JPH07290024A - Construction and architectural material obtained by reutilizing harmful heavy metal-containing waste - Google Patents

Abstract

PURPOSE:To reutilize a harmful heavy metal-contg. waste for the construction and architectural material as a substitute for natural resources by safely solidifying the waste. CONSTITUTION:One hundred pts.wt. of the mixture of harmful heavy metal- contg. wastes and slag, 5-100 pts.wt. of sulfur polymer cement(SPC) formed by sulfur or by the reaction of sulfur with petroleum hydrocarbons and 1-30 pts.wt. of the heavy metal sequestering stabilizer consisting of sodium silicate, sodium sulfide and/or a chelating agent are mixed. The mixture is held at about 120-150 deg.C, melted, kneaded, then cooled and solidified to obtain the construction and architectural material. Accordingly, the harmful heavy metals are hardly eluted from the industrial waste contg. the heavy metals, a product excellent in strength is obtained, and the product is reutilized as the construction and architectural material as a substitute for natural ballast or crushed stone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for civil engineering and construction using a treated product of hazardous waste, and more particularly to a material for civil engineering and building obtained by solidifying a waste containing a heavy metal.

[0002]

2. Description of the Related Art Conventionally, natural materials such as gravel, crushed stone, crushed stone, and cobblestone have been used as aggregates for civil engineering. The shortage is a problem. It has also been attempted to crush and size slag, etc. generated from metal smelters such as blast furnaces, open hearth furnaces, converters, and electric furnaces, and use it as a substitute for gravel, crushed stone, etc. Therefore, not all of them have been used effectively. In addition, concrete lumps and asphalt lumps obtained from construction sites are also used in some areas, but due to reasons such as securing a place for recovery processing, consideration of the surrounding environment, uniformity of quality, and economic efficiency, it is still unusable. This is a sufficient stage.

On the other hand, the amount of steelmaking dust, general incineration ash, fly ash, slag slag, etc. tends to increase year by year, while the sites for their disposal have become more and more tight in recent years. Especially in these wastes, Cd, Pb, Zn, Hg, C
When harmful heavy metals such as r ... Are contained, the disposal method itself is a problem because the surrounding area of the dumping site may be contaminated by the elution of heavy metals.

As a method of treating these wastes, a method of sealing heavy metals with Portland cement (PC) has been generally attempted, but since various drawbacks are involved, it is not possible to complete a technique for completely sealing heavy metals. I haven't arrived. That is, although this method is based on the hydration reaction of PC, it takes a long time to coagulate, and many salts and other impurities present in the waste interfere with the coagulation reaction.
Cement solidification strength and durability are deteriorated, cracks and the like are likely to occur, and heavy metals may be eluted to cause environmental pollution particularly due to weakness in acidity.

Further, paying attention to the morphological change due to the temperature of sulfur, sulfur is mixed with the industrial waste and heated, and the heavy metal in the waste particles kneaded with the molten sulfur and solidified during cooling is a polymer of sulfur. It has also been proposed to solidify the waste as it is incorporated into the chain. This method is suitable for solidification treatment of waste containing heavy metals, since the treatment is rapid and the harmful substance is taken into the solidified polymer sulfur chain and is difficult to be eluted outside.

However, in the conventional sulfur treatment method, when a large amount of salts are present in the waste or when the waste itself is ultrafine particles of micron or less, such as steelmaking dust, the heavy metal is fixed and blocked. In this case, a large amount of sulfur, which is more than the waste to be treated, may be required, and still the secondary elution may not be completely suppressed.

The object of the present invention is that by the solidification treatment of industrial waste containing harmful heavy metals, there is almost no outflow of heavy metals, which are harmful substances, to the environment, and they have high density and strength, and have acid resistance, salt resistance and It is intended to provide a stable material for civil engineering and construction having excellent liquid permeation resistance.

[0008]

The above-mentioned object of the present invention is to provide 100 parts by weight of hazardous heavy metal-containing waste and 5 to 1 sulfur.
00 parts by weight and 1 to 30 parts by weight of a heavy metal sequestering stabilizer comprising sodium silicate, sodium sulfide and / or a chelating agent, and the mixture is about 120 to 150 ° C.
It is achieved by a material for civil engineering and construction obtained by heating, melting and kneading at the temperature of, and then cooling and solidifying.

An object of the present invention is also the sulfur polymer cement (SPC) 5-100 produced by the reaction of 100 parts by weight of hazardous heavy metal-containing waste with sulfur and petroleum hydrocarbons.
1 to 30 parts by weight of a heavy metal sequestering stabilizer comprising sodium silicate, sodium sulfide and / or a chelating agent, and the mixture is about 120 to 150 ° C.
It is achieved by a material for civil engineering and construction obtained by heating, melting and kneading at the temperature of, and then cooling and solidifying.

The object of the invention is also a mixture of hazardous heavy metal-containing waste and slag slag in a ratio of 1: 0.5 to 2 by weight.
Parts by weight, 5 to 100 parts by weight of sulfur, and 1 to 30 parts by weight of a heavy metal sequestering stabilizer consisting of sodium silicate, sodium sulfide and / or a chelating agent, and the mixture at about 120 to 150 ° C. This is achieved by a material for civil engineering and construction obtained by heating, melting and kneading at a temperature and then cooling and solidifying.

The object of the invention is also a mixture of hazardous heavy metal-containing waste and slag slag in a ratio of 1: 0.5 to 2 by weight.
Parts by weight, 5-100 parts by weight of sulfur polymer cement (SPC) produced by the reaction of sulfur and petroleum hydrocarbons, and 1 to 30 parts by weight of a heavy metal sequestering stabilizer comprising sodium silicate, sodium sulfide and / or a chelating agent. It is achieved by a material for civil engineering and construction obtained by heating, melting and kneading the mixture at a temperature of about 120 to 150 ° C. and then cooling and solidifying the mixture.

[0012]

The hazardous heavy metal-containing waste to be treated in the present invention is a waste containing one or more harmful heavy metals such as Cd, Pb, Zn, Hg and Cr, and particularly contains such harmful heavy metals. Industrial wastes of high risk, such as steelmaking dust, general incineration ash and fly ash.

Sulfur reacts with heavy metal salts in waste such as steelmaking dust to form sulfides, and the heavy metal in the waste particles is taken in and discarded in the polymer chain of sulfur that cools and solidifies when the shape changes with temperature. Solidify the whole thing.

Sulfur is added to 100 parts by weight of the above waste,
5 to 100 parts by weight of sulfur are mixed. When the amount of sulfur is less than 5 parts by weight with respect to 100 parts by weight of waste, it is difficult to take in heavy metals in the waste almost completely. On the other hand, even if the amount is more than 100 parts by weight, the effect obtained by that does not improve so much, but rather it is disadvantageous in terms of strength and cost. The preferable amount of sulfur mixed with 100 parts by weight of waste depends on the waste to be treated, but in the case of steelmaking dust from an electric furnace, for example,
It is suitable to be 40 to 50 parts by weight.

The heavy metal sequestering stabilizer used in the present invention is well miscible with sulfur or SPC in a molten state,
Physically contributes to the blockage of heavy metals. That is, sodium silicate (Na ₂ SiO ₃ ) reacts with the heavy metal salts in the waste to react with silicate metal salts or metal hydroxides, and is further dehydrated into metal oxides or the like. Further, sodium sulfide (Na ₂ S) reacts with a heavy metal salt to form a metal sulfide, which is stabilized as a water-insoluble compound. Further, Na ₂ SiO ₃ forms a strong film by dehydration, and its adhesive effect contributes to volume reduction of powdery waste dust, that is, contributes to an increase in apparent specific gravity and reduces the amount of sulfur used.

The chelating agent stabilizes the heavy metal in the waste as a chelating compound. As such a chelating agent, a so-called chelating agent which is generally used for separation, purification and analysis of a metal salt and forms a stable complex salt with an alkaline earth metal, a rare earth and a transition metal is used, and ethylenediamine and EDTA are used. , NTA, acetylacetone glycine and the like. Examples of commercially available chelating agents which are particularly preferably used in the present invention include Epolba 500.
(Registered trademark: Miyoshi Yushi Co., Ltd.) and NKK heavy metal stabilizer A-100 (Nippon Steel Tube Co., Ltd.).

The heavy metal sequestering stabilizer comprising sodium silicate, sodium sulfide and / or a chelating agent as described above may be used alone or as a mixture of two or more of 1 to 100 parts by weight of waste.
30 parts by weight are mixed. If the amount of the heavy metal sequestering stabilizer mixed is less than 1 part by weight, the intended sequestering effect becomes unstable. On the other hand, even if added in an amount of 30 parts by weight or more, the blocking effect is not improved accordingly, which is disadvantageous in terms of cost.

Next, the temperature at which the waste is mixed with sulfur and the heavy metal sequestering stabilizer and kneaded by heating is about 120 to 15
It is 0 ° C. If the temperature at this time is lower than 120 ° C, the melting of sulfur is insufficient and kneading becomes difficult.
If it is higher than this, sulfur shifts to the highly viscous μ phase and reduces the kneading work efficiency.

The sulfur and the heavy metal sequestering stabilizer may be mixed into the waste material at the same time, or the sulfur may be added after the heavy metal sequestering stabilizer is previously mixed with the waste material and heated. When the sequestering stabilizer is mixed with the waste in advance, it is preferable to heat the sequestering stabilizer to about 100 to 120 ° C., which causes the reaction in the state where the heavy sequestering stabilizer is sufficiently mixed in the waste. Further, the working time when adding sulfur and then heating, melting and kneading can be significantly shortened as compared with the case of simultaneous addition.

After sulfur, the heavy metal sequestering stabilizer and the waste are heated and melted and kneaded, they are transferred to an appropriate mold and left to cool and solidify.
In this case, the heavy metal was almost completely blocked by a normal pressurization or vibration molding machine or by half-briquetteing by allowing the mold to be poured and allowed to cool, and secondary contamination due to elution of them was suppressed and obtained. A compression strength of at least 150 to 200 kg / cm ² or more is obtained for the treated molded product. This compressive strength increases with the passage of time.

This solidified product has the above-mentioned excellent compressive strength because the elution value of the heavy metal contained therein sufficiently satisfies the legally regulated value as described in Examples below, and
By itself, it becomes a civil engineering and construction material that can be used for roadbed reinforcement work, wall type pouring work, and the like. Further, these can be crushed to an appropriate size and shape to be used as a substitute for gravel, crushed stone, crushed stone, cobblestone, crushed stone, and the like. In this respect, it is possible to manufacture concrete that is comparable to conventional PC concrete and has almost no risk of elution of harmful heavy metals.

In the present invention, when treating waste containing harmful heavy metals, so-called SPC, which is a reaction product of sulfur and a petroleum hydrocarbon compound, is used in place of the sulfur to further improve the cement effect of sulfur. be able to. SPC has been conventionally used as a substitute or improvement material for concrete or asphalt (US Pat. No. 4,190,816, 4391969, etc.), and contains sulfur and one or more petroleum hydrocarbons, for example, 60-80%: 40- 20% mixing ratio (weight ratio)
It is obtained by reacting at 130 to 150 ° C. Examples of such petroleum hydrocarbons are C _4-20 olefinic hydrocarbons, diolefinic hydrocarbons, diene hydrocarbons such as dicyclopentadiene and its oligomers, and other aromatics such as vinyltoluene and methylstyrene. Group hydrocarbons may be mentioned.

The heat-melted SPC reacts with the heavy metal salts in the waste to form sulfides, which combine with the glassy SPC formed by cooling, and further include the product treated with the heavy metal sequestering stabilizer. Are polymerized, and the fine particles of the waste dust are combined and integrated while being covered with the SPC. In this case, the hydrocarbon in the SPC lowers the viscosity of the mixture at the time of stirring and kneading to improve the mixing efficiency, thereby contributing to the promotion and homogenization of the reaction, and the effect of the combined use with the heavy metal sequestering stabilizer is further improved. A further improvement, which results in a smaller and more effective treatment as compared to the use of elemental sulfur. The amount of SPC mixed with the heavy metal-containing waste varies depending on the type of the waste, but if the waste is a 1: 1 mixture of steelmaking dust and iron smelting slag, 20 to 30% by weight of the waste is included.
The degree is enough.

Further in the present invention, sulfur or SPC
When melt-kneading and solidifying the dust by using, a granular material such as a slag slag is mixed to obtain a solid material having a high compressive strength although it varies depending on the mixing ratio.

Among the above-mentioned wastes, a relatively large amount of sulfur or SPC is required for melt-kneading fine powdery industrial wastes having a particle size of micron order or less such as steelmaking dust and fly ash with sulfur or SPC. And the physical properties such as the compressive strength of the obtained solidified molded article do not always completely satisfy the characteristics as a material for civil engineering and construction in all applications. For such fine-grained waste, the amount of sulfur used in the melting process should be determined by mixing crushed pieces of molten slag (milli-order), which is also a typical industrial waste, with a relatively large particle size. Can be significantly reduced in accordance with the amount of slag added, and the physical properties such as the compressive strength of the obtained solidified molded product are remarkably excellent, and more practical use as a material for civil engineering and construction or an aggregate. Be expected.

When processing is carried out by mixing a granular material such as slag slag, the amount of sulfur or SPC used is slightly different depending on the kind and mixing ratio of the slag slag, but decreases almost in proportion to the amount of slag mixed. To do. Further, the mixing ratio of the hazardous metal waste and the slag slag is preferably in the range of 1: 0.5 to 2.0 parts by weight. When the mixing ratio of the molten slag is 2.0 or more, the cement binding force due to sulfur (or SPC) is reduced as a whole, so that the strength of the treated product is reduced. When the mixing ratio is 0.5 or less, the effect obtained by mixing the slag, that is, the required amount of sulfur (or SPC) is reduced and the strength of the treated product is not substantially obtained. The present invention will be described below with reference to examples.

Example 1 10 kg of steel-making dust shown in Table 1 and 0.5 kg of sodium silicate
Was added, and the mixture was stirred and mixed at a temperature of 100 to 120 ° C. for 5 minutes, then 4 kg of sulfur was added, and the mixture was heated and melted at a temperature of 130 to 140 ° C. and stirred and kneaded for 15 minutes to be sufficiently uniform, and the diameter was 5
cm and a height of 10 cm were transferred to a cylindrical container to be cooled and solidified (Table 2, No. 1). The analysis results are shown in Table 3.

Example 2 7 kg of steelmaking dust and 3 kg of copper smelting slag shown in Table 1
0.5kg of sodium sulfide is added to the temperature of 100-120 ℃
Stir to mix for 5 minutes, then add 4 kg of sulfur and
Heat and melt at 0-140 ° C, and make sure it is uniform.
The mixture was stirred and kneaded for a minute, transferred to a cylindrical container having a diameter of 5 cm and a height of 10 cm, and cooled and solidified (Table 2, No. 2).
2). The analysis results are shown in Table 3.

Example 3 6 kg of steelmaking dust and 4 kg of iron smelting slag shown in Table 1
0.4kg of sodium silicate is added to the temperature of 100-120 ℃
Stir and mix for 5 minutes, then add 3.2 kg of sulfur, heat and melt at a temperature of 130 to 140 ° C., stir and knead for 15 minutes to obtain a sufficiently uniform mixture, diameter 5 cm and height 10 c
m into a cylindrical container and cooled and solidified (No. 2 in Table 2).
3). The analysis results are shown in Table 3.

Example 4 5 kg of steelmaking dust and 5 kg of copper smelting slag shown in Table 1
Sodium sulfide 0.3kg is added to the temperature of 100-1
Stir and mix at 20 ° C. for 5 minutes, add 3 kg of sulfur, heat and melt at a temperature of 130 to 140 ° C., stir and knead for 15 minutes to obtain a sufficiently uniform mixture, diameter 5 cm and height 10 c
m into a cylindrical container and cooled and solidified (No. 2 in Table 2).
4). The analysis results are shown in Table 3.

Example 5 0.5 kg of sodium silicate was added to 10 kg of steelmaking dust shown in Table 1.
Is added, and the mixture is stirred and mixed at a temperature of 100 to 120 ° C. for 5 minutes, then 3 kg of SPC is added, the mixture is heated and melted at a temperature of 130 to 140 ° C., and the mixture is stirred and kneaded for 15 minutes to be sufficiently uniform,
It was transferred to a cylindrical container having a diameter of 5 cm and a height of 10 cm to be cooled and solidified (Table 2, No. 5). The analysis results are shown in Table 3.

Example 6 7 kg of steelmaking dust and 3 kg of copper smelting slag shown in Table 1
0.5 kg of sodium sulfide is added to the temperature of 100-1
Stir and mix at 20 ° C. for 5 minutes, then add 3 kg of SPC, heat and melt at a temperature of 130 to 140 ° C., and stir and knead for 15 minutes to obtain a sufficiently uniform mixture, diameter 5 cm and height 1
It was transferred to a container on a 0 cm cylinder and solidified by cooling (Table 2, N
o. 6). The analysis results are shown in Table 3.

Example 7 6 kg of steelmaking dust and 4 kg of iron smelting slag shown in Table 1
Sodium silicate 0.4kg is added to the temperature of 100-1
Stir and mix at 20 ° C. for 5 minutes, then add 2.2 kg of SPC, heat and melt at a temperature of 130 to 140 ° C., stir and knead for 15 minutes so as to be sufficiently uniform, and put into a cylindrical container having a diameter of 5 cm and a height of 10 cm. It was transferred and solidified by cooling (Table 2, No. 7). The analysis results are shown in Table 3.

Example 8 5 kg of steelmaking dust and 5 kg of copper smelting slag shown in Table 1
Sodium sulfide 0.3kg is added to the temperature of 100-1
Stir and mix at 20 ° C. for 5 minutes, add 2 kg of SPC, heat and melt at a temperature of 130 to 140 ° C., and stir and knead for 15 minutes to obtain a sufficiently uniform mixture, diameter 5 cm, height 10 c
It was transferred to a cylindrical container of m and cooled and solidified (Table 2, No,
8). The analysis results are shown in Table 3.

The solidified product obtained in each of the above examples was pulverized and tested by the dissolution test method stipulated by the Prime Minister's Ordinance. Each solidified product (diameter 5c
m, height 10 cm) was tested by the compressive strength test method defined in JIS A1108. As shown in Table 3, the elution values of harmful metals from the solidified products of the industrial wastes obtained in Examples 1 to 8 were all below the environmental standard.

The uniaxial compressive strength of the solidified product obtained in each example is 150 to 200 kg in all cases.
/ Cm ² or more, and when used as an actual product, it is expected that the compression strength will be further increased by pressing and compression molding. Further, the solidified product processed according to the present invention tends to further increase its compression density or stability with the passage of time. The numerical value of each metal in Table 3 is ppm, indicating that ND was not detected. The unit of compressive strength is kg / cm ² .

[0037]

[Table 1] Steelmaking dust Iron smelting slag Copper smelting slag (%) (%) (%) Fe 28 27 35 Zn 14-1 Cd 3 -Mn 2 7 -Pb 2 -0.2 Cr 1 0.5 -Cu 1 0.1 0.7 SiO _2-12 34 Al ₂ 0 ₃ - 4 5 particle size 0.5 ~3μm 0.5 ~5mm 0.5 ~5mm bulk density 0.5-0.9 1.0-1.5 1.5-2.0

[0038]

[Table 2] Example 1 2 3 4 5 6 7 8 (kg) Steelmaking dust 10 7 6 5 10 7 6 5 Iron and steel slag 4 5 4 5 Copper steel slag 3 5 3 5 Sodium silicate 0.5 ー 0.4 ー 0.5 ー 0.4 ー Sodium sulfide 0.5 ー 0.3 ー 0.5 ー 0.3 Sulfur 4 4 3.2 3 ー ー SPC ー ー 3 3 3 2.2 2

[0039]

[Table 3] Example 1 2 3 4 5 6 7 8 Item Fe ND ND ND ND ND ND ND ND Zn Zn <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 Cd <0.1 <0.1 <0.1 <0.1 <0.03 <0.03 <0.03 <0.03 Mn ND ND ND ND ND ND ND ND Pd <0.4 <0.4 <0.4 <0.4 <0.3 <0.3 <0.3 <0.3 Cr <0.2 <0.2 <0.2 <0.2 <0.15 <0.15 <0.15 < 0.15 Cu ND ND ND ND ND ND ND ND Compressive strength ＞ 150 ＞ 150 ＞ 200 ＞ 300 ＞ 200 ＞ 250 ＞ 300 ＞ 400 Density 3.4 3.3 3.2 3.2 3.5 3.5 3.2 3.1

[0040]

INDUSTRIAL APPLICABILITY In the present invention, harmful heavy metal-containing waste is mixed with sulfur or sulfur polymer cement (SPC) and heavy metal sequestering stabilizer, heated, melted and kneaded, and then cooled and solidified to be placed in a natural environment. A stable solidified product with almost no physical or chemical aging is obtained, and the elution of harmful heavy metals contained in the waste is well below legally regulated values. By treating with a combination of fine powdery steel-making dust, which is difficult to treat as a hazardous heavy metal-containing waste, and a relatively coarse-grained molten slag, which can reduce the treatment amount of sulfur content, Since the physical properties such as density and compressive strength are further excellent, it can be used as it is as a paint for civil engineering and construction.
Further, the obtained product can be used as a concrete product by crushing it into an appropriate shape and size to mix it with cement or the like as a substitute for conventional gravel or the like.

According to the present invention, the problem of safe treatment of industrial waste containing harmful metals such as dust, fly ash, slag, etc. from various metal smelting facilities can be effectively solved, and these treated products can be effectively treated. Reusing as a civil engineering building material also provides a strategy for the depletion of natural resources and their protection.

Claims (4)

[Claims] 1. 100 parts by weight of hazardous heavy metal-containing waste,
A mixture comprising 5 to 100 parts by weight of sulfur and 1 to 30 parts by weight of a heavy metal sequestering stabilizer comprising sodium silicate, sodium sulfide and / or a chelating agent, wherein the mixture is about 120 parts by weight.
A material for civil engineering and construction obtained by heating, melting and kneading at a temperature of 150 ° C and then cooling and solidifying. 2. 100 parts by weight of hazardous heavy metal-containing waste,
Consists of 5 to 100 parts by weight of a sulfur polymer cement (SPC) produced by the reaction of sulfur and petroleum hydrocarbons, and 1 to 30 parts by weight of a heavy metal sequestering stabilizer composed of sodium silicate, sodium sulfide and / or a chelating agent. A material for civil engineering and construction, which comprises a mixture, and is obtained by heating, melting and kneading the mixture at a temperature of about 120 to 150 ° C., and then cooling and solidifying the mixture. 3. 100 parts by weight of a mixture of hazardous heavy metal-containing waste and slag slag in a ratio of 1: 0.5 to 2 and sulfur 5
˜100 parts by weight and 1 to 30 parts by weight of a heavy metal sequestering stabilizer comprising sodium silicate, sodium sulfide and / or a chelating agent, and the mixture is about 120 to 15 parts by weight.
Materials for civil engineering and construction obtained by heating, melting and kneading at a temperature of 0 ° C and then cooling and solidifying 4. Sulfur polymer cement (SPC) 5-100 produced by the reaction of sulfur with petroleum hydrocarbons, and 100 parts by weight of a mixture of hazardous heavy metal-containing waste and slag slag in a ratio of 1: 0.5 to 2 by weight. Parts by weight, sodium silicate,
A mixture of 1 to 30 parts by weight of a heavy metal sequestering stabilizer composed of sodium sulfide and / or a chelating agent, which is obtained by heating, melting and kneading the mixture at a temperature of about 120 to 150 ° C. and then cooling and solidifying the mixture. material