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A method for the treatment of silica sol wastewater and the co-production of sodium salt

A silica sol and wastewater technology, which is applied in water/sewage multi-stage treatment, water/sludge/sewage treatment, silicate and other directions, can solve the problems of complex equipment and high cost, achieve good treatment effect and high COD removal rate , the effect of increasing added value

Active Publication Date: 2016-05-04
ZHEJIANG QICAI ECO TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It adopts extraction, and the industrial equipment is complex and the cost is too high

Method used

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  • A method for the treatment of silica sol wastewater and the co-production of sodium salt

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] A certain silica sol wastewater, pH=0.8, original COD=300mg / L, contains mixed salt of sodium silicate and sodium chloride, and the salt content (mass fraction) is about 9%.

[0036] The pH of the waste water was adjusted to 5 with a 1% NaOH solution, and no colloidal precipitate appeared at this time. Feed chlorine dioxide in waste water, and keep the chlorine dioxide concentration in the solution about 500mg / L, after oxidation reaction 2 hours, add mixed adsorbent (activated carbon and attapulgite are mixed with the mass ratio of 1:4 to prepare ), the quality of adding the mixed adsorbent is 0.1% of the waste water quality, stirred and adsorbed for 20min, filtered to obtain a clear and colorless mixed salt solution of sodium silicate and sodium chloride, and the COD=13mg / L of the solution was recorded at this time.

[0037] The mixed salt solution is further processed using a reverse osmosis membrane to obtain a concentrated solution I and a weak solution.

[0038] Wh...

Embodiment 2

[0054] A certain silica sol wastewater, pH=1, original COD=460mg / L, contains mixed salt of sodium silicate and sodium sulfate, and the salt content is 12.5%.

[0055] The pH of the wastewater was adjusted to 5 with a 1% NaOH solution. Pass ozone into the solution to oxidize {the flow rate of ozone is 2.5g / (L·h)} for 1 hour, add H with a mass fraction of 30% 2 o 2 , join H 2 o 2 The quality is 0.1% of the waste water quality, stirring.

[0056] The solution was clear and transparent after treatment.

[0057] Then add mixed adsorbent (activated carbon and attapulgite are prepared by mixing in a mass ratio of 1:5) to the waste water, the added mass of the mixed adsorbent is 0.5% of the waste water quality, and filter.

[0058] Filter to obtain a colorless saline solution with COD=10mg / L.

[0059] The filtered mixed salt solution is further processed using a reverse osmosis membrane.

[0060] The organic matter is removed, and the fresh water part is reused.

[0061] Conce...

Embodiment 3

[0069] A certain silica sol wastewater is acidic, COD=600mg / L, contains mixed salt of sodium silicate and sodium chloride, the salt content is about 8%, and the sodium chloride content is about 3%.

[0070] The pH of the wastewater was adjusted to 5, no sol was precipitated, and activated carbon was added to the solution, and the mass of activated carbon added was 0.1% of the mass of the wastewater.

[0071] Pass ozone oxidation in the solution again {the flow rate of ozone is 2g / (L h)}, after ozone oxidation 2 hours, add the H that mass fraction is 30% 2 o 2 , join H 2 o 2 The quality is 0.2% of the waste water quality, stirring.

[0072] A colorless solution was obtained, and the COD=20mg / L of the waste water was measured at this time.

[0073] The oxidized waste water is then adsorbed by a sodium ion exchange resin (the volume of the waste water passing through the column is 180 times the volume of the resin) to obtain a clean salty mixed solution.

[0074] Adjust the ...

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Abstract

The invention discloses a method for treating the silica sol wastewater and co-producing a sodium salt. The method comprises the following steps: (1) adjusting the pH value of the silica sol wastewater to 2-5, and performing oxidation treatment by chlorine dioxide or ozone; (2) after adsorbing the oxidized waste water by an adsorber, adopting a reverse osmosis membrane or ion exchange resin to perform adsorption and concentration to obtain a strong liquid I and a thin liquid; (3) adjusting the pH value of the strong liquid I to more than 14, performing evaporation and concentration, and cooling and separating to obtain a sodium salt and a strong liquid II; (4) heating up the strong liquid II to 80-90 DEG C and adjusting the pH value to 8.5-9.5, and separating to obtain sodium silicate nanahydrate and a strong liquid III. An advanced oxidation technology and reverse osmosis membrane treatment are combined in the whole process, the processing effect is excellent, the COD removal rate of the wastewater is high; the COD of the effluent is less than 10 mg / L, and the effluent can be used as the industrial water; the high-purity sodium silicate and the sodium salt can be separated and recovered in the process, and the added value of the wastewater treatment can be increased.

Description

technical field [0001] The invention relates to the technical field of industrial wastewater, in particular to a method for treating silica sol wastewater and co-producing sodium salt. Background technique [0002] Sodium silicate is divided into two types, sodium orthosilicate Na 4 SiO 4 and sodium metasilicate Na 2 SiO 3 . Sodium orthosilicate is uncommon. Sodium silicate is a soluble silicate, commonly known as water glass, and its trade name is sodium silicate. Sodium silicate is a colorless orthorhombic biconical crystal or white to off-white block or powder, which can be weathered. Sodium silicate crystals lose 6 molecules of crystal water at 100°C. Soluble in water, the solution is more alkaline than soda ash. [0003] Sodium silicate is an important inorganic chemical raw material. In addition to being used as a binder component, it is also an important raw material for the manufacture of fine chemical products such as silica gel, molecular sieve, silica sol, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/10C01B33/32
Inventor 陈磊刘妍张静郭莉娜
Owner ZHEJIANG QICAI ECO TECH CO LTD