JP2017036176A - Rapid hardening agent for wet type spray material, manufacturing method therefor, wet type spray material and construction method of wet type spray material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rapid hardening agent excellent in workability and good rapid hardening property and curability, a manufacturing method therefor, a wet type spray material and a construction method of the wet type spray material.SOLUTION: There is provided a rapid hardening agent for a wet type spray material of a monolithic refractory prepared from a calcium hydroxide slurry to which calcium chloride is added if needed, where oxalic acid reactivity, precipitation volume and viscosity of the calcium hydroxide slurry are oxalic acid reactivity:40 minutes or less, precipitation volume:less than 60 ml and viscosity:less than 200 mPa s, the total amount of contents of calcium hydroxide and calcium chloride in the rapid hardening agent is less than 46 mass% and percentage content of the calcium hydroxide:calcium chloride is in a range of 50:50 to 100:0.SELECTED DRAWING: None

Description

  The present invention relates to a quick setting agent for wet spray materials, a method for producing the same, a wet spray material including the same, and a method for constructing the wet spray material.

  For lining or repairing various industrial kilns with irregular refractories, the irregular refractories are pre-kneaded with a predetermined amount of moisture, then pumped to the nozzle, sprayed with a quick setting agent added in front of the nozzle or nozzle Wet spray construction methods are known. The role of the quick setting agent used in this method includes a quick setting action and a hardening accelerating action. The quick setting action is an action that instantaneously loses the fluidity of the mud so that the mud having fluidity that can be pumped does not fall off the work surface at the moment of spraying. It is. This loss of fluidity is manifested by the rapid setting agent agglomerating the particles in the mud.

  Conventionally, an alkali aluminate solution, an alkali silicate solution, a calcium chloride solution, a calcium hydroxide slurry or the like has been used as the quick setting agent. However, alkali aluminates and silicates are not preferable in terms of working environment because they contain caustic soda.

  Therefore, Patent Document 1 proposes a quick setting agent in which calcium chloride is mixed with a specific calcium hydroxide slurry.

Japanese Patent Application Laid-Open No. 2014-101242

  However, the calcium hydroxide slurry used in Patent Document 1 has a high viscosity, has poor transportability with a pump, and has a problem that clogging due to adhesion occurs in the quick setting agent supply pipe. It was. Further, as the quick setting agent, it is described that it is used by mixing with a large amount of calcium chloride.

By using a calcium hydroxide slurry having a low viscosity, the present inventors have improved transportability by a pump and obtained excellent workability, while maintaining good quick setting,
It has been found that good curability can be obtained without using a large amount of calcium chloride.

  An object of the present invention is to provide a quick setting agent that is excellent in workability and that provides good quick setting properties and curability, a method for producing the same, a wet spray material including the same, and a method for applying the wet spray material. .

  The quick setting agent of the present invention is a quick setting agent for wet spraying material of an amorphous refractory prepared from a calcium hydroxide slurry to which calcium chloride is added if necessary. The defined oxalic acid reactivity, sedimentation volume, and viscosity are oxalic acid reactivity: 40 minutes or less, sedimentation volume: less than 60 ml, and viscosity: less than 200 mPa · S, respectively, and calcium hydroxide in the rapid setting agent and The total content of calcium chloride is less than 46% by mass, and the content ratio of calcium hydroxide: calcium chloride is in the range of 50:50 to 100: 0.

  Oxalic acid reactivity: 50 g of calcium hydroxide slurry prepared at a concentration of 5% by mass and kept at 25 ± 1 ° C., 40 g of oxalic acid aqueous solution having a concentration of 0.5 mol / liter kept at 25 ± 1 ° C. Is added all at once, and the time from addition to pH 7.0 is reached (min)

  Sedimentation volume: Calcium hydroxide slurry prepared to a concentration of 2% by mass is placed in a 100 ml graduated cylinder and allowed to stand at room temperature for 1 hour.

  Viscosity: Viscosity when calcium hydroxide slurry prepared to a concentration of 8% by mass is measured with a B-type viscometer

  The oxalic acid reactivity is preferably 20 minutes or less.

The BET specific surface area of calcium hydroxide is preferably 5 m ² / g or more.

  The method for producing the quick setting agent of the present invention includes a step of grinding the calcium hydroxide slurry, a step of drying the calcium hydroxide slurry after the grinding treatment, and powdering the calcium hydroxide, A step of preparing a quick setting agent of the present invention by adding water to powdered calcium hydroxide to prepare a calcium hydroxide slurry and adding calcium chloride to the obtained calcium hydroxide slurry as necessary. It is characterized by comprising.

  The wet spray material of the present invention is characterized by containing refractory powder, alumina cement, and the rapid setting agent of the present invention.

  The wet spraying method of the present invention is a method of adding water to an amorphous refractory containing refractory powder and alumina cement to knead into a mud, and to the mud, the quick setting agent of the present invention is added. It is characterized by spraying the added wet spray material.

  According to the present invention, excellent workability and good quick setting and curability can be obtained.

  Hereinafter, preferred embodiments will be described. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments.

  The quick setting agent of the present invention is prepared from a calcium hydroxide slurry to which calcium chloride is added if necessary. The calcium hydroxide slurry has an oxalic acid reactivity of 40 minutes or less, a sedimentation volume of less than 60 ml, and a viscosity of 200 mPa · It is characterized by being less than S.

  In addition, the oxalic acid reactivity, sedimentation volume, and viscosity of the calcium hydroxide slurry in the present invention are the oxalic acid reactivity, sedimentation volume, and viscosity of the calcium hydroxide slurry before adding calcium chloride when calcium chloride is added. Viscosity.

(Calcium hydroxide slurry)
The calcium hydroxide slurry can be prepared, for example, by reacting water with quick lime (calcium oxide) obtained by firing limestone. For example, a calcium hydroxide slurry can be prepared by firing limestone in a kiln at about 1000 ° C. to produce quicklime, adding about 10 times the amount of hot water to the quicklime, and stirring for 30 minutes. it can.

  As described above, the calcium hydroxide slurry in the present invention has an oxalic acid reactivity of 40 minutes or less, a sedimentation volume of less than 60 ml, and a viscosity of less than 200 mPa · S. Such a calcium hydroxide slurry can be manufactured by grinding the calcium hydroxide slurry prepared as described above. Examples of the grinding treatment include a bead mill. In particular, the oxalic acid reactivity value can be reduced by performing a grinding treatment.

<Oxalic acid reactivity>
The oxalic acid reactivity in the present invention is adjusted to a concentration of 5% by mass, and 50 g of calcium hydroxide slurry maintained at 25 ± 1 ° C. is added to a concentration of 0.5 mol / liter maintained at 25 ± 1 ° C. It can be obtained by adding 40 g of an oxalic acid aqueous solution at once and measuring the time (minutes) until pH 7.0 is reached after the addition. The oxalic acid reactivity is more preferably 30 minutes or less, and further preferably 20 minutes or less. When the value of oxalic acid reactivity becomes large, it becomes difficult to obtain excellent quick setting properties and curability.

<Settling volume>
The sedimentation volume in the present invention is a sedimentation volume measured after putting a calcium hydroxide slurry prepared to a concentration of 2% by mass into a 100 ml graduated cylinder and leaving it at room temperature for 1 hour.

  In the present invention, the sedimentation volume is less than 60 ml, more preferably 50 ml or less, and particularly preferably 40 ml or less. When the sedimentation volume is increased, the transportability by the pump is deteriorated, and workability may be reduced.

<Viscosity>
The calcium hydroxide slurry in the present invention is prepared to 8% by mass, and the viscosity when measured with a B-type viscometer is less than 200 mPa · s, more preferably 100 mPa · s or less, and particularly preferably 80 mPa · s. It is as follows. When the viscosity is high, the transportability by the pump is deteriorated, and workability may be lowered.

<BET specific surface area>
BET specific surface area of the calcium hydroxide slurry of the present invention is preferably ^{5 m} 2 / g or more, still more preferably ^8m 2 / g or more, particularly preferably in the range of 6~10m ² / g. The BET specific surface area can be obtained by drying the calcium hydroxide slurry and measuring the BET specific surface area of the powdered calcium hydroxide. If the BET specific surface area is too low, it may be difficult to obtain excellent quick setting properties and curability.

(Preparation of calcium hydroxide slurry)
As described above, the calcium hydroxide slurry in the present invention can be prepared by subjecting the calcium hydroxide slurry to a grinding treatment. Moreover, it can also prepare by drying the powdered calcium hydroxide slurry after grinding and adding water to the powdered calcium hydroxide slurry to obtain a calcium hydroxide slurry again. By using powdered calcium hydroxide, costs such as transportation costs can be reduced, and handling and the like can be facilitated.

(Quick setting agent)
The quick setting agent of the present invention is prepared by adding calcium chloride to the calcium hydroxide slurry as necessary. The total content of calcium hydroxide and calcium chloride in the quick setting agent is less than 46% by mass, more preferably 40% by mass or less, and particularly preferably 35% by mass or less. If the total content of calcium hydroxide and calcium chloride in the quick setting agent is too high, the viscosity becomes high, so that blockage occurs due to adhesion in the quick setting material supply pipe, and the transportability by the pump decreases. Further, the quick setting action is strong, and the amorphous refractory solidifies before reaching the construction surface, resulting in an increase in rebound loss. Furthermore, since solidification occurs in the nozzle, the nozzle is blocked, and it becomes difficult to spray.

  The total content of calcium hydroxide and calcium chloride in the quick setting agent is preferably 10% by mass or more. If the total content of calcium hydroxide and calcium chloride in the quick setting agent is too low, the quick setting action is insufficient, which is not preferable.

  In the present invention, the content ratio of calcium hydroxide: calcium chloride in the quick setting agent is in the range of 50:50 to 100: 0. Calcium hydroxide has a function of preventing the construction body attached to the construction surface from dropping due to its own weight by accelerating the curing of the construction body. Calcium chloride has a function of preventing the construction body from falling off the work surface when sprayed by aggregating the construction body.

  When there is too much content rate of calcium chloride, the hardening delay of a construction body will occur and the said function of calcium hydroxide will not fully be exhibited. The content ratio of calcium hydroxide: calcium chloride in the quick setting agent is more preferably in the range of 60:40 to 100: 0, and further preferably in the range of 70:30 to 100: 0.

(Wet spray material)
The wet spray material of the present invention contains a refractory powder, alumina cement, and the rapid setting agent of the present invention.

  In addition to these, the wet spray material may include a binder, a dispersant, an organic fiber, a metal component, a thickener, and the like.

  Examples of the refractory powder include alumina materials such as fused alumina, sintered alumina, bauxite, diaspore, clay shale, and calcined alumina, silica stone, silica sand, amorphous silica (for example, microsilica, silica flour, etc. Siliceous raw materials such as fumed silica and white carbon), alumina silica raw materials such as wax, chamotte, clay, andalusite, sillimanite, kyanite and mullite, coal, coke, pitch, artificial graphite, natural graphite (for example, Carbonaceous raw materials such as carbon black, fused spinel, sintered spinel, magnesia raw materials such as magnesia clinker, dolomitic raw materials such as dolomite clinker, fused zirconia, etc. Zirconia materials, zircon materials such as zircon sand, nitriding From raw materials, aluminum nitride raw materials, silicon carbide raw materials, boron carbide raw materials, titanium boride raw materials, zirconium boride raw materials, etc., and pulverized refractory waste materials mainly composed of at least one of them One or more selected can be used.

  The particle size of the refractory powder is appropriately adjusted to coarse particles, medium particles, and fine particles in consideration of fluidity / adhesion during construction, denseness of the construction body, and the like. The fine particles are preferably combined with ultrafine powder having an average particle size of 10 μm or less such as calcined alumina, light calcined magnesia, volatile silica, calcined spinel and the like.

  The alumina cement functions as a binder, and the addition amount thereof is preferably 0.5 to 20 parts by mass, and more preferably 2 to 10 parts by mass with respect to 100 parts by mass of the refractory powder. Good corrosion resistance can be maintained because it is 0.5 mass part or more. In addition, the alumina cement preferably has an average particle size of 10 μm or less because the pumpability of the mud can be improved.

  Examples of binders other than alumina cement include aluminum lactate, calcium lactate, aluminum glycolate, lactic acid-aluminum glycolate, hydraulic alumina, magnesia cement, Portland cement, phosphate, and silicate. When these are used in combination, the amount added is suitably 20 parts by mass or less, for example, with respect to 100 parts by mass of the refractory powder.

  The dispersant has the effect of increasing the fluidity of the mud. Specific examples thereof include sodium tripolyphosphate, sodium hexametaphosphate, sodium polyacrylate, sodium polyacrylate, polycarboxylic acid, sodium lignin sulfonate, and carboxyl group-containing polyether. If the amount added is too small, the effect of improving the fluidity cannot be obtained, and if too large, the fluidity is impaired, so 0.01 to 0.5 parts by mass with respect to 100 parts by mass of the refractory powder is preferable. .

  Examples of the organic fiber include polypropylene fiber, nylon fiber, PVA fiber, polyethylene fiber, acrylic fiber, polyester fiber, and pulp. The addition amount is preferably 0.02 to 1 part by mass with respect to 100 parts by mass of the refractory powder.

  Examples of the thickener include bentonite, CMC, isoban and the like, and the addition amount is preferably 5 parts by mass or less with respect to 100 parts by mass of the refractory powder.

  Examples of the metal powder include aluminum, silicon, ferrosilicon, an aluminum alloy, and a silicon alloy, and the addition amount is preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of the refractory powder.

  The wet spray material can be prepared by adding water to an amorphous refractory containing refractory powder and alumina cement to knead it into a mud and adding a calcium hydroxide slurry to the mud. . Moreover, when using together with calcium chloride, a wet spray material can be prepared by adding a mixture of calcium hydroxide slurry and calcium chloride to mud.

  The amount of water added when preparing the mud is not particularly limited, but generally, for example, 3 to 15 parts by mass is preferable with respect to 100 parts by mass of the amorphous refractory, and 5 to 12 parts by mass. Is more preferable.

  The amount of the calcium hydroxide slurry added to the amorphous refractory is preferably in the range of 0.3 to 1.5 parts by mass with respect to 100 parts by mass of the irregular refractory.

  The quick setting agent of the present invention may contain a dispersant, a dispersion state stabilizer, a foaming agent and the like.

  Examples of the dispersant include the same ones as those contained in the amorphous refractory.

  Examples of the dispersion state stabilizer include inorganic thickeners such as silicic anhydride and clay, and water-soluble polymers such as CMC, PVA, and polyacrylate.

  A foaming agent attaches bubbles to the particle surface of calcium hydroxide and suppresses sedimentation by the buoyancy of the bubbles. Examples thereof include various surfactants such as lauryl sulfate.

<Preparation of calcium hydroxide slurry>
Example 1
Calcium hydroxide slurry with a solid content concentration of 16.0% by mass and a BET specific surface area of 6.0 m ² / g is wet milled at a flow rate of 15 kg / h using a bead mill (Dynomill KDL-PILOT type manufactured by Willy et Bacofen) And a calcium hydroxide slurry having a BET specific surface area of 11.4 m ² / g and a sedimentation volume of 54 ml / 60 min at a concentration of 2% by mass was prepared. The oxalic acid reactivity and viscosity of the obtained calcium hydroxide slurry were measured, and the measurement results are shown in Table 1.

(Example 2)
A calcium hydroxide slurry having a BET specific surface area of 10.5 m ² / g and a sedimentation volume of 42 ml / 60 min at a concentration of 2% by mass, except that the flow rate in the wet grinding treatment is 20 kg / h. Was prepared. The oxalic acid reactivity and viscosity of the obtained calcium hydroxide slurry were measured, and the measurement results are shown in Table 1.

(Example 3)
A calcium hydroxide slurry having a BET specific surface area of 9.7 m ² / g and a sedimentation volume of 35 ml / 60 min at a concentration of 2% by mass, except that the flow rate in the wet milling process is 25 kg / h. Was prepared. The oxalic acid reactivity and viscosity of the obtained calcium hydroxide slurry were measured, and the measurement results are shown in Table 1.

Example 4
Calcium hydroxide slurry having a BET specific surface area of 9.6 m ² / g and a sedimentation volume of 30 ml / 60 min at a concentration of 2% by mass, except that the flow rate in the wet grinding treatment is 35 kg / h. Was prepared. The oxalic acid reactivity and viscosity of the obtained calcium hydroxide slurry were measured, and the measurement results are shown in Table 1.

(Example 5)
A calcium hydroxide slurry having a BET specific surface area of 9.2 m ² / g and a sedimentation volume of 28 ml / 60 min at a concentration of 2% by mass, except that the flow rate in the wet milling process is 45 kg / h. Was prepared. The oxalic acid reactivity and viscosity of the obtained calcium hydroxide slurry were measured, and the measurement results are shown in Table 1.

(Example 6)
Calcium hydroxide slurry having a BET specific surface area of 8.9 m ² / g and a sedimentation volume of 25 ml / 60 min at a concentration of 2% by mass, except that the flow rate in the wet grinding treatment is 70 kg / h. Was prepared. The oxalic acid reactivity and viscosity of the obtained calcium hydroxide slurry were measured, and the measurement results are shown in Table 1.

(Example 7)
A calcium hydroxide slurry having a BET specific surface area of 7.7 m ² / g and a sedimentation volume of 18 ml / 60 min at a concentration of 2% by mass, except that the flow rate in the wet milling process is 100 kg / h. Was prepared. The oxalic acid reactivity and viscosity of the obtained calcium hydroxide slurry were measured, and the measurement results are shown in Table 1.

(Example 8)
A calcium hydroxide slurry having a BET specific surface area of 6.5 m ² / g and a sedimentation volume of 10 ml / 60 min at a concentration of 2% by mass, except that the flow rate in the wet milling process is 200 kg / h. Was prepared. The oxalic acid reactivity and viscosity of the obtained calcium hydroxide slurry were measured, and the measurement results are shown in Table 1.

(Comparative Example 1)
Calcium hydroxide slurry with a solid content concentration of 16.0% by mass and a BET specific surface area of 6.5 m ² / g is wet milled at a flow rate of 3 kg / h using a bead mill (Dynomill KDL-PILOT type manufactured by Willy et Bacofen) And a calcium hydroxide slurry with a BET specific surface area of 17.5 m ² / g and a sedimentation volume of 98 ml / 60 min at a concentration of 2% by mass was prepared. The oxalic acid reactivity and viscosity of the obtained calcium hydroxide slurry were measured, and the measurement results are shown in Table 1.

(Comparative Example 2)
Calcium hydroxide slurry having a BET specific surface area of 9.0 m ² / g and a sedimentation volume of 62 ml / 60 min at a concentration of 2% by mass, except that the flow rate in the wet grinding treatment is 10 kg / h. Was prepared. The oxalic acid reactivity and viscosity of the obtained calcium hydroxide slurry were measured, and the measurement results are shown in Table 1.

(Comparative Example 3)
A calcium hydroxide slurry with a BET specific surface area of 20.3 m ² / g was prepared and used without wet milling. The sedimentation volume, oxalic acid reactivity, and viscosity of the calcium hydroxide slurry at a concentration of 2% by mass were measured, and the measurement results are shown in Table 1.

<Preparation of quick setting agent>
In Examples 1 to 8 and Comparative Examples 1 to 3, the mass ratio of calcium hydroxide: calcium chloride was 100: 0, and the quick setting agent was prepared using only calcium hydroxide slurry.

  In Examples 9-12 and Comparative Example 4, the mass ratio of calcium hydroxide: calcium chloride was 90:10 (Example 9), 80:20 (Example 10), 70:30 (Example 11), Quick setting agents were prepared as 50:50 (Example 12) and 40:60 (Comparative Example 4). The calcium hydroxide slurry of Example 4 was used as the calcium hydroxide slurry.

  In Example 13 and Comparative Example 5, the mass ratio of calcium hydroxide: calcium chloride was 80:20, and the total content of calcium hydroxide and calcium chloride in the quick setting agent was 45% by mass (Example 13). And the quick setting agent was prepared so that it might become 50 mass% (comparative example 5).

<Evaluation of quick setting agent>
[Measurement of viscosity]
Viscosity was measured for each prepared quick setting agent. The viscosity was measured using a B-type viscometer (manufactured by Tokyo Keiki). Specifically, the viscosity value was measured 1 minute after dissolving calcium chloride in the calcium hydroxide slurry alone or in the calcium hydroxide slurry.

[Evaluation in construction of wet spray material]
Using the quick setting agents of the above Examples and Comparative Examples, the cohesiveness, curability and rebound loss in the construction of the wet spray material were evaluated.

  The measurement conditions for wet spraying are described below.

  The wet spraying apparatus includes a pressure pump (manufactured by Sayama Seisakusho) that feeds an unshaped refractory after kneading to a pressure feed pipe, and the pressure feed pipe is connected to the pressure feed pump. The pressure feed pipe used was a 20 m iron pipe with an inner diameter of 2.0 inches and a pressure hose with an inner diameter of 1.5 inches via a reducer. Moreover, what connected the nozzle made from a pre-drawing rubber | gum was used for the front-end | tip of a pressure | voltage resistant hose. The transportation and supply of the quick-setting agent to the amorphous refractory material was performed through a quick-setting agent supply pipe connected to a rubber nozzle using compressed air as a carrier using a MONO pump having a snake pump.

  The construction surface was a concrete wall and the construction thickness was 150 mm.

  The amorphous refractory is composed of 33% by mass of alumina and mullite having a particle size of 1 to 5 mm and 48% by mass of alumina and mullite having a particle size of 1 mm or less as a refractory powder, 7% by mass of calcined alumina and silica. A composition in which 0.1% by mass of sodium tripolyphosphate was added as an external coating to 100% by mass of a total amount of 5% by mass of fume and 7% by mass of alumina cement as a binder was used. At the time of construction, 7.8% by mass of construction moisture was added and kneaded sufficiently beforehand with a mixer. The addition amount of the quick setting agent was set to 0.3% by mass as an outer shell with respect to the amorphous refractory (amount excluding the amount of construction water).

  Next, a method for evaluating cohesiveness and curability will be described.

(Cohesiveness)
In the case where 2% by mass of the quick setting agent was added to 500 g of a kneaded product of water and a wet spray material, the cohesiveness when kneaded quickly by hand was evaluated. Specifically, the time when the material became damped was visually evaluated. If the time when the material became lumped was within 10 seconds, ◯ if it was within 8 seconds, ◎ if it was over 10 seconds, and x. .

(Curable)
The curability was evaluated by measuring the penetration resistance using a penetration hardness meter with a tip of 6 mmφ on the construction body obtained by spraying, and the time until the penetration resistance reached about 3.5 MPa.

  The curing time is measured for penetration resistance using a penetration hardness meter with a tip of 6 mmφ for the construction body obtained by spraying, and the time until the penetration resistance reaches about 3.5 MPa is 2 hours or less. The case was marked with ◯ and the case of over 2 hours was marked with ×. In the case of more than 2 hours, when the construction body is tilted, the construction body may drop, and the work process is delayed.

(Rebound loss)
Rebound loss is often less than 20% by mass when the amount of rebound loss after spraying does not adhere to the work surface and falls by rebounding is 20% by mass or more with respect to the total kneading amount of the irregular refractory. The number of cases was small (◯).

  Tables 1 to 3 show the evaluation results of the quick setting agent.

  As shown in Table 1, it can be seen that the quick setting agents of Examples 1 to 8 according to the present invention have good cohesiveness and curability and little rebound loss. The quick setting agents of Comparative Example 1 and Comparative Example 2 were clogged due to adhesion in the quick setting agent supply pipe, could not be sprayed, and could not measure curability and rebound loss. On the other hand, the quick setting agents of Examples 1 to 8 were excellent in workability without causing clogging due to adhesion in the quick setting agent supply pipe.

  The quick setting agent of Comparative Example 3 whose oxalic acid reactivity is outside the scope of the present invention is inferior in cohesiveness and has a large rebound loss.

As shown in Table 2, the content ratio of calcium hydroxide: calcium chloride is 50: 50-1
It can be seen that by setting it within the range of 00: 0, good curability can be obtained and rebound loss can be reduced.

  As shown in Table 3, it can be seen that when the total content of calcium hydroxide and calcium chloride in the quick setting agent is less than 46% by mass, good curability can be obtained and rebound loss can be reduced.

Claims (6)

A quick setting agent for a wet blasting material of an amorphous refractory prepared from a calcium hydroxide slurry to which calcium chloride is added if necessary,
The oxalic acid reactivity, sedimentation volume, and viscosity defined below of the calcium hydroxide slurry are oxalic acid reactivity: 40 minutes or less, sedimentation volume: less than 60 ml, and viscosity: less than 200 mPa · S,
Wet spraying in which the total content of calcium hydroxide and calcium chloride in the quick setting agent is less than 46% by mass, and the content ratio of calcium hydroxide: calcium chloride is in the range of 50:50 to 100: 0. Quick setting agent for materials.
Oxalic acid reactivity: 50 g of calcium hydroxide slurry prepared at a concentration of 5% by mass and kept at 25 ± 1 ° C., 40 g of oxalic acid aqueous solution having a concentration of 0.5 mol / liter kept at 25 ± 1 ° C. Is added all at once, and the time from addition to pH 7.0 is reached (min)
Sedimentation volume: Calcium hydroxide slurry prepared to a concentration of 2% by mass is placed in a 100 ml graduated cylinder, and the sedimentation volume is measured after standing for 1 hour at room temperature. Viscosity: water prepared to a concentration of 8% by mass Viscosity when calcium oxide slurry is measured with B-type viscometer   The quick setting agent for wet spray materials of Claim 1 whose oxalic acid reactivity is 20 minutes or less. The rapid setting agent for wet spray materials according to claim 1 or 2, wherein the calcium hydroxide has a BET specific surface area of 5 m ² / g or more. A step of grinding the calcium hydroxide slurry;
Drying the calcium hydroxide slurry after milling to powder calcium hydroxide;
Water is added to the powdered calcium hydroxide to prepare a calcium hydroxide slurry, and calcium chloride is added to the obtained calcium hydroxide slurry as necessary. And a step of preparing the quick setting agent according to the description.   The wet spraying material containing a refractory powder, an alumina cement, and the quick setting agent of any one of Claims 1-3.   Water is added to an amorphous refractory containing refractory powder and alumina cement to form a mud, and the quick setting agent according to any one of claims 1 to 3 is added to the mud. A method for constructing a wet spray material, which is constructed by spraying a wet spray material.