Preparation method of silica sol

A technology of silica sol and peptization, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problems of low value of recyclables, environmental pollution, and the inability to recycle or recycle waste water containing salt and acid

Inactive Publication Date: 2012-08-15
ZHEJIANG YUDA CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Therefore, when using this process to produce silica sol, in addition to consuming sodium silicate as a silicon source, it also needs to consume corresponding hydrochloric acid or sulfuric acid. In addition to cost factors, another problem that cannot be ignored is that in this process, ion exchange , Resin washing, regeneration and other processes will produce a large amount of salty and acidic wastewater. Due to factors such as concentration and process costs, the recovery cost of these salty and acidic wastewater is relatively high, and the value of the recyclables is not large, so it is inevitable will discharge a large amount of waste water
[0008] Since the above-mentioned process consumes a large amount of inorganic acid, a large amount of salty and acidic waste water is generated which cannot be recycled or recycled, and there are problems such as high production costs and environmental pollution.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0054] Take a kind of sodium silicate with a Baume degree of 37°Be' (20°C, the same below), add 4 times the amount (weight, the same below) of water to dilute, naturally settle to clear, separate the clear liquid, and measure it. SiO in liquid 2 %=5.0%, Na 2 O%=1.4%, its modulus n=3.7, weigh 600g of the clear liquid, and mix with 600g 3.8% NaHCO under stirring 3 Mix the solution (reaction molar ratio is 1:2.0), until the test liquid phase is basically free of SiO 2 , Continue to stir for about 15 minutes, filter, wash the precipitate with clean water until the washing water is nearly neutral, add about 500ml of deionized water, stir evenly, and set aside.

[0055] In a three-necked flask, add 60g of the aforementioned diluted, naturally settled and clear sodium silicate solution, heat to increase, and continuously add about 60g of acidic dilute silica sol solution under stirring, control the feeding speed to keep the pH value at 8.0~10.0, after the addition is complete Heat and ke...

Embodiment 2

[0058] Take a kind of sodium silicate with a Baume degree of 40°Be', add 3 times the amount of water to dilute and filter, and it is determined that the diluent contains SiO 2 %=7.3%, Na 2 O%=2.3%, its modulus n=3.3, weigh 4000g of the dilute sodium silicate solution, and mix with 4500g containing 6.1% NaHCO under stirring 3 Mix the solution (the reaction molar ratio is 1:2.2), until the test liquid phase is basically free of SiO 2 , Continue to stir for about 15 minutes, filter, wash with clean water until the washing water is nearly neutral, and then use about 1% NH 4 HCO 3 Wash the dilute solution twice, take about 90% of the filter cake, add 5000 ml of deionized water, and beat with a high-speed shearing disperser to obtain about 6000 g of slurry for use.

[0059] In a three-necked flask, add 200g of about 5% NaOH solution, heat to increase the temperature, and continuously add the remaining 10% precipitate after washing with high speed stirring. After adding, continue to stir t...

Embodiment 3

[0061] Take a sodium silicate with a Baume degree of 50°Be', add 4 times the amount of water to dilute, filter, and measure that the dilution contains SiO 2 %=5.6%, Na 2 O%=2.6%, its modulus n=2.2, weigh 500g of this kind of dilute sodium silicate solution, and mix with 900g containing 4.5% NaHCO under stirring 3 Mix the solution (reaction molar ratio is 1:2.3), until the test liquid phase is basically free of SiO 2 , Continue to stir for about 15 minutes, filter, wash the precipitate with clean water until the pH value of the washing water is ≈ 8.5, add about 500 ml of deionized water, and beat with a high-speed shearing disperser to obtain about 650 g of slurry for use.

[0062] Add 200g of SiO in a three-necked flask 2 %≈1.5% alkaline dilute silica sol solution, heating while stirring, to about 90℃, continuously add all about 650g of the slurry obtained by precipitation and dispersion, and add NH appropriately 3 ·H 2 O adjusts the pH value and keeps the pH value around 9.0 to mak...

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Abstract

The invention discloses a preparation method of silica sol, comprising the following steps: reacting with NaHCO3 or NH4HCO3 and sodium silicate Na2O.nSiO2 as raw materials to obtain hydrated SiO2 sediment; filtering to remove filtrate; washing, peptizing, grain-increasing and concentrating filter cake to obtain the silica sol. In the preparation method, the filtrate mainly contains Na2CO3; when NaHCO3 is used as the raw material, a small amount of NaHCO3 is contained; and when NH4HCO3 is used as the raw material, NH3.H2O and a small amount of NH4HCO3 are contained. As the main ingredient of the filtrate can be regenerated into reaction materials by different processing modes, the preparation method disclosed by the invention has the characteristic of cycle use, thereby reducing the production cost of the silica sol, the resource consumption, the emission and the environment damage and avoiding the problems that a great amount of inorganic acid is consumed so as to cause the environmental pollution in the prior art, and the like.

Description

Technical field [0001] The invention relates to a method for preparing silica sol and belongs to the technical field of chemical engineering. Background technique [0002] Silica sol is also called colloidal silica, silicate sol, silica gel, and silica solution. It is amorphous SiO 2 For colloidal solution in water, mSiO can be used 2 ·NH 2 O said. The most used in industry is the particle size of 8-20nm, and contains a small amount of stabilizers such as NaOH, NH 3 ·H 2 Alkaline silica sols such as O, and acidic silica sols are mostly made from this kind of alkaline silica sol. [0003] Since the main component of silica sol is colloidal SiO 2 , So it is chemically inert, odorless, tasteless, non-toxic, non-corrosive, and has a large specific surface area (generally 200m 2 / g or so) and strong adsorption. Therefore, silica sol can be widely used in refractory materials, investment casting, coatings, papermaking, wool spinning and catalyst industries, and is a very important fine ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/141
Inventor 章浩龙
Owner ZHEJIANG YUDA CHEM IND
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