JPH11179107A - Powder flocculant and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a flocculant which can be used in a wide pH region, and has excellent cohesive force. SOLUTION: A powder acidic flocculant containing at least one of aluminum sulfate and aluminum sodium sulfate and acidic soil is mixed with powder alkaline flocculant which contains sodium aluminate and alkaline material such as alkaline soil and lime at the rate showing neutrality in water. Then, a powder polymer flocculant is blended with the mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a powder coagulant used for coagulating wastewater containing sewage and soil and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, regulations on water turbidity and the like have become more and more strict, such as the Okinawa Prefecture Red Soil Ordinance for the Prevention of Runoff. Fine suspended solids that cause water turbidity and color are mainly colloidal particles, but the colloidal particles have a very low sedimentation rate in water, and most of them are negatively charged, and also negatively charged. Because of the repulsive force from the filter media particles, it is difficult to remove them by a simple settling separation operation or filtration. For this reason, a coagulant is added to neutralize the charge on the surface of the particles, reduce the repulsive force between the particles, and easily gather together. As the coagulant, inorganic and organic electrolytes, surfactants, electrolyte polymers, and the like are used.

[0003]

However, the conventional flocculant has a narrow pH range in which it can be used because its effect depends on the acidity and basicity of the wastewater or sewage of the wastewater to be treated.

[0004] In addition, since wastewater and sewage including soil have a very large amount of treatment, it is necessary to add a large amount of a flocculant.
Processing costs increase. An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an inexpensive flocculant that exhibits excellent cohesive force in a wide pH range.

[0005]

According to the present invention, there is provided a powdery acidic coagulant containing at least one of aluminum sulfate and sodium aluminum sulfate and an acidic soil, sodium aluminate and an alkaline soil,
Provided is a powder coagulant obtained by mixing a powder alkaline coagulant containing an alkaline material such as lime and the like in water at a ratio exhibiting neutrality and blending a powdered polymer coagulant.

Although the detailed mechanism of action of the above-mentioned powder flocculant is unknown, aluminum sulfate and sodium aluminum sulfate, which are conventionally known to have a flocculant effect, and sodium aluminate and a powdery polymer flocculant have a wide pH range. Exerts the coagulation effect, and the flocs formed thereby take in acidic soil and alkaline materials and grow larger,
It is thought that the acid soil and alkaline material taken in play the role of the weight and increase the sedimentation speed of the floc.

The present invention also relates to a method for producing a powder coagulant as described above, wherein aluminum fine pieces are gradually added to dilute sulfuric acid, salt water is added, and the mixture is stirred and mixed. The acidic soil is solidified by gradually mixing, solidifying and pulverizing to obtain a powdered acidic coagulant, and gradually adding aluminum strips to an aqueous solution of caustic soda.After the reaction is completed, the reaction mixture is mixed with alkaline soil, lime, etc. Solidify by gradually mixing the alkaline material,
Pulverizing to obtain a powdered alkaline coagulant, mixing the powdered acidic coagulant and the powdered alkaline coagulant in a ratio exhibiting neutrality in water, and further mixing a powdered polymer coagulant And a method for producing the same.

In addition, aluminum scrap is used as aluminum strip.
The present invention provides a method for producing a powder flocculant using strips of the above. This
According to the method for producing aluminum, the reaction between aluminum, sulfuric acid and brine is
The aluminum is easily melted.
Aluminum sulfate (Al_Two(SO_Four)_Three) And sodium sulfate
Lumium aluminum (Al_Two(SO_Four)_Three・ Na_TwoSO_Four)
Is formed, and the reaction between aluminum and caustic soda
Is sodium aluminate (NaAlO) _Two) Produces
You.

In other words, using an easily available material such as aluminum, sulfuric acid, caustic soda, acidic soil, alkaline soil, lime, etc., an excellent powder flocculant can be produced only by mixing a small amount of a powdery polymer flocculant. Can be
When using aluminum waste materials such as aluminum cans, the effective use of waste can be achieved.

For example, Kunigami Merge (distributed in northern Okinawa, red soil containing iron and alumina) is used as acidic soil, Jargal (distributed in central and southern Okinawa) is used as alkaline soil, and quicklime and slaked lime are used as lime. it can.

As the powdered polymer flocculant, a water-soluble one capable of crosslinking between particles, such as a polyacrylamide-based polymer flocculant, can be used. Usually, about 2 parts by weight of 100 parts by weight of the powdered flocculant is used. Is a powder polymer flocculant,
It is not limited to this.

Usually, dilute sulfuric acid having a concentration of about 10 to 30 v / v% is used. Usually, a salt water having a concentration of about 10% w / w or more is used. The mixing ratio of dilute sulfuric acid, aluminum flakes, salt water and acidic soil is not critical. Almost all of the dilute sulfuric acid reacts, the generation of reactive gas stops, and the aluminum flakes are introduced until the liquid surface calms down I do. Thereafter, salt water is usually added in an amount of about 50 to 70 v / v% of dilute sulfuric acid. Also,
Acid soil is added until the viscous precipitate formed by the reaction solidifies and becomes difficult to stir.

The aqueous solution of caustic soda is 15 to 35 w /
Use about v%. The mixing ratio of the aqueous solution of caustic soda, the aluminum flakes, and the alkaline material is not critical, and almost all of the caustic soda reacts, and the generation of the reaction gas stops, and the aluminum flakes are introduced until the liquid surface is calmed. The alkaline material is added until the reaction mixture is solidified by the alkaline material and stirring becomes difficult.

[0014]

Embodiments of the present invention will be described below. Example 1 Into a reaction vessel containing 1500 ml of 20 v / v% diluted sulfuric acid, 50 g of finely ground aluminum waste material was gradually charged, and
When 1000 ml of 0% w / w salt water was added and the mixture was stirred for a while, a viscous white precipitate was formed, and no reaction gas was generated even when more aluminum waste material was added. 200 g of acid soil, which was collected by filtration and finely crushed, was gradually added thereto, followed by stirring and mixing to solidify. The resulting solid is pulverized to obtain Al ₂ (SO ₄ ) ₃ and Al ₂ (S
900 g of a powdered acidic coagulant containing O ₄ ) ₃ .Na ₂ SO ₄ and acidic soil was obtained.

When 100 g of finely crushed aluminum waste material was gradually introduced into a reaction vessel containing 2,000 ml of 25% w / v caustic soda, even if more aluminum waste material was introduced, no reaction gas was generated. The substance was removed by filtration, 900 g of slaked lime was gradually added to the filtrate, and the mixture was stirred and mixed for a while to solidify. The produced solid was pulverized to obtain 1900 g of a powder alkaline coagulant containing NaAlO ₂ and slaked lime.

The above-mentioned powdered acidic coagulant and powdered alkaline coagulant are combined at a ratio at which the pH when dissolved in water becomes neutral (900 g: 300 g), and a polyacrylamide-based powdered polymer coagulant ( Acoflock A110) 2
4 g were combined and uniformly mixed to obtain 1224 g of a powder coagulant.

In order to examine the flocculating effect of the obtained powder flocculant, sewage (3000 pp) containing soil (Kunigami Merge) was used.
m) 500 ml mixed with stirring. The results are as follows.

[0018]

[Table 1]

As can be seen from the above results, the powder flocculant of the present invention exhibits an excellent flocculating effect in a wide pH range,
The amount of addition is small.

[0020]

As described above, the powder coagulant of the present invention exhibits an excellent coagulation effect in a wide pH range, has no adverse effect on the environment, and has no adverse effects on the environment, such as aluminum cans, aluminum waste materials, acidic soils and alkaline soils. It can be manufactured at low cost by effectively utilizing soil.

Claims (3)

[Claims] 1. A powdered acid flocculant containing at least one of aluminum sulfate and sodium aluminum sulfate and acidic soil, sodium aluminate and alkaline soil,
A powder coagulant obtained by mixing a powder alkaline coagulant containing an alkaline material such as lime with water in a ratio that exhibits neutrality and blending a powdered polymer coagulant. 2. An aluminum flake is gradually added to dilute sulfuric acid, salt water is added thereto, and the mixture is stirred and mixed. Then, a viscous precipitate formed is separated, solidified by gradually mixing acidic soil, and pulverized. Along with obtaining a powdered acidic coagulant, gradually add aluminum flakes to an aqueous solution of caustic soda, and after the reaction, solidify the reaction mixture by gradually mixing an alkaline soil, an alkaline material such as lime,
Pulverizing to obtain a powdered alkaline coagulant, mixing the powdered acidic coagulant and the powdered alkaline coagulant in a ratio exhibiting neutrality in water, and further mixing a powdered polymer coagulant Manufacturing method. 3. The method for producing a powder coagulant according to claim 2, wherein a strip of aluminum waste material is used as the aluminum strip.