阅读说明：本技术 硅酸钠的生产方法 (Process for producing sodium silicate ) 是由 蒋卫和 罗小沅 于 2019-12-23 设计创作，主要内容包括：本发明提供了一种硅酸钠的生产方法,该方法利用环己烷氧化法生产环己酮过程中产生的废碱溶液或己内酰胺精制过程中产生的浓缩液作为钠源,石英砂提供硅源,焚烧得到硅酸钠。避免了废碱液或浓缩液的焚烧处理过程中产生碳酸钠与硫酸钠等“危险废物”,变废为宝,减少了企业的环保治理成本,同时废碱液或浓缩液的焚烧提供了硅酸钠生产所需要的能量,从而减少了燃料的用量,进而达到降低硅酸钠生产成本、并降低能耗与二氧化碳排放,减少环境污染。(The invention provides a method for producing sodium silicate, which uses waste alkali solution produced in the process of producing cyclohexanone by a cyclohexane oxidation method or concentrated solution produced in the process of refining caprolactam as a sodium source, quartz sand provides a silicon source, and sodium silicate is obtained by burning. The method avoids the generation of dangerous wastes such as sodium carbonate and sodium sulfate in the incineration treatment process of the waste alkali liquor or the concentrated solution, changes waste into valuable, reduces the environmental protection treatment cost of enterprises, and simultaneously provides energy required by the production of sodium silicate by the incineration of the waste alkali liquor or the concentrated solution, thereby reducing the consumption of fuel, further reducing the production cost of the sodium silicate, reducing the energy consumption and the emission of carbon dioxide, and reducing the environmental pollution.)

1. The production method of sodium silicate is characterized by comprising the following steps:

providing a sodium source and a silicon source, wherein the sodium source is waste liquid generated in the process of producing cyclohexanone by a cyclohexane oxidation method or waste liquid generated in the refining process of caprolactam, and the silicon source is quartz sand;

and mixing and burning the sodium source, the silicon source and the fuel to obtain the sodium silicate.

2. The method of claim 1, further comprising the steps of:

and measuring the mass of the Na element in the sodium source and the mass of the Si element in the silicon source.

3. The production method according to claim 1 or 2, wherein a ratio of a mass of the Na element in the sodium source to a mass of the Si element in the silicon source is 23 (12 to 16).

4. The production method according to claim 1 or 2, wherein a ratio of a mass of Na element in the sodium source to a mass of Si element in the silicon source is 23: 14.

5. The production method according to claim 1 or 2, further comprising the steps of:

determining a heating value of the sodium source and a heating value of the fuel;

adjusting the amount of addition of the fuel so that the amount of heat released per kg of the waste liquid and the fuel upon the incineration is controlled to 1000 to 30000kcal on average, based on the measured calorific values of the sodium source and the fuel.

6. The production process according to claim 1 or 2, wherein the sodium source is a waste alkali solution produced in the alkali washing in the process of producing cyclohexanone by the cyclohexane oxidation method or a concentrated solution produced in the refining process of caprolactam.

7. The production method according to claim 6, wherein the spent caustic solution contains a sodium carboxylate and sodium hydroxide; the concentrate contains caprolactam, sodium sulfate, ammonium sulfate and sodium nitrate.

8. The production method according to claim 1 or 2, wherein the fuel is natural gas or fuel oil.

9. The production method according to claim 1 or 2, wherein the incineration is performed in an air atmosphere.

10. The production method according to claim 1 or 2, wherein the conditions for the incineration are: incinerating for 2-10 h at 1400-1700 ℃.

Technical Field

The invention relates to the field of sodium silicate production, in particular to a production method of sodium silicate.

Background

The cyclohexane oxidation method for producing cyclohexanone is an important ring for producing caprolactam, but in the production process, the selectivity is only about 85%, oxidation byproducts mainly comprise dicarboxylic acid, hydroxycarboxylic acid, caprolactone and other substances, and the substances are washed by alkali to form a waste liquid solution (commonly called 'saponification liquid') containing a large amount of sodium carboxylate and sodium hydroxide. Meanwhile, in the ion exchange refining process of caprolactam, an aqueous solution (commonly called as a concentrated solution) containing caprolactam, sodium sulfate, ammonium sulfate and sodium nitrate is generated. At present, the main treatment method for the above-mentioned waste alkali liquor and concentrated solution in the industry is a mixed burning method, which uses fuel oil or natural gas as fuel and burns the waste alkali liquor and concentrated solution at high temperature to convert into water vapor, carbon dioxide, sodium carbonate and sodium sulfate; the treatment method not only needs to consume a large amount of energy, but also generates a large amount of carbon dioxide in the incineration process, and finally generates solids mainly comprising sodium carbonate and sodium sulfate, and because the solubility of the two sodium salts in water is almost similar, the two sodium salts cannot be effectively separated, so that the two sodium salts can only be used as 'dangerous waste' for landfill treatment in industry, a plurality of environmental hidden dangers are brought, and the environmental protection treatment cost of caprolactam enterprises is increased.

The traditional sodium silicate production process comprises the following steps: mixing coal powder, quartz sand (silicon dioxide) and sodium carbonate, burning at high temperature, and cooling with air to obtain sodium silicate solid, wherein the reaction equation is as follows:

Na₂CO₃+SiO₂→Na₂O·SiO₂+CO₂↑

the main functions of the coal powder are to provide heat, sodium carbonate provides a sodium source, and quartz sand provides a silicon source. The production process needs to consume a large amount of energy, and simultaneously, the combustion of the fuel can release a large amount of carbon dioxide to cause environmental pollution.

Disclosure of Invention

Therefore, the method for producing sodium silicate comprehensively utilizes the waste liquid generated in the process of producing cyclohexanone by a cyclohexane oxidation method or the waste liquid generated in the process of refining caprolactam to produce sodium silicate, can reduce energy consumption and discharge of carbon dioxide, and reduces environmental pollution.

The technical scheme of the invention is as follows.

The invention provides a production method of sodium silicate, which comprises the following steps:

providing a sodium source and a silicon source, wherein the sodium source is waste liquid generated in the process of producing cyclohexanone by a cyclohexane oxidation method or waste liquid generated in the refining process of caprolactam, and the silicon source is quartz sand;

and mixing and burning the sodium source, the silicon source and the fuel to obtain the sodium silicate.

The above production method further comprises the steps of:

the mass of the Na element in the sodium source and the mass of the Si element in the silicon source were measured.

The ratio of the mass of the Na element in the sodium source to the mass of the Si element in the silicon source is 23 (12 to 16).

The ratio of the mass of the Na element in the sodium source to the mass of the Si element in the silicon source is 23: 14.

The above production method further comprises the steps of:

measuring the calorific value of the sodium source and the calorific value of the fuel;

the amount of addition of the fuel is adjusted so that the amount of heat released per kg of the sodium source and the fuel during the incineration is controlled to 1000 to 30000kcal on average, based on the measured calorific values of the sodium source and the fuel.

The sodium source is waste alkali solution generated in alkali washing in the process of producing cyclohexanone by a cyclohexane oxidation method or concentrated solution generated in a caprolactam refining process.

The waste alkali solution contains sodium carboxylate and sodium hydroxide; the concentrate contains caprolactam, sodium sulfate, ammonium sulfate and sodium nitrate.

The fuel is natural gas or fuel oil.

The above incineration was performed in an air atmosphere.

The conditions of the incineration are as follows: incinerating for 2-10 h at 1400-1700 ℃.

In the method, the waste liquid generated in the process of producing cyclohexanone by a cyclohexane oxidation method or the waste liquid generated in the refining process of caprolactam is used as a sodium source, quartz sand provides a silicon source, and sodium silicate is prepared by high-temperature incineration. The main component of the waste alkali solution generated in the process of alkali washing in the process of producing cyclohexanone by a cyclohexane oxidation method is sodium carboxylate, and sodium carbonate is mainly formed in the process of high-temperature incineration treatment; sodium sulfate is formed in the concentrated solution generated in the refining process of caprolactam during high-temperature incineration treatment, and simultaneously, sodium silicate is generated by quartz sand (silicon dioxide) and formed sodium carbonate or sodium sulfate during high-temperature incineration. On one hand, the waste liquid in the method provides a sodium source required for producing sodium silicate, avoids 'dangerous wastes' such as sodium carbonate and sodium sulfate generated in the traditional mixed burning method, changes waste into valuable, and simultaneously reduces the environmental protection treatment cost of enterprises.

Detailed Description

In order that the invention may be more fully understood, a more particular description of the invention will now be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

One embodiment of the present invention provides a method for producing sodium silicate, comprising the following steps S1 to S2.

S1, providing a sodium source and a silicon source, wherein the sodium source is waste liquid generated in the process of producing cyclohexanone by a cyclohexane oxidation method or waste liquid generated in the refining process of caprolactam, and the silicon source is quartz sand;

in one embodiment, the sodium source is a waste alkali solution generated in alkali washing in the process of producing cyclohexanone by a cyclohexane oxidation method or a concentrated solution generated in a caprolactam refining process. Further, the waste alkali solution contains sodium carboxylate and sodium hydroxide, and the concentrated solution contains caprolactam, sodium sulfate, ammonium sulfate and sodium nitrate.

In the process of producing cyclohexanone by cyclohexane oxidation, alkali washing is carried out in the post-treatment process to form waste alkali aqueous solution containing 30-90% of sodium carboxylate and 10-30% of sodium hydroxide; meanwhile, in the ion exchange refining process of caprolactam, an aqueous solution (commonly called as a concentrated solution) containing 5-15% of caprolactam, 3-6% of sodium sulfate, 5-15% of ammonium sulfate and 5-15% of sodium nitrate is generated; at present, the main treatment method for waste alkali liquor and concentrated solution in the industry is a mixed burning method, the solid phase mainly formed after oxygen-containing high-temperature burning is sodium carbonate, the solid phase mainly formed after high-temperature burning of concentrated solution is sodium sulfate, and the finally generated solid is mainly sodium carbonate and sodium sulfate.

The technicians try to recover dicarboxylic acid from waste alkali liquor, but new acid-containing waste water is generated, and a large part of carboxylic acid cannot be recovered, so that how to treat waste liquor generated in the production process in a green and efficient manner is a great challenge for the technicians in the field.

In one embodiment, step S1 further includes step S11.

And S11, measuring the mass of the Na element in the waste liquid and the mass of the Si element in the quartz sand.

In order to treat the waste liquid generated in the production process in a green and efficient way, a great deal of research and analysis finds that: the mass fraction of Na element in the waste liquid and the mass fraction of Si element in the quartz sand are obtained through elemental analysis and measurement, then the mass of Na element contained in the waste liquid to be treated is calculated, the addition amount of the quartz sand is adjusted according to the calculated result, and the mass of the Si element in the added quartz sand and the mass of the Na element contained in the waste liquid to be treated are controlled in a proper proportion, so that the sodium ions in the waste liquid can be recovered to the maximum extent, and the quartz sand is fully utilized.

It is understood that other methods in the art for measuring the mass of Na element in the waste liquid and the mass of Si element in the silica sand can be used.

In one embodiment, the mass ratio of Na element in the waste liquid to Si element in the quartz sand is 23 (12-16).

In one embodiment, the mass ratio of the Na element in the waste liquid to the Si element in the quartz sand is 23: 14.

In one embodiment, step S1 further includes step S12.

And S21, measuring the heat value of the sodium source and the heat value of the fuel.

In one embodiment, the amount of fuel added is adjusted to control the amount of heat released per kg of the sodium source and the fuel during the incineration to 1000kcal to 30000kcal on average, based on the measured calorific value of the sodium source and the measured calorific value of the fuel.

In one embodiment, the amount of fuel added is adjusted to control the amount of heat released per kg of the sodium source and the fuel upon the incineration to 10000kcal to 30000kcal on average, based on the measured calorific value of the sodium source and the calorific value of the fuel.

It is understood that the heating value of the sodium source and the heating value of the fuel can be measured using a calorimeter, and other methods of measuring the heating value known in the art can be used.

The method for calculating the heat quantity includes: the total heat given off by the waste liquid and the fuel during incineration is divided by the total mass of the waste liquid and the fuel.

It should be noted that step S21 and step S11 have no specific sequence.

And S2, mixing and burning the sodium source, the silicon source and the fuel to obtain the sodium silicate.

The waste liquid produced in the process of producing cyclohexanone by using a cyclohexane oxidation method or the waste liquid produced in the refining process of caprolactam is used as a sodium source, and through a large amount of research and analysis, the addition amount of fuel is adjusted, so that the heat produced during the incineration of the waste liquid can just meet the energy required by the production of sodium silicate, the use of the fuel is reduced, the waste of energy is avoided, and then the production cost of sodium silicate is reduced, the energy consumption and the carbon dioxide emission are reduced, and the environmental pollution is reduced.

Meanwhile, sodium carbonate or sodium sulfate generated by quartz sand (silicon dioxide) and waste alkali liquor or concentrated solution generates sodium silicate when incinerated at high temperature. The method avoids the dangerous wastes such as sodium carbonate, sodium sulfate and the like generated in the traditional mixed burning method, changes waste into valuable, and reduces the environmental protection treatment cost of enterprises.

In one embodiment, the fuel is natural gas or fuel oil.

In one of the embodiments, the incineration is performed in an air atmosphere.

In one embodiment, the conditions of incineration are: incinerating for 2-10 h at 1400-1700 ℃.

While the present invention will be described with respect to particular embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover by the appended claims the scope of the invention, and that certain changes in the embodiments of the invention will be suggested to those skilled in the art and are intended to be covered by the appended claims.