TW201605511A - Hazardous substance treatment agent - Google Patents

Abstract

The present invention provides a powdery hazardous substance treatment agent for insoluble treatment of harmful substances in sludge, incineration ash or soil, which comprises 5 to 90% by weight of at least one selected from the group consisting of iron, manganese and aluminum. a water-soluble acidic metal salt of a metal, and a mixture of 2 to 80% by weight of an alkali metal and/or an alkaline earth metal water-insoluble basic compound, and 1 to 30% by weight of water, which are powder-mixed, and A reaction product obtained by reacting at least a part of a water-soluble acidic metal salt and a poorly water-soluble basic compound when the powder is mixed is contained. According to the insoluble treatment of the present invention, even if the waste is wetted by rain or the like, the heavy metal is not dissolved again, or the amount of elution is remarkably reduced, and the waste can be safely disposed by landfill or the like.

Description

Hazardous substance treatment agent

The present invention relates to arsenic, lead, cadmium, hexavalent chromium, selenium, mercury, fluorine, boron, nickel in order to safely use sludge, incineration ash or contaminated soil generated by a factory or the like for landfilling. A chemical agent in which harmful substances such as copper, zinc, bismuth, and antimony become stable and insoluble.

In the processes of product manufacturing, smelting, surface treatment, electroplating, incineration, etc. in chemical plants, mines, smelters, steel plants, incineration plants, etc., various wastes containing harmful substances are produced, which contain high concentrations of components. It will be recycled through the recycling process, returned to the raw material as a resource, and treated as a waste if it contains a low concentration or is originally considered as an impurity.

The harmful substances contained in the wastewater are generally precipitated in the form of flocs by adding an alkaline agent or an oxidizing agent in a wastewater treatment process, and a coagulant is added, followed by concentration and precipitation using a thickener, and finally, After being dehydrated by a filter press or the like, it is treated as sludge and disposed of by landfill or the like.

When the sludge or incineration ash is disposed of in a landfill or other manner, in order to prevent contamination of the surrounding environment, it is necessary to immobilize and stabilize the harmful substances to prevent them from being dissolved, and in order to maintain the workability during the treatment, it is necessary to have a certain construction. strength.

Wastes containing hazardous materials and soil contaminated with harmful substances When disposing of the treatment, it is necessary to stabilize the harmful substances contained in order to prevent it from being dissolved. Chelate is known to be effective in the insoluble treatment of harmful substances, but since it is used in the acidic to neutral range, insolubility occurs when it is mixed with a solidified material such as inexpensive cement for maintaining workability. The problem of performance degradation. If the amount of the chelating agent added is increased for this, the processing cost becomes high.

Prior art literature Patent literature

Patent Document 1 Japanese Patent Laid-Open Publication No. 2001-121131

Patent Document 2 Japanese Patent Laid-Open Publication No. 2006-272144

Patent Document 3 Japanese Patent Laid-Open Publication No. 2012-188544

Patent Document 4 Japanese Patent Laid-Open Publication No. 2012-210577

Patent Document 1 discloses a method of adding iron (II) sulfate and water to waste containing the harmful metal in order to detoxify harmful metals, and then adding a calcium compound to adjust the pH. This method requires a large amount of water and the whole becomes muddy. Further, Patent Document 2 discloses a calcined calcium aluminate hydrate at a high temperature to form a heavy metal insoluble agent having a poorly water-soluble calcium salt on the surface of the particles. This method requires high temperature calcination and surface treatment steps. Further, Patent Document 3 discloses a heavy metal insoluble agent containing phosphoric acid or a phosphate such as hypophosphorous acid. Patent Document 4 discloses a method in which an oxidizing bacterium is used to incinerate arsenic into a pentavalent form in order to detoxify arsenic in the soil, and then iron-based sulphate and smoldering dolomite are mixed in the soil to perform insoluble treatment. The above various methods or treatment agents have problems in that the production is complicated or complicated, or that the effects on various heavy metals and non-metallic harmful substances are insufficient.

It is an object of the present invention to provide an insoluble treatment agent for harmful substances in sludge, incineration ash or soil.

The present invention provides a powdery hazardous substance treatment agent for insoluble treatment of harmful substances, which comprises a water-soluble acidic metal salt containing 5 to 90% by weight of at least one metal selected from the group consisting of iron, manganese and aluminum, and 2 a mixture of ~80% by weight of a poorly water-soluble basic compound of an alkali metal and/or an alkaline earth metal, and a material of 1 to 30% by weight of water, which is obtained by powder mixing, and which contains water-soluble acidity when the powder is mixed. A reaction product obtained by reacting at least a part of a metal salt and a poorly water-soluble basic compound.

Further, the water-soluble acidic metal salt is a powder selected from at least one of ferric chloride, iron nitrate, iron sulfate, manganese chloride, aluminum chloride, and aluminum sulfate or an aqueous solution of 15 to 35% by weight.

Furthermore, the poorly water-soluble basic compound is selected from the group consisting of calcium oxide, calcium hydroxide, calcium citrate, magnesium oxide, magnesium hydroxide, sodium citrate, potassium citrate, silicate glass, steel slag, and cement. At least one powder.

In addition, the hazardous substance treatment agent is a harmful substance treatment agent for insoluble treatment of harmful substances in sludge, incineration ash or contaminated soil, and the harmful substance is selected from the group consisting of arsenic, lead, cadmium, hexavalent chromium, selenium, An ion of at least one of mercury, fluorine, boron, nickel, copper, zinc, cerium, and cerium.

Preferably, the hazardous substance treatment agent comprises 10 to 90% by weight of iron sulfate and/or aluminum sulfate, and 3 to 80% by weight of magnesium oxide and/or calcium citrate, and 1 to 30% by weight. The material of the water is obtained by mixing the powder.

As another preferred embodiment, the hazardous substance treatment agent will contain 10 to 90% by weight of iron sulfate and/or aluminum sulfate, and 3 to 80% by weight of calcium hydroxide and 1 to 30% by weight of water are obtained by powder mixing.

In another preferred embodiment, the hazardous substance treatment agent is a material comprising 10 to 90% by weight of iron sulfate and/or aluminum sulfate, and 3 to 80% by weight of cement, and 1 to 30% by weight of water. The powder is obtained by mixing.

In another preferred embodiment, the hazardous substance treatment agent is a material containing 10 to 90% by weight of iron sulfate and/or aluminum sulfate, and 3 to 80% by weight of steel slag powder, and 1 to 30% by weight of water. It is obtained by mixing powders.

According to the present invention, insoluble treatment of sludge, incineration ash, and harmful substances in the soil can be carried out in a simple manner. After the insoluble treatment, even if the waste is wetted by rain or the like, the heavy metal is not dissolved again, or the amount of elution is remarkably reduced, and the waste can be safely disposed of by landfill or the like.

Fig. 1 is a graph showing the results of thermal analysis of the hazardous substance treatment agent 5.

Fig. 2 is a graph showing the results of thermal analysis of the hazardous substance treatment agent 7.

In order for your review board to have a clear understanding of the contents of the present invention, please refer to the following description for matching drawings.

The harmful substances contained in the treatment of the present invention mainly include: inorganic pollutants discharged from processes such as chemical plant, mining, smelting, steel, electroplating, incineration, and the like, manufacturing, smelting, surface treatment, electroplating, incineration, and the like. Mud, incineration ash, fly ash, or transportation of these factories Contaminated soil produced during the transfer.

The harmful substance treating agent of the present invention is composed of a mixture of a water-soluble acidic metal salt of at least one of iron, manganese and aluminum and a poorly water-soluble basic compound of an alkali metal or an alkaline earth metal, and contains at least a part of the powder in the presence of water when mixed. A reaction product obtained by a chemical reaction takes place.

A water-soluble acidic metal salt of iron, manganese or aluminum used as a raw material for treating a harmful substance, which is required to have a high solubility in water and an acidic property when added to water, ferric chloride, iron nitrate, iron sulfate , manganese chloride, manganese sulfate, aluminum chloride, aluminum sulfate can be used, but the ferric chloride, iron sulfate, aluminum chloride, aluminum sulfate is less polluting to the natural environment, and the cost is lower, which is more suitable. Among the iron compounds, divalent or trivalent compounds can be used. Further, the acidic metal salt used should be a powder or an aqueous solution of 15 to 35% by weight.

An alkali metal or alkaline earth metal poorly water-soluble basic compound used as a raw material for a harmful substance treatment agent is required to have a small solubility in water and a pH-alkali property when added to water, calcium oxide, calcium hydroxide, and barium. Calcium acid, magnesium oxide, magnesium hydroxide, sodium citrate, potassium citrate, bismuth silicate glass, steel slag, cement, etc. can be used, but calcium hydroxide, calcium citrate, magnesium oxide, steel slag, and cement are easily obtained. And the cost is low, more suitable. The water-insoluble basic salt of an alkali metal and an alkaline earth metal is more suitable as a powder.

The harmful substance treating agent of the present invention is characterized in that 1 to 30% by weight of water is added and mixed in a mixture of a water-soluble acidic metal salt and a poorly water-soluble basic compound, and the content is required to occur by at least a part thereof in the presence of water. A hydration reaction product obtained by a chemical reaction. At this time, if the amount of water added is too large, the mixture will be slurried, and a powdery hazardous substance treatment agent cannot be obtained. In addition, if the amount of water added is too small, the amount of hydration reaction product will decrease, The handling properties of harmful substances will be reduced. As a water adding method, water may be added to the water-soluble acidic metal salt, or water may be added to the water-soluble acidic metal salt and the water-insoluble basic compound, and then mixed, or the water-soluble acidic metal salt and water may be poorly soluble. The compound and water are mixed at the same time.

The material containing a water-soluble acidic metal salt, a poorly water-soluble basic compound, and water is powder-mixed. At this time, a part of the water-soluble acidic metal salt or the poorly water-soluble basic compound is reacted in the presence of water to form a hydration reaction product. Assuming that the water-soluble acidic metal salt and the water-insoluble basic compound are represented by MX and AY, respectively, it is presumed that the product is a compound such as MY, AX and a double salt thereof, and a crystalline mineral containing MY or AX or a hydrate thereof ( Metal hydroxide). If the above material is a powder, it is presumed that the reaction will occur on the surface portion thereof, the hydration reaction product is present on the surface of the powder, and the inside of the powder is still a water-soluble acidic metal salt or a poorly water-soluble basic compound. If the water-soluble acidic metal salt or the water-insoluble basic compound is simply mixed in the anhydrous state, the performance of the harmful substance treating agent cannot be sufficiently improved, so it is preferable to use a mixer to make the two powders in the presence of water. Fully in touch. The mixing time with a kneader should be 2 minutes or more, and more preferably 5 minutes or more. The harmful substance treatment agent obtained in this manner is consumed because the added water is generated as the hydration reaction product is formed, so that the surface is relatively dry and dry powder, but it may be dried by heating or granulated as needed. Processing to improve usability.

The amount of the hazardous substance treatment agent of the present invention to be treated with respect to sludge, incinerated ash, or soil (hereinafter referred to as "waste, etc.") is 0.5 to 50% by weight of the waste. In addition, when waste or the like contains a large amount of water, it is preferably calculated as a solid content, but if the water content is 20% or less, the weight can be used as it is.

When mixing waste and other hazardous substances, you can use it to make the whole A uniform mixing device can be mixed or mixed for a few minutes or more. The insoluble treated waste obtained in this manner is adsorbed by the highly active metal hydroxide formed by the reaction of the water-soluble acidic metal salt and the poorly water-soluble basic compound contained in the harmful substance treatment agent of the present invention, and is harmful. The unreacted water-soluble acidic metal salt and the alkali metal, alkaline earth metal basic compound and the mixed waste contained in the substance treatment agent chemically react with each other to form a water-insoluble reactant, and the harmful substance ions contained in the sludge at that time Adsorption and coprecipitation to achieve insolubilization. That is, the adsorption of the metal hydroxide contained in the harmful substance treatment agent and the adsorption and coprecipitation of the chemical reaction occurring when the unreacted water-soluble acidic metal salt and the basic compound are mixed in the waste are performed. Stabilization of the stages. Therefore, no matter whether the waste which has been insoluble treated is stacked outdoors or used for landfill, no harmful substances are dissolved or the amount of elution is greatly reduced.

As a harmful substance treatment agent, the water-soluble acidic metal salt, the poorly water-soluble basic compound, and water were mixed at a mixing ratio (% by weight) shown in Table 1, and the chemicals 1 to 12 shown in Table 1 were prepared by mixing reaction. The water-soluble acidic metal salts used are powdered industrial chemicals of ferrous sulfate (FS), ferrous chloride (FC), aluminum sulfate (AS) and aluminum chloride (AC), and the poorly water-soluble basic compound is magnesium oxide. (MO), calcium hydroxide (CH) powdered industrial chemicals and synthetic calcium sulphate (Tobermorite) as the main component of calcium citrate powder (CS), water is added to use purified water. The above materials were mixed in a ratio shown in Table 1 using a commercially available powder mixing device, and reacted to prepare a harmful substance treating agent 1 to 12.

Comparative Agents 1 to 18 shown in Table 2 were prepared by using a powder mixing device and mixing the same water-soluble acidic metal salt (A), water-insoluble basic compound (B) and water as used in the examples. In the table, FS, FC, AS, AC, MO, CH, and CS are abbreviations for the above-described water-soluble acidic metal salt and water-insoluble basic compound. The formulated amount % means % by weight.

Example 1

As the sludge containing the harmful substances, the dehydrated product (water content: 45%) (sludge 1) of the sludge generated in the sewage treatment process of the chemical plant was used. To the sludge, any one of the agents 1 to 12 was added in an amount (% by weight) shown in Table 3, and mixed by a mixer for 10 minutes. The obtained insoluble sludge was immersed for 1 day, and then subjected to a dissolution test according to a conventional analysis method, and the results are shown in Table 3. For comparison, the dissolution test was performed after the same procedure except that no drug was added. In the case where no drug was added, the lead elution amount was 0.21 mg/L, and in the case where 3 wt% of the drug was added, the elution amount was decreased below the detection limit, or decreased to 0.004 mg/L or less and 1 /50 or less.

Example 2

As the sludge containing the harmful substances, the dehydrated product (water content: 40%) (sludge 2) generated by the sludge generated in the surface treatment process of the metal processing plant was used. The drug was added to the sludge in the amount (% by weight) shown in Table 4, and mixed by a mixer for 10 minutes. The obtained insoluble treated sludge was subjected to a dissolution test for 1 day after moisturizing, and the results were shown in Table 4 according to a conventional analysis method. In the case where no drug was added, the amount of Ni eluted was 5.0 mg/L, and the amount of eluted Cr6+ was 0.48 mg/L. When 3 wt% of the drug was added, the amount of elution was reduced to 0.005 below the detection limit. Below mg/L.

Example 3

As the sludge containing the harmful substances, the dehydrated product (water content: 49%) (sludge 3) generated by the sludge in the sewage treatment process of the chemical plant was used. The drug was added to the sludge in the amount (% by weight) shown in Table 5, and mixed by a mixer for 10 minutes. The insoluble treated sludge obtained was moistened for 1 day, and subjected to a dissolution test according to a conventional analysis method, and the results are shown in Table 5. When the drug was not added, the amount of As eluted was 0.14 mg/L, and when the drug was added in an amount of 3% by weight, the amount of elution was reduced to 0.001 mg/L or less below the detection limit.

Example 4

As a soil containing heavy metals, contaminated soil (water content 26%) produced by the former site of the chemical plant (contaminated soil 1) was used. The drug was added to the contaminated soil in the amount (% by weight) shown in Table 6, and mixed by a mixer for 10 minutes. For the obtained insoluble treated contaminated soil, after one day of moisturizing, the dissolution test was carried out according to a conventional analysis method, and the results are shown in Table 6. In the case where no drug is added, the amount of As eluted is 0.060 mg/L, and in the case of adding 0.5, 1 or 2% by weight of the drug 1 or 1% by weight of the drug 2, 3, 5, the amount of elution is Both are reduced to less than 0.001 mg/L below the detection limit. When the comparative agent was not added, the amount of Pb eluted was 0.21 mg/L, and when 3% by weight of any of the comparative agents I to 12 was added, the amount of elution was reduced, but to a lesser extent. low.

Example 5

As a soil containing heavy metals, contaminated soil (water content 28%) produced by the former site of the chemical plant (contaminated soil 2) was used. The drug was added to the contaminated soil in the amount (% by weight) shown in Table 7, and mixed by a mixer for 10 minutes. For the obtained insoluble treated contaminated soil, after one day of moisturizing, the dissolution test was carried out according to a conventional analysis method, and the results are shown in Table 7. In the absence of a drug In the case where the amount of Se dissolved was 0.18 mg/L, the amount of elution was reduced to 0.001 mg/L or less below the detection limit in the case of adding 3% by weight of the drug 7, 8, or 9.

Example 6

As a soil containing heavy metals, contaminated soil (water content 25%) produced by the former site of the chemical plant (contaminated soil 3) was used. The drug was added to the contaminated soil in the amount (% by weight) shown in Table 8, and mixed by a mixer for 10 minutes. For the obtained insoluble treated contaminated soil, after one day of moisturizing, the dissolution test was carried out according to a conventional analysis method, and the results are shown in Table 8. When the drug was not added, the amount of Cd eluted was 32.3 mg/L, and the amount of Pb eluted was 1.34 mg/L. When 3, 5 or 7 wt% of the drug 1 was added, the amount of elution was large. cut back.

Example 7

As a soil containing heavy metals, contaminated soil (water content 27%) produced by the former site of the chemical plant (contaminated soil 4) was used. Adding the agent in the contaminated soil in the amount (% by weight) shown in Table 9, Mix with a mixer for 10 minutes. For the obtained insoluble treated contaminated soil, after one day of moisturizing, the dissolution test was carried out according to a conventional analysis method, and the results are shown in Table 9. When the drug was not added, the amount of Cd eluted was 6.7 mg/L, and the amount of Pb eluted was 7.5 mg/L. When 3 wt% of the drug was added, the amount of elution was reduced below the detection limit. 0.001 mg / L or less.

Example 8

As a soil containing heavy metals, contaminated soil (water content 25%) produced by the former site of the chemical plant (contaminated soil 5) was used. The drug was added to the contaminated soil in the amount (% by weight) shown in Table 10, and mixed by a mixer for 10 minutes. For the obtained insoluble treated contaminated soil, after one day of moisturizing, the dissolution test was carried out according to a conventional analysis method, and the results are shown in Table 10. When the drug was not added, the amount of Hg eluted was 5.3 mg/L, and when the drug was added in an amount of 3% by weight, the amount of elution was greatly reduced.

Example 9

As a soil containing heavy metals, contaminated soil (water content 23%) produced by the former site of the chemical plant (contaminated soil 6) was used. The drug was added to the contaminated soil in the amount (% by weight) shown in Table 11, and mixed by a mixer for 10 minutes. For the obtained insoluble treated contaminated soil, after one day of moisturizing, the dissolution test was carried out according to a conventional analysis method, and the results are shown in Table 11. When the drug was not added, the amount of F eluted was 5.0 mg/L, and when the drug was added in an amount of 2% by weight, the amount of elution was reduced to 1/10 or less.

Comparative example 1

As the heavy metal-containing sludge, the same sludge 1 as in Example 1 was used, and the comparative agents 1 to 12 shown in Table 2 were added to the sludge in the amounts (% by weight) shown in Table 12, and mixed. Mix for 10 minutes. The insoluble treated sludge obtained was moistened for 1 day, and subjected to a dissolution test according to a conventional analysis method, and the results are shown in Table 12. In the case where the comparative agent was not added, the amount of Pb eluted was 0.21 mg/L, and compared with the addition of any of the comparative agents 1 to 12 in which 3% by weight was added, the amount of elution was reduced, but to a lesser extent. .

Comparative example 2

As the heavy metal-containing sludge, the same sludge 2 as in Example 2 was used, and the comparative agent shown in Table 2 was added to the sludge in the amount (% by weight) shown in Table 13, and mixed by a mixer 10 minute. The insoluble treated sludge obtained was moist-preserved for 1 day, and subjected to a dissolution test according to a conventional analysis method, and the results are shown in Table 13. When the comparative agent was not added, the Ni elution amount was 5.0 mg/L, and the Cr ⁶⁺ elution amount was 0.48 mg/L.

Comparative example 3

As the heavy metal-containing sludge, the same sludge 3 as in Example 3 was used, and the comparative agent shown in Table 2 was added to the sludge in the amount (% by weight) shown in Table 14, and mixed by a mixer. minute. The obtained insoluble treated sludge was subjected to a dissolution test for 1 day after moisturizing, and the results of the dissolution test were shown in Table 14. In the case where no comparative agent was added, the amount of As eluted was 0.14 mg/L.

Table 14

Comparative example 4

As the heavy metal-containing soil, the same contaminated soil 1 as in Example 4 was used, and the comparative agent shown in Table 2 was added to the soil in the amount (% by weight) shown in Table 15, and mixed by a mixer for 10 minutes. The obtained insoluble treated sludge was left to be moisturized for 1 day, and subjected to a dissolution test according to a conventional analysis method, and the results are shown in Table 15. In the case where the comparative agent was not added, the amount of As eluted was 0.060 mg/L.

Example 10

For the hazardous substance treatment chemicals 5 and 7 prepared in the above examples, the sample temperature was raised from 30 ° C to 1000 ° C at a temperature increase rate of 10 ° C using a thermal difference analyzer (TG/DTA), and this was measured. In the case of DTA and TG, the results of the drug 5 are shown in Fig. 1, and the results of the drug 7 are shown in Fig. 2.

Claims (8)

A powdery hazardous substance treatment agent for insoluble treatment of harmful substances, which comprises a water-soluble acidic metal salt containing 5 to 90% by weight of at least one metal selected from the group consisting of iron, manganese and aluminum, and 2 to 80 parts by weight a mixture of a mixture of an alkali metal and/or an alkaline earth metal water-insoluble basic compound and a material of 1 to 30% by weight of water, which is a mixture of powders, which comprises a water-soluble acidic metal salt when the powder is mixed and A reaction product obtained by reacting at least a part of the poorly water-soluble basic compound. The hazardous substance treatment agent according to claim 1, wherein the water-soluble acidic metal salt is at least one selected from the group consisting of ferric chloride, iron nitrate, iron sulfate, manganese chloride, aluminum chloride, and aluminum sulfate. Powder or 15~35 wt% aqueous solution. The hazardous substance treatment agent according to claim 1 or 2, wherein the poorly water-soluble basic compound is selected from the group consisting of calcium oxide, calcium hydroxide, calcium citrate, magnesium oxide, magnesium hydroxide, and sodium citrate. a powder of at least one of potassium citrate, silicate glass, steel slag, and cement. The hazardous substance treatment agent according to any one of claims 1 to 3, wherein the harmful substance treatment agent is a harmful substance treatment agent for insoluble treatment of harmful substances in sludge, incineration ash or contaminated soil. The harmful substance is an ion selected from at least one of arsenic, lead, cadmium, hexavalent chromium, selenium, mercury, fluorine, boron, nickel, copper, zinc, cerium, and cerium. The hazardous substance treatment agent according to claim 1, wherein the harmful substance treatment agent contains 10 to 90% by weight of iron sulfate and/or aluminum sulfate, and 3 to 80% by weight of magnesium oxide and/or Or calcium citrate, and a material of 1 to 30% by weight of water is obtained by powder mixing. The hazardous substance treatment agent according to claim 1, wherein the harmful substance treatment The chemical agent is obtained by powder-mixing a material containing 10 to 90% by weight of iron sulfate and/or aluminum sulfate, and 3 to 80% by weight of calcium hydroxide and 1 to 30% by weight of water. The hazardous substance treatment agent according to claim 1, wherein the harmful substance treatment agent comprises 10 to 90% by weight of iron sulfate and/or aluminum sulfate, and 3 to 80% by weight of cement, and 1 A material of ~30% by weight of water is obtained by powder mixing. The hazardous substance treatment agent according to claim 1, wherein the harmful substance treatment agent is a steel slag powder containing 10 to 90% by weight of iron sulfate and/or aluminum sulfate, and 3 to 80% by weight, and A material of 1 to 30% by weight of water is obtained by mixing powders.