JP2001130933A - Solidifying material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an exhausted gas dust generated in a cement clinker- calcining process as a regenerated resource. SOLUTION: This solidifying material contains a dried cake powder obtained by blowing the exhausted gas generated in the cement clinker calcination into water for dissolving chlorine in the exhausted gas, filtering the water and drying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solidified material made from dust generated in a cement manufacturing process such as an exhaust gas from a cement kiln.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 5-504 discloses a technique for separating and discharging volatile components such as alkali and chlorine contained in a cement raw material and a calcined fuel during the production of cement outside a cement kiln.
No. 58 discloses a method for bleeding exhaust gas generated from a cement kiln by chlorine bypass. Further, the exhaust gas dust discharged by this treatment can be reused as a raw material for cement by washing and removing chlorine by the method disclosed in Japanese Patent Application Laid-Open No. H11-100243, thereby reusing waste. And reduction of cement raw material cost.

[0003]

However, the exhaust gas dust has not been found to have any particular use other than as a raw material for cement, and is often still disposed of.
An object of the present invention is to create a new utilization destination of the exhaust gas dust.

[0004]

Means for Solving the Problems When the present inventors examined the mineral components of the dried cake obtained by washing the exhaust gas dust with water again and again, it was found that most of the components were slaked lime, Focusing on the similarities with the constituents of the solidified material, we investigated the use of this dried cake as a solidified material, and as a result, a solidified material with properties equal to or better than conventional products was obtained at relatively low cost Thus, the present invention has been completed.

That is, the present invention is a solidified material containing a dry cake powder obtained by filtering water in which exhaust gas generated by cement clinker baking is blown and chlorine is eluted.

The present invention also provides a dried cake obtained by filtering water in which exhaust gas generated by cement clinker firing is blown and chlorine is eluted, and the above-mentioned solidified material mainly containing hydraulic inorganic substances.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The solidified material of the present invention is obtained by blowing dried gas generated by cement clinker calcination into water and filtering the water in which the chlorine content in the discharged gas has been eluted to obtain a dried desalted cake. It is the main constituent material. Specific means for obtaining such a cake is preferably disclosed in
It can be obtained by the same means as the method for washing chlorine bypass dust with water disclosed in No. 100243. More specifically, in the exhaust gas generated from the kiln during the firing of cement clinker, in addition to volatile components such as chlorine and alkali formed by the reaction and decomposition of the cement raw material at high temperatures, vaporized components such as combustion gas, and fine powder such as fly ash Solids. This exhaust gas is designated
Using a chlorine bypass facility as disclosed in US Pat. No. -50458, bleeding, and desirably, coarse solids (coarse dust) classified in the classification section of the apparatus are returned to the kiln during clinker firing as a cement material again. The remaining exhaust gas, that is, the high-temperature vaporized component and the fine solid content (fine dust) are washed with the above equipment. Kiln exhaust gas blown into water mainly contains chlorine and water-soluble components dissolve in water. The water containing the insoluble component is filtered, the liquid component and the insoluble solid component are separated, and the insoluble solid component is dried to obtain a dry cake. The filtrate is sent to a wastewater treatment facility as necessary to be detoxified.
The method of filtration and drying, the device used for the method, and the like are not particularly limited, and any known method may be used. The dried cake used as the solidified material has a chlorine concentration of 0.5% or less and a water content of about 0.5%.
It should be less than the standard.

[0008] The obtained dried cake contains a large amount of slaked lime formed by reacting quicklime dust, which is a raw material for cement formation, with water.
It generally contains components such as alkali metal oxides and alumina which are also contained in ordinary cement raw materials, but the chlorine content in dust was eluted into water, resulting in a considerably reduced content. ing.

The solidified material of the present invention is a solidified material containing such a dry cake. That is, the solidified material of the present invention may be composed of only the dried cake, or may contain other components in addition to the dried cake. In any case, it is preferable to use a powdered solidified material which is preferably pulverized to a specific surface area of 2500 cm ² / g or more because the activity of the solidified material itself is increased.

[0010] The component other than the dried cake of the solidified material of the present invention is preferably a hydraulic inorganic substance. The hydraulic inorganic substance may be a single compound, a composition or a mixture. More specifically, examples include cement and blast furnace slag. As the cement, generally Portland cement is inexpensive and is most recommended as a hydraulic inorganic substance, but is not particularly limited as long as it is a known cement. Further, the solidified material may appropriately contain inorganic components other than hydraulic inorganic materials such as dried cake and cement, and may include, for example, clay minerals, silica fume, calcium carbonate, and the like.

The mixing ratio of the dried cake and the hydraulic inorganic material in producing the solidified material is not particularly limited, but is preferably determined by the hydraulic inorganic material to be compounded, and more preferably the object using the solidified material. It is preferable to change the compounding ratio in order to exhibit a more optimal solidification action. For example, in a solidified material containing dried cake and cement,
It is preferable to mix 100 parts by weight of cement and 5 to 200 parts by weight of a dry cake. This is a dry cake 5
If the compounding amount is less than part by weight, the effect of mixing the dried cake is not exhibited, and if the compounding amount exceeds 200 parts by weight, it is difficult to obtain sufficient solidification strength, which is not preferable.

In the case of a solidified material containing a plurality of hydraulic inorganic components, for example, a solidified material containing cement, blast furnace slag, and a dried cake, the total of the plurality of hydraulic inorganic components is 50 to 100 parts by weight of the dried cake. It is preferable to use 2,000 parts by weight. However, if the amount of the hydraulic inorganic component exceeds 2,000 parts by weight, the effect of dry cake compounding does not appear depending on the solidified product, and the stability of the solidified property may be easily lost. It is not preferable to use the component in an amount that only a brittle solid state can be obtained.

Further, when the solidified material contains an inorganic component other than the hydraulic inorganic substance, the content is preferably smaller than that of the dried cake and the hydraulic inorganic substance in order to secure a sufficient solidifying action.

The method of using the solidified material of the present invention is not particularly limited. For example, for use in soil improvement, solidification of soft ground, etc., the powder is sprayed as it is on a target area, and a stabilizer is used. Or a method in which water is added to a powder, a slurry is formed, and the mixture is poured into a target site and stirred and mixed.

[0015]

EXAMPLE Using a chlorine bypass facility disclosed in Japanese Patent Publication No. 50458/1993, flue gas dust generated from a clinker calcining kiln during production of ordinary Portland is recovered, and about 1 part by weight of the dust is recovered. Washing treatment was performed while adding about 5 parts by weight of warm water at 50 ° C. and stirring for about 1 hour. The treated water was filtered with a belt filter. After filtration and separation, the cake as a solid residue was washed with 5 parts by weight of warm water. The washed cake was dried by a dryer kept at 105 ° C. to obtain a dried cake having a mineral composition shown in Table 1.

[0016]

[Table 1]

The dried cake was pulverized by a ball mill until the specific surface area became 2500 cm ² / g or more. The pulverized dried cake, commercially available ordinary Portland cement, natural anhydrous gypsum, and blast furnace slag were mixed in the amounts shown in Table 2 to prepare a powdered solidified material. This solidified material was used as a target soil with a cohesive soil and sludge having the properties described in Table 3. For each target soil of 1 m ³ , 80 Kg for the cohesive soil and 200 Kg for the sludge.
The solidifying material was added at a rate of g. This was kneaded with a Hobart mixer for about 5 minutes, and the uniaxial compressive strength of 7 days old was measured according to the method according to JIS A1216. Table 2 also shows the results. For reference, the same measurement was performed using a commercially available solidified material made of slaked lime. The results are also shown in Table 2.

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

The solidified material of the present invention has created a promising resource for recycling chlorine by-bass dust, which has been conventionally disposed of as dust waste, and is a generally used slaked lime-based solidified material. Its solidification properties are comparable to those of. The raw material cost is also very low, and the production can be easily carried out simply by assembling a very simple apparatus and process to the existing cement exhaust gas desalination treatment equipment.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kansaburo Sudo 3-8-1, Nishikanda, Chiyoda-ku, Tokyo Taiheiyo Cement Co., Ltd. F term (reference) 2D040 AB03 AB11 AC05 BA12 CA01 CA03 CA04 CB01 CB03 4H026 CA01 CA04 CA05 CC02 CC05 CC06

Claims (2)

[Claims] 1. A solidified material containing a dry cake powder obtained by filtering water in which exhaust gas generated by cement clinker baking is blown and chlorine is eluted. 2. The solidified material according to claim 1, wherein a dried cake obtained by filtering water in which exhaust gas generated by cement clinker firing and chlorine eluted is blown, and a hydraulic inorganic substance are main components.