JPH0873252A - Dust generation suppressing method of lime or cement - Google Patents

Abstract

PURPOSE: To easily and inexpensively suppress the dust generation of line or cement by adding a prescribed quantity of an asphalt, tar or viscous oil, which are adjusted to a prescribed viscosity, to the lime or cement to agglomerate and granulate. CONSTITUTION: At least one kind selected from among the asphalt, the tar and the viscous oils is adjusted to 10-5000cP in viscosity by heating or adding a softening agent (e.g. kerosene). Next, the dust generation of the lime or the cement is suppressed by adding and mixing 1-15wt.% asphalt, tar or viscous oil to the lime or cement to make the fine particle of the lime or the cement adhere to the asphalt, tar or viscous oil as a nucleus, agglomerating and granulating. And also the dust generation of the lime or the cement can be suppressed by mixing the lime or the cement after the asphalt or tar is made fine particulate or fibrous, and heating, agglomerating and granulating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing dust generation of lime or cement, and is particularly used for solidifying soft ground, sludge, etc., or for refilling residual soil to improve soil quality. This is a method of preventing dust generation from lime or cement.

[0002]

2. Description of the Related Art A predetermined amount of lime or cement is added and mixed and hardened to improve the soil quality of soft ground, to solidify sludge, or to solidify industrial waste such as sewage sludge, oil mud and various sludges. Although the treatment method is widely used, lime and cement generate dust during the work, which worsens the work environment and avoids not only the health problems associated with worker dust collection, but also the surrounding atmosphere. In addition, it was inevitable that it would cause a great deal of trouble to the local residents.

As a method for preventing the dust generation of such lime and cement, there have hitherto been made a slurry, compaction by compaction by pressing, addition of fibrillated Teflon having a cohesive action, and wetting like slaked lime. There are known methods such as converting to water, moistening with water at the time of addition, and attaching an aliphatic polyhydric alcohol to the surface.

[0004]

However, there are various problems in such a method of suppressing dust generation. First, in the slurry method, about half of the slurry is water, so the amount of addition and mixing to the soft ground is 2% compared to the case of handling in powder form.
It is necessary to more than double, and since slurried lime and cement cannot be preserved, it is necessary to temporarily install a plant for slurry near the site, which is costly except for large-scale ground improvement work, etc. When this slurry forming method is used in the deep layer mixing method, there is a problem in that a large amount of surplus soil corresponding to the amount of the injected slurry is generated.

In the agglomeration method, the pellets may be partly crushed during transportation, or quick lime components may absorb moisture and self-disintegrate, which may cause some dusting.
Since it is in the form of pellets, it is necessary to wait for the progress of hydration to carry out the secondary mixing, which requires time and labor, and in the case of lime, dust of slaked lime may be generated due to digestion during secondary mixing.

In addition, in the method of adding the cohesive fibrillated Teflon, the equipment therefor is bulky, the utility of a large number of equipment and the like becomes excessive, and a complicated process such as heat treatment is required, and the whole equipment is required. Inevitably increases costs.

In addition, the method using wet slaked lime is unavoidable that the range of utilization is limited because the soil quality for which the improvement effect is practically obtained is limited and the degree of improvement in soil strength is not large. There is a drawback that the dust generation suppressing effect decreases with time after the treatment.

Further, in the method of moisturizing with water, the added water lowers the original solidification performance of lime or cement, hinders the improvement of soil strength, and the water easily evaporates. For example, there is a problem that the effect of moisturizing and eventually the effect of suppressing dust generation disappears and lime or cement re-dusts.

Further, in the method of adhering a predetermined polyhydric alcohol to the surface, the predetermined polyhydric alcohol such as diethylene glycol coated on the surface lowers the solidification performance of lime or cement, which hinders the improvement of soil strength. In addition, the processing material is expensive, so that it is not economical.

Under such circumstances, the present invention does not impair the performance of lime or cement, does not reduce the dust generation suppressing effect even when the temperature changes, and is simple and inexpensive. The purpose of the invention is to provide a method for suppressing dust generation.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted various studies in order to develop a method for suppressing dust generation of lime or cement having the above-mentioned preferable characteristics, and as a result, lime or cement has a predetermined viscosity. Adjusted asphalt, tar,
Alternatively, it has been found that the object can be achieved by adding and mixing viscous oil in a predetermined ratio, and the present invention has been completed based on this finding.

That is, according to the present invention, at least one selected from asphalt, tar and viscous oil, whose viscosity is adjusted to 10 to 5000 cp by heating or addition of a softening agent, is added to lime or cement in an amount of 1 to 15% by weight. Add and mix in a ratio of lime or cement to attach asphalt, tar, or viscous oil as a core,
The present invention provides a method for suppressing dust generation of lime or cement, which is characterized by causing agglomeration of aggregates.

As the lime to be used in the present invention, quick lime and slaked lime are used alone, and various lime-based solidifying materials in which pozzolan, cement, gypsum and the like are mixed are also used.

Examples of the above-mentioned cement to be used in the present invention include various types of normal type, early-strength type, ultra-early-strength type, moderate heat type, and other portland cements, blast furnace cement, fly ash cement, silica cement, pozzolan cement, and the like. In addition to various mixed cements, special cements such as alumina cement, water glass cement and acid resistant cement, and various cement-based solidifying materials are used.

The asphalt, tar, or viscous oil added to lime or cement in the method of the present invention has a viscosity of 10 to 5000 cp, preferably 20 to 1000, by preheating or adding a softening agent.
It is necessary to adjust to cp. This viscosity is 10 cp
If it is less than less than 5,000 cp
If it exceeds, it will not be sufficiently mixed with lime or cement, and it will inevitably become difficult to adhere and aggregate.

The heat treatment for adjusting the viscosity is carried out with asphalt, usually at 80 ° C to 180 ° C, preferably 110 ° C.
The temperature is usually 150 ° C. to 180 ° C., preferably 120 ° C. to 160 ° C. for tar, and 15 ° C. to 50 ° C., preferably 25 ° C. to 35 ° C. for viscous oil.

As the softening agent added for adjusting the viscosity, a viscosity adjusting agent or the like which is commonly used as an additive component of an oily substance is preferably used. As such a viscosity adjusting agent, for example, heavy oil can be used. , Light oil, kerosene, etc.

In the method of the present invention, the asphalt, tar or viscous oil adjusted to have a predetermined viscosity is
It is necessary to add and mix 1 to 15% by weight with respect to lime or cement. If the addition ratio is less than 1% by weight, a sufficient effect cannot be obtained, and if it exceeds 15% by weight, the surface of lime or cement is excessively coated and strength development due to hydration or the like becomes insufficient, which is satisfactory. Soil strength cannot be improved.

Further, in the method of the present invention, the asphalt or tar is atomized or made into a fibrous form, and then mixed with lime or cement, and then heated to agglomerate to produce agglomerate aggregates to generate dust from the lime or cement. Can be suppressed. As the finely granulating method, for example, a method of cutting a solid asphalt or tar by rotating a blade, etc., as the fibrous method, for example, a method of injecting liquefied asphalt into water or air at high pressure, or Examples include a method of blowing off the asphalt to be dropped with high-pressure air. In addition, the heat treatment is performed by direct flame, steam, or an electric heater.

In the method of the present invention, by such treatment, fine particles of lime or cement adhere to the asphalt, tar, or viscous oil as a core to form agglomerated aggregates. Dust generation of lime or cement will be suppressed. Further, since asphalt, tar, etc. are tacky, they also function as soil improvement agents, and have the effect of amplifying the soil improvement effect of lime or cement.

[0021]

EFFECTS OF THE INVENTION According to the method of the present invention, a predetermined asphalt, tar, viscous oil or the like and lime or cement are adhered to each other to form a nucleus and an aggregate of fine powder is generated to suppress dust generation. In addition, it is possible to suppress the dust generation of lime or cement easily and inexpensively without impairing the performance of lime or cement, and when asphalt and tar are used, they have adhesiveness, so the soil quality It also functions as an improving material, and has the advantage that the soil improvement effect of lime or cement is amplified.

[0022]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Example 1 3 against straight asphalt made by Nippon Oil Co., Ltd.
No. Diesel oil was variously added in the range of 10 to 95% by weight to obtain various modified asphalts having a viscosity of 5 cp to 10,000 cp. Average particle size of each modified asphalt 350μ
The amount of dust generated for each modified asphalt addition treatment was determined by adding 7% by weight to quicklime powder of m and mixing them well. The resulting relationship between the modified asphalt viscosity and the amount of dust is shown in a graph in FIG.

Example 2 3 against straight asphalt made by Nippon Oil Co., Ltd.
70% by weight of No. light oil was added to obtain modified asphalt having a viscosity of 150 cp. This modified asphalt was used in various addition amounts in the range of 0.5 to 20% by weight with respect to ordinary Portland cement, and each was added and mixed well to obtain the dust generation amount for each modified asphalt treatment with various addition amounts. The resulting relationship between the amount of asphalt added and the amount of dust generated is shown graphically in FIG.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between asphalt viscosity and dust generation amount in Example 1 of the present invention.

FIG. 2 is a graph showing the relationship between the amount of asphalt added and the amount of dust generated in Example 2 of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area C09K 17/42 P 17/44 P // C09K 103: 00

Claims (2)

[Claims] 1. At least one selected from asphalt, tar and viscous oil whose viscosity is adjusted to 10 to 5000 cp by heating or addition of a softening agent is added to lime or cement at a ratio of 1 to 15% by weight. Mix and mix fine particles of lime or cement with asphalt, tar,
Alternatively, a method for suppressing dust generation of lime or cement, which comprises depositing viscous oil as a nucleus to form aggregates. 2. A method for suppressing dust generation of lime or cement, which comprises finely granulating or fibrating asphalt or tar, mixing it with lime or cement, and then heating it to form agglomerated aggregates.