JP2881410B2 - Industrial waste treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for treating industrial waste, and more particularly to a method for detoxifying oily sludge, liquid hazardous substances, solid hazardous substances, organic hazardous substances, and the like.

[0002]

2. Description of the Related Art In recent years, various attempts to recycle resources have been promoted on a global scale as part of environmental issues, and various types of oily sludge, liquid harmful substances, and solids discharged from various factories have been promoted. There is a long-awaited demand for a processing method that can make harmful substances contained in harmful substances, organic harmful substances, and the like non-polluting, and that is excellent in economic efficiency.

[0003]

The present invention has been made under such circumstances. That is, the present invention provides an economical method of detoxifying carbon compounds such as heavy metals and harmful chemical substances contained in an object to be treated such as oily sludge in a super-stabilized form as a sodium silicate-generating substance according to a fixed schedule. It is intended to propose a processing method having excellent properties. Further, the present invention proposes a processing method for effectively utilizing waste glass by recycling it as a solidifying agent for harmful substances.

[0004]

The method for treating industrial waste according to the present invention is basically a method of introducing a substance to be treated into a treatment liquid obtained by mixing slaked lime, sodium silicate and water. It is. More specifically, an object to be treated is introduced into a treatment solution in which slaked lime, sodium silicate and water are mixed, and calcium silicate generated by a reaction between slaked lime and sodium silicate, and sodium silicate and the object to be treated are included. The method is to precipitate heavy metal silicate generated by the reaction with heavy metal ions. Then, when performing this treatment method, sodium silicate contained in waste glass is utilized.

[0005] The object to be treated is one type selected from oily sludge, liquid hazardous material, solid hazardous material, and organic hazardous material, or a plurality of types selected from these. Most of these objects to be processed contain heavy metals and oil components. The following concrete wastes are known as these industrial wastes. (A) Oily sludge: waste oil containing PCB, cadmium, mercury and other harmful substances, residual oil component in oil storage tank, mechanical waste oil, printing residual pigment oil component, dye residual pigment oil component, oil mud adhering in tanker tank,
Oil mud adhering to large oil storage tanks, essential oil residual harmful oil components, other oily drainage, etc. (B) Liquid harmful substances: washing wastewater containing various metal components, cyan wastewater, PCB wastewater, hexavalent chromium wastewater, cadmium wastewater, chlorohexane wastewater, tetrachloroethylene wastewater, other heavy metal-containing wastewater, Organic matter washing drainage, odor solution etc. (C) Solid hazardous substances: Hazardous substances used in waste batteries, dry cells, fluorescent lamps, cathode ray tubes, electric parts, etc., incinerated ash, smoke ash, fly ash, etc. Waste, high-concentration toxic substance containing waste, deposits on various toxic substance transport containers, dredged sludge, etc. (D) organic harmful substances: marine product processing residue, agricultural product processing residue, animal livestock excreta,
Food processing residues.

[0006] In the above-mentioned various objects to be treated, when they are solids, they are subjected to a pre-treatment by a pulverizer, and the objects to be treated after such pre-treatment are to be treated.

In the present invention, it is desirable to adopt a method of adsorbing an oil component in the object to be treated on the calcium silicate.

In the present invention, the slaked lime is
Desirably, it is obtained by reacting quicklime powder produced by heating calcium carbonate powder with the water.

Further, in the present invention, it is preferable that the particles of the quick lime are surrounded by a film of an oil component.

Further, in the present invention, it is desirable to employ a method of stirring the quicklime with the water.

In each of the above-mentioned inventions, the following reactions and phenomena can occur.

That is, waste glass containing slaked lime and sodium silicate obtained by reacting quicklime powder produced by heating calcium carbonate powder with the above water,
When an object to be treated such as harmful sludge containing a complex oil component or the like is introduced into a treatment solution containing a mixture of water and a mixture, the mixture generates heat due to a hydration reaction between quicklime and water. The heat generated by the exothermic reaction causes volatile oil components and the like contained in the sludge to evaporate and evaporate. In addition, chain compounds (including heavy metals and harmful substances), which are remaining non-volatile oily substances, contained in the sludge are separated and released by the exothermic effect of the hydration reaction. The thus separated chain compound undergoes a chemical reaction with sodium silicate, and the chain compound is silanolized, which is usually very difficult to separate. As a result, chain compounds such as heavy metals easily combine to form heavy-binding substances. This heavy-binding substance combines with the alkaline aqueous solution obtained from the mixed water and the quicklime component,
While generating hydrogen, it causes a dissolving action to produce sodium silicate again, and this sodium silicate serves as a solidifying agent for harmful substances. Due to the schedule of these reactions, all the carbon compounds such as heavy metals and harmful chemicals contained in the oily sludge become sodium silicate-producing substances, are super-stabilized and made harmless (pollution-free).

In the final stage, a considerable amount of calcium silicate (silica gel) obtained by a chemical reaction with the silicon, calcium component, oxygen and the like constituting the treating agent is a porous spongy material having a very large number of fine spaces. The calcium silicate surrounds and covers harmful heavy metals and carbon compounds. This is generally not stable and cannot be exuded or eluted.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the processing method of the present invention will be described below.

In this processing method, the following phenomena 1 to 4 are considered to proceed simultaneously.

1. Hydration of quick lime and water It is desirable that quick lime (CaO) be subjected to a process of burning marble or limestone (calcium carbonate: CaCO ₃ ), crushing it into fine powder, and obtaining fluidity and reaction control. When calcium carbonate is heated, quick lime is obtained by the reaction formula (A).

Embedded image Quicklime reacts with water to react with slaked lime (calcium hydroxide: Ca
(OH) ₂ ) is produced.

Embedded image The obtained aqueous solution of slaked lime (transparent) is extremely alkaline. Quick lime that has not been subjected to any treatment may be used as it is, but quick lime reacts by absorbing moisture (humidity) in the air, so particles of quick lime are coated with an oil component or the like to remove moisture in the air. It is desirable to cut off the contact with and use the one stored in that state. This extends the active period. When water is added to such quicklime particles and stirred, the coating of the oil component or the like surrounding the quicklime particles is broken, and the quicklime particles come into contact with water, and the reaction (B) occurs while generating heat. And if the temperature rises due to heat generation, the film such as oil component will be more easily broken,
The calorific value increases at an accelerated rate, and the temperature rises. This is the first
It is a step reaction.

2. Reaction of slaked lime with sodium silicate Sodium silicate (Na ₂
SiO ₃ ) becomes transparent when dissolved in water and exhibits a syrup shape, and is therefore generally called water glass. Slaked lime produced by the reaction of (B) reacts with sodium silicate as shown in (C) and calcium silicate (CaSiO ₃ : also called silica lime)
become.

Embedded image The resulting calcium silicate is insoluble in water and forms as a white precipitate. This is generally a monovalent metal ion, Na
The silicate compounds of (+) and K (+) are soluble in water, but the silicate compounds such as divalent metal ions, Ca (2+) and Mg (2+) are insoluble in water and precipitate. Na (+), K
(+), Ca (2+) and Mg (2+) are 1
Monovalent Na ion, monovalent K ion, divalent Ca ion,
Shows divalent Mg ions. This is the second stage reaction.

3. When heavy metal ions are contained in the object to be treated, most of the heavy metal ions are ions of two or more valencies, and therefore, as in the case of Ca (2+), sodium silicate is used according to the reaction formula (D). Reacts to form a precipitate. M
(2+) indicates a divalent metal ion.

Embedded image This is the reason why heavy metals are taken in, insolubilized, and stabilized. Therefore, when an object to be treated is introduced into a treatment liquid obtained by mixing quick lime, sodium silicate, and water, a large amount of calcium silicate and a small amount of heavy metal silicate are generated.

4. Adsorption of waste oil by calcium silicate The precipitated calcium silicate is porous and has a very large surface area per unit weight. Generally calcium silicate 1g is said to have a surface area of 500~600m ^2. Then, the oil component in the industrial waste is adsorbed on the generated calcium silicate while being surrounded and covered by the CaSiO ₃ matrix. This may be considered as the same phenomenon as the phenomenon in which moisture in the air is adsorbed on silica gel (desiccant) or the phenomenon in which the odor of a refrigerator is adsorbed by activated carbon (deodorant). Further, since the surface area is large, the oil is adsorbed as a monomolecular film or a very thin film, and the holding power when held by calcium silicate is quite strong. In particular, calcium silicate is generated in situ where oil coexists, so that oil is adsorbed very efficiently.

In the above, the silicic acid is SiO ₃ , SiO ₂
However, it is not a material having a simple structure, but a collection of very complicated structures. When monovalent sodium metal ion Na (+) is present, the molecular weight does not increase because Na (+) is monovalent, but the molecular weight is low because calcium ions and most heavy metal ions are divalent ions. It increases rapidly and becomes insoluble in water and precipitates. In this case, the heavy metal is stable because it is combined with the silicic acid, and it can be considered that the heavy metal ion does not seep out from the product.
If the product is boiled in a solution of caustic soda, all will be dissolved and heavy metals will come out, but such a thing cannot be considered under the subsequent standing conditions, so it may be considered safe.

[0021]

As described above, according to the present invention, all carbon compounds such as heavy metals and harmful chemical substances contained in an object to be treated, such as oily sludge, are converted into sodium silicate-forming substances according to a fixed duplication schedule. It becomes possible to propose a processing method which is excellent in economical efficiency and is made harmless in a stabilized form. Further, according to the present invention, there is an advantage that waste glass can be effectively used by recycling it as a solidifying agent for harmful substances.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C02F 11/00 B09B 3/00 304K

Claims (6)

(57) [Claims] An object to be treated is introduced into a treatment liquid obtained by mixing powder of waste glass containing slaked lime and sodium silicate and water, and calcium silicate generated by a reaction between slaked lime and sodium silicate; A method for treating industrial waste, comprising precipitating heavy metal silicate generated by the reaction between soda and heavy metal ions contained in the material to be treated. 2. The method for treating industrial waste according to claim 1, wherein the calcium silicate adsorbs an oil component in the material to be treated. 3. The industrial waste according to claim 1, wherein said slaked lime is obtained by reacting quicklime granules generated by heating calcium carbonate granules with said water. Processing method. 4. The method for treating industrial waste according to claim 3, wherein the particles of the quick lime are surrounded by a film of an oil component. 5. The method of claim 4, wherein the quicklime is stirred with the water.
The industrial waste treatment method described in 1. 6. The object to be treated is one or more kinds selected from oily sludge, liquid harmful substances, solid harmful substances, and organic harmful substances. 4. The method for treating industrial waste according to claim 5.