JPH083317A - Sulfur polymer cement, its production and treating method for waste - Google Patents

Abstract

PURPOSE:To improve treating characteristics in producing sulfur polymer cement (SPC) and a sequestering property for harmful heavy metals and a strength characteristic of a treated product obtained by treating a waste containing heavy metals into a solid by using the SPC. CONSTITUTION:This sulfur polymer cement comprises a polymerization reaction product between sulfur and a reaction agent comprising 10-90wt.% ethylidene norbornene and styrene monomer. This method for treating a waste containing heavy metals is to mix the sulfur polymer cement with the waste containing heavy metals, heat and melt the mixture and solidify the molten product by cooling after kneading. The product is used as a civil engineering material. The treating characteristics in producing the SPC and characteristics of the product are improved by this method. The waste containing harmful metals solidified with the SPC is excellent in compressive strength and inhibition of heavy metal elution and, accordingly, it is suitable for a civil engineering material and aggregate for the material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a sulfur polymer cement obtained by reacting sulfur with a specific petroleum-based carbohydrate, a method for producing the same, and solidifying a heavy metal-containing waste using the sulfur polymer cement to dispose of it. The present invention relates to a method for preventing outflow of heavy metals, which are harmful substances, to the environment when disposing of materials, and reducing the volume of waste, as well as civil engineering and construction materials and aggregates obtained from the processed products by the method.

[0002]

2. Description of the Related Art It has long been practiced to use sulfur as a cementing agent, for example, in pavement materials. In the test pavement conducted in Ohio, USA around 1935, asphalt was heated to 140 ° C. It is used by heating it to 50% of sulfur and mixing it vigorously with stirring (US Pat. No. 2,182,837). In the 1970s, the most active research was made on the use of sulfur as a paving agent or cement agent, but it has not reached the stage of general practical use.

When sulfur is used as a cement agent, various studies have been made so far to react it with asphalt or olefinic hydrocarbon, and many examples using cyclopentadiene hydrocarbon are known. The product of the reaction between sulfur and petroleum hydrocarbons is generally called sulfur polymer cement (SPC). SPC has been conventionally used as a substitute or improver for concrete or asphalt, and contains sulfur and one or more petroleum hydrocarbons, for example, 60 to 98% by weight of sulfur,
It is obtained by reacting hydrocarbons at a mixing ratio of 40 to 2% by weight at 120 to 150 ° C. (US Pat. Nos. 4,190,816 and 4391969).

On the other hand, regarding the treatment of waste containing heavy metals, for example, the amount of steelmaking dust, general incinerators, fly ash, etc., tends to increase year by year, while the sites for their disposal are becoming more and more tight in recent years. In particular, when these wastes contain harmful heavy metals such as Cd, Pd, Zn, Hg, Cr ..., the disposal area is likely to be contaminated by elution of heavy metals. It's a problem in itself. Many studies have been conducted on the development of new technologies for the reuse of waste by recycling, but there is currently no definitive method.

Regarding the treatment of such heavy metal-containing wastes, a heavy metal sealing method using Portland cement (PC) has been generally attempted. However, there are various drawbacks and it is not possible to complete a technique for completely sealing heavy metals. I haven't arrived. Although this method is based on the hydration reaction of PC, it takes a long time to solidify, and many salts and other impurities present in the waste interfere with the solidification reaction. The durability is deteriorated and cracks and the like are likely to occur. Especially, there is a defect that acidity is weak and heavy metals may be eluted to cause contamination.

Further, it has been attempted to use sodium sulfide or a chelating agent in combination with PC to capture heavy metals and solidify and seal them with PC, but it is said that there is a possibility of decomposition and dissolution due to instability due to aging. Therefore, it has not reached the level of general diffusion.

Further, paying attention to the morphological change due to the temperature of sulfur, sulfur is mixed with industrial waste and the like is heated, and the heavy metal in the waste particles mixed with the molten sulfur and kneaded is solidified during cooling. It has also been proposed to solidify the waste as it is incorporated into the chain. In this method, the treatment is quick, and the hazardous substance is incorporated into the solidified polymer sulfur chain in the state where it binds to sulfur and it becomes difficult to elute to the outside. Suitable for

However, in the conventional sulfur treatment method, when a large amount of salts is present in the waste, or when the dust is ultrafine particles of micron or less, when the heavy metal is fixed and sequestered, it is more than the waste to be treated. Large amounts of sulfur may be needed and still may not completely suppress secondary elution.

An object of the present invention is to provide a sulfur polymer cement (SPC) which is more excellent in processing characteristics during production and properties of a product after solidification.

Another object of the present invention is that when the heavy metal-containing waste is solidified by using SPC, it is easy to treat, the obtained treatment product is dense, hardly elutes harmful metals, and has high strength. It is an object of the present invention to provide a method for treating waste, and civil engineering and construction materials and aggregates obtained by the method.

Examples of petroleum hydrocarbons used in the SPC are C4 to C20 olefinic hydrocarbons, diolefinic hydrocarbons, diene hydrocarbons such as dicyclopentadiene and its oligomers, other vinyltoluene, methylstyrene. Aromatic hydrocarbons such as are known, but the present inventors have conducted various studies and experiments on petroleum hydrocarbons more suitable as a reactant in such SPC, and as a result, have used ethylidene norbornene (ENB). I focused on.

ENB is a kind of norbornene derivative having two highly reactive double bonds, and is a colorless and transparent liquid at room temperature, for example, EBH which is a kind of ENB.
Has been used as a third component of ethylene propylene rubber in the synthetic rubber industry. The ethylene-propylene copolymer is an elastomer obtained by copolymerizing ethylene and propylene with a Ziegler-based catalyst,
It has no unsaturated bond in the molecule and has excellent heat resistance and weather resistance that are not found in conventional rubbers, but the usual sulfur vulcanization system could not be applied and there was a problem in terms of use. Therefore, by introducing a small amount of the third component having an unsaturated bond, a terpolymer of ethylene, propylene and diene is obtained, and sulfur vulcanizability is imparted. By imparting such vulcanizability, in the synthesis of the synthetic rubber copolymer, the viscosity is improved to contribute to the polymerization reaction and the product quality is improved.

The present inventors have found that this combination of EBH, styrene monomer and sulfur has an extremely excellent kneading effect due to its excellent viscosity when producing SPC, and the treated substance after cooling and solidification is dense and homogeneous. Have found it very good.

The processing mixture obtained by melt-kneading such SPC with the heavy metal-containing waste is processed by pressure molding or the like to sufficiently suppress the elution of heavy metals and to achieve excellent compression. It was discovered that a civil engineering building material having strength can be obtained, or the mixture can be crushed to an appropriate particle size after cooling, and can be sufficiently put into practical use as an aggregate of concrete as a substitute for conventional natural gravel, split stone, etc. .

The above object of the present invention is achieved by a sulfur polymer cement preparation comprising a reaction product of ethylidene norbornene of 10 to 90% by weight and a reaction product of styrene monomer and a polymerization reaction product of sulfur.

Another object of the present invention is achieved by a material for civil engineering and construction, which is obtained by mixing the above-mentioned sulfur polymer cement with a waste containing a harmful heavy metal, heating, melting, and kneading a product obtained by cooling and press-molding the product. To be done.

[0017]

In general, an SPC product is obtained by mixing and heating sulfur and various reactants such as cyclopentadiene or its derivative to carry out a melting reaction, and cooling and solidifying after completion of the reaction. In the present invention, a reaction to react with sulfur E as an agent
SPC is produced by reacting NB, for example, 5-ethylidene bicyclo (2.2.1) hept-2-ene (EBH) as a main component with styrene monomer in combination. EBH
Is produced by the reaction of dicyclobenz-2-ene (DCPD) and butadiene according to the following formula.

[0018]

Embedded image DCPD dicyclopenta2ene EBH 5-ethylidene bicyclo (2.2.1) hept-2-ene CPD cyclopenta2ene VCH 4-vinyl-1-cyclohexene VBH 5-vinylcyclo (2.2.1) pept-2-
EN THI 3a, 4,7,7a tetrahydroindene BD butadiene

The production of SPC using EBH and styrene monomer as a reactant is specifically carried out, for example, as follows. Sulfur is charged into a closed reaction tank equipped with a stirrer, and the internal temperature is maintained at 125 to 140 ° C. Add styrene monomer within 5 minutes after adding sulfur 10
Mix for ~ 15 minutes. Further, EBH is added and mixing is continued for 2 to 4 hours. Immediately after adding the styrene monomer and EBH, the temperature in the tank decreases, but the temperature viscosity gradually increases as the reaction with sulfur progresses. The temperature during mixing is maintained at 140 ° C or lower. The allowable range of viscosity is 25 to 100 cp / 135 ° C, and the optimum viscosity is 40 cp / 135 ° C. After the reaction is completed, the target SPC can be obtained by discharging the product from the reaction tank and cooling and solidifying.

The reaction between sulfur and EBH in producing SPC by ENB, for example, EBH, is carried out in the molten state of sulfur 120 to
The following reaction proceeds in the presence of 130 ° C. However, it is necessary to pay attention to the heat generated by the reaction and to carefully control the handling.

[0021]

Embedded image

The reaction (1) causes the reaction of EBH with sulfur. Further, depending on the reaction conditions, the process moves to (2). The products produced by (1) to (2) are polymerized by (3), and then linear SPC (4) which is a necessary component of ENB (EBH) -based SPC can be obtained.

When a styrene monomer is used together in the preparation of an ENB (EBH) type SPC, the highly polymerizable styrene monomer becomes a styrene polymer to maintain the stability of the viscosity during the reaction and to prepare the prepared SPC. This will increase the strength of the molded product when used as a cement agent. The increase in strength is approximately proportional to the amount of styrene added.

In the reaction of the above sulfur, EBH and styrene monomer, 1 to 30% by weight of the reactant is added to 70 to 99% by weight of the sulfur, preferably 3 to 15% by weight of 85 to 97% by weight of the sulfur. It is desirable to use a reactant. The weight ratio of EBH as a reactant to styrene monomer is 10 to 90% by weight of EBH, and the ratio of styrene monomer is changed depending on the purpose of use of the SPC agent. EBH
Alternatively, the same purpose can be achieved by using VBH which is its precursor or VCH which is a by-product as shown in the following formula.

[0025]

Embedded image

In the treatment of wastes containing harmful heavy metals, S
PC reacts with heavy metal salts in the dust to form sulfides,
When the morphology changes due to temperature, the heavy metal in the waste particles is taken into the polymer chain of SPC that solidifies during cooling and the waste is solidified. Heavy metal sequestration stabilizer is SPC in molten state
It is mixed with and chemically and physically sequesters heavy metals.

In a preferred embodiment of the present invention, SPC produced by the reaction of sulfur with ethylidene norbornene and styrene monomer on hazardous heavy metal containing waste.
And a heavy metal sequestering stabilizer composed of sodium silicate, sodium sulfide, and / or a chelating agent, and mixed at about 120 ° C to 150 ° C.
It is melted and kneaded by heating at a temperature of ℃, and then solidified by cooling, or further crushed into an appropriate size and shape at the time of solidifying by cooling.

The heavy metal sequestering stabilizer comprising sodium silicate, sodium sulfide and / or a chelating agent stabilizes the heavy metal as a water-insoluble compound. The hazardous heavy metal-containing wastes to be treated in the present invention include Cd, Pb, Zn, Hg,
Industrial wastes that contain one or more harmful heavy metals such as Cr, and may contain heavy metals and other harmful substances, are, for example, steelmaking dust, general incineration ash, and fly ash.

SPC for 100 parts by weight of these wastes
5 to 100 parts by weight and sodium silicate (Na ₂ Si
O ₃ ), sodium sulfide (Na ₂ S), and / or 1 to 30 parts by weight of a heavy metal sequestering stabilizer composed of a chelating agent are mixed. SPC is solidified in a state in which heavy metals in waste particles kneaded in a molten state are taken into a polymer chain of sulfur that solidifies during cooling. 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 polymerize, including the product treated with the heavy metal sequestering stabilizer. ,
Fine particles of waste dust are combined and integrated in a state of being covered with SPC.

In this case, the hydrocarbon in the SPC lowers the viscosity of the mixture at the time of stirring and kneading to make the mixing more efficient, thereby further promoting the reaction and contributing to the homogeneity, and the effect of the combined use with the heavy metal sequestering stabilizer. Is further improved and efficient processing is performed.

When the amount of SPC is 5 parts by weight or less with respect to 100 parts by weight of waste, it becomes difficult to completely take in heavy metals in the waste. On the other hand, even if the amount of SPC is more than 100 parts by weight, the effect obtained by that does not improve so much, which is rather disadvantageous in terms of cost. The preferred amount of SPC mixed with 100 parts by weight of waste varies depending on the waste to be treated, but for example, in the case of steelmaking dust from an electric furnace, 15 to 30 parts by weight of SPC is sufficient.

The heavy metal sequestering stabilizer is well miscible with the SPC in the molten state and chemically and physically contributes to sequestering the heavy metal.
That is, sodium silicate reacts with the heavy metal salt in the waste to be a metal silicate or metal hydroxide, and further dehydrated to a metal oxide. Also, sodium sulfide reacts with heavy metals to form metal sulfides and is stabilized as a water-insoluble compound. Furthermore, sodium silicate forms a strong film by dehydration, and its adhesive effect reduces the volume of powdery waste dust and contributes to an increase in apparent specific gravity, thus reducing the amount of SPC used.

The chelating agent stabilizes heavy metals in waste as a chelating compound. As such a chelating agent, a so-called chelating agent that is commonly used for separation of metal salts, refinement and analysis, and forms stable complex salts of alkaline earth metals, rare earths and transition metals, ethylenediamine, Examples thereof include EDTA, NTA, acetylacetone, glycine and the like. Examples of commercially available chelating agents that 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 chelating agent may be used alone or as a mixture of two or more kinds. If the mixing amount of the heavy metal sequestration stabilizer with respect to 100 parts by weight of waste 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 sequestering effect is improved accordingly. It is disadvantageous in terms of cost.

The temperature at which the SPC and the heavy metal sequestering stabilizer are mixed with the waste and the mixture is heated and kneaded is about 120 to 150 ° C.
° C. If the temperature is lower than 120 ° C, sulfur or SP
The melting of C is insufficient and kneading becomes difficult. On the other hand, when the temperature is higher than 150 ° C., sulfur shifts to the μ phase having a high viscosity and the kneading work efficiency is reduced.

The SPC and the heavy metal sequestration stabilizer may be mixed into the waste material at the same time, or the heavy metal sequestration stabilizer may be mixed with the waste material in advance and heated before adding the SPC. When the heavy metal sequestration stabilizer is mixed with the waste in advance, it is preferable to heat it to about 60 to 120 ° C., so that the heavy metal sequestration stabilizer is sufficiently mixed in the waste to cause a reaction, and thereafter SPC is performed. It is possible to remarkably shorten the working time when adding, heating, melting and kneading, as compared with the case of simultaneous addition.

The SPC, the heavy metal sequestering stabilizer and the waste are heated, melted and kneaded, transferred to an appropriate mold and allowed to cool and solidify. This solidified product is appropriately disposed of at the disposal site. When the resulting melt-kneaded product is allowed to cool and solidify, it is possible to completely block heavy metals by briquetting and allowing to cool in a semi-molten state by a pressure molding machine, and to prevent secondary pollution due to their elution. It is possible, and it is 150-200kg / cm
^It has a compressive strength of ² or more and can be reused as a civil engineering and building material.

Further, these can be crushed to an appropriate size and shape and used as a substitute for gravel, crushed stone, crushed stone, cobblestone, crushed stone, etc. Further, these can be blended with Portland cement etc. as an aggregate. Thus, it is possible to produce concrete which is comparable in strength to conventional PC concrete and which has almost no risk of elution of harmful heavy metals.

[0039]

【Example】

SPC Production Example Using the weight composition shown in Table 1, SPC was prepared under the reaction conditions shown below.
Was manufactured.

[0040]

[Table 1] a b c (kg) (%) (kg) (%) (kg) (%) Sulfur 9.5 95 9.0 90 9.7 97 EBH 0.4 4 0.6 6 0.2 2 Styrene monomer 0.1 1 0.4 4 0.1 1 Reaction time ( Time) 3 43 Reaction temperature (° C) 125-135 125-140 125-135 Viscosity at discharge 40 50 30 (cp / 135 ° C) Reaction conditions (1) 10-liter sealed reaction tank with a stirrer 12
The mixture was heated to 5 ° C, sulfur was added, and the mixture was melted and stirred. (2) Add styrene monomer within 5 minutes after adding sulfur 1
Mixing was performed for 0 to 15 minutes. (3) EBH was intermittently charged and a stirring and mixing reaction was performed for 2 to 4 hours. Immediately after feeding the raw materials, the material temperature decreases, but the temperature and viscosity increase as the reaction progresses. The temperature is 135-
The temperature was maintained at 145 ° C. and the operation was controlled. (4) After completion of the reaction, the product was discharged from the reaction tank, cooled, and solidified into flakes.

Example of waste treatment

Table 2 Fe 28% Zn 14 Cd 3 Mn 2 Pb 2 Cr 3 Cu 1 Cl 4

Example 1 To 10 kg of steelmaking dust having the composition shown in Table 2, 0.5 kg of sodium silicate No. 3 product and 0.3 kg of water were added, and the temperature was 60 to 100.
Stir and mix for 10 minutes at ℃, then SPC- (a) 2.5
kg, and the mixture is heated and melted at a temperature of 130 to 140 ° C. and stirred and kneaded for 20 minutes so as to be sufficiently uniform, and the diameter is 5 c.
It was then transferred to a cylindrical container having a height of 10 cm and a height of 10 cm and allowed to cool and solidify. The analytical test results are shown in Table 3.

Example 2 To 10 kg of steelmaking dust having the composition shown in Table 2, 0.25 kg of sodium silicate No. 3 product, 0.25 kg of sodium sulfide, and 0.3 k of water
g, and the mixture is stirred and mixed at a temperature of 60 to 100 ° C. for 10 minutes, then 2.5 kg of SPC- (b) is added, and a temperature of 130 to 1 is added.
The mixture was heated and melted at 40 ° C., stirred and kneaded for 20 minutes so as to be sufficiently uniform, transferred to a cylindrical container having a diameter of 5 cm and a height of 10 cm, and allowed to cool and solidify. The analytical test results are shown in Table 3.

Example 3 10 kg of steelmaking dust having the composition shown in Table 2 was mixed with sodium sulfide of 0.
5 kg and 0.3 kg of water are added, and the temperature is 60 to 100 ° C.
Stir and mix for 2 minutes, then add 2.5 kg of SPC- (c), heat and melt at a temperature of 130 to 140 ° C., and stir and knead for 20 minutes to obtain a sufficiently uniform mixture, diameter 5 cm, height 1
It was transferred to a 0 cm cylindrical container and allowed to cool and solidify. The analytical test results are shown in Table 3.

Example 4 To 10 kg of steelmaking dust having the composition shown in Table 2, 0.2 kg of a commercially available chelating agent Evolver and 0.3 kg of water were added, and the mixture was stirred and mixed at a temperature of 60 to 100 ° C. for 10 minutes, and then SPC.
-(A) Add 2.5 kg, heat and melt at a temperature of 130-140 ° C., stir and knead for 20 minutes so as to be sufficiently uniform, and transfer to a cylindrical container having a diameter of 5 cm and a height of 10 cm to solidify by cooling. Let The analytical test results are shown in Table 3.

[0046]

[Table 3] Analysis results Example 1 2 3 4 (ppm) (ppm) (ppm) (ppm) Fe ND ND ND ND Zn <1.0 <1.0 <1.0 <1.0 Cd <0. 03 <0.03 <0.03 <0.03 Mn ND ND ND ND Pb <0.3 <0.3 <0.3 <0.3 Cr <0.15 <0.15 <0.15 <0 .15 Cu ND ND ND ND Compressive strength>250>300>200> 250 (kg / cm ² ) (ND is below detection limit)

[0047]

EFFECTS OF THE INVENTION According to the present invention, the processing characteristics in the production of SPC and the characteristics of the product are improved, and the hazardous metal-containing waste solidified using this SPC has excellent compressive strength and suppresses elution of heavy metals. Its excellent properties make it suitable for use as a material for civil engineering and construction or its aggregate.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location B09B 3/00 (72) Inventor Hiroshi Kato 3-12-11 Tsubakimori, Chuo-ku, Chiba-shi, Chiba (72) Inventor Kaoru Ichinomiya 3-5-12 Higashi Narashino, Narashino City, Chiba Prefecture La Fole No. 206

Claims (6)

[Claims] 1. A sulfur polymer cement comprising 10 to 90% by weight of ethylidene norbornene and a reaction product of styrene monomer and a polymerization reaction product of sulfur. 2. The sulfur polymer cement according to claim 1, which is obtained by reacting 1 to 30% by weight of a reactant with 70 to 99% by weight of sulfur. 3. A reactant comprising 10 to 90% by weight of ethylidene norbornene and styrene monomer and 1% of sulfur.
A method for producing a sulfur polymer cement, which comprises reacting at 10 to 160 ° C. 4. Claim 1 for waste containing hazardous heavy metals.
Alternatively, a method for treating hazardous heavy metal-containing waste by mixing the sulfur polymer cement according to 2 and heating, fusing, kneading, cooling and solidifying the mixture. 5. Claim 1 for waste containing hazardous heavy metals
Alternatively, a material for civil engineering and construction, which is obtained by mixing the sulfur polymer cement according to 2 and heating, melting, and kneading the product, and cooling and press-molding the product. 6. Claim 1 for waste containing hazardous heavy metals
Alternatively, an aggregate obtained by mixing the sulfur polymer cement described in 2, heating, melting, and kneading the product, and then pulverizing the product after cooling.