CN110697723A - Method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane residual liquid - Google Patents
Method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane residual liquid Download PDFInfo
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- CN110697723A CN110697723A CN201911063927.9A CN201911063927A CN110697723A CN 110697723 A CN110697723 A CN 110697723A CN 201911063927 A CN201911063927 A CN 201911063927A CN 110697723 A CN110697723 A CN 110697723A
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- silicon dioxide
- phosphoric acid
- residual liquid
- sodium
- chlorosilane residual
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/113—Silicon oxides; Hydrates thereof
- C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
- C01B33/126—Preparation of silica of undetermined type
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/18—Phosphoric acid
- C01B25/22—Preparation by reacting phosphate-containing material with an acid, e.g. wet process
- C01B25/2208—Preparation by reacting phosphate-containing material with an acid, e.g. wet process with an acid or a mixture of acids other than sulfuric acid
- C01B25/2212—Preparation by reacting phosphate-containing material with an acid, e.g. wet process with an acid or a mixture of acids other than sulfuric acid with hydrochloric acid or hydrogen chloride in aqueous medium
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/30—Alkali metal phosphates
- C01B25/308—Methods for converting an alkali metal orthophosphate into another one; Purification; Decolorasing; Dehydrating; Drying
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D3/00—Halides of sodium, potassium or alkali metals in general
- C01D3/04—Chlorides
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/12—Surface area
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- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Silicon Compounds (AREA)
Abstract
The invention discloses a method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane residual liquid, which comprises the following steps: mixing chlorosilane residual liquid and sodium phosphate saturated solution, and adjusting the pH value of the silicon dioxide precursor suspension obtained after mixing by changing the adding amount of the sodium phosphate saturated solution; filtering the suspension of the silica precursor, washing the obtained filter cake with water until the pH value is 6-8, drying the filter cake to obtain silica, concentrating and crystallizing the obtained filtrate, separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution. The invention avoids the pollution of the hydrochloric acid solution to the environment, the corrosion of equipment and the injury of personnel due to a large amount of volatilization, reduces the equipment cost and maintains the health of production personnel. The invention can adjust the production process according to the needs to obtain silicon dioxide and phosphoric acid and salts thereof or silicon dioxide and hydrochloric acid solution, and the obtained products are various and have wide application range.
Description
Technical Field
The invention relates to the technical field of chlorosilane residual liquid recycling and preparation of silicon dioxide, phosphoric acid and sodium salts thereof, in particular to a method for preparing silicon dioxide, phosphoric acid and sodium salts thereof by using chlorosilane residual liquid.
Background
The chlorosilane raffinate is hydrolyzed to produce a hydrochloric acid solution and amorphous silica. The hydrochloric acid solution has strong volatility, severe production environment, severe corrosion to equipment and damage to human health. And the concentration of the prepared hydrochloric acid solution is low, and the energy consumption for concentration and recovery is high. Therefore, a common method is to pass a hydrochloric acid solution into a calcium carbonate suspension to convert the hydrochloric acid solution into nonvolatile calcium chloride. However, the calcium chloride is not used in high quantity in industry, and is piled up for a long time, occupies a large amount of fields, wastes hydrochloric acid resources, and does not really utilize chlorosilane residual liquid.
Disclosure of Invention
The invention aims to provide a method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate, which aims to solve the problem of low utilization rate of the existing chlorosilane raffinate.
The technical scheme for solving the technical problems is as follows:
a method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane residual liquid comprises the following steps: mixing chlorosilane residual liquid and sodium phosphate saturated solution to obtain silicon dioxide precursor suspension, and adjusting the pH value of the silicon dioxide precursor suspension by changing the adding amount of the sodium phosphate saturated solution; and filtering the suspension of the silica precursor, washing the obtained filter cake with water until the pH value is 6-8, and drying the filter cake to obtain the silica. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain phosphate and sodium chloride as crystals and phosphoric acid as solution.
According to the invention, the chlorosilane residual liquid is introduced into a sodium phosphate saturated solution, so that main components in the chlorosilane residual liquid such as silicon tetrachloride and the like react with water to generate silicon dioxide precursor precipitate and hydrochloric acid solution, and the hydrochloric acid can convert the added low-grade sodium phosphate into high-grade sodium phosphate or phosphoric acid. Filtering the precipitate, and drying at high temperature to obtain amorphous silica powder. Reacting hydrogen chloride in the filtrate with sodium phosphate in an additional sodium phosphate saturated solution, and controlling the pH value of the solution and the addition amount of sodium phosphate to convert the added sodium phosphate into sodium dihydrogen phosphate, sodium hydrogen phosphate or phosphoric acid and simultaneously generate sodium chloride.
SiCl as a main component in chlorosilane raffinate4The main reactions with water are:
SiCl4+2H2O→SiO2↓+4HCl。
therefore, the residual chlorosilane liquid is hydrolyzed to obtain silicon dioxide and hydrochloric acid.
The main reaction of sodium phosphate with the generated hydrochloric acid is as follows:
Na3PO4+HCl→Na2HPO4+NaCl；
Na3PO4+2HCl→NaH2PO4+2NaCl；
Na3PO4+3HCl→H3PO4+3NaCl；
the sodium phosphate is converted into sodium dihydrogen phosphate, sodium hydrogen phosphate or phosphoric acid by changing the adding amount of the saturated solution of the sodium phosphate salt so that sodium phosphate reacts with hydrochloric acid with different molar ratios in the solution. That substance is specifically obtained, depending on the control of the pH of the solution. Adjusting the pH value of the silica precursor suspension by changing the addition of the sodium phosphate saturated solution, wherein when the pH value is less than 1, the main product is phosphoric acid; pH is approximately equal to 4.7, and the main product is sodium dihydrogen phosphate; pH 10, the main product is disodium hydrogen phosphate. Thus, different phosphates and phosphoric acid were obtained.
Further, in a preferred embodiment of the invention, the mass ratio of the chlorosilane residual liquid to the sodium phosphate saturated solution is 1 (18-22), and the pH of the obtained silica precursor suspension is 8-8.5.
Further, in a preferred embodiment of the invention, the mass ratio of the chlorosilane residual liquid to the sodium phosphate saturated solution is 1: 20.
Further, in a preferred embodiment of the invention, the mass ratio of the chlorosilane residual liquid to the sodium phosphate saturated solution is 1 (8-12), and the pH of the obtained silica precursor suspension is 4-4.5.
Further, in a preferred embodiment of the invention, the mass ratio of the chlorosilane residual liquid to the sodium phosphate saturated solution is 1: 10.
Further, in a preferred embodiment of the invention, the mass ratio of the chlorosilane residual liquid to the sodium phosphate saturated solution is 1 (2-6), and the pH of the obtained silica precursor suspension is 1-2.5.
Further, in a preferred embodiment of the invention, the mass ratio of the chlorosilane residual liquid to the sodium phosphate saturated solution is 1:5 or 1: 3.
Further, in a preferred embodiment of the present invention, the saturated solution of sodium phosphate salt is a saturated solution of trisodium phosphate.
Further, in the preferred embodiment of the present invention, the drying temperature of the filter cake is 120-180 ℃.
Further, in a preferred embodiment of the present invention, the obtained crystals are disodium hydrogen phosphate, sodium dihydrogen phosphate or sodium chloride.
The invention has the following beneficial effects:
the method converts hydrochloric acid generated by hydrolyzing the chlorosilane residual liquid into the phosphoric acid and the salt solution thereof, avoids the pollution of a large amount of volatile hydrochloric acid solution to the environment, the corrosion of equipment and the injury of personnel, reduces the equipment cost and maintains the health of production personnel. According to the invention, high-grade phosphoric acid, disodium hydrogen phosphate, sodium dihydrogen phosphate and sodium chloride can be prepared by adding low-grade sodium phosphate.
According to the method, the pH value change range of the solution is controlled through the sodium phosphate saturated solution, so that the hydrolysis speed of the chlorosilane residual liquid is controlled, and the method is favorable for obtaining the amorphous silicon dioxide powder with stable quality. By adjusting the adding speed of chlorosilane residual liquid, the amorphous silicon dioxide with different specific surface areas can be obtained. The addition speed of 1L/h to 3L/h, the specific surface area of the obtained silicon dioxide can be 100m2G to 500m2Between/g. Silica of different specific surface sizes can vary widely in its ability to support as a catalyst support. As a dispersing agent, the water-soluble organic acid can form a uniform solution in the solution, and is convenient for the stable placement of the solution.
The invention can adjust the production process according to the needs to obtain silicon dioxide and phosphoric acid and salts thereof or silicon dioxide and hydrochloric acid solution, and the obtained products are various and have wide application range.
Detailed Description
The principles and features of this invention are described below in conjunction with embodiments, which are included to explain the invention and not to limit the scope of the invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
Example 1:
the method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate comprises the following steps:
mixing the chlorosilane residual liquid and the trisodium phosphate saturated solution according to the mass ratio of 1:18 to obtain the silicon dioxide precursor suspension with the pH value of 8.
And filtering the silica precursor suspension, washing the obtained filter cake with water until the pH value is 6, and drying the filter cake at 120 ℃ to obtain the silica. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution.
Example 2:
the method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate comprises the following steps:
mixing the chlorosilane residual liquid and the trisodium phosphate saturated solution according to the mass ratio of 1:22 to obtain the silicon dioxide precursor suspension with the pH value of 8.5.
And filtering the silica precursor suspension, washing the obtained filter cake with water until the pH value is 6-8, and drying the filter cake at 180 ℃ to obtain the silica. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution.
Example 3:
the method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate comprises the following steps:
mixing the chlorosilane residual liquid and the industrial sodium phosphate dodecahydrate saturated solution according to the mass ratio of 1:20 to obtain a silicon dioxide precursor suspension with the pH value of 8.2.
And filtering the suspension of the silica precursor, washing the obtained filter cake with water until the pH value is 7, and drying the filter cake at 150 ℃ to obtain the silica. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution.
Example 4:
the method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate comprises the following steps:
mixing chlorosilane residual liquid and industrial sodium phosphate dodecahydrate saturated solution according to the weight ratio of 1: 8, and the pH value of the obtained silica precursor suspension is 4.
And filtering the silicon dioxide precursor suspension, washing the obtained filter cake with water until the pH value is 6, and drying the filter cake at 150 ℃ to obtain the silicon dioxide. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution.
Example 5:
the method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate comprises the following steps:
mixing chlorosilane residual liquid and industrial sodium phosphate dodecahydrate saturated solution according to the weight ratio of 1: 12, the pH value of the obtained silica precursor suspension is 4.5.
And filtering the suspension of the silica precursor, washing the obtained filter cake with water until the pH value is 8, and drying the filter cake at 150 ℃ to obtain the silica. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution.
Example 6:
the method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate comprises the following steps:
mixing the chlorosilane residual liquid and the trisodium phosphate saturated solution according to the mass ratio of 1:10 to obtain the silica precursor suspension with the pH value of 4.2.
And filtering the suspension of the silica precursor, washing the obtained filter cake with water until the pH value is 7, and drying the filter cake at 150 ℃ to obtain the silica. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution.
Example 7:
the method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate comprises the following steps:
mixing the chlorosilane residual liquid and the trisodium phosphate saturated solution according to the mass ratio of 1:2 to obtain the silica precursor suspension with the pH value of 1.
And filtering the suspension of the silica precursor, washing the obtained filter cake with water until the pH value is 7, and drying the filter cake at 150 ℃ to obtain the silica. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution.
Example 8:
the method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate comprises the following steps:
mixing the chlorosilane residual liquid and the trisodium phosphate saturated solution according to the mass ratio of 1:6 to obtain a silicon dioxide precursor suspension with the pH value of 2.5.
And filtering the suspension of the silica precursor, washing the obtained filter cake with water until the pH value is 7, and drying the filter cake at 150 ℃ to obtain the silica. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution.
Example 9:
the method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate comprises the following steps:
mixing the chlorosilane residual liquid and the industrial sodium phosphate dodecahydrate saturated solution according to the mass ratio of 1:3 to obtain a silicon dioxide precursor suspension with the pH value of 1.5.
And filtering the suspension of the silica precursor, washing the obtained filter cake with water until the pH value is 7, and drying the filter cake at 150 ℃ to obtain the silica. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution.
Example 10:
the method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane raffinate comprises the following steps:
mixing the chlorosilane residual liquid and the industrial sodium phosphate dodecahydrate saturated solution according to the mass ratio of 1:5 to obtain a silicon dioxide precursor suspension with the pH value of 2.
And filtering the suspension of the silica precursor, washing the obtained filter cake with water until the pH value is 7, and drying the filter cake at 150 ℃ to obtain the silica. Concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain sodium phosphate crystals and phosphoric acid solution.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane residual liquid is characterized by comprising the following steps: mixing chlorosilane residual liquid and a sodium phosphate saturated solution to obtain a silicon dioxide precursor suspension, and adjusting the pH value of the silicon dioxide precursor suspension by changing the adding amount of the sodium phosphate saturated solution; filtering the silicon dioxide precursor suspension, washing the obtained filter cake with water until the pH value is 6-8, drying the filter cake to obtain silicon dioxide, concentrating and crystallizing the obtained filtrate, and separating crystals and solution to obtain the crystals which are phosphate, sodium chloride and phosphoric acid.
2. The method for preparing silicon dioxide, phosphoric acid and sodium salts thereof by using chlorosilane residual liquid as claimed in claim 1, wherein the mass ratio of the chlorosilane residual liquid to the saturated solution of the sodium salts is 1 (18-22), and the pH value of the obtained silicon dioxide precursor suspension is 8-8.5.
3. The method for preparing silicon dioxide and phosphoric acid and sodium salt thereof by using chlorosilane residual liquid as claimed in claim 2, wherein the mass ratio of the chlorosilane residual liquid to the saturated solution of sodium salt of phosphoric acid is 1: 20.
4. The method for preparing silicon dioxide, phosphoric acid and sodium salts thereof by using chlorosilane residual liquid as claimed in claim 1, wherein the mass ratio of the chlorosilane residual liquid to the saturated solution of the sodium salts is 1 (8-12), and the pH value of the obtained silicon dioxide precursor suspension is 4-4.5.
5. The method for preparing silicon dioxide and phosphoric acid and sodium salt thereof by using chlorosilane residual liquid as claimed in claim 4, wherein the mass ratio of the chlorosilane residual liquid to the saturated solution of sodium salt of phosphoric acid is 1: 10.
6. The method for preparing silicon dioxide, phosphoric acid and sodium salts thereof by using chlorosilane residual liquid as claimed in claim 1, wherein the mass ratio of the chlorosilane residual liquid to the saturated solution of the sodium salts is 1 (2-6), and the pH value of the obtained silicon dioxide precursor suspension is 1-2.5.
7. The method for preparing silicon dioxide and phosphoric acid and sodium salt thereof by using chlorosilane residual liquid as claimed in claim 6, wherein the mass ratio of the chlorosilane residual liquid to the saturated solution of sodium salt of phosphoric acid is 1:5 or 1: 3.
8. The method for preparing silicon dioxide and phosphoric acid and sodium salt thereof using chlorosilane residual liquid as claimed in claim 1, wherein the saturated solution of sodium phosphate salt is saturated solution of trisodium phosphate.
9. The method for preparing silica and phosphoric acid and sodium salt thereof using chlorosilane residual liquid as claimed in claim 1, wherein the drying temperature of the filter cake is 120-180 ℃.
10. The method for preparing silica and phosphoric acid and sodium salts thereof using chlorosilane raffinate according to any one of claims 1 to 9, wherein the obtained crystals are disodium hydrogen phosphate, sodium dihydrogen phosphate or sodium chloride.
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| CN201911063927.9A CN110697723A (en) | 2019-11-04 | 2019-11-04 | Method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane residual liquid |
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| CN201911063927.9A CN110697723A (en) | 2019-11-04 | 2019-11-04 | Method for preparing silicon dioxide, phosphoric acid and sodium salt thereof by using chlorosilane residual liquid |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4690810A (en) * | 1986-03-26 | 1987-09-01 | Union Carbide Corporation | Disposal process for contaminated chlorosilanes |
| US5080804A (en) * | 1989-12-19 | 1992-01-14 | Huels Aktiengesellschaft | Waste liquid-free processing of chlorosilane distillation residues with calcium carbonate |
| CN101386415A (en) * | 2008-10-21 | 2009-03-18 | 魏昭荣 | Method for preparing inorganic chemical product using waste produced by polycrystalline silicon |
| CN104649281A (en) * | 2013-11-22 | 2015-05-27 | 赵云 | Method for preparing nano white carbon black microspheres from polycrystalline silicon byproduct SiC14 |
-
2019
- 2019-11-04 CN CN201911063927.9A patent/CN110697723A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4690810A (en) * | 1986-03-26 | 1987-09-01 | Union Carbide Corporation | Disposal process for contaminated chlorosilanes |
| US5080804A (en) * | 1989-12-19 | 1992-01-14 | Huels Aktiengesellschaft | Waste liquid-free processing of chlorosilane distillation residues with calcium carbonate |
| CN101386415A (en) * | 2008-10-21 | 2009-03-18 | 魏昭荣 | Method for preparing inorganic chemical product using waste produced by polycrystalline silicon |
| CN104649281A (en) * | 2013-11-22 | 2015-05-27 | 赵云 | Method for preparing nano white carbon black microspheres from polycrystalline silicon byproduct SiC14 |
Non-Patent Citations (2)
| Title |
|---|
| 倪静安 等主编: "《无机及分析化学实验》", 28 February 2007, 高等教育出版社 * |
| 潘长华 主编: "《实用小化工生产大全 第1卷 无机化工产品•复混肥料•农药•兽药》", 30 September 1996, 化学工业出版社 * |
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Application publication date: 20200117 |