阅读说明：本技术 一种合成法生产二氧化硅的方法 (Method for producing silicon dioxide by synthesis method ) 是由 闫福全 于 2021-11-24 设计创作，主要内容包括：本发明公开了一种合成法生产二氧化硅的方法,涉及二氧化硅生产领域,其步骤包括将将三苯基氧膦原料经计量后由电动葫芦吊装加入到备料釜中,溶剂甲苯通过计量泵由罐区加入到所述备料釜中,开启夹套通循环水冷却,保持常压下通过高位槽压入三氯硅烷,所述三氯硅烷加完毕后将夹套通蒸汽缓慢升温到80℃,在保温条件下进行回流反应,待保温回流反应达到工艺规定时间后,夹套通蒸汽升温。有益效果在于：本发明二氧化硅通过合成法进行制得,其本身的纯度要优于传统的水玻璃沉淀法产生的二氧化硅产品,杂质更少,可以广泛应用于轮胎工业、硅橡胶工业的增强改性,并且反应过程中的另一产物三苯基膦也是生产所需的重要原料,工艺产物利用率。(The invention discloses a method for producing silicon dioxide by a synthesis method, which relates to the field of silicon dioxide production and comprises the steps of hoisting a triphenylphosphine oxide raw material into a material preparation kettle by an electric hoist after the triphenylphosphine oxide raw material is metered, adding a solvent toluene into the material preparation kettle from a tank area through a metering pump, opening a jacket, cooling by circulating water, keeping the pressure of the trichlorosilane pressed in through a head tank under normal pressure, slowly heating the jacket to 80 ℃ by steam after the trichlorosilane is added, carrying out reflux reaction under a heat preservation condition, and heating the jacket by steam after the heat preservation reflux reaction reaches a process specified time. Has the advantages that: the silicon dioxide is prepared by a synthesis method, the purity of the silicon dioxide is superior to that of a silicon dioxide product generated by a traditional water glass precipitation method, impurities are less, the silicon dioxide can be widely applied to enhancement modification in the tire industry and the silicon rubber industry, another product triphenylphosphine in the reaction process is also an important raw material required by production, and the utilization rate of a process product is high.)

1. A method for producing silica by a synthesis method, comprising the steps of:

firstly, a triphenylphosphine oxide raw material is metered and then is hoisted by an electric hoist to be added into a material preparation kettle, a solvent toluene is added into the material preparation kettle from a tank area through a metering pump, a jacket is opened to be cooled by circulating water, trichlorosilane is pressed in through an overhead tank under normal pressure, the temperature of the jacket is slowly raised to 80 ℃ through steam after the trichlorosilane is added, reflux reaction is carried out under a heat preservation condition, after the heat preservation reflux reaction reaches a process specified time, the temperature of the jacket is raised through steam, unreacted trichlorosilane is evaporated for later use, the evaporated toluene is recovered for later use by deep cooling, the condensed organic noncondensable gas is sent into an RTO device through a pipeline to be incinerated, and after the recovery of trichlorosilane is finished, the temperature of the jacket is reduced to below 30 ℃ through circulating water;

step two, firstly, quantitative process water is metered into a hydrolysis kettle, the hydrolysis kettle is started for stirring, then a discharge valve of a reduction reaction kettle is started, a reduction reaction product is dripped into the hydrolysis reaction kettle through a closed pipeline for hydrolysis reaction, the dripping speed and the jacket circulating water flow are controlled, the temperature in the kettle is not more than 35 ℃, hydrogen chloride gas generated by the hydrolysis reaction is absorbed by a falling film absorption device to obtain a byproduct hydrochloric acid, then the hydrolysis reaction product precipitated in the hydrolysis reaction process is separated by a centrifuge to obtain a hydrolysis solid phase product silicon dioxide, a centrifugate generated in the centrifugation process is discharged into a washing kettle or a filtrate intermediate tank, and the obtained solid phase silicon dioxide filter cake silicon dioxide is transferred into a desorption refining tank;

desorbing the silicon dioxide through an alkali dissolving stage, a standing layering stage and a liquid separating stage;

and step four, preparing the silicon dioxide through an acidification precipitation stage, a drying stage and a cooling packaging stage.

2. A method of synthesizing silica in accordance with claim 1 wherein: the alkali dissolving stage in the third step comprises the steps of adding a quantitative alkaline solution into an alkali dissolving kettle through a liquid caustic soda pump, starting stirring, then metering a silicon dioxide filter cake generated in a filter pressing process, and stirring until the silicon dioxide is completely dissolved;

the standing and layering stage comprises the step of separating toluene from a triphenylphosphine organic liquid phase, a triphenylphosphine oxide solid phase and a sodium silicate inorganic liquid phase;

and in the liquid separation stage, the separated inorganic liquid phase of the sodium silicate is sent to an acidification precipitation unit for treatment, and the organic solid phase and the liquid phase enter a recovery unit.

3. A method of synthesizing silica in accordance with claim 1 wherein: the acidification and precipitation stage comprises adding a quantitative sodium silicate solution into an acidification and precipitation kettle, controlling the temperature to be not more than 80 ℃, dropwise adding hydrochloric acid to adjust the pH value to be 5-6, keeping the temperature for 3 hours, measuring the pH value to be unchanged, then performing filter pressing, cleaning a filter cake with hot water, taking a filter pressing solution as a sodium chloride solution to perform an evaporation salt manufacturing process, and removing the volatilized hydrogen chloride gas to a falling film absorption device through a pipeline;

in the drying stage, the silicon dioxide filter cake is sent into a circulating rotary kiln, high-temperature tail gas discharged by an RTO device is used for drying the silicon dioxide at high temperature to prepare a silicon dioxide product, and a small amount of adsorbed organic matters are decomposed into carbon dioxide and water vapor in the drying stage;

and in the cooling and packaging stage, the prepared silicon dioxide dry powder is pumped into a storage bin with a cooling system, and automatic packaging is carried out when the temperature reaches normal temperature.

4. A method of synthesizing silica in accordance with claim 1 wherein: and (4) sending the organic waste gas discharged in the second step and the third step into an RTO device through a pipeline for incineration treatment.

Technical Field

The invention relates to the field of silicon dioxide production, in particular to a method for producing silicon dioxide by a synthesis method.

Background

The silicon dioxide is an inorganic substance, has a chemical formula of SiO2, and is formed by long-range ordered arrangement of silicon atoms and oxygen atoms and amorphous silicon dioxide formed by short-range ordered or long-range disordered arrangement. In the silicon dioxide crystal, silicon atom is positioned at the center of a regular tetrahedron, four oxygen atoms are positioned at four top corners of the regular tetrahedron, a plurality of the tetrahedrons are connected through the oxygen atoms at the top corners, and each oxygen atom is shared by two tetrahedrons, namely each oxygen atom is combined with two silicon atoms;

at present, the preparation of silicon dioxide products is mainly applied to the enhancement and modification of rubber and plastic products by a water glass precipitation method, but all technical quality indexes are relatively low.

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for producing silica by a synthesis method.

The invention realizes the purpose through the following technical scheme:

a method for producing silica by a synthesis method, comprising the steps of:

firstly, a triphenylphosphine oxide raw material is metered and then is hoisted by an electric hoist to be added into a material preparation kettle, a solvent toluene is added into the material preparation kettle from a tank area through a metering pump, a jacket is opened to be cooled by circulating water, trichlorosilane is pressed in through an overhead tank under normal pressure, the temperature of the jacket is slowly raised to 80 ℃ through steam after the trichlorosilane is added, reflux reaction is carried out under a heat preservation condition, after the heat preservation reflux reaction reaches a process specified time, the temperature of the jacket is raised through steam, unreacted trichlorosilane is evaporated for later use, the evaporated toluene is recovered for later use by deep cooling, the condensed organic noncondensable gas is sent into an RTO device through a pipeline to be incinerated, and after the recovery of trichlorosilane is finished, the temperature of the jacket is reduced to below 30 ℃ through circulating water;

step two, firstly, quantitative process water is metered into a hydrolysis kettle, the hydrolysis kettle is started for stirring, then a discharge valve of a reduction reaction kettle is started, a reduction reaction product is dripped into the hydrolysis reaction kettle through a closed pipeline for hydrolysis reaction, the dripping speed and the jacket circulating water flow are controlled, the temperature in the kettle is not more than 35 ℃, hydrogen chloride gas generated by the hydrolysis reaction is absorbed by a falling film absorption device to obtain a byproduct hydrochloric acid, then the hydrolysis reaction product precipitated in the hydrolysis reaction process is separated by a centrifuge to obtain a hydrolysis solid phase product silicon dioxide, a centrifugate generated in the centrifugation process is discharged into a washing kettle or a filtrate intermediate tank, and the obtained solid phase silicon dioxide filter cake silicon dioxide is transferred into a desorption refining tank;

desorbing the silicon dioxide through an alkali dissolving stage, a standing layering stage and a liquid separating stage;

and step four, preparing the silicon dioxide through an acidification precipitation stage, a drying stage and a cooling packaging stage.

Further, the alkali dissolving stage in the third step comprises the steps of adding a quantitative alkaline solution into an alkali dissolving kettle through a liquid caustic soda pump, starting stirring, metering a silicon dioxide filter cake generated in a filter pressing process, and stirring until the silicon dioxide is completely dissolved;

the standing and layering stage comprises the step of separating toluene from a triphenylphosphine organic liquid phase, a triphenylphosphine oxide solid phase and a sodium silicate inorganic liquid phase;

and in the liquid separation stage, the separated inorganic liquid phase of the sodium silicate is sent to an acidification precipitation unit for treatment, and the organic solid phase and the liquid phase enter a recovery unit.

Further, the acidification and precipitation stage comprises adding a quantitative sodium silicate solution into an acidification and precipitation kettle, controlling the temperature to be not more than 80 ℃, dropwise adding hydrochloric acid to adjust the pH value to be 5-6, keeping the temperature for 3 hours, measuring the pH value to be unchanged, then performing filter pressing, cleaning a filter cake with hot water, taking the filter pressing liquid as a sodium chloride solution to perform an evaporation salt manufacturing process, and removing the volatilized hydrogen chloride gas to a falling film absorption device through a pipeline;

in the drying stage, the silicon dioxide filter cake is sent into a circulating rotary kiln, high-temperature tail gas discharged by an RTO device is used for drying the silicon dioxide at high temperature to prepare a silicon dioxide product, and a small amount of adsorbed organic matters are decomposed into carbon dioxide and water vapor in the drying stage;

and in the cooling and packaging stage, the prepared silicon dioxide dry powder is pumped into a storage bin with a cooling system, and automatic packaging is carried out when the temperature reaches normal temperature.

And further, the organic waste gas discharged in the second step and the organic waste gas discharged in the third step are sent to an RTO device through pipelines for incineration treatment.

Has the advantages that:

the silicon dioxide provided by the invention is prepared by a synthesis method, the purity of the silicon dioxide is superior to that of a silicon dioxide product generated by a traditional water glass precipitation method, the impurities are less, the silicon dioxide can be widely applied to enhancement modification in the tire industry and the silicon rubber industry, another product triphenylphosphine in the reaction process is also an important raw material required by production, and the utilization rate of a process product is high.

Detailed Description

The invention is further illustrated by the following examples and comparative examples:

examples

A method for producing silica by a synthesis method, comprising the steps of:

step one, a reduction reaction process, namely, hoisting a triphenylphosphine oxide raw material by an electric hoist after metering, adding a solvent toluene into a material preparation kettle from a tank area through a metering pump, starting a jacket, cooling by circulating water, keeping the pressure of trichlorosilane pressed in through a head tank under normal pressure, slowly heating the jacket to 80 ℃ by steam after the trichlorosilane is added, carrying out reflux reaction under a heat preservation condition, heating the jacket by steam after the heat preservation reflux reaction reaches a process specified time, evaporating unreacted trichlorosilane for later use, recovering evaporated toluene by deep cooling, sending condensed organic noncondensable gas into an RTO device through a pipeline for incineration treatment, and cooling to below 30 ℃ by circulating water after the trichlorosilane is recovered;

in this step, the triphenylphosphine oxide raw material needs to be dehydrated by toluene for dehydration treatment before use, so toluene exists in the raw material, and a part of toluene also remains after evaporation, and the reduction reaction principle of this step is mainly that triphenylphosphine oxide reacts with trichlorosilane to generate triphenylphosphine, chlorosiloxane and hydrogen chloride, and the reaction formula is as follows:

Ph3PO+SiHCl3→PPh3+1/n(OSiCl2)n+HCl。

step two, a hydrolysis reaction process, namely firstly, metering quantitative process water into a hydrolysis kettle, starting the hydrolysis kettle for stirring, then, starting a discharge valve of a reduction reaction kettle, dropwise adding a reduction reaction product into the hydrolysis reaction kettle through a closed pipeline, carrying out hydrolysis reaction, controlling the dropwise adding speed and the jacket circulating water flow, enabling the temperature in the kettle to be not more than 35 ℃, absorbing hydrogen chloride gas generated by the hydrolysis reaction through a falling film absorption device to obtain a byproduct hydrochloric acid, and sending organic waste gas discharged by the device into an RTO device through a pipeline for incineration treatment;

separating the hydrolysis reaction product precipitated in the hydrolysis reaction process by a centrifugal machine to obtain a hydrolysis solid-phase product silicon dioxide, discharging the centrifugate generated in the centrifugation process into a washing kettle or a filtrate intermediate tank, transferring the obtained solid-phase silicon dioxide filter cake into silicon dioxide desorption and refining, and intensively collecting the organic waste gas generated in the centrifugation process and then feeding the organic waste gas into an RTO device through a pipeline for incineration treatment;

in the step, the principle of the hydrolysis reaction is mainly that chlorosiloxane and a small amount of unrecovered unreacted trichlorosilane in a reduction reaction product react with water to generate silicon dioxide precipitate, hydroxyl hydrogen silicon condensation product precipitate and hydrogen chloride respectively, and then the hydroxyl hydrogen silicon condensation product reacts with oxygen to generate silicon dioxide and water, wherein the reaction formula is as follows:

(OSiCl2)n+H2O→SiO2↓+HCL，

2SiHCl3+3H2O→(HSiO)2O↓+6HCL，

(HSiO)2O+O2→2SiO2↓+H2O，

wherein the latter two reaction formulas can be combined into 2SiHCl3+2H2O + O2 → 2SiO2 ↓ +6 HCL;

solid-phase silica hydrate is continuously generated in the hydrolysis reaction process and precipitated, and meanwhile, unreacted triphenylphosphine oxide in the reduction reaction is absorbed by silica and precipitated in the lower layer of the hydrolysis kettle together with the silica hydrate.

Step three, desorbing the silicon dioxide, wherein the main process is as follows:

in the alkali dissolving stage, quantitative alkaline solution is pumped into an alkali dissolving kettle through a liquid alkali pump, stirring is started, then silicon dioxide filter cakes generated in the filter pressing procedure are metered and counted, stirring is carried out until the silicon dioxide is completely dissolved,

the alkaline solution at this stage is mainly calcium hydroxide or sodium hydroxide solution, taking sodium hydroxide solution as an example, silicon dioxide and sodium hydroxide solution react to generate sodium silicate and water, and the specific equation is

SiO₂+2NaOH→Na₂SiO₃+H₂O；

Standing and layering, stopping stirring, standing and layering, and separating the toluene from a triphenylphosphine organic liquid phase, a triphenylphosphine oxide solid phase and a sodium silicate inorganic liquid phase;

in the liquid separation stage, the separated inorganic liquid phase of the sodium silicate is sent to an acidification precipitation unit for treatment, and the organic solid phase and the liquid phase enter a recovery unit;

in the step, the organic noncondensable gas generated in the desorption process of the silicon dioxide is sent to an RTO device through a pipeline for incineration treatment.

Step four, preparing the silicon dioxide, wherein the specific process is as follows:

an acidification precipitation stage, namely adding a quantitative sodium silicate solution into an acidification precipitation kettle, controlling the temperature to be not more than 80 ℃, dropwise adding hydrochloric acid to adjust the pH value to be 5-6, keeping the temperature for 3 hours, measuring the pH value to be unchanged, then performing filter pressing, cleaning a filter cake with hot water, taking a sodium chloride solution as a filter pressing liquid to perform an evaporation salt manufacturing process, and removing volatile hydrogen chloride gas to a falling film absorption device through a pipeline, wherein the sodium silicate and the hydrochloric acid in an acidification precipitation unit react to obtain sodium chloride, silicon dioxide precipitate and water, and the reaction formula is Na2SiO3+2HCl → 2NaCl + SiO2 ↓ + H2O;

in the drying stage, the silicon dioxide filter cake is sent into a circulating rotary kiln, high-temperature tail gas discharged by an RTO device is used for drying the silicon dioxide at high temperature to prepare a silicon dioxide product, and a small amount of adsorbed organic matters are decomposed into carbon dioxide and water vapor in the drying stage;

and in the cooling and packaging stage, the prepared silicon dioxide dry powder is pumped into a storage bin with a cooling system, and automatic packaging is carried out when the temperature reaches normal temperature.

In this embodiment, the above steps include organic waste gas and inorganic waste gas, and the specific treatment process is as follows:

(1) the production process is mostly carried out in closed equipment, and a distillation recovery device is arranged for a process of using a large amount of solvent to recycle the solvent.

(2) And arranging a hydrochloric acid absorption device for preparing a byproduct of hydrogen chloride, absorbing the tail gas by using three-stage water, then absorbing the tail gas by using a first-stage dilute alkali solution, finally performing adsorption treatment by using activated carbon, and discharging the treated waste gas through an exhaust funnel in a high-altitude standard-reaching manner.

(3) Absorbing the tail gas with secondary water, absorbing with primary dilute alkali solution, adsorbing and desorbing with active carbon, incinerating the treated waste gas with RTO, and discharging via an exhaust funnel to reach the standard.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.