JP2008001559A - Concrete retarder and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete retarder effectively reducing the time and effort on chemical synthesis and the cost of the equipment for the chemical synthesis, and to provide a method for producing the same. <P>SOLUTION: The method for producing the concrete retarder X at least comprises an organic retarding substance-extracting step S1 for extracting an organic retarding substance ya present in an organic impurity y into an alkaline solution 1 by bringing mountain sand Y, which is an earth and sand containing the organic impurity y, into contact with the alkaline solution 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a concrete retarder that delays the hardening of cement by adding it to a concrete material.

  Conventionally, a retarder for concrete has been proposed. The retarder is used, for example, to secure a working time according to construction conditions by delaying the time until curing by adding a required amount of the retarder to cement concrete material. .

Most of the retarders are mainly composed of chemically synthesized organic compounds. And various things which can ensure workability | operativity suitably were developed and disclosed by examining the composition and combination of the said organic compound variously (for example, refer patent document 1).
JP 2004-262718 A

  However, any retarder as described above undergoes various steps related to the synthesis of the compound during production. And the special synthesis | combination is needed for the synthesis | combination of a compound. Therefore, the expense spent on various steps for performing such chemical synthesis and the expense spent on equipment required for the synthesis of the compound are included in the production cost of the retarder.

  The present invention pays attention to such points, and it is possible to effectively reduce the labor involved in chemical synthesis and the cost associated with the equipment for the chemical synthesis, and the production of the concrete retarder. Provide a method.

  In order to achieve such an object, the present invention takes the following measures. That is, in the method for producing a concrete retarder according to the present invention, an organic retarding substance that extracts an organic retarding substance present in the organic impurity into the alkaline solution by contacting earth and sand containing the organic impurity with an alkaline solution. It has at least an extraction step.

  Here, in particular, organic impurities contained in earth and sand such as mountain sand are known to contain organic retarding substances that can retard the hardening of concrete, and these organic retarding substances are mainly composed of humic acid. It is said. Humic acid is contained in soil and sediments of young geological age, and is said to have a molecular weight of hundreds to thousands or tens of thousands, and its molecular structure has not been clarified, but protein degradation products and hydrocarbons It is said that it is a high molecular compound produced | generated by coupling | bonding.

  If this is the case, it is possible to effectively avoid the costs associated with chemical synthesis and equipment by effectively avoiding the use of various processes related to chemical synthesis as before and the use of special equipment for chemical synthesis. It can be accepted or rejected. By doing so, it is possible to produce a retarder for concrete at a low cost. Furthermore, organic retarding substances that normally exist in organic impurities contained in earth and sand such as mountain sand can be used effectively.

  In order to suitably extract the organic retardation substance, it is desirable that the alkaline solution is a sodium hydroxide aqueous solution having a pH of 10 to 14.

  In order to make the extract obtained by extracting the organic delay substance in the organic delay substance extraction process easy to handle, it is desirable to further provide a neutralization process for neutralizing the extract. Furthermore, in order to produce such a concrete retarder with uniform quality, it is desirable to further provide a concentration adjusting step for concentrating or diluting the extract.

  And in order to make it easy to use such a retarder for concrete as a solid material, an organic retarder that adsorbs the organic retarder to the porous material by bringing the extract into contact with the porous material It is desirable to further provide an adsorption step.

  If activated carbon or calcium silicate hydrate is employed as the porous material, the organic retardation substance can be effectively adsorbed.

  Here, as the calcium silicate hydrate powder, at least one powder selected from known synthetic calcium silicate hydrate and natural calcium silicate hydrate can be used. As the synthetic calcium silicate hydrate, for example, zonotlite, tobermorite, fosjaite, gyrolite, hirebtanlite, rosenhanite, trussite, rielite, obtained by hydrothermal reaction from lime raw material and silicic acid raw material, Examples include calciochondrodite, affilite, and quasicrystalline calcium silicate hydrate (C—S—Hn).

Here, it is necessary to use a porous material having a BET specific surface area value of 30 m ² / g or more, and preferably a BET specific surface area value of 60 m ² / g or more.

Than the particle surface than to the porous material BET specific surface area 30 m ² / g or more can be adsorbed organic impurities in the air gap of the particles, by a more than 60 m ² / g, more It is possible to adsorb organic impurities.

  In addition, the BET specific surface area in this invention means the specific surface area value by BET method calculated | required based on the adsorption amount of nitrogen gas.

  And the retarder for concrete which concerns on this invention is manufactured by the manufacturing method of the retarder for concrete mentioned above, It is characterized by the above-mentioned.

  That is, the retarder according to the present invention is characterized by comprising at least an organic retarder present in organic impurities contained in the earth and sand.

  If this is the case, the concrete delay that can be produced at low cost by effectively accepting the cost of various processes for chemical synthesis and the cost of special equipment for chemical synthesis. It is possible to provide an agent. Furthermore, organic retarding substances that are usually present in organic impurities contained in mountain sand can be used effectively.

  And in order to use suitably as a liquid agent, it is desirable to further comprise the liquid which can melt | dissolve an organic delay substance.

  For example, in order to make it easy to handle as a solid state such as a powder, it is desirable to further include a porous material capable of adsorbing an organic retardation substance. As the porous material, it is desirable to employ activated carbon or calcium silicate hydrate as described above.

  And if mountain sand is adopted as the earth and sand, not only the above-mentioned organic retarding substance such as humic acid can be easily used, but also mountain sand existing abundantly in nature can be used effectively. Can do.

  According to the present invention, there is provided a concrete retarder that can be produced at low cost by effectively accepting the cost of various processes for chemical synthesis and the cost of special equipment for chemical synthesis. It is possible to provide.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  A series of steps in the method for producing a concrete retarder according to the present embodiment is schematically shown in FIGS.

  Here, the method for producing a concrete retarder (hereinafter referred to as a retarder) X according to the present embodiment brings the mountain sand Y, which is earth and sand containing the organic impurity y, and the alkaline solution 1 into contact with each other in the organic impurity y. The organic retarding substance extraction process S1 which extracts the organic retarding substance ya which exists in the alkaline solution 1 at least is characterized.

  Hereinafter, a series of steps in the manufacturing method will be described.

  The manufacturing method includes the organic retardation substance extraction step S1, the neutralization step S2, and the concentration adjustment step S3. Moreover, when manufacturing the solid retarder X2 as the retarder X, it has further organic delay substance adsorption | suction process S4 and drying process S5.

  As shown in FIG. 1, the organic retarding substance extraction step S1 includes an alkaline solution 1 having twice the weight of the mountain sand Y that is harmful in the organic impurity y determination test, specifically 1N hydroxylation. It includes a dipping procedure S11 for dipping in an aqueous sodium solution for 6 hours, and a mountain sand filtration procedure S12 for filtering the mountain sand Y after the dipping procedure S11. And the filtrate after passing the said mountain sand filtration procedure S12 is used for each subsequent process as extract 1y. The alkaline solution 1 is not limited to a 1N sodium hydroxide aqueous solution, and may be a sodium hydroxide aqueous solution having a pH of 10 to 14 or an aqueous solution of another compound exhibiting alkalinity.

  Here, it is known that the organic delay substance ya which can delay the hardening of concrete exists in the organic impurity y contained in the mountain sand Y, and the organic delay substance ya is mainly composed of humic acid. It is said. Humic acid is contained in soil and sediments of young geological age, and is said to have a molecular weight of hundreds to thousands or tens of thousands, and its molecular structure has not been clarified, but protein degradation products and hydrocarbons It is said that it is a high molecular compound produced | generated by coupling | bonding. In addition, the TOC (total organic carbon) concentration of the organic impurity y in the extract 1y obtained by one organic delay substance extraction step S1 was 360 ppm.

  In the neutralization step S2, as shown in FIG. 2, the filtrate that neutralizes the extract 1y obtained by extracting the organic delay substance ya in the organic delay substance extraction step S1 is converted into 1N HCl HCl, which is an acidic liquid in this embodiment. It is the process of setting it as the neutral extract 1ny which exhibits neutrality by neutralizing by. Here, the neutralization step S2 is not limited to an embodiment using 1N hydrochloric acid HCl, and other various acidic compounds can be employed. Moreover, the neutral extract 1ny is not limited to the aspect which exhibits neutrality correctly. For example, a pH that can be handled safely in each of the subsequent steps may be exhibited.

  In the concentration adjustment step S3, as shown in FIG. 2, the neutral extract 1ny neutralized in the neutralization step S2, the TOC concentration of the organic impurity y containing the organic delay substance ya in this embodiment is 50000 ppm, or 50000 ppm or more. Concentration procedure S31 by which it concentrates to become 100 ny by concentrating until it becomes, and sodium chloride removal procedure S32 which removes sodium chloride NaCl which precipitates by recrystallization at the time of performing the said concentration procedure S31 by filtration. Here, as a specific method according to the concentration procedure S31, various existing methods can be employed. In addition to the concentration procedure S31 and the sodium chloride removal procedure S32, for example, when the TOC concentration of the organic impurity y exceeds a predetermined concentration of 50000 ppm, the concentrated extract is added by adding water Wh as necessary. In this embodiment, the TOC concentration may be adjusted to 50000 ppm by adding a dilution procedure S33 for diluting 100 ny.

  As described above, the aqueous solution obtained by adjusting the TOC concentration of the organic impurity y including the organic delay substance ya to 50000 ppm in the neutral extract 1ny by the concentration adjustment step S3 becomes the liquid delay agent X1 according to the present embodiment. In other words, the liquid retarder X1 includes the organic impurity y including the organic retarder ya and the predetermined amount of liquid 10n having the predetermined concentration described above.

  Thus, in the present embodiment, as shown in FIG. 3, the organic delay substance that adsorbs the organic delay substance ya to the porous material T by bringing the extract 1 y that has undergone the organic delay substance extraction step S <b> 1 into contact with the porous material T. It further includes an adsorption step S4.

  Specifically, the organic delay substance adsorption step S4 is an adsorption procedure S41 in which the porous material T is charged and stirred into the extract 1y to adsorb the organic delay substance ya, and the organic delay substance ya is adsorbed by the adsorption procedure S41. And an extraction procedure S42 for taking out the porous material by filtration, for example. The filtrate after the porous material T is taken out by the taking-out procedure S42 can be used again as the alkaline solution 1 as it is or by readjusting the pH.

Here, the porous material T includes activated carbon and calcium silicate hydrate exhibiting a characteristic of a BET specific surface area value of 30 m ² / g or more in the present embodiment. The kind of the porous material T is not particularly limited as long as it can adsorb the organic retardation substance ya, but the porous material T can adsorb and retain a sufficient amount of the organic retardation substance ya. Further, the BET specific surface area value is 30 m ² / g or more. In addition, in order to further increase the adsorption amount of the organic retardation substance ya, a substance having a BET specific surface area value of 60 m ² / g or more may be used. In addition, as the calcium silicate hydrate powder, at least one powder selected from known synthetic calcium silicate hydrate and natural calcium silicate hydrate can be used. As the synthetic calcium silicate hydrate, for example, zonotlite, tobermorite, foshygite, gyrolite, hirebutanite, rosenhanite, trascotite, rielite, obtained by hydrothermal reaction from lime raw material and silicic acid raw material, Examples include calciochondrodite, affilite, and quasicrystalline calcium silicate hydrate (C—S—Hn).

  Then, as shown in FIG. 3, the drying step S5 is a step of drying the porous material T on which the organic delay substance ya has been adsorbed through the organic delay substance adsorption process S4, for example, by the sun. Here, the method of drying the porous material T is not limited to the sun, and a heating method, a dedicated dryer, or another dryer may be used.

  As shown in FIG. 4, the solid retarder X2 produced in this way is adopted as the porous material T in this embodiment, so that the organic retarder ya is the surface of the calcium silicate hydrate as well as The organic retardation substance ya can be effectively held in the holes t formed on the particle surface.

  As described above, the method for producing the concrete retarder X according to the present embodiment is characterized by having at least the organic retarding substance extraction step S1 for extracting the organic retarding substance ya into the alkaline solution 1, and therefore, the sand sand Y It is possible to effectively use the organic retarding substance ya which is usually present in the organic impurity y contained in the material, and to reduce the cost of the concrete retarding agent from the organic retarding substance ya at a low cost without including the labor and facilities for chemical synthesis. X can be manufactured. By using a sodium hydroxide aqueous solution having a pH of 10 to 14, specifically, a 1N sodium hydroxide aqueous solution, as the alkaline solution 1, the organic retardation substance ya can be suitably extracted. Further, the neutralization step S2 for neutralizing the extract 1y makes the extract 1y a neutral extract 1ny that is easy for the operator to handle, and the subsequent steps are easy to perform. In addition, by passing through the concentration adjusting step S3, the concrete retarder X can be produced as a liquid retarder X1 having a uniform quality.

On the other hand, the organic retarding substance adsorbing step S4 for adsorbing the organic retarding substance ya to the porous material T makes it possible to suitably manufacture a solid retarder X2 such as granular or powder that is easy to handle in the field. Specifically, the porous material T is assumed to contain activated carbon or calcium silicate hydrate so that the organic retardation substance ya can be adsorbed suitably. Specifically, by setting the BET specific surface area of these porous materials T to 30 m ² / g or more, an effective amount of the organic retardation substance ya is adsorbed to the porous material T.

  As described above, the liquid retarder X1 and the solid retarder X2 as the concrete retarder X according to the present embodiment are manufactured through the above-described steps, respectively, and both are included in the earth and sand. The organic retarding substance ya is present in the organic impurity y.

  In this embodiment, the liquid retarder X1 is in a state in which the organic retarding substance is held at a constant concentration by holding the organic impurity y having a TOC concentration of 50000 ppm in the liquid 10n. The amount of the organic retarding substance ya can be accurately adjusted by adjusting the amount of the liquid retarder X1 added.

  The solid retarder X2 has a solid form such as granular or powdery by further comprising the porous material T together with the organic retarding substance ya, so that it is easily handled in terms of transportation and application. ing.

  And the mountain sand Y which exists abundantly in the natural world can be utilized effectively by employ | adopting the mountain sand Y as earth and sand containing the organic impurity y.

  Although the embodiment of the present invention has been described above, the specific configuration of each unit is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the porous material is introduced into the alkaline extract, but the solid retarder is introduced by introducing the porous material into the neutral extract, the concentrated extract, or the liquid retarder, for example. May be manufactured. The organic retardation substance extraction step described above may be repeated a plurality of times in order to reliably extract the organic retardation substance. Moreover, even if it leads to the organic delay substance adsorption | suction process using a porous material, it is good also as what is repeatedly introduce | transduced into an extract.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

Explanatory drawing which shows the manufacturing method of the retarder for concrete which concerns on one Embodiment of this invention. Same as above. Same as above. Explanatory drawing which shows the structure of the solid retardation agent which concerns on the same embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Alkaline solution 10n ... Liquid S1 ... Organic delay substance extraction process S2 ... Neutralization process S3 ... Concentration adjustment process S4 ... Organic delay substance adsorption process.

Y ... earth and sand, mountain sand (mountain sand)
T ... Porous material X ... Concrete retarder (retarder)
X1 ... Concrete retarder (liquid retarder)
X2: Concrete retarder (solid retarder)
y ... Organic impurities ya ... Organic retarding substances

Claims (13)

A retarder for concrete comprising at least an organic retarding substance extracting step for extracting an organic retarding substance present in the organic impurity into the alkaline solution by contacting earth and sand containing the organic impurity with an alkaline solution. Production method. The method for producing a concrete retarder according to claim 1, wherein the alkaline solution is a sodium hydroxide aqueous solution having a pH of 10 to 14. The method for producing a concrete retarder according to claim 1 or 2, further comprising a neutralization step of neutralizing the extract obtained by extracting the organic delay material in the organic delay material extraction step. 4. The method for producing a concrete retarder according to claim 1, 2 or 3, further comprising a concentration adjusting step of concentrating or diluting an extract obtained by extracting the organic delay material by the organic delay material extracting step. 2. The organic delay substance adsorption step of bringing the organic delay substance extracted into contact with a porous material by the organic delay substance extraction step in the organic delay substance extraction step to adsorb the organic delay substance to the porous material. The manufacturing method of the retarder for concrete of 2, 3, or 4. The method for producing a retarder for concrete according to claim 5, wherein the porous material contains activated carbon or calcium silicate hydrate. The method for producing a concrete retarder according to claim 5 or 6, wherein the porous material has a BET specific surface area of 30 m ² / g or more. The method for producing a concrete retarder according to claim 1, wherein the earth and sand are mountain sand. A concrete retarder produced by the method for producing a concrete retarder according to claim 1. A concrete retarder comprising at least an organic retarding substance present in an organic impurity contained in earth and sand. The concrete retarder according to claim 10, wherein the earth and sand are mountain sand. The concrete retarder according to claim 10 or 11, further comprising a liquid capable of dissolving the organic retarder. The concrete retarder according to claim 10 or 11, further comprising a porous material capable of adsorbing the organic retarder.

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