JP5637634B2 - Quick setting agent and wet spraying method - Google Patents

Description

  The present invention relates to a quick setting agent and a wet spraying method using the quick setting agent.

  For lining or repairing various industrial kilns with irregular refractories, the irregular refractories are pre-kneaded with the required amount of construction moisture, then pumped to the nozzle and sprayed with a quick setting agent added in front of the nozzle or nozzle. Wet spray construction methods are known.

  As quick setting agents used in this wet spraying construction method, conventionally, alkali aluminate solution, alkali silicate solution, calcium chloride solution, lime slurry mainly composed of slaked lime, and further calcium hydroxide and calcium chloride A solution in which is combined is known.

  Among these, alkali aluminate or silicic acid alkali salt solutions are excellent in quick setting, but due to the high basicity including caustic soda, the skin becomes irritated or burned when touched directly. Moreover, a part floats in a mist form from a nozzle at the time of spraying construction, and a rhinitis arises by sucking this. Thus, its use has a problem in work safety. On the other hand, lime slurry, calcium chloride solution, etc. have low basicity and excellent work safety, and Patent Document 1 describes using lime slurry containing calcium chloride as a quick setting agent. .

  Patent Document 1 describes that the concentration of calcium hydroxide and calcium chloride in the lime slurry is preferably 10 to 70% by mass in terms of the total amount of calcium hydroxide and calcium chloride. However, Patent Document 1 only describes an example in which the concentration of the total amount of calcium hydroxide and calcium chloride in the lime slurry is 45 mass%, and the specific concentration is 10 to 70 mass%. The rationale is not described.

  Patent Document 1 is an application filed by the applicant of the present application, so its contents are well known. However, as in Patent Document 1, a quick-setting agent containing calcium hydroxide and calcium chloride has conventionally been prepared by combining a lime slurry and a calcium chloride solution. It was common knowledge to produce by mixing. Therefore, due to the limitation of the solubility of calcium chloride, there is an upper limit to the concentration of calcium hydroxide and calcium chloride in the lime slurry, and the upper limit is actually 45% by mass described in Patent Document 1.

  The present inventors sprayed a ceiling surface having a construction thickness of 250 mm to 350 mm using the quick setting agent (concentration of calcium hydroxide and calcium chloride of 45 mass%) described in the example of Patent Document 1. As a result, the sprayed construction body sometimes dropped. This is because, in the case of a thick ceiling surface with a construction thickness of 250 mm to 350 mm, the rapid setting action is poor when the solid content is about 45% by mass.

  In addition, although the favorable adhesion rate is obtained in the Example of patent document 1, this is based on the difference in construction conditions. That is, the construction surface described in Patent Document 1 is made by implanting stainless steel anchor studs having a length of 150 mm and a diameter of 5 mm at a pitch of 150 mm. However, in the actual construction surface, anchor studs are often planted at a pitch of 200 mm to 250 mm. This is because the increase in the number of anchor studs prevents deterioration of the fire resistance of the sprayed construction body and the increase in the thermal conductivity of the sprayed construction body, thereby preventing the iron skin from being easily deformed. Thus, the Example of patent document 1 was implemented on the construction conditions from which the adhesion rate becomes better than the construction conditions employ | adopted more by the actual to-be-constructed surface, The ceiling which the present inventors implemented It cannot be handled in the same way as the result of surface spraying.

  It is necessary to strengthen the quick setting action of the quick setting agent in order to suppress the falling of the sprayed body in the spraying construction, and for that purpose, it is effective to increase the concentration of calcium hydroxide and calcium chloride in the lime slurry. . However, in the conventional method for producing a quick setting agent, as described above, it was difficult to make the concentration 45% by mass or more due to the limitation of the solubility of calcium hydroxide. Even if the concentration of calcium hydroxide and calcium chloride can be increased to 45% by mass or more, if the concentration increases, the viscosity of the quick setting agent increases from the technical common sense, and the quick setting agent is conveyed and supplied. Attempts to increase these concentrations have not been made so far because there has been concern about conveyance troubles such as clogging in the binder supply pipe.

JP 2004-233005 A

  The problem to be solved by the present invention is to provide a quick setting agent that can suppress the falling of the sprayed construction body in wet spraying construction and that does not easily cause a conveyance trouble, and a wet spraying method using the quick setting agent. There is.

  As a result of intensive studies by the inventor in order to solve the above problems, rather than mixing the lime slurry and the calcium chloride solution, when the solid calcium chloride is dissolved in the lime slurry, a large amount of calcium chloride is generated by the heat of dissolution. In addition, the quick setting agent in which the concentration of calcium hydroxide and calcium chloride is as high as 46% by mass or more due to the dissolution of a large amount of calcium chloride has a low viscosity against the conventional technical common sense. New knowledge was obtained.

  The present invention has been completed based on this finding, and is a quick setting agent in which calcium chloride is dissolved in a lime slurry, and the solid content of calcium hydroxide and the total amount of calcium chloride in the lime slurry. Is contained in the rapid setting agent in an amount of 46% by mass or more and 70% by mass or less, and the viscosity is 1 Pa · s or less.

  Thus, the quick setting agent of the present invention has a high concentration of 46 mass% or more and 70 mass% or less of the total amount of calcium hydroxide solids and calcium chloride dissolved, so that the quick setting action is improved. For example, even in the case of spraying a ceiling surface with a construction thickness of 250 mm to 350 mm, the spray construction body can be prevented from falling. In addition, the quick setting agent of the present invention has a viscosity of 1 Pa · s or less despite its high concentration. For this reason, it is possible to prevent the occurrence of conveyance troubles such as clogging in the rapid setting agent supply pipe for conveying and supplying the rapid setting agent. The total concentration of the solid content of calcium hydroxide and the dissolved amount of calcium chloride is preferably 50% by mass or more and 70% by mass or less.

  In the present invention, the quick setting agent is preferably prepared using calcium chloride having a particle size of 1 mm to 10 mm. When the particle size of calcium chloride is less than 1 mm, it has deliquescence and is difficult to handle as an additive. Further, when the particle size of calcium chloride exceeds 10 mm, it takes time for calcium chloride to dissolve, which is not preferable in actual work.

  The wet spraying construction method of the present invention is a wet spraying construction method in which an amorphous refractory previously kneaded with construction moisture is pumped to a nozzle, and the quick setting agent is added and sprayed before the nozzle or the nozzle. It is characterized by using the quick setting agent.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to suppress the fall of a spray construction body in wet spray construction, it becomes difficult to produce the conveyance trouble of rapid setting agent.

  The quick setting agent of the present invention is obtained by dissolving calcium chloride in a lime slurry. Calcium chloride has a function of preventing the construction body from falling off the work surface by aggregating the construction body. The calcium hydroxide in the lime slurry has a function of preventing the construction body attached to the construction surface from falling due to its own weight by accelerating the curing of the construction body.

  As a lime slurry, it is preferable to use what contains 5 mass% or more and 20 mass% or less of solid content of calcium hydroxide. If the solid content of calcium hydroxide is less than 5% by mass, the amount of solid content of calcium hydroxide is small, and the hardening promoting effect of calcium hydroxide cannot be sufficiently exhibited, which is not preferable. On the other hand, if it exceeds 20% by mass, the viscosity becomes high, and the quick setting agent adheres in the quick setting agent supply pipe (hereinafter referred to as “adhesion in the supply pipe”), which is likely to cause clogging due to adhesion in the supply pipe. .

  The rapid setting agent of this invention adjusts so that the total amount of the solid content of calcium hydroxide and the dissolution amount of calcium chloride may be 46 mass% or more and 70 mass% or less. If the total amount is less than 46% by mass, the rapid setting action is insufficient, and if it exceeds 70% by mass, the viscosity becomes high, so that clogging due to adhesion in the supply pipe occurs. On the other hand, if it exceeds 70% by mass, the rapid 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.

  In addition, it is preferable to adjust so that the mass ratio of calcium hydroxide solid content and calcium chloride in a quick setting agent may be 78 / 22-97 / 3 with the solid content of calcium chloride / calcium hydroxide.

  The quick setting agent of the present invention becomes a quick setting agent having a viscosity of 1 Pa · s or less by dissolving calcium chloride in the lime slurry under the above conditions. The viscosity was measured using a B-type viscometer (manufactured by Tokyo Keiki). Specifically, the viscosity value 1 minute after dissolving calcium chloride in the lime slurry was measured.

  The wet spraying method of the present invention is not particularly different from the conventional method in that the amorphous refractory previously kneaded with construction water is pumped to the nozzle, and the spraying agent is added and sprayed before the nozzle or the nozzle. The quick setting agent of the present invention described above is used as an agent.

  The composition of the amorphous refractory specifically includes a refractory raw material, a binder, and a dispersant, and if necessary, an organic fiber, a metal powder, a thickener, a curing accelerator, a curing retarder and the like are combined.

Refractory raw material, alumina, bauxite, bands shale, mullite, pyrophyllite, silica stone, chamotte, andalusite, silica rock, fused silica, magnesia, magnesia - _calcia, Al ₂ O 3 -MgO spinel, chromium ore One or more selected from sillimanite or the like is used as a main material, and if necessary, one or more selected from zirconia, carbon, silicon carbide, clay, pitch, or the like is further combined. Moreover, you may use what grind | pulverized the refractory waste material to the one part.

  The particle size adjustment of the refractory raw material 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.

  As the binder, alumina cement, magnesia cement, Portland cement, calcium lactate, aluminum lactate or the like is used. The addition amount is preferably adjusted in the range of 1 to 15% by mass depending on the kind of the binder with respect to 100% by mass of the refractory raw material. Especially, the alumina cement which has intensity | strength provision and fire resistance of a construction body is preferable. If a sufficient agglomeration effect is obtained for the amorphous refractory by using, for example, refractory ultrafine powder such as volatile silica and calcined alumina as a part of the refractory raw material of the amorphous refractory, a binder Is not always necessary.

  The dispersant has the effect of imparting fluidity to the amorphous refractory. Specific examples thereof include sodium tripolyphosphate, sodium hexametaphosphate, sodium polyacrylate, sodium polyacrylate, polycarboxylic acid, sodium lignin sulfonate, and carboxyl group-containing polyether. A preferable addition amount is 0.01 to 1% by mass with respect to 100% by mass of the refractory raw material.

  At the time of construction, construction moisture is added to knead the amorphous refractory in advance. The construction moisture content is preferably 12% by mass or less, more preferably 5 to 8% by mass, based on the total amount of the amorphous refractory composition.

  Next, the amorphous refractory after kneading is sent out to a pressure feed pipe by a pressure feed pump, sent to a nozzle, and a quick setting agent is added and sprayed at the nozzle or in front of the nozzle. In order to mix the quick setting agent and to assist the ejection of the amorphous refractory, the addition of the quick setting agent to the amorphous refractory is preferably performed with compressed air through the quick setting agent supply pipe.

  In addition, when kneading the amorphous refractory, a part of the construction moisture may be used, and the remaining construction moisture may be added and sprayed before the nozzle or the nozzle.

  Examples of wet spraying using the quick setting agent of the present invention will be described below together with comparative examples.

  The wet spraying apparatus used in the examples and comparative examples includes a pressure feed pump (manufactured by Sayama Seisakusho) that feeds the unshaped refractory after kneading to the 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 work surface was an iron plate with staggered anchor studs arranged at a pitch of 260 mm, taking the ceiling surface of the drying furnace into consideration. The construction thickness was 60 mm and 250 mm. When the construction thickness was 60 mm, a V-shaped anchor stud having a height of 40 mm was used. When the construction thickness was 250 mm, a Y-shaped anchor stud having a height of 230 mm was used.

  The amorphous refractory has a particle diameter of 5 to 1 mm 33 mass% and a particle diameter of 1 mm or less 48 mass% as a refractory raw material, calcined alumina 7 mass% and evaporated silica 5 mass% as a fine powder raw material, and alumina cement 7 mass% as a binder. A composition having a composition in which 0.1% by mass of sodium tripolyphosphate was added as a dispersing agent to the total amount of 100% by mass of the above 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). As the quick setting agent, a lime slurry made of calcium hydroxide and water and calcium chloride powder were mixed, and calcium chloride was dissolved in the lime slurry. Specifically, it is as shown in Table 1.

  Table 1 shows the viscosity of the quick setting agent, the temperature at which the quick setting agent tank that stores the quick setting agent, and the time from mixing the lime slurry and calcium chloride to adding to the amorphous refractory. is there. The viscosity of the quick setting agent was measured using a B-type viscometer. The time from mixing the lime slurry and calcium chloride to adding it to the amorphous refractory was measured from the time when the lime slurry and calcium chloride were added to the quick-setting agent tank until the lime slurry and calcium chloride were discharged from the nozzle. .

  Evaluation of the wet spraying construction according to Examples and Comparative Examples was performed by rebound loss, presence or absence of dropping of the construction body, adhesion amount of the quick setting agent in the quick setting agent supply pipe, and comprehensive evaluation by these.

  Rebound loss is often 20% by mass or more when the amount dropped by rebound without spraying to the work surface after spraying, compared to the total kneaded amount of the irregular refractory (×), less than 20% (○).

  The presence or absence of the construction body falling was evaluated by whether or not the construction body dropped from the construction surface 120 minutes after construction.

  The adhesion amount of the quick setting agent in the quick setting agent supply pipe was relatively evaluated in three stages: large, small, and none. Specifically, if the irregular refractory material sprayed from the nozzle adheres to the work surface, the rapid setting agent does not adhere at all in the rapid setting agent supply pipe, and there is no blockage due to adhesion in the supply pipe. The amount of the quick setting agent in the binder supply pipe was “None”. In addition, when the irregular refractory blown from the nozzle adheres almost to the work surface, there is no complete blockage due to adhesion in the supply pipe, so the amount of quick setting agent in the rapid setting agent supply pipe is small. It was. In addition, if the irregular refractory sprayed from the nozzle does not adhere to the work surface at all, it is clogged due to adhesion in the supply pipe, so the adhesion amount of the rapid setting agent in the nozzle rapid setting agent supply pipe is `` Large '' evaluated.

  The overall evaluation is x when the rebound loss is x, the fall of the construction body is “Yes”, and the amount of adhesion in the quick setting agent supply pipe is “Large”. Moreover, it was set as △ when the rebound loss was ◯, the fall of the construction body was “none”, and the adhesion amount in the quick setting agent supply pipe was “small”. In addition, when the rebound loss was ◯, the dropped construction body was “none”, and the adhesion amount of the quick setting agent in the quick setting agent supply pipe was “none”, it was evaluated as “good”.

  From Table 1, Examples 2-10 using the quick setting agent within the scope of the present invention were all good in overall evaluation. In Example 1 and Example 11, since the adhesion amount in the quick setting pipe was “small”, the overall evaluation was “Δ”, but the level was satisfactory for construction.

  On the other hand, in Comparative Example 1, since the concentration of the total amount of the solid content of calcium hydroxide and the dissolved amount of calcium chloride (hereinafter simply referred to as “total concentration”) is as low as 45% by mass, a sufficient quick setting action is obtained. It was not obtained, and when the construction thickness was 250 mm, the construction body dropped.

  In Comparative Example 2, since the concentration of the total amount was as low as 20% by mass, the quick setting action was further insufficient, and the construction body dropped even when the construction thickness was 60 mm.

  In Comparative Example 3, since the total concentration was as high as 75% by mass, the viscosity of the quick setting agent was as high as 1 pa · s or more. For this reason, the adhesion amount of the quick setting agent in the quick setting agent supply pipe becomes large, resulting in blockage. In addition, the quick setting action was strong, and the unshaped refractory solidified before arriving at the work surface, resulting in many rebound losses. Since there were many rebound losses, the presence or absence of the fall of a construction body was not able to be evaluated.

  From the above, when the concentration of the total amount in the quick setting agent is 46% by mass or more and 70% by mass or less and the viscosity value of the quick setting agent is 1 Pa · s or less, the fall of the sprayed construction body is suppressed. In addition, it is possible to make it difficult for a conveyance trouble to occur. In addition, since the fall of a construction body can be suppressed more if the density | concentration of the total amount of quick setting agent can be more than 50 mass% and 70 mass%, it is preferable.

Claims (5)

A quick-setting agent made by dissolving calcium chloride in lime slurry,
The rapid setting agent whose solid content of the calcium hydroxide in the said lime slurry and the total amount of the said calcium chloride are contained 46 to 70 mass% in an rapid setting agent, and a viscosity is 1 Pa.s or less.   The quick setting agent according to claim 1, wherein the solid content of calcium hydroxide in the lime slurry and the total amount of the calcium chloride are contained in the quick setting agent in an amount of 50% by mass to 70% by mass.   The quick setting agent according to claim 1 or 2, wherein the lime slurry contains 5% by mass or more and 20% by mass or less of the solid content of the calcium hydroxide.   The quick setting agent according to any one of claims 1 to 3, wherein the calcium chloride is prepared using a calcium particle having a particle diameter of 1 mm or more and 10 mm or less.   In the wet spraying construction method in which an amorphous refractory previously kneaded with construction moisture is pumped to a nozzle, and the quick setting agent is added and sprayed before the nozzle or the nozzle, the quick setting agent is any one of claims 1 to 4. A wet spraying method characterized by using the quick setting agent described in 1.