strong solution formed is between 1.01g/cm
3and 1.40g/cm
3between, preferred value is between 1.1g/cm
3and 1.3g/cm
3between.
In set-up procedure, the water glass strong solution obtained in dissolving step and water being joined adjusts in tank, thus regulate the solubility of sodium silicate solution between 1.0mol/L and 3.0mol/L, preferred value is between 1.5mol/L and 2.5mol/L, and further preferred value is between 2.0mol/L and 2.5mol/L.
The size of the silica dioxide granule prepared by method provided by the invention is suitable, even particle size distribution, large aggregate quantity obviously reduces and fine powder content greatly reduces.In addition, by purifying the process gas that obtains compared with high carbon dioxide concentration to the initial gas containing carbonic acid gas and it can be used as reaction raw materials, not only reduce production cost and improve production efficiency.
Accompanying drawing explanation
Fig. 1 is the method flow diagram preparing silicon-dioxide S1 according to embodiments of the invention 1;
Fig. 2 is the method flow diagram preparing silicon-dioxide S2 according to embodiments of the invention 2;
Fig. 3 is the method flow diagram preparing silicon-dioxide S3 according to embodiments of the invention 3.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described.Illustrated preferred embodiment is only for illustration of technical scheme of the present invention, and non-limiting the present invention.Based on the embodiment in the present invention, the every other embodiment that those of ordinary skill in the art obtain, all belongs to the scope of protection of the invention.
The detailed process using production technique of the present invention to prepare silicon-dioxide is described below by specific embodiment.
Embodiment 1: the preparation of silicon-dioxide S1
1) dissolve: as shown in S102 in Fig. 1, sodium silicate solid (Anhui Que Cheng chemistry of silicones company limited: Gu-2 types) and water are added in dissolving static pressure kettle according to the mass ratio of 2:1, pass into the water vapour that pressure is 0.4Mpa, abundant dissolving 1.5 hours, obtain transparent pure concentrated liquid water glass after leaching throw out with pressure filter, its density (20 DEG C) is 1.1g/cm
3;
Wherein in sodium silicate solid, SiO
2/ Na
2the weight ratio 3.35 of O;
2) regulate: as shown in S104 in Fig. 1, to by step 1) add water, to adjust wherein Na in the concentrated liquid water glass that obtains
2onSiO
2concentration obtain dilute liquid water glass to 2.20mol/l;
3) synthesize: 3-1) by pressure-swing absorption apparatus, hotblast stove tail gas is purified to the process gas (with volume percentage) that gas concentration lwevel is 35%; Wherein, hotblast stove tail gas comprises the carbon dioxide of volume fraction between 8% and 12%, can further include nitrogen, the oxygen of volume fraction between 8% and 12%, the volume fraction sulfurous gas and the volume fraction oxynitride that is less than 0.05% that are less than 0.02% that volume fraction is 79%.
3-2) as shown in S106 in Fig. 1, in stirred-tank reactor, add step 2 according to the ratio of mass ratio 1:1) in sodium silicate solution and the hot water of 60 DEG C, passing into the water vapour that pressure is greater than 0.3Mpa makes reactor be warming up to 76 DEG C, turn on agitator, setting stir speed (S.S.) is 80rpm, open roots blower by gas concentration lwevel be 35% process gas boost to 60kpa, and sent in stirred-tank reactor by air-distributor, add sodium silicate solution simultaneously, the carbonic acid gas added and the mol ratio of sodium silicate solution are 0.9:1, in this step, use air-distributor can evenly spread in sodium silicate solution by carbonated bubble, wherein, bubble diameter is between 1mm and 2mm, the total flux of the pore of air-distributor is set to 200L/s, the diameter of pore is 1.4mm, the gas speed of pore is set to 19m/s, controlling the reaction times is 27 minutes,
3-3) again passing into the water vapour that pressure is greater than 0.3Mpa makes reactor be warming up to 88 DEG C, makes carbonic acid gas and sodium silicate solution carry out reacting and the pH value controlling sodium silicate solution is 8.8; Reaction times control is 22 minutes;
3-4) then, according to step 3-2) identical working method, add carbonic acid gas and sodium silicate solution that mol ratio is 0.9:1 to react simultaneously; Reaction times control is 25 minutes, termination reaction;
3-5) after reaction terminating, the sulfuric acid dripping concentration >=98% regulates the pH value of silica slurry to be 4.5 obtain rare silica slurry; Wherein, the flow≤0.8L/h of sulfuric acid.
Reaction equation is as follows:
Na
2O·nSiO
2+CO
2→nSiO
2·H
2O+Na
2CO
3；
4) filter: as shown in S108 in Fig. 1, use pressure filter to filter silica slurry, first charging 13 minutes under the pressure of 0.45Mpa, then washs under the pressure of 0.65Mpa, repeated washing, until washing water specific conductivity is that 8000 μ s/cm are with removing impurity Na wherein
2sO
4, form much filtrate, the solid content in much filtrate be 22.2%, sulphate content 2.0%;
5) pulp: as shown in S110 in Fig. 1, by step 4) much filtrate that obtains adds in pulp tank by rotary conveyor, and the shearing rate of setting hollander impeller is 150rpm, much filtrate is broken into the liquid of the pulpous state of mobility, control viscosity is 600cp, obtains silica slurry.
6) dry: as shown in S112 in Fig. 1, silica slurry water pump step 5 obtained is delivered to drying tower pressure type drying plant and carried out spraying dry, set spray-dired temperature in drying tower is 600 DEG C simultaneously, obtains silicon-dioxide S1.
Embodiment 2: the preparation of silicon-dioxide S2
1) dissolve: as shown in S202 in Fig. 2, sodium silicate solid (Anhui Que Cheng chemistry of silicones company limited: Gu-2 types) and water are added in dissolving static pressure kettle according to the mass ratio of 2:1, pass into the water vapour that pressure is 0.4Mpa, abundant dissolving 2.0 hours, obtain transparent pure concentrated liquid water glass after leaching throw out with pressure filter, its density (20 DEG C) is 1.3g/cm
3;
Wherein in sodium silicate solid, SiO
2/ Na
2the weight ratio 3.40 of O;
2) regulate: as shown in S204 in Fig. 2, to by step 1) add water, to adjust wherein Na in the concentrated liquid water glass that obtains
2onSiO
2concentration obtain dilute liquid water glass to 2.35mol/l;
3) synthesize: 3-1) by pressure-swing absorption apparatus, hotblast stove tail gas is purified to the process gas (with volume percentage) that gas concentration lwevel is 40%; Wherein, hotblast stove tail gas comprises the carbon dioxide of volume fraction between 8% and 12%, can further include nitrogen, the oxygen of volume fraction between 8% and 12%, the volume fraction sulfurous gas and the volume fraction oxynitride that is less than 0.05% that are less than 0.02% that volume fraction is 79%.
3-2) as shown in S206 in Fig. 2, according to mass ratio 1:2 ratio to stir autoclave answer in device add step 2) in sodium silicate solution and the hot water of 65 DEG C, passing into the water vapour that pressure is greater than 0.3Mpa makes reactor be warming up to 78 DEG C, turn on agitator, setting stir speed (S.S.) is 80rpm, open roots blower by gas concentration lwevel be 40% process gas boost to 60kpa, and sent in stirred-tank reactor by air-distributor, add sodium silicate solution simultaneously, the carbonic acid gas added and the mol ratio of sodium silicate solution are 1:1, in this step, use air-distributor can evenly spread in sodium silicate solution by carbonated bubble, wherein, bubble diameter is between 1mm and 2mm, the total flux of the pore of air-distributor is set to 180L/s, the diameter of pore is 1.2mm, the gas speed of pore is set to 17m/s, controlling the reaction times is 30 minutes,
3-3) again passing into the water vapour that pressure is greater than 0.3Mpa makes reactor be warming up to 90 DEG C, makes carbonic acid gas and sodium silicate solution carry out reacting and the pH value controlling sodium silicate solution is 8.9; Reaction times control is 25 minutes;
3-4) then, according to step 3-2) identical working method, add carbonic acid gas and sodium silicate solution that mol ratio is 1:1 to react simultaneously; Reaction times control is 25 minutes, termination reaction;
3-5) after reaction terminating, the sulfuric acid dripping concentration >=98% regulates the pH value of silica slurry to be 4.6 obtain rare silica slurry; Wherein, the flow≤0.8L/h of sulfuric acid.
Reaction equation is as follows:
Na
2O·nSiO
2+CO
2→nSiO
2·H
2O+Na
2CO
3；
4) filter: as shown in S208 in Fig. 2, use pressure filter to filter silica slurry, first charging 15 minutes under the pressure of 0.6Mpa, then washs under the pressure of 0.7Mpa, repeated washing, until washing water specific conductivity is that 6000 μ s/cm are with removing impurity Na wherein
2sO
4, form much filtrate, the solid content in much filtrate be 23.6%, sulphate content 1.5%;
5) pulp: as shown in S210 in Fig. 2, by step 4) much filtrate that obtains adds in pulp tank by rotary conveyor, and the shearing rate of setting hollander impeller is 200rpm, much filtrate is broken into the liquid of the pulpous state of mobility, control viscosity is 700cp, obtains silica slurry.
6) dry: as shown in S212 in Fig. 2, by step 5) the silica slurry water pump that obtains delivers to drying tower pressure type drying plant and carries out spraying dry, and in setting drying tower, spray-dired temperature is 500 DEG C, obtains silicon-dioxide S2.
Embodiment 3: the preparation of silicon-dioxide S3
1) dissolve: as shown in S302 in Fig. 3, sodium silicate solid (Anhui Que Cheng chemistry of silicones company limited: Gu-2 types) and water are added in dissolving static pressure kettle according to the mass ratio of 2:1, pass into the water vapour that pressure is 0.4Mpa, abundant dissolving 2.2 hours, obtain transparent pure concentrated liquid water glass after leaching throw out with pressure filter, its density (20 DEG C) is 1.2g/cm
3;
Wherein in sodium silicate solid, SiO
2/ Na
2the weight ratio 3.34 of O;
2) regulate: as shown in S304 in Fig. 3, to by step 1) add water, to adjust wherein Na in the concentrated liquid water glass that obtains
2onSiO
2concentration obtain dilute liquid water glass to 2.37mol/l;
3) synthesize: 3-1) by pressure-swing absorption apparatus, hotblast stove tail gas is purified to the process gas (with volume percentage) that gas concentration lwevel is 38%; Wherein, hotblast stove tail gas comprises the carbon dioxide of volume fraction between 8% and 12%, can further include nitrogen, the oxygen of volume fraction between 8% and 12%, the volume fraction sulfurous gas and the volume fraction oxynitride that is less than 0.05% that are less than 0.02% that volume fraction is 79%.
3-2) as shown in S306 in Fig. 3, according to mass ratio 1.2:1 ratio to stir autoclave answer in device add step 2) in sodium silicate solution and the hot water of 70 DEG C, passing into the water vapour that pressure is greater than 0.3Mpa makes reactor be warming up to 80 DEG C, turn on agitator, setting stir speed (S.S.) is 80rpm, open roots blower by gas concentration lwevel be 38% process gas boost to 60kpa, and send in stirred-tank reactor by air-distributor, add sodium silicate solution simultaneously, the carbonic acid gas added and the mol ratio of sodium silicate solution are 1.2:1, in this step, use air-distributor can evenly spread in sodium silicate solution by carbonated bubble, wherein, bubble diameter is between 1mm and 2mm, the total flux of the pore of air-distributor is set to 160L/s, the diameter of pore is 1mm, the gas speed of pore is set to 16m/s, controlling the reaction times is 34 minutes,
3-3) again passing into the water vapour that pressure is greater than 0.3Mpa makes reactor be warming up to 92 DEG C, makes carbon dioxide and sodium silicate solution carry out reacting and the pH value controlling sodium silicate solution is 8.7; Reaction times control is 26 minutes;
3-4) then, according to step 3-2) identical working method, add carbonic acid gas and sodium silicate solution that mol ratio is 1.2:1 to react simultaneously; Reaction times control is 28 minutes, termination reaction;
3-5) after reaction terminating, the sulfuric acid dripping concentration >=98% regulates the pH value of silica slurry to be 5.1 obtain rare silica slurry; Wherein, the flow≤0.8L/h of sulfuric acid.
Reaction equation is as follows:
Na
2O·nSiO
2+CO
2→nSiO
2·H
2O+Na
2CO
3；
4) filter: as shown in S308 in Fig. 3, use pressure filter to filter silica slurry, first charging 15 minutes under the pressure of 0.5Mpa, then washs under the pressure of 0.7Mpa, repeated washing, until washing water specific conductivity is that 5000 μ s/cm are with removing impurity Na wherein
2sO
4, form much filtrate, the solid content in much filtrate be 23.4%, sulphate content 1.4%;
5) pulp: as shown in S310 in Fig. 3, by step 4)) much filtrate that obtains adds in pulp tank by rotary conveyor, and the shearing rate of setting hollander impeller is 250rpm, much filtrate is broken into the liquid of the pulpous state of mobility, control viscosity is 700cp, obtains silica slurry.
6) dry: as shown in S312 in Fig. 3, by step 5) the silica slurry water pump that obtains delivers to drying tower pressure type drying plant and carries out spraying dry, and in setting drying tower, spray-dired temperature is 400 DEG C, obtains silicon-dioxide S3.
Comparative example: the preparation of silicon-dioxide S4
Use the method identical with embodiment 1 to prepare silicon-dioxide, finally obtain silicon-dioxide S4.Difference is, the process gas containing carbonic acid gas of use is the hotblast stove tail gas without purification process, and wherein, the volume integral ratio of carbonic acid gas is 8%, and does not arrange air-distributor in the reactor used.
Carry out test chemical to four crowdes of silicon-dioxide S1, S2, S3 and S4 prepared by above 3 embodiments and 1 comparative example respectively according to the testing method of HG/T3061-2009 " rubber ingredients precipitated hydrated silica ", test result is in table 1.By 500,000 times of electronic transmission electron microscopic observation silicon-dioxide initiating particle sizes, according to the pore volume of the testing method test silicon-dioxide of ISO 15901-1:2005.
Table 1
Known by data in table 1, compared with comparative example, the initial particle size of the silicon-dioxide of prepared in accordance with the method for the present invention is between 20nm and 30nm, and pore volume is at 1.9cm
3/ g and 2.1cm
3between/g, compared to the particle size range (between 20nm and 90nm) of comparative example, the size distribution of silicon dioxide granule prepared by method of the present invention is more even.In addition, by electron microscope observation, large aggregate obviously reduces, and dispersiveness significantly improves; Found by particle size analysis, product particle degree improves, and fine powder content greatly reduces.
In the above-mentioned methods, the process gas (CO with higher concentration carbonic acid gas in the application of the invention
2volume percent more than 30%) replace the vitriol oil that uses in traditional precipitator method, saved the consumption of concentrated acid and decreased the discharge of carbon dioxide, there is certain economic benefit.In addition, use the process gas with high concentration carbon dioxide after purifying can accelerate speed of reaction as reactant gases, in addition, introducing air sparger not only can eliminate the peracid phenomenon existed in reactive liquid solution in the reactor, but also the process gas containing carbonic acid gas can be enable to be evenly dispersed in sodium silicate solution with the form of the bubble with uniform diameter, it is enable fully to mix with sodium silicate solution, thus avoid reactant in reaction process can not Homogeneous phase mixing and the product problem that causes thus completely, also speed of reaction can be accelerated simultaneously, enhance productivity.From in table 1, use method of the present invention, the average daily production of silicon-dioxide is 130 tons/day, improves about 30%, thus can make maximization of economic benefit compared to the day output of comparative example.
It is to be understood that foregoing invention content and embodiment are intended to the practical application proving technical scheme provided by the present invention, should not be construed as limiting the scope of the present invention.Those skilled in the art in spirit of the present invention and principle, when doing various amendment, equivalent replace or improve.Protection scope of the present invention is as the criterion with appended claims.
Claims (14)
1. a preparation method for silicon-dioxide, is characterized in that, comprises the following steps:
By the air bubbles dispersion of the process gas of uniform diameter in sodium silicate solution, to make described sodium silicate solution and carbonic acid gas react, generate silica slurry, wherein, described process gas contains carbonic acid gas;
Filter described silica slurry and obtain much filtrate;
Pulp is carried out to described much filtrate, obtains silica slurry; And
Dry described silica slurry.
2. preparation method according to claim 1, is characterized in that, is evenly spread in described sodium silicate solution by described bubble by air-distributor.
3. preparation method according to claim 1, is characterized in that, the diameter of described bubble is between 1mm and 2mm.
4. preparation method according to claim 1, it is characterized in that, described by the air bubbles dispersion of the process gas of uniform diameter to the step in sodium silicate solution before, carbon dioxide purifying device is utilized to be purified by the initial gas containing carbonic acid gas as the described process gas containing carbonic acid gas, wherein, the gas concentration lwevel in described process gas is greater than the gas concentration lwevel in described initial gas.
5. the preparation method according to claim 1 or 4, is characterized in that, with volume fraction, the gas concentration lwevel in described process gas is more than 30%.
6. preparation method according to claim 4, is characterized in that, described carbon dioxide purifying device comprises pressure-swing absorption apparatus, embrane method purification devices, low-temperature fractionation device and/or their combination; With volume fraction, the gas concentration lwevel in described initial gas is between 8% and 12%.
7. preparation method according to claim 2, it is characterized in that, in gas liquid phase reactor, make described sodium silicate solution and described carbonic acid gas react, described air-distributor is arranged in described gas liquid phase reactor, described process gas containing carbonic acid gas is entered by the gas feed of described air-distributor and evenly spreads in described sodium silicate solution by the pore of described air-distributor with the form of described bubble, and described gas liquid phase reactor is loop reactor or stirred-tank reactor.
8. preparation method according to claim 7, is characterized in that, the total flux of the pore of described air-distributor is between 150L/s and 200L/s, and the diameter of pore is between 1mm and 1.5mm, and the gas speed of pore is between 15m/s and 20m/s.
9. preparation method according to claim 1, is characterized in that, described by the air bubbles dispersion of the process gas of uniform diameter to the step in sodium silicate solution before, also comprise: with water dissolution sodium silicate solid Na
2onSiO
2to form described sodium silicate solution, and by the concentration adjustment of described sodium silicate solution be between 2.0mol/L and 2.5mol/L.
10. preparation method according to claim 1, it is characterized in that, make described sodium silicate solution and described carbonic acid gas carry out in the process of reacting, the mol ratio of described carbonic acid gas and described sodium silicate solution is between 0.9:1 and 1.2:1, and temperature of reaction is between 76 DEG C and 92 DEG C;
After described reaction terminating, drip sulfuric acid and regulate the pH value of described silica slurry between 4.4 and 5.4; Wherein, concentration >=98% of described sulfuric acid; Flow≤the 0.8L/h of described sulfuric acid.
11. preparation methods according to claim 1, is characterized in that, use pressure filter to implement filter described silica slurry and obtain the step of much filtrate, and filter described silica slurry and the step obtaining described much filtrate comprises further:
Filter described silica slurry;
Wash described silica slurry; And
Silica slurry described in press filtration also obtains described much filtrate;
Wherein, in the step of filtering described silica slurry, the pressure of described pressure filter is between 0.4Mpa and 0.6Mpa; Implement the time of press filtration between 12 minutes and 17 minutes; Silica slurry step described in repeated washing is until the washing electrical conductivity of water < 10000 μ s/cm that formed after washing described silica slurry; In silica slurry described in press filtration and after obtaining the step of much filtrate, the solid content of described much filtrate is between 20.0% and 25.0%, and content≤3.0% of vitriol in described much filtrate.
12. preparation methods according to claim 1, it is characterized in that, utilize hollander to implement to carry out the step of pulp to make the viscosity of described silica slurry between 600cp and 800cp to described much filtrate, wherein, the shearing rate of described hollander is between 150rpm and 250rpm.
13. preparation methods according to claim 1, it is characterized in that, implemented the step of dry described silica slurry by spray-dired mode in pressure type drying tower, wherein, the inlet temperature of described pressure type drying tower is between 400 DEG C and 700 DEG C, and temperature out is between 80 DEG C and 150 DEG C.
14. preparation methods according to claim 9, it is characterized in that, implement to dissolve described sodium silicate solid to form the step of described sodium silicate solution in static pressure kettle, in adjustment tank, implement the step regulating described sodium silicate solution concentration, SiO in described sodium silicate solid
2with Na
2the mass ratio of O is between 3.0:1 and 3.7:1;
Described dissolved solids water glass comprises with the step forming described sodium silicate solution: make mass ratio be that the sodium silicate solid of 2:1 and water fully dissolve under water vapour pressure is greater than the condition of 0.3Mpa, dissolution time, between 1.5 hours and 2.5 hours, forms water glass just liquid; And in pressure filter, filter the first liquid of described water glass to form described sodium silicate solution.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105671522A (en) * | 2016-01-20 | 2016-06-15 | 东北大学 | Method for coating amorphous silicon dioxide membranes on surfaces of solid particles |
| CN108453854A (en) * | 2018-03-28 | 2018-08-28 | 中国科学院理化技术研究所 | A kind of high thermal conductivity coefficient timber and the preparation method and application thereof based on waterglass filling |
| CN111957293A (en) * | 2020-07-15 | 2020-11-20 | 确成硅化学股份有限公司 | Low-heavy metal high-adsorption silicon dioxide and preparation method thereof |
| CN112811433A (en) * | 2019-11-18 | 2021-05-18 | 光宇材料股份有限公司 | Process for preparing silicon dioxide |
| CN112850721A (en) * | 2021-01-28 | 2021-05-28 | 华东理工大学 | White carbon black particles and preparation method and application thereof |
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| CN101786633A (en) * | 2010-02-26 | 2010-07-28 | 无锡恒诚硅业有限公司 | Production technology of white microbead-shaped white carbon black |
| CN102259874A (en) * | 2011-06-30 | 2011-11-30 | 中煤平朔煤业有限责任公司 | Method for preparing white carbon black by continuous carbon precipitation |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101786633A (en) * | 2010-02-26 | 2010-07-28 | 无锡恒诚硅业有限公司 | Production technology of white microbead-shaped white carbon black |
| CN102259874A (en) * | 2011-06-30 | 2011-11-30 | 中煤平朔煤业有限责任公司 | Method for preparing white carbon black by continuous carbon precipitation |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105671522A (en) * | 2016-01-20 | 2016-06-15 | 东北大学 | Method for coating amorphous silicon dioxide membranes on surfaces of solid particles |
| CN108453854A (en) * | 2018-03-28 | 2018-08-28 | 中国科学院理化技术研究所 | A kind of high thermal conductivity coefficient timber and the preparation method and application thereof based on waterglass filling |
| CN112811433A (en) * | 2019-11-18 | 2021-05-18 | 光宇材料股份有限公司 | Process for preparing silicon dioxide |
| CN111957293A (en) * | 2020-07-15 | 2020-11-20 | 确成硅化学股份有限公司 | Low-heavy metal high-adsorption silicon dioxide and preparation method thereof |
| CN112850721A (en) * | 2021-01-28 | 2021-05-28 | 华东理工大学 | White carbon black particles and preparation method and application thereof |
| CN112850721B (en) * | 2021-01-28 | 2023-12-08 | 华东理工大学 | White carbon black particles and preparation method and application thereof |
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