Preparation method of silica gel

A technology of silica gel and sodium silicate, which is applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve problems such as high production costs, unrecyclable or recycled waste water containing salt and acid, and environmental pollution, so as to reduce raw materials cost, reduction of emissions, reduction of environmental damage effects

Inactive Publication Date: 2012-11-07
ZHEJIANG YUDA CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Due to the consumption of sulfuric acid in the above process, 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

[0052] Take a sodium silicate with a Baume degree of 52°Be' (20°C, the same below), add 5 times the amount (weight, the same below) of water to dilute, filter, and measure the diluent containing SiO 2 % = 4.9%, Na 2 O%=2.3%, its modulus n=2.2, weighs 600g of this dilute solution, mixes with 1200g 3.1% NaHCO under stirring 3 The solutions were mixed (the reaction molar ratio was 1:2.0), and the stirring was continued for about 1 hr. After standing for precipitation for 12 hours, about 1200 g of the supernatant liquid was poured out and set aside. Wash the lower sediment part with tap water for 3 to 4 times, then wash with tap water acidified by sulfuric acid with a pH value of 3 to 4, then soak the hydrogel in tap water containing about 0.02% sulfuric acid for 24 hours, remove it, pour water, and Dry to obtain silica gel product.

[0053] In the supernatant that was poured out from the aforementioned upper layer, CO 2 Reaction, about 1200g solution after the reaction was com...

Embodiment 2

[0055] Get a kind of sodium silicate whose Baume degree is 36 ° Be', add 4 times of water to dilute, filter, and measure that the diluted solution contains SiO 2 %=4.85%, Na 2 O% = 1.36%, its modulus n = 3.7, weigh 600g of the dilute solution, mix it with 800g of 1.3% NH 4 HCO 3 The solutions were mixed (the reaction molar ratio was 1:1.0), and the stirring was continued for about 1 hr. After standing for 36 hours of precipitation, about 800 grams of the supernatant was poured out and set aside. The precipitated part of the lower layer was washed 3 to 4 times with tap water, and then washed with 0.15% NH 3 Wash and soak in tap water for 3 to 4 times, remove, pour water, and dry to obtain silica gel products.

[0056] In the supernatant that was poured out from the aforementioned upper layer, CO 2 After the reaction, about 800g of solution was obtained after the reaction was completed, which was NaHCO 3 and NH 4 HCO 3 Mixed solution, tested to contain NaHCO 3 About 1.5%...

Embodiment 3

[0058] Get a kind of sodium silicate whose Baume degree is 41 ° Be', add 3 times the amount of water to dilute, filter, and measure that the diluted solution contains SiO 2 % = 6.5%, Na 2 O%=2.1%, its modulus n=3.2, this dilute solution and 6.8% NaHCO 3 The solution is mixed at a high speed in the nozzle of the jet mixer at a ratio of about 1:1 (reaction molar ratio is about 1:2.4), enters the turbine oil column through the distribution umbrella, and is brought out by the circulating water at the bottom of the forming column. The circulating water temperature is 40-50°C. The spherical hydrogel brought out by the circulating water enters the sieve and is separated.

[0059] Treat the separated hydrogel with 2.3% dilute sulfuric acid solution, then rinse the oil stain with synthetic washing liquid, and then wash it with hot water at 40-60°C until the acid content in the colloidal particles is 4-6×10 -5 , take it out, and then dry it to get the finished silica gel.

[0060] T...

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Abstract

The invention discloses a preparation method of silica gel. According to the preparation method, a raw material NaHCO3 or NH4HCO3 reacts with sodium silicate Na2O.nSiO2 to generate SiO2 hydrogel, which undergoes moulding, aging and drying processes to prepare silica gel. When the raw materials are sodium silicate Na2O.nSiO2 and NaHCO3, their mol ratio is 1:2-2.4. When the raw materials are Na2O.nSiO2 and NH4HCO3, their mol ratio is 1:1-1.2. By the adoption of the above technical scheme, as a recovered washing lotion (or filtrate) mainly contains Na2CO3 (or also contains NH3.H2O), CO2 can be added to perform a reaction so as to regain reaction raw materials. Therefore, recycling is realized, raw material cost is reduced, few resources are consumed, sulfuric acid consumption is avoided, and the damage to the environment is minimized.

Description

technical field [0001] The invention relates to a method for preparing silica gel, which belongs to the technical field of chemical industry. Background technique [0002] Silica gel is a silica xerogel with a three-dimensional network structure. It is a porous substance with a large internal surface area and specific micropore volume, which makes it an important desiccant, adsorption and catalyst carrier. [0003] Regarding the production of silica gel, the "Production and Application of Silicon Compounds" ((Chuan) Xindengzi No. 015) issued by Chengdu University of Science and Technology Press in May 1994 introduced the production process of silica gel, Principles and related equipment. [0004] The raw materials used in the production of silica gel in the current process are sodium silicate and sulfuric acid, and the reaction formula is as follows: [0005] Na 2 O nSiO 2 +H 2 SO 4 +(nx-1)H 2 O→nSiO 2 ·xH 2 O↓+Na 2 SO 4 [0006] Through the control of different...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/158C01B33/152
Inventor 章浩龙
Owner ZHEJIANG YUDA CHEM IND
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