JP6551905B2 - Material and method for treating harmful substances - Google Patents

Description

  The present invention can be used to safely treat and discharge harmful substance-containing wastewater, sludge, incinerated ash or contaminated soil generated in factories, mines, waste treatment facilities, civil engineering sites, etc., or for use in landfills, etc. The present invention relates to a material for stabilizing and insolubilizing harmful compounds such as arsenic compounds, fluorine compounds and boron compounds, and a method of treating harmful compounds using the materials.

  In chemical plants, mines, smelters, steel mills, incinerators, etc., waste products containing various harmful substances are generated from product manufacturing process, smelting process, surface treatment process, plating process, incineration process etc. Among them, those containing high concentration components are recovered by the recycling process and returned to resources as resources, but those with low concentration and those originally contained as impurities are treated as waste There is.

  The harmful substances contained in the wastewater are generally precipitated as floc in water by the addition of alkaline chemicals, oxidizing agents, etc. in the wastewater treatment process, and after adding flocculant, it is concentrated and precipitated using a thickener etc. and further filtered It is dewatered by a press etc. and disposed of as sludge in landfills etc.

  When sludge or incineration ash is disposed of in landfills, etc., it is necessary that the harmful substances be fixed and stabilized so that they do not dissolve out in order to prevent environmental pollution, and at the same time maintain the workability at the time of disposal Therefore, it is necessary to have a certain degree of construction strength. In addition, in order to dispose or reuse surplus soil generated at civil engineering work sites, it is often desired to insolubilize harmful substances.

  When disposing of hazardous substance-containing wastewater, hazardous substance-containing waste, or hazardous substance-contaminated soil, it is necessary to precipitate and separate the harmful substances contained, and to perform stabilization treatment so that the harmful substances are not eluted. Chelating agents are known to be effective for insolubilizing harmful substances, but since they are used in the acidic to neutral range, inexpensive cements are needed to maintain applicability at the time of disposal. When solidifying materials such as are mixed, there arises a problem that the insolubilization performance is lowered. Therefore, increasing the addition amount of the chelating agent has a problem of increasing the processing cost.

JP, 2015-81270, A JP, 2013-119068, A

  Patent Document 1 discloses a harmful substance treating agent obtained by powder mixing a material containing water, a water-soluble acidic metal salt of iron, manganese or aluminum, a hardly water-soluble basic compound of alkali metal or alkaline earth metal, and water. Disclose. Here, the water-soluble acidic metal salt may be aluminum sulfate, and harmful substances include arsenic, lead, cadmium, hexavalent chromium, selenium, mercury, fluorine, boron, nickel, copper, zinc, antimony or barium. It can be an ion. And the poorly water-soluble basic compound is said to be calcium oxide, calcium hydroxide, calcium silicate, magnesium oxide, magnesium hydroxide, sodium silicate, potassium silicate, silicate glass, iron slag, cement, etc. I will not give an example of using cement. The technique of Patent Document 1 requires a special chemical reaction when mixing powder in the presence of water, and is difficult to adjust.

  Patent Document 2 relates to a construction waste liquid treatment material containing amorphous calcium aluminate, aluminum sulfate, calcium oxide and polysaccharides, and has an object to treat waste water containing cement and mud generated in construction work. Aluminum sulfate and polysaccharides are said to cause precipitation of contaminants and to promote clarification. Examples of amorphous calcium aluminate are exemplified by certain clinkers, and examples of polysaccharides are only exemplified by hemicellulose and alginic acids. It does not teach removal of harmful compounds such as boron.

  The present invention provides a treatment material for insolubilizing harmful compounds such as arsenic compounds, fluorine compounds and boron compounds in waste water, sludge, incineration ash or soil, and a method for treating harmful substances using the treatment materials Intended to provide.

The present invention comprises a mixture containing cement, aluminum sulfate and sucrose, wherein the total content of cement, aluminum sulfate and sucrose is 100 wt%, the content of cement is 50 to 98 wt%, the content of aluminum sulfate It is a treatment material for harmful substances containing at least one harmful compound selected from boron, fluorine and arsenic, which is characterized in that the content of sucrose is 1 to 10 wt% and the content of sucrose is 0.5 to 5 wt%. .
And the content of cement in the treatment material of this harmful substance is 50 to 95 wt%, the content of aluminum sulfate is 1 to 10 wt%, and the content of sucrose is 0.5 to 5 wt% Good.

  In addition, the present invention adds or mixes the above-mentioned harmful substance treating material to waste water or sludge containing at least one harmful compound selected from boron, fluorine and arsenic, or contaminated soil to adsorb the harmful compound. A method for treating harmful substances, characterized by carrying out precipitation or solidification.

  Furthermore, the present invention is the above-mentioned insolubilization method characterized in that a pH adjuster is added to and mixed with the waste material or the contaminated material containing the harmful compound, together with the treatment material for the harmful substance.

  According to the material for treating harmful substances of the present invention and the treatment method using the same, waste water, sludge, incineration ash and harmful substances in the soil can be insolubilized by simple means. In addition, since the insolubilized waste does not re-elute or greatly reduce harmful compounds even if it gets wet with rain water or the like, it can be safely disposed of in landfills or the like.

  Production of products such as chemical factories, mines, smelters, steelworks, metallurgical plants, incineration sites, civil engineering sites, etc. as hazardous substances containing hazardous compounds treated with the hazardous substance treatment material of the present invention Waste water, sludge, incinerated ash, contaminated soil, etc. discharged in the process, smelting process, surface treatment process, plating process, incineration process, disposal process and the like.

  The harmful substances suitable for the treatment with the treatment material of the present invention include at least one harmful compound selected from a boron compound, a fluorine compound and an arsenic compound, and in particular, it is excellent against harmful substances containing a boron compound Show the effect. Accordingly, a substance containing a boron compound is suitable as the harmful substance. However, since it is also effective for fluorine compounds or arsenic compounds, it can also be used for harmful substances that do not contain boron compounds.

  The treatment material of the present invention is a mixture containing cement, aluminum sulfate and sucrose as essential components.

  Although there is no restriction | limiting in particular in the cement used as a raw material of a processing material, If it is general cement, such as Portland cement and blast furnace cement, acquisition is easy. Since cement is a basic material, it is considered that the harmful substances to be treated are made basic and have the action of fixing harmful compounds. Cement has the advantage of being easier to handle and store than basic materials such as calcium hydroxide.

Also, the aluminum sulfate is not limited, but an anhydride (Al ₂ (SO ₄ ) ₃ ) or a hydrate (Al ₂ (SO ₄ ) ₃ .16H ₂ O) is suitable. Aluminum sulfate has an aggregating action, and is considered to have the action of aggregating or coagulating insolubilized or immobilized harmful substances to prevent their elution. In addition to aluminum sulfate, aluminum chloride or the like can also be used, and a part thereof may be aluminum chloride or the like. However, although the sulfate radical can be insolubilized by binding to calcium in cement, it is difficult to use chlorine, so it may be small if elution of other harmful compounds such as chlorine is limited. Good.

  Further, sucrose is not limited, but sugar for food, crude sugar for industrial use and the like are suitable. Sucrose is water soluble and is considered to have the effect of preventing cement solidification. Therefore, when a harmful substance is treated with a treatment material containing an appropriate amount of sucrose, the harmful substance is prevented from firmly solidifying with the treatment material, thereby preventing clogging of the treatment facility or solidification of the treatment substance, and treatment It facilitates the removal, processing and transportation of objects. In addition, when the cement is solidified, ettringite is produced and aluminum is consumed at this time, but sucrose also prevents this.

  These contents are 50 to 98 wt% cement, 1 to 10 wt% aluminum sulfate, and 0. 5 wt% of sucrose, when the total amount of cement, aluminum sulfate and sucrose is 100 wt%. 5 to 5 wt%. Preferably, cement is 90-95 wt%, aluminum sulfate is 2-8 wt%, and sucrose is 1-4 wt%.

  From another point of view, it is preferable that the cement content in the treatment material is 50 to 95 wt%, the aluminum sulfate content is 1 to 10 wt%, and the sucrose content is 0.5 to 5 wt%. Preferably, additives such as pH adjusters, extenders, specific gravity adjusters, etc. are required if the cement content is 70 to 95 wt%, the aluminum sulfate content is 2 to 8 wt%, and the sucrose content is 1 to 4 wt%. You may mix | blend. Here, an inactive component such as a filler is not included in the calculation of the above blending amount.

  If the content of sucrose is low, the solidification action of the cement may progress in the material to be treated mixed with the treatment material, and solidification may occur, and if it is high, the concentration of contaminants such as COD will increase.

  The treatment material for the harmful substance of the present invention is obtained by mixing the above-mentioned raw material components in a predetermined ratio to obtain a treatment material. There is no restriction | limiting in a mixing method, and the powder degree has a preferable range of 1-1000 micrometers as an average particle diameter (Md50). When the harmful substance to be treated is a solid such as soil, the particle size should be relatively large from the viewpoint of workability, and when it is wastewater or sludge, it is relatively small from the viewpoint of solubility and dispersibility. The particle size of

  The compounding amount of the treated material of the present invention to the material to be treated (referred to as waste etc.) such as waste water, sludge, incinerated ash or soil is 0.1 to 50% by weight, preferably 1 to 50% by weight based on the waste etc. It is 20% by weight. In addition, when waste etc. are the waste water and sludge which contain a large amount of water | moisture content, a comparatively small amount may be used. In addition, when the waste or the like does not contain moisture, it is preferable to add a sufficient amount of water to dissolve sucrose and aluminum sulfate in the treatment material.

  Mixing equipment for wastes and processing materials is generally agitating and mixing in the case of liquids such as wastewater and sludge, and in the case of solids such as incineration ash or soil, etc., a mixing apparatus that makes the whole uniform. And mixing or kneading for several minutes or more.

  The waste after treatment for insolubilization thus obtained has the above-mentioned chemical reaction and aggregation action by the cement and aluminum sulfate contained in the treatment material of the present invention, and further, the cement solidification prevention action by sucrose Is formed to form a water-insoluble reactant, at which time harmful substance ions contained in waste etc. are absorbed and coprecipitated to achieve insolubilization. That is, it is stabilized in two steps by adsorption and coprecipitation of harmful substance ions by the chemical reaction that occurs when metal hydroxide is generated by basification with cement and aluminum sulfate and cement are mixed in waste . Furthermore, since sucrose prevents solidification by cement, the insolubilized waste can be easily taken out, piled up, landfilled, and the like. Then, harmful substances from the insolubilized waste prevent re-elution or significantly decrease.

Example 1
Treated materials 1 to 3 were prepared by mixing commercially available Portland cement (manufactured by Pacific Cement Co., Ltd., Hidaka Plant), aluminum sulfate (anhydride), and sucrose at the compounding ratio (wt%) shown in Table 1.

Comparative Example 1
Commercially available Portland cement (manufactured by Taiheiyo Cement Co., Ltd., Hidaka Factory), commercially available magnesium oxide (light calcined magnesia), or aluminum sulfate (anhydride) was used alone or in combination to obtain treated materials 4-6. .

Example 2
The leachate of boron-containing rock (boron concentration 108 mg / L) was used as the boron-containing wastewater (Wastewater A). In 1000 mL of the waste water, 60 g of the treated materials 1, 2 or 3 was added, and the mixture was stirred and allowed to stand at 25 ° C. for 15 minutes. After 24 hours, the solution was filtered through a 5A filter paper, and the boron concentration in the filtrate was measured by a standard method. The results are shown in Table 2.

Comparative example 2
The wastewater A used in Example 2 was used, 60 g of the treatment materials 4, 5 or 6 was added to 1000 mL of this wastewater, and the concentration of boron in the filtrate was measured in the same manner as in Example 2. The results are shown in Table 2.

Example 3
Boron-containing rock leachate (boron concentration 54 mg / L) was used as the boron-containing waste water (waste water B). In 1000 mL of the waste water, 60 g of the treated materials 1, 2 or 3 were added, and stirred and allowed to stand at 25 ° C. for 15 minutes. After 24 hours, the solution was filtered through a 5A filter to determine the concentration of boron in the filtrate. The results are shown in Table 3.

Example 4
As the fluorine-containing wastewater, leachate of fluorine-containing rock (fluorine concentration: 212 mg / L) was used (Waste water C). In 1000 mL of this waste water, 100 g of the treatment materials 1, 2 or 3 was added, and stirred at 25 ° C. for 15 minutes and allowed to stand. After 24 hours, the solution was filtered through a 5A filter paper, and the fluorine concentration in the filtrate was measured by a standard method. The results are shown in Table 4.

Comparative example 3
The same wastewater as used in Example 4 was used, 100 g of the treating material 5 or 6 was added to 1000 mL of the wastewater, and the fluorine concentration in the filtrate was measured in the same manner as in Example 4. The results are shown in Table 4.

Example 5
As a solution containing arsenic, an aqueous solution of arsenic acid as reagent (arsenic concentration: 7.5 mg / L) was used (waste water D). In 1000 mL of this waste water, 100 g of the treatment materials 1, 2 or 3 was added, and stirred at 25 ° C. for 15 minutes and allowed to stand. After 24 hours, the solution was filtered through a 5A filter paper, and the arsenic concentration in the filtrate was measured by a standard method. The results are shown in Table 5.

Example 6 and Comparative Example 4
In Example 2 and Comparative Example 2, 60 g of the treatment materials 1, 2, 3, 4, 5 or 6 were added to 1000 mL of waste water A, and stirred at 25 ° C. for 15 minutes and allowed to stand.
The mixture was allowed to stand for 3 days, and the properties of the precipitate were investigated. The results are shown in Table 6.
The evaluation of the solidification state of the precipitate is as follows.
A: Solidified (very hard)
B: Solidified (slightly hard)
C; Consolidation (fragile, can be crushed with fingers)
D; Slightly consolidated (very brittle, can be crushed with fingers)

Claims (4)

  It consists of a mixture containing cement, aluminum sulfate and sucrose, and when the total content of cement, aluminum sulfate and sucrose is 100 wt%, the content of cement is 50 to 98 wt% and the content of aluminum sulfate is 1 to 10 wt% %, And the content of sucrose is 0.5 to 5 wt%, the hazardous material treating material containing at least one harmful compound selected from boron, fluorine and arsenic.   The harmful substance according to claim 1, wherein the content of cement in the treated material is 50 to 95 wt%, the content of aluminum sulfate is 1 to 10 wt%, and the content of sucrose is 0.5 to 5 wt%. Processing material.   An agent for treating harmful substances according to claim 1 or 2 is added to or mixed with waste water or sludge containing at least one harmful compound selected from boron, fluorine and arsenic, or contaminated soil to adsorb the harmful compounds. A method for treating harmful substances, characterized by performing precipitation or solidification.   4. The method for treating harmful substances according to claim 3, wherein a pH adjuster is added to and mixed with the wastewater or sludge containing harmful compounds, or the contaminated material, together with the treatment material for the harmful substances.